// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Copyright 2008 Openmoko, Inc.
 * Copyright 2008 Simtec Electronics
 *      Ben Dooks <ben@simtec.co.uk>
 *      http://armlinux.simtec.co.uk/
 *
 * S3C USB2.0 High-speed / OtG driver
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/of_platform.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/phy.h>

#include "core.h"
#include "hw.h"

/* conversion functions */
static inline struct dwc2_hsotg_req *our_req(struct usb_request *req)
{
        return container_of(req, struct dwc2_hsotg_req, req);
}

static inline struct dwc2_hsotg_ep *our_ep(struct usb_ep *ep)
{
        return container_of(ep, struct dwc2_hsotg_ep, ep);
}

static inline struct dwc2_hsotg *to_hsotg(struct usb_gadget *gadget)
{
        return container_of(gadget, struct dwc2_hsotg, gadget);
}

static inline void dwc2_set_bit(struct dwc2_hsotg *hsotg, u32 offset, u32 val)
{
        dwc2_writel(hsotg, dwc2_readl(hsotg, offset) | val, offset);
}

static inline void dwc2_clear_bit(struct dwc2_hsotg *hsotg, u32 offset, u32 val)
{
        dwc2_writel(hsotg, dwc2_readl(hsotg, offset) & ~val, offset);
}

static inline struct dwc2_hsotg_ep *index_to_ep(struct dwc2_hsotg *hsotg,
                                                u32 ep_index, u32 dir_in)
{
        if (dir_in)
                return hsotg->eps_in[ep_index];
        else
                return hsotg->eps_out[ep_index];
}

/* forward declaration of functions */
static void dwc2_hsotg_dump(struct dwc2_hsotg *hsotg);

/**
 * using_dma - return the DMA status of the driver.
 * @hsotg: The driver state.
 *
 * Return true if we're using DMA.
 *
 * Currently, we have the DMA support code worked into everywhere
 * that needs it, but the AMBA DMA implementation in the hardware can
 * only DMA from 32bit aligned addresses. This means that gadgets such
 * as the CDC Ethernet cannot work as they often pass packets which are
 * not 32bit aligned.
 *
 * Unfortunately the choice to use DMA or not is global to the controller
 * and seems to be only settable when the controller is being put through
 * a core reset. This means we either need to fix the gadgets to take
 * account of DMA alignment, or add bounce buffers (yuerk).
 *
 * g_using_dma is set depending on dts flag.
 */
static inline bool using_dma(struct dwc2_hsotg *hsotg)
{
        return hsotg->params.g_dma;
}

/*
 * using_desc_dma - return the descriptor DMA status of the driver.
 * @hsotg: The driver state.
 *
 * Return true if we're using descriptor DMA.
 */
static inline bool using_desc_dma(struct dwc2_hsotg *hsotg)
{
        return hsotg->params.g_dma_desc;
}

/**
 * dwc2_gadget_incr_frame_num - Increments the targeted frame number.
 * @hs_ep: The endpoint
 *
 * This function will also check if the frame number overruns DSTS_SOFFN_LIMIT.
 * If an overrun occurs it will wrap the value and set the frame_overrun flag.
 */
static inline void dwc2_gadget_incr_frame_num(struct dwc2_hsotg_ep *hs_ep)
{
        hs_ep->target_frame += hs_ep->interval;
        if (hs_ep->target_frame > DSTS_SOFFN_LIMIT) {
                hs_ep->frame_overrun = true;
                hs_ep->target_frame &= DSTS_SOFFN_LIMIT;
        } else {
                hs_ep->frame_overrun = false;
        }
}

/**
 * dwc2_hsotg_en_gsint - enable one or more of the general interrupt
 * @hsotg: The device state
 * @ints: A bitmask of the interrupts to enable
 */
static void dwc2_hsotg_en_gsint(struct dwc2_hsotg *hsotg, u32 ints)
{
        u32 gsintmsk = dwc2_readl(hsotg, GINTMSK);
        u32 new_gsintmsk;

        new_gsintmsk = gsintmsk | ints;

        if (new_gsintmsk != gsintmsk) {
                dev_dbg(hsotg->dev, "gsintmsk now 0x%08x\n", new_gsintmsk);
                dwc2_writel(hsotg, new_gsintmsk, GINTMSK);
        }
}

/**
 * dwc2_hsotg_disable_gsint - disable one or more of the general interrupt
 * @hsotg: The device state
 * @ints: A bitmask of the interrupts to enable
 */
static void dwc2_hsotg_disable_gsint(struct dwc2_hsotg *hsotg, u32 ints)
{
        u32 gsintmsk = dwc2_readl(hsotg, GINTMSK);
        u32 new_gsintmsk;

        new_gsintmsk = gsintmsk & ~ints;

        if (new_gsintmsk != gsintmsk)
                dwc2_writel(hsotg, new_gsintmsk, GINTMSK);
}

/**
 * dwc2_hsotg_ctrl_epint - enable/disable an endpoint irq
 * @hsotg: The device state
 * @ep: The endpoint index
 * @dir_in: True if direction is in.
 * @en: The enable value, true to enable
 *
 * Set or clear the mask for an individual endpoint's interrupt
 * request.
 */
static void dwc2_hsotg_ctrl_epint(struct dwc2_hsotg *hsotg,
                                  unsigned int ep, unsigned int dir_in,
                                 unsigned int en)
{
        unsigned long flags;
        u32 bit = 1 << ep;
        u32 daint;

        if (!dir_in)
                bit <<= 16;

        local_irq_save(flags);
        daint = dwc2_readl(hsotg, DAINTMSK);
        if (en)
                daint |= bit;
        else
                daint &= ~bit;
        dwc2_writel(hsotg, daint, DAINTMSK);
        local_irq_restore(flags);
}

/**
 * dwc2_hsotg_tx_fifo_count - return count of TX FIFOs in device mode
 *
 * @hsotg: Programming view of the DWC_otg controller
 */
int dwc2_hsotg_tx_fifo_count(struct dwc2_hsotg *hsotg)
{
        if (hsotg->hw_params.en_multiple_tx_fifo)
                /* In dedicated FIFO mode we need count of IN EPs */
                return hsotg->hw_params.num_dev_in_eps;
        else
                /* In shared FIFO mode we need count of Periodic IN EPs */
                return hsotg->hw_params.num_dev_perio_in_ep;
}

/**
 * dwc2_hsotg_tx_fifo_total_depth - return total FIFO depth available for
 * device mode TX FIFOs
 *
 * @hsotg: Programming view of the DWC_otg controller
 */
int dwc2_hsotg_tx_fifo_total_depth(struct dwc2_hsotg *hsotg)
{
        int addr;
        int tx_addr_max;
        u32 np_tx_fifo_size;

        np_tx_fifo_size = min_t(u32, hsotg->hw_params.dev_nperio_tx_fifo_size,
                                hsotg->params.g_np_tx_fifo_size);

        /* Get Endpoint Info Control block size in DWORDs. */
        tx_addr_max = hsotg->hw_params.total_fifo_size;

        addr = hsotg->params.g_rx_fifo_size + np_tx_fifo_size;
        if (tx_addr_max <= addr)
                return 0;

        return tx_addr_max - addr;
}

/**
 * dwc2_hsotg_tx_fifo_average_depth - returns average depth of device mode
 * TX FIFOs
 *
 * @hsotg: Programming view of the DWC_otg controller
 */
int dwc2_hsotg_tx_fifo_average_depth(struct dwc2_hsotg *hsotg)
{
        int tx_fifo_count;
        int tx_fifo_depth;

        tx_fifo_depth = dwc2_hsotg_tx_fifo_total_depth(hsotg);

        tx_fifo_count = dwc2_hsotg_tx_fifo_count(hsotg);

        if (!tx_fifo_count)
                return tx_fifo_depth;
        else
                return tx_fifo_depth / tx_fifo_count;
}

/**
 * dwc2_hsotg_init_fifo - initialise non-periodic FIFOs
 * @hsotg: The device instance.
 */
static void dwc2_hsotg_init_fifo(struct dwc2_hsotg *hsotg)
{
        unsigned int ep;
        unsigned int addr;
        int timeout;

        u32 val;
        u32 *txfsz = hsotg->params.g_tx_fifo_size;

        /* Reset fifo map if not correctly cleared during previous session */
        WARN_ON(hsotg->fifo_map);
        hsotg->fifo_map = 0;

        /* set RX/NPTX FIFO sizes */
        dwc2_writel(hsotg, hsotg->params.g_rx_fifo_size, GRXFSIZ);
        dwc2_writel(hsotg, (hsotg->params.g_rx_fifo_size <<
                    FIFOSIZE_STARTADDR_SHIFT) |
                    (hsotg->params.g_np_tx_fifo_size << FIFOSIZE_DEPTH_SHIFT),
                    GNPTXFSIZ);

        /*
         * arange all the rest of the TX FIFOs, as some versions of this
         * block have overlapping default addresses. This also ensures
         * that if the settings have been changed, then they are set to
         * known values.
         */

        /* start at the end of the GNPTXFSIZ, rounded up */
        addr = hsotg->params.g_rx_fifo_size + hsotg->params.g_np_tx_fifo_size;

        /*
         * Configure fifos sizes from provided configuration and assign
         * them to endpoints dynamically according to maxpacket size value of
         * given endpoint.
         */
        for (ep = 1; ep < MAX_EPS_CHANNELS; ep++) {
                if (!txfsz[ep])
                        continue;
                val = addr;
                val |= txfsz[ep] << FIFOSIZE_DEPTH_SHIFT;
                WARN_ONCE(addr + txfsz[ep] > hsotg->fifo_mem,
                          "insufficient fifo memory");
                addr += txfsz[ep];

                dwc2_writel(hsotg, val, DPTXFSIZN(ep));
                val = dwc2_readl(hsotg, DPTXFSIZN(ep));
        }

        dwc2_writel(hsotg, hsotg->hw_params.total_fifo_size |
                    addr << GDFIFOCFG_EPINFOBASE_SHIFT,
                    GDFIFOCFG);
        /*
         * according to p428 of the design guide, we need to ensure that
         * all fifos are flushed before continuing
         */

        dwc2_writel(hsotg, GRSTCTL_TXFNUM(0x10) | GRSTCTL_TXFFLSH |
               GRSTCTL_RXFFLSH, GRSTCTL);

        /* wait until the fifos are both flushed */
        timeout = 100;
        while (1) {
                val = dwc2_readl(hsotg, GRSTCTL);

                if ((val & (GRSTCTL_TXFFLSH | GRSTCTL_RXFFLSH)) == 0)
                        break;

                if (--timeout == 0) {
                        dev_err(hsotg->dev,
                                "%s: timeout flushing fifos (GRSTCTL=%08x)\n",
                                __func__, val);
                        break;
                }

                udelay(1);
        }

        dev_dbg(hsotg->dev, "FIFOs reset, timeout at %d\n", timeout);
}

/**
 * dwc2_hsotg_ep_alloc_request - allocate USB rerequest structure
 * @ep: USB endpoint to allocate request for.
 * @flags: Allocation flags
 *
 * Allocate a new USB request structure appropriate for the specified endpoint
 */
static struct usb_request *dwc2_hsotg_ep_alloc_request(struct usb_ep *ep,
                                                       gfp_t flags)
{
        struct dwc2_hsotg_req *req;

        req = kzalloc(sizeof(*req), flags);
        if (!req)
                return NULL;

        INIT_LIST_HEAD(&req->queue);

        return &req->req;
}

/**
 * is_ep_periodic - return true if the endpoint is in periodic mode.
 * @hs_ep: The endpoint to query.
 *
 * Returns true if the endpoint is in periodic mode, meaning it is being
 * used for an Interrupt or ISO transfer.
 */
static inline int is_ep_periodic(struct dwc2_hsotg_ep *hs_ep)
{
        return hs_ep->periodic;
}

/**
 * dwc2_hsotg_unmap_dma - unmap the DMA memory being used for the request
 * @hsotg: The device state.
 * @hs_ep: The endpoint for the request
 * @hs_req: The request being processed.
 *
 * This is the reverse of dwc2_hsotg_map_dma(), called for the completion
 * of a request to ensure the buffer is ready for access by the caller.
 */
static void dwc2_hsotg_unmap_dma(struct dwc2_hsotg *hsotg,
                                 struct dwc2_hsotg_ep *hs_ep,
                                struct dwc2_hsotg_req *hs_req)
{
        struct usb_request *req = &hs_req->req;

        usb_gadget_unmap_request(&hsotg->gadget, req, hs_ep->dir_in);
}

/*
 * dwc2_gadget_alloc_ctrl_desc_chains - allocate DMA descriptor chains
 * for Control endpoint
 * @hsotg: The device state.
 *
 * This function will allocate 4 descriptor chains for EP 0: 2 for
 * Setup stage, per one for IN and OUT data/status transactions.
 */
static int dwc2_gadget_alloc_ctrl_desc_chains(struct dwc2_hsotg *hsotg)
{
        hsotg->setup_desc[0] =
                dmam_alloc_coherent(hsotg->dev,
                                    sizeof(struct dwc2_dma_desc),
                                    &hsotg->setup_desc_dma[0],
                                    GFP_KERNEL);
        if (!hsotg->setup_desc[0])
                goto fail;

        hsotg->setup_desc[1] =
                dmam_alloc_coherent(hsotg->dev,
                                    sizeof(struct dwc2_dma_desc),
                                    &hsotg->setup_desc_dma[1],
                                    GFP_KERNEL);
        if (!hsotg->setup_desc[1])
                goto fail;

        hsotg->ctrl_in_desc =
                dmam_alloc_coherent(hsotg->dev,
                                    sizeof(struct dwc2_dma_desc),
                                    &hsotg->ctrl_in_desc_dma,
                                    GFP_KERNEL);
        if (!hsotg->ctrl_in_desc)
                goto fail;

        hsotg->ctrl_out_desc =
                dmam_alloc_coherent(hsotg->dev,
                                    sizeof(struct dwc2_dma_desc),
                                    &hsotg->ctrl_out_desc_dma,
                                    GFP_KERNEL);
        if (!hsotg->ctrl_out_desc)
                goto fail;

        return 0;

fail:
        return -ENOMEM;
}

/**
 * dwc2_hsotg_write_fifo - write packet Data to the TxFIFO
 * @hsotg: The controller state.
 * @hs_ep: The endpoint we're going to write for.
 * @hs_req: The request to write data for.
 *
 * This is called when the TxFIFO has some space in it to hold a new
 * transmission and we have something to give it. The actual setup of
 * the data size is done elsewhere, so all we have to do is to actually
 * write the data.
 *
 * The return value is zero if there is more space (or nothing was done)
 * otherwise -ENOSPC is returned if the FIFO space was used up.
 *
 * This routine is only needed for PIO
 */
static int dwc2_hsotg_write_fifo(struct dwc2_hsotg *hsotg,
                                 struct dwc2_hsotg_ep *hs_ep,
                                struct dwc2_hsotg_req *hs_req)
{
        bool periodic = is_ep_periodic(hs_ep);
        u32 gnptxsts = dwc2_readl(hsotg, GNPTXSTS);
        int buf_pos = hs_req->req.actual;
        int to_write = hs_ep->size_loaded;
        void *data;
        int can_write;
        int pkt_round;
        int max_transfer;

        to_write -= (buf_pos - hs_ep->last_load);

        /* if there's nothing to write, get out early */
        if (to_write == 0)
                return 0;

        if (periodic && !hsotg->dedicated_fifos) {
                u32 epsize = dwc2_readl(hsotg, DIEPTSIZ(hs_ep->index));
                int size_left;
                int size_done;

                /*
                 * work out how much data was loaded so we can calculate
                 * how much data is left in the fifo.
                 */

                size_left = DXEPTSIZ_XFERSIZE_GET(epsize);

                /*
                 * if shared fifo, we cannot write anything until the
                 * previous data has been completely sent.
                 */
                if (hs_ep->fifo_load != 0) {
                        dwc2_hsotg_en_gsint(hsotg, GINTSTS_PTXFEMP);
                        return -ENOSPC;
                }

                dev_dbg(hsotg->dev, "%s: left=%d, load=%d, fifo=%d, size %d\n",
                        __func__, size_left,
                        hs_ep->size_loaded, hs_ep->fifo_load, hs_ep->fifo_size);

                /* how much of the data has moved */
                size_done = hs_ep->size_loaded - size_left;

                /* how much data is left in the fifo */
                can_write = hs_ep->fifo_load - size_done;
                dev_dbg(hsotg->dev, "%s: => can_write1=%d\n",
                        __func__, can_write);

                can_write = hs_ep->fifo_size - can_write;
                dev_dbg(hsotg->dev, "%s: => can_write2=%d\n",
                        __func__, can_write);

                if (can_write <= 0) {
                        dwc2_hsotg_en_gsint(hsotg, GINTSTS_PTXFEMP);
                        return -ENOSPC;
                }
        } else if (hsotg->dedicated_fifos && hs_ep->index != 0) {
                can_write = dwc2_readl(hsotg,
                                       DTXFSTS(hs_ep->fifo_index));

                can_write &= 0xffff;
                can_write *= 4;
        } else {
                if (GNPTXSTS_NP_TXQ_SPC_AVAIL_GET(gnptxsts) == 0) {
                        dev_dbg(hsotg->dev,
                                "%s: no queue slots available (0x%08x)\n",
                                __func__, gnptxsts);

                        dwc2_hsotg_en_gsint(hsotg, GINTSTS_NPTXFEMP);
                        return -ENOSPC;
                }

                can_write = GNPTXSTS_NP_TXF_SPC_AVAIL_GET(gnptxsts);
                can_write *= 4; /* fifo size is in 32bit quantities. */
        }

        max_transfer = hs_ep->ep.maxpacket * hs_ep->mc;

        dev_dbg(hsotg->dev, "%s: GNPTXSTS=%08x, can=%d, to=%d, max_transfer %d\n",
                __func__, gnptxsts, can_write, to_write, max_transfer);

        /*
         * limit to 512 bytes of data, it seems at least on the non-periodic
         * FIFO, requests of >512 cause the endpoint to get stuck with a
         * fragment of the end of the transfer in it.
         */
        if (can_write > 512 && !periodic)
                can_write = 512;

        /*
         * limit the write to one max-packet size worth of data, but allow
         * the transfer to return that it did not run out of fifo space
         * doing it.
         */
        if (to_write > max_transfer) {
                to_write = max_transfer;

                /* it's needed only when we do not use dedicated fifos */
                if (!hsotg->dedicated_fifos)
                        dwc2_hsotg_en_gsint(hsotg,
                                            periodic ? GINTSTS_PTXFEMP :
                                           GINTSTS_NPTXFEMP);
        }

        /* see if we can write data */

        if (to_write > can_write) {
                to_write = can_write;
                pkt_round = to_write % max_transfer;

                /*
                 * Round the write down to an
                 * exact number of packets.
                 *
                 * Note, we do not currently check to see if we can ever
                 * write a full packet or not to the FIFO.
                 */

                if (pkt_round)
                        to_write -= pkt_round;

                /*
                 * enable correct FIFO interrupt to alert us when there
                 * is more room left.
                 */

                /* it's needed only when we do not use dedicated fifos */
                if (!hsotg->dedicated_fifos)
                        dwc2_hsotg_en_gsint(hsotg,
                                            periodic ? GINTSTS_PTXFEMP :
                                           GINTSTS_NPTXFEMP);
        }

        dev_dbg(hsotg->dev, "write %d/%d, can_write %d, done %d\n",
                to_write, hs_req->req.length, can_write, buf_pos);

        if (to_write <= 0)
                return -ENOSPC;

        hs_req->req.actual = buf_pos + to_write;
        hs_ep->total_data += to_write;

        if (periodic)
                hs_ep->fifo_load += to_write;

        to_write = DIV_ROUND_UP(to_write, 4);
        data = hs_req->req.buf + buf_pos;

        dwc2_writel_rep(hsotg, EPFIFO(hs_ep->index), data, to_write);

        return (to_write >= can_write) ? -ENOSPC : 0;
}

/**
 * get_ep_limit - get the maximum data legnth for this endpoint
 * @hs_ep: The endpoint
 *
 * Return the maximum data that can be queued in one go on a given endpoint
 * so that transfers that are too long can be split.
 */
static unsigned int get_ep_limit(struct dwc2_hsotg_ep *hs_ep)
{
        int index = hs_ep->index;
        unsigned int maxsize;
        unsigned int maxpkt;

        if (index != 0) {
                maxsize = DXEPTSIZ_XFERSIZE_LIMIT + 1;
                maxpkt = DXEPTSIZ_PKTCNT_LIMIT + 1;
        } else {
                maxsize = 64 + 64;
                if (hs_ep->dir_in)
                        maxpkt = DIEPTSIZ0_PKTCNT_LIMIT + 1;
                else
                        maxpkt = 2;
        }

        /* we made the constant loading easier above by using +1 */
        maxpkt--;
        maxsize--;

        /*
         * constrain by packet count if maxpkts*pktsize is greater
         * than the length register size.
         */

        if ((maxpkt * hs_ep->ep.maxpacket) < maxsize)
                maxsize = maxpkt * hs_ep->ep.maxpacket;

        return maxsize;
}

/**
 * dwc2_hsotg_read_frameno - read current frame number
 * @hsotg: The device instance
 *
 * Return the current frame number
 */
static u32 dwc2_hsotg_read_frameno(struct dwc2_hsotg *hsotg)
{
        u32 dsts;

        dsts = dwc2_readl(hsotg, DSTS);
        dsts &= DSTS_SOFFN_MASK;
        dsts >>= DSTS_SOFFN_SHIFT;

        return dsts;
}

/**
 * dwc2_gadget_get_chain_limit - get the maximum data payload value of the
 * DMA descriptor chain prepared for specific endpoint
 * @hs_ep: The endpoint
 *
 * Return the maximum data that can be queued in one go on a given endpoint
 * depending on its descriptor chain capacity so that transfers that
 * are too long can be split.
 */
static unsigned int dwc2_gadget_get_chain_limit(struct dwc2_hsotg_ep *hs_ep)
{
        int is_isoc = hs_ep->isochronous;
        unsigned int maxsize;

        if (is_isoc)
                maxsize = hs_ep->dir_in ? DEV_DMA_ISOC_TX_NBYTES_LIMIT :
                                           DEV_DMA_ISOC_RX_NBYTES_LIMIT;
        else
                maxsize = DEV_DMA_NBYTES_LIMIT;

        /* Above size of one descriptor was chosen, multiple it */
        maxsize *= MAX_DMA_DESC_NUM_GENERIC;

        return maxsize;
}

/*
 * dwc2_gadget_get_desc_params - get DMA descriptor parameters.
 * @hs_ep: The endpoint
 * @mask: RX/TX bytes mask to be defined
 *
 * Returns maximum data payload for one descriptor after analyzing endpoint
 * characteristics.
 * DMA descriptor transfer bytes limit depends on EP type:
 * Control out - MPS,
 * Isochronous - descriptor rx/tx bytes bitfield limit,
 * Control In/Bulk/Interrupt - multiple of mps. This will allow to not
 * have concatenations from various descriptors within one packet.
 *
 * Selects corresponding mask for RX/TX bytes as well.
 */
static u32 dwc2_gadget_get_desc_params(struct dwc2_hsotg_ep *hs_ep, u32 *mask)
{
        u32 mps = hs_ep->ep.maxpacket;
        int dir_in = hs_ep->dir_in;
        u32 desc_size = 0;

        if (!hs_ep->index && !dir_in) {
                desc_size = mps;
                *mask = DEV_DMA_NBYTES_MASK;
        } else if (hs_ep->isochronous) {
                if (dir_in) {
                        desc_size = DEV_DMA_ISOC_TX_NBYTES_LIMIT;
                        *mask = DEV_DMA_ISOC_TX_NBYTES_MASK;
                } else {
                        desc_size = DEV_DMA_ISOC_RX_NBYTES_LIMIT;
                        *mask = DEV_DMA_ISOC_RX_NBYTES_MASK;
                }
        } else {
                desc_size = DEV_DMA_NBYTES_LIMIT;
                *mask = DEV_DMA_NBYTES_MASK;

                /* Round down desc_size to be mps multiple */
                desc_size -= desc_size % mps;
        }

        return desc_size;
}

/*
 * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
 * @hs_ep: The endpoint
 * @dma_buff: DMA address to use
 * @len: Length of the transfer
 *
 * This function will iterate over descriptor chain and fill its entries
 * with corresponding information based on transfer data.
 */
static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
                                                 dma_addr_t dma_buff,
                                                 unsigned int len)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        int dir_in = hs_ep->dir_in;
        struct dwc2_dma_desc *desc = hs_ep->desc_list;
        u32 mps = hs_ep->ep.maxpacket;
        u32 maxsize = 0;
        u32 offset = 0;
        u32 mask = 0;
        int i;

        maxsize = dwc2_gadget_get_desc_params(hs_ep, &mask);

        hs_ep->desc_count = (len / maxsize) +
                                ((len % maxsize) ? 1 : 0);
        if (len == 0)
                hs_ep->desc_count = 1;

        for (i = 0; i < hs_ep->desc_count; ++i) {
                desc->status = 0;
                desc->status |= (DEV_DMA_BUFF_STS_HBUSY
                                 << DEV_DMA_BUFF_STS_SHIFT);

                if (len > maxsize) {
                        if (!hs_ep->index && !dir_in)
                                desc->status |= (DEV_DMA_L | DEV_DMA_IOC);

                        desc->status |= (maxsize <<
                                                DEV_DMA_NBYTES_SHIFT & mask);
                        desc->buf = dma_buff + offset;

                        len -= maxsize;
                        offset += maxsize;
                } else {
                        desc->status |= (DEV_DMA_L | DEV_DMA_IOC);

                        if (dir_in)
                                desc->status |= (len % mps) ? DEV_DMA_SHORT :
                                        ((hs_ep->send_zlp) ? DEV_DMA_SHORT : 0);
                        if (len > maxsize)
                                dev_err(hsotg->dev, "wrong len %d\n", len);

                        desc->status |=
                                len << DEV_DMA_NBYTES_SHIFT & mask;
                        desc->buf = dma_buff + offset;
                }

                desc->status &= ~DEV_DMA_BUFF_STS_MASK;
                desc->status |= (DEV_DMA_BUFF_STS_HREADY
                                 << DEV_DMA_BUFF_STS_SHIFT);
                desc++;
        }
}

/*
 * dwc2_gadget_fill_isoc_desc - fills next isochronous descriptor in chain.
 * @hs_ep: The isochronous endpoint.
 * @dma_buff: usb requests dma buffer.
 * @len: usb request transfer length.
 *
 * Fills next free descriptor with the data of the arrived usb request,
 * frame info, sets Last and IOC bits increments next_desc. If filled
 * descriptor is not the first one, removes L bit from the previous descriptor
 * status.
 */
static int dwc2_gadget_fill_isoc_desc(struct dwc2_hsotg_ep *hs_ep,
                                      dma_addr_t dma_buff, unsigned int len)
{
        struct dwc2_dma_desc *desc;
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        u32 index;
        u32 maxsize = 0;
        u32 mask = 0;
        u8 pid = 0;

        maxsize = dwc2_gadget_get_desc_params(hs_ep, &mask);

        index = hs_ep->next_desc;
        desc = &hs_ep->desc_list[index];

        /* Check if descriptor chain full */
        if ((desc->status >> DEV_DMA_BUFF_STS_SHIFT) ==
            DEV_DMA_BUFF_STS_HREADY) {
                dev_dbg(hsotg->dev, "%s: desc chain full\n", __func__);
                return 1;
        }

        /* Clear L bit of previous desc if more than one entries in the chain */
        if (hs_ep->next_desc)
                hs_ep->desc_list[index - 1].status &= ~DEV_DMA_L;

        dev_dbg(hsotg->dev, "%s: Filling ep %d, dir %s isoc desc # %d\n",
                __func__, hs_ep->index, hs_ep->dir_in ? "in" : "out", index);

        desc->status = 0;
        desc->status |= (DEV_DMA_BUFF_STS_HBUSY << DEV_DMA_BUFF_STS_SHIFT);

        desc->buf = dma_buff;
        desc->status |= (DEV_DMA_L | DEV_DMA_IOC |
                         ((len << DEV_DMA_NBYTES_SHIFT) & mask));

        if (hs_ep->dir_in) {
                if (len)
                        pid = DIV_ROUND_UP(len, hs_ep->ep.maxpacket);
                else
                        pid = 1;
                desc->status |= ((pid << DEV_DMA_ISOC_PID_SHIFT) &
                                 DEV_DMA_ISOC_PID_MASK) |
                                ((len % hs_ep->ep.maxpacket) ?
                                 DEV_DMA_SHORT : 0) |
                                ((hs_ep->target_frame <<
                                  DEV_DMA_ISOC_FRNUM_SHIFT) &
                                 DEV_DMA_ISOC_FRNUM_MASK);
        }

        desc->status &= ~DEV_DMA_BUFF_STS_MASK;
        desc->status |= (DEV_DMA_BUFF_STS_HREADY << DEV_DMA_BUFF_STS_SHIFT);

        /* Increment frame number by interval for IN */
        if (hs_ep->dir_in)
                dwc2_gadget_incr_frame_num(hs_ep);

        /* Update index of last configured entry in the chain */
        hs_ep->next_desc++;
        if (hs_ep->next_desc >= MAX_DMA_DESC_NUM_GENERIC)
                hs_ep->next_desc = 0;

        return 0;
}

/*
 * dwc2_gadget_start_isoc_ddma - start isochronous transfer in DDMA
 * @hs_ep: The isochronous endpoint.
 *
 * Prepare descriptor chain for isochronous endpoints. Afterwards
 * write DMA address to HW and enable the endpoint.
 */
static void dwc2_gadget_start_isoc_ddma(struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        struct dwc2_hsotg_req *hs_req, *treq;
        int index = hs_ep->index;
        int ret;
        int i;
        u32 dma_reg;
        u32 depctl;
        u32 ctrl;
        struct dwc2_dma_desc *desc;

        if (list_empty(&hs_ep->queue)) {
                hs_ep->target_frame = TARGET_FRAME_INITIAL;
                dev_dbg(hsotg->dev, "%s: No requests in queue\n", __func__);
                return;
        }

        /* Initialize descriptor chain by Host Busy status */
        for (i = 0; i < MAX_DMA_DESC_NUM_GENERIC; i++) {
                desc = &hs_ep->desc_list[i];
                desc->status = 0;
                desc->status |= (DEV_DMA_BUFF_STS_HBUSY
                                    << DEV_DMA_BUFF_STS_SHIFT);
        }

        hs_ep->next_desc = 0;
        list_for_each_entry_safe(hs_req, treq, &hs_ep->queue, queue) {
                ret = dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
                                                 hs_req->req.length);
                if (ret)
                        break;
        }

        hs_ep->compl_desc = 0;
        depctl = hs_ep->dir_in ? DIEPCTL(index) : DOEPCTL(index);
        dma_reg = hs_ep->dir_in ? DIEPDMA(index) : DOEPDMA(index);

        /* write descriptor chain address to control register */
        dwc2_writel(hsotg, hs_ep->desc_list_dma, dma_reg);

        ctrl = dwc2_readl(hsotg, depctl);
        ctrl |= DXEPCTL_EPENA | DXEPCTL_CNAK;
        dwc2_writel(hsotg, ctrl, depctl);
}

/**
 * dwc2_hsotg_start_req - start a USB request from an endpoint's queue
 * @hsotg: The controller state.
 * @hs_ep: The endpoint to process a request for
 * @hs_req: The request to start.
 * @continuing: True if we are doing more for the current request.
 *
 * Start the given request running by setting the endpoint registers
 * appropriately, and writing any data to the FIFOs.
 */
static void dwc2_hsotg_start_req(struct dwc2_hsotg *hsotg,
                                 struct dwc2_hsotg_ep *hs_ep,
                                struct dwc2_hsotg_req *hs_req,
                                bool continuing)
{
        struct usb_request *ureq = &hs_req->req;
        int index = hs_ep->index;
        int dir_in = hs_ep->dir_in;
        u32 epctrl_reg;
        u32 epsize_reg;
        u32 epsize;
        u32 ctrl;
        unsigned int length;
        unsigned int packets;
        unsigned int maxreq;
        unsigned int dma_reg;

        if (index != 0) {
                if (hs_ep->req && !continuing) {
                        dev_err(hsotg->dev, "%s: active request\n", __func__);
                        WARN_ON(1);
                        return;
                } else if (hs_ep->req != hs_req && continuing) {
                        dev_err(hsotg->dev,
                                "%s: continue different req\n", __func__);
                        WARN_ON(1);
                        return;
                }
        }

        dma_reg = dir_in ? DIEPDMA(index) : DOEPDMA(index);
        epctrl_reg = dir_in ? DIEPCTL(index) : DOEPCTL(index);
        epsize_reg = dir_in ? DIEPTSIZ(index) : DOEPTSIZ(index);

        dev_dbg(hsotg->dev, "%s: DxEPCTL=0x%08x, ep %d, dir %s\n",
                __func__, dwc2_readl(hsotg, epctrl_reg), index,
                hs_ep->dir_in ? "in" : "out");

        /* If endpoint is stalled, we will restart request later */
        ctrl = dwc2_readl(hsotg, epctrl_reg);

        if (index && ctrl & DXEPCTL_STALL) {
                dev_warn(hsotg->dev, "%s: ep%d is stalled\n", __func__, index);
                return;
        }

        length = ureq->length - ureq->actual;
        dev_dbg(hsotg->dev, "ureq->length:%d ureq->actual:%d\n",
                ureq->length, ureq->actual);

        if (!using_desc_dma(hsotg))
                maxreq = get_ep_limit(hs_ep);
        else
                maxreq = dwc2_gadget_get_chain_limit(hs_ep);

        if (length > maxreq) {
                int round = maxreq % hs_ep->ep.maxpacket;

                dev_dbg(hsotg->dev, "%s: length %d, max-req %d, r %d\n",
                        __func__, length, maxreq, round);

                /* round down to multiple of packets */
                if (round)
                        maxreq -= round;

                length = maxreq;
        }

        if (length)
                packets = DIV_ROUND_UP(length, hs_ep->ep.maxpacket);
        else
                packets = 1;    /* send one packet if length is zero. */

        if (hs_ep->isochronous && length > (hs_ep->mc * hs_ep->ep.maxpacket)) {
                dev_err(hsotg->dev, "req length > maxpacket*mc\n");
                return;
        }

        if (dir_in && index != 0)
                if (hs_ep->isochronous)
                        epsize = DXEPTSIZ_MC(packets);
                else
                        epsize = DXEPTSIZ_MC(1);
        else
                epsize = 0;

        /*
         * zero length packet should be programmed on its own and should not
         * be counted in DIEPTSIZ.PktCnt with other packets.
         */
        if (dir_in && ureq->zero && !continuing) {
                /* Test if zlp is actually required. */
                if ((ureq->length >= hs_ep->ep.maxpacket) &&
                    !(ureq->length % hs_ep->ep.maxpacket))
                        hs_ep->send_zlp = 1;
        }

        epsize |= DXEPTSIZ_PKTCNT(packets);
        epsize |= DXEPTSIZ_XFERSIZE(length);

        dev_dbg(hsotg->dev, "%s: %d@%d/%d, 0x%08x => 0x%08x\n",
                __func__, packets, length, ureq->length, epsize, epsize_reg);

        /* store the request as the current one we're doing */
        hs_ep->req = hs_req;

        if (using_desc_dma(hsotg)) {
                u32 offset = 0;
                u32 mps = hs_ep->ep.maxpacket;

                /* Adjust length: EP0 - MPS, other OUT EPs - multiple of MPS */
                if (!dir_in) {
                        if (!index)
                                length = mps;
                        else if (length % mps)
                                length += (mps - (length % mps));
                }

                /*
                 * If more data to send, adjust DMA for EP0 out data stage.
                 * ureq->dma stays unchanged, hence increment it by already
                 * passed passed data count before starting new transaction.
                 */
                if (!index && hsotg->ep0_state == DWC2_EP0_DATA_OUT &&
                    continuing)
                        offset = ureq->actual;

                /* Fill DDMA chain entries */
                dwc2_gadget_config_nonisoc_xfer_ddma(hs_ep, ureq->dma + offset,
                                                     length);

                /* write descriptor chain address to control register */
                dwc2_writel(hsotg, hs_ep->desc_list_dma, dma_reg);

                dev_dbg(hsotg->dev, "%s: %08x pad => 0x%08x\n",
                        __func__, (u32)hs_ep->desc_list_dma, dma_reg);
        } else {
                /* write size / packets */
                dwc2_writel(hsotg, epsize, epsize_reg);

                if (using_dma(hsotg) && !continuing && (length != 0)) {
                        /*
                         * write DMA address to control register, buffer
                         * already synced by dwc2_hsotg_ep_queue().
                         */

                        dwc2_writel(hsotg, ureq->dma, dma_reg);

                        dev_dbg(hsotg->dev, "%s: %pad => 0x%08x\n",
                                __func__, &ureq->dma, dma_reg);
                }
        }

        if (hs_ep->isochronous && hs_ep->interval == 1) {
                hs_ep->target_frame = dwc2_hsotg_read_frameno(hsotg);
                dwc2_gadget_incr_frame_num(hs_ep);

                if (hs_ep->target_frame & 0x1)
                        ctrl |= DXEPCTL_SETODDFR;
                else
                        ctrl |= DXEPCTL_SETEVENFR;
        }

        ctrl |= DXEPCTL_EPENA;  /* ensure ep enabled */

        dev_dbg(hsotg->dev, "ep0 state:%d\n", hsotg->ep0_state);

        /* For Setup request do not clear NAK */
        if (!(index == 0 && hsotg->ep0_state == DWC2_EP0_SETUP))
                ctrl |= DXEPCTL_CNAK;   /* clear NAK set by core */

        dev_dbg(hsotg->dev, "%s: DxEPCTL=0x%08x\n", __func__, ctrl);
        dwc2_writel(hsotg, ctrl, epctrl_reg);

        /*
         * set these, it seems that DMA support increments past the end
         * of the packet buffer so we need to calculate the length from
         * this information.
         */
        hs_ep->size_loaded = length;
        hs_ep->last_load = ureq->actual;

        if (dir_in && !using_dma(hsotg)) {
                /* set these anyway, we may need them for non-periodic in */
                hs_ep->fifo_load = 0;

                dwc2_hsotg_write_fifo(hsotg, hs_ep, hs_req);
        }

        /*
         * Note, trying to clear the NAK here causes problems with transmit
         * on the S3C6400 ending up with the TXFIFO becoming full.
         */

        /* check ep is enabled */
        if (!(dwc2_readl(hsotg, epctrl_reg) & DXEPCTL_EPENA))
                dev_dbg(hsotg->dev,
                        "ep%d: failed to become enabled (DXEPCTL=0x%08x)?\n",
                         index, dwc2_readl(hsotg, epctrl_reg));

        dev_dbg(hsotg->dev, "%s: DXEPCTL=0x%08x\n",
                __func__, dwc2_readl(hsotg, epctrl_reg));

        /* enable ep interrupts */
        dwc2_hsotg_ctrl_epint(hsotg, hs_ep->index, hs_ep->dir_in, 1);
}

/**
 * dwc2_hsotg_map_dma - map the DMA memory being used for the request
 * @hsotg: The device state.
 * @hs_ep: The endpoint the request is on.
 * @req: The request being processed.
 *
 * We've been asked to queue a request, so ensure that the memory buffer
 * is correctly setup for DMA. If we've been passed an extant DMA address
 * then ensure the buffer has been synced to memory. If our buffer has no
 * DMA memory, then we map the memory and mark our request to allow us to
 * cleanup on completion.
 */
static int dwc2_hsotg_map_dma(struct dwc2_hsotg *hsotg,
                              struct dwc2_hsotg_ep *hs_ep,
                             struct usb_request *req)
{
        int ret;

        ret = usb_gadget_map_request(&hsotg->gadget, req, hs_ep->dir_in);
        if (ret)
                goto dma_error;

        return 0;

dma_error:
        dev_err(hsotg->dev, "%s: failed to map buffer %p, %d bytes\n",
                __func__, req->buf, req->length);

        return -EIO;
}

static int dwc2_hsotg_handle_unaligned_buf_start(struct dwc2_hsotg *hsotg,
                                                 struct dwc2_hsotg_ep *hs_ep,
                                                 struct dwc2_hsotg_req *hs_req)
{
        void *req_buf = hs_req->req.buf;

        /* If dma is not being used or buffer is aligned */
        if (!using_dma(hsotg) || !((long)req_buf & 3))
                return 0;

        WARN_ON(hs_req->saved_req_buf);

        dev_dbg(hsotg->dev, "%s: %s: buf=%p length=%d\n", __func__,
                hs_ep->ep.name, req_buf, hs_req->req.length);

        hs_req->req.buf = kmalloc(hs_req->req.length, GFP_ATOMIC);
        if (!hs_req->req.buf) {
                hs_req->req.buf = req_buf;
                dev_err(hsotg->dev,
                        "%s: unable to allocate memory for bounce buffer\n",
                        __func__);
                return -ENOMEM;
        }

        /* Save actual buffer */
        hs_req->saved_req_buf = req_buf;

        if (hs_ep->dir_in)
                memcpy(hs_req->req.buf, req_buf, hs_req->req.length);
        return 0;
}

static void
dwc2_hsotg_handle_unaligned_buf_complete(struct dwc2_hsotg *hsotg,
                                         struct dwc2_hsotg_ep *hs_ep,
                                         struct dwc2_hsotg_req *hs_req)
{
        /* If dma is not being used or buffer was aligned */
        if (!using_dma(hsotg) || !hs_req->saved_req_buf)
                return;

        dev_dbg(hsotg->dev, "%s: %s: status=%d actual-length=%d\n", __func__,
                hs_ep->ep.name, hs_req->req.status, hs_req->req.actual);

        /* Copy data from bounce buffer on successful out transfer */
        if (!hs_ep->dir_in && !hs_req->req.status)
                memcpy(hs_req->saved_req_buf, hs_req->req.buf,
                       hs_req->req.actual);

        /* Free bounce buffer */
        kfree(hs_req->req.buf);

        hs_req->req.buf = hs_req->saved_req_buf;
        hs_req->saved_req_buf = NULL;
}

/**
 * dwc2_gadget_target_frame_elapsed - Checks target frame
 * @hs_ep: The driver endpoint to check
 *
 * Returns 1 if targeted frame elapsed. If returned 1 then we need to drop
 * corresponding transfer.
 */
static bool dwc2_gadget_target_frame_elapsed(struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        u32 target_frame = hs_ep->target_frame;
        u32 current_frame = hsotg->frame_number;
        bool frame_overrun = hs_ep->frame_overrun;

        if (!frame_overrun && current_frame >= target_frame)
                return true;

        if (frame_overrun && current_frame >= target_frame &&
            ((current_frame - target_frame) < DSTS_SOFFN_LIMIT / 2))
                return true;

        return false;
}

/*
 * dwc2_gadget_set_ep0_desc_chain - Set EP's desc chain pointers
 * @hsotg: The driver state
 * @hs_ep: the ep descriptor chain is for
 *
 * Called to update EP0 structure's pointers depend on stage of
 * control transfer.
 */
static int dwc2_gadget_set_ep0_desc_chain(struct dwc2_hsotg *hsotg,
                                          struct dwc2_hsotg_ep *hs_ep)
{
        switch (hsotg->ep0_state) {
        case DWC2_EP0_SETUP:
        case DWC2_EP0_STATUS_OUT:
                hs_ep->desc_list = hsotg->setup_desc[0];
                hs_ep->desc_list_dma = hsotg->setup_desc_dma[0];
                break;
        case DWC2_EP0_DATA_IN:
        case DWC2_EP0_STATUS_IN:
                hs_ep->desc_list = hsotg->ctrl_in_desc;
                hs_ep->desc_list_dma = hsotg->ctrl_in_desc_dma;
                break;
        case DWC2_EP0_DATA_OUT:
                hs_ep->desc_list = hsotg->ctrl_out_desc;
                hs_ep->desc_list_dma = hsotg->ctrl_out_desc_dma;
                break;
        default:
                dev_err(hsotg->dev, "invalid EP 0 state in queue %d\n",
                        hsotg->ep0_state);
                return -EINVAL;
        }

        return 0;
}

static int dwc2_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
                               gfp_t gfp_flags)
{
        struct dwc2_hsotg_req *hs_req = our_req(req);
        struct dwc2_hsotg_ep *hs_ep = our_ep(ep);
        struct dwc2_hsotg *hs = hs_ep->parent;
        bool first;
        int ret;
        u32 maxsize = 0;
        u32 mask = 0;


        dev_dbg(hs->dev, "%s: req %p: %d@%p, noi=%d, zero=%d, snok=%d\n",
                ep->name, req, req->length, req->buf, req->no_interrupt,
                req->zero, req->short_not_ok);

        /* Prevent new request submission when controller is suspended */
        if (hs->lx_state != DWC2_L0) {
                dev_dbg(hs->dev, "%s: submit request only in active state\n",
                        __func__);
                return -EAGAIN;
        }

        /* initialise status of the request */
        INIT_LIST_HEAD(&hs_req->queue);
        req->actual = 0;
        req->status = -EINPROGRESS;

        /* In DDMA mode for ISOC's don't queue request if length greater
         * than descriptor limits.
         */
        if (using_desc_dma(hs) && hs_ep->isochronous) {
                maxsize = dwc2_gadget_get_desc_params(hs_ep, &mask);
                if (hs_ep->dir_in && req->length > maxsize) {
                        dev_err(hs->dev, "wrong length %d (maxsize=%d)\n",
                                req->length, maxsize);
                        return -EINVAL;
                }

                if (!hs_ep->dir_in && req->length > hs_ep->ep.maxpacket) {
                        dev_err(hs->dev, "ISOC OUT: wrong length %d (mps=%d)\n",
                                req->length, hs_ep->ep.maxpacket);
                        return -EINVAL;
                }
        }

        ret = dwc2_hsotg_handle_unaligned_buf_start(hs, hs_ep, hs_req);
        if (ret)
                return ret;

        /* if we're using DMA, sync the buffers as necessary */
        if (using_dma(hs)) {
                ret = dwc2_hsotg_map_dma(hs, hs_ep, req);
                if (ret)
                        return ret;
        }
        /* If using descriptor DMA configure EP0 descriptor chain pointers */
        if (using_desc_dma(hs) && !hs_ep->index) {
                ret = dwc2_gadget_set_ep0_desc_chain(hs, hs_ep);
                if (ret)
                        return ret;
        }

        first = list_empty(&hs_ep->queue);
        list_add_tail(&hs_req->queue, &hs_ep->queue);

        /*
         * Handle DDMA isochronous transfers separately - just add new entry
         * to the descriptor chain.
         * Transfer will be started once SW gets either one of NAK or
         * OutTknEpDis interrupts.
         */
        if (using_desc_dma(hs) && hs_ep->isochronous) {
                if (hs_ep->target_frame != TARGET_FRAME_INITIAL) {
                        dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
                                                   hs_req->req.length);
                }
                return 0;
        }

        if (first) {
                if (!hs_ep->isochronous) {
                        dwc2_hsotg_start_req(hs, hs_ep, hs_req, false);
                        return 0;
                }

                /* Update current frame number value. */
                hs->frame_number = dwc2_hsotg_read_frameno(hs);
                while (dwc2_gadget_target_frame_elapsed(hs_ep)) {
                        dwc2_gadget_incr_frame_num(hs_ep);
                        /* Update current frame number value once more as it
                         * changes here.
                         */
                        hs->frame_number = dwc2_hsotg_read_frameno(hs);
                }

                if (hs_ep->target_frame != TARGET_FRAME_INITIAL)
                        dwc2_hsotg_start_req(hs, hs_ep, hs_req, false);
        }
        return 0;
}

static int dwc2_hsotg_ep_queue_lock(struct usb_ep *ep, struct usb_request *req,
                                    gfp_t gfp_flags)
{
        struct dwc2_hsotg_ep *hs_ep = our_ep(ep);
        struct dwc2_hsotg *hs = hs_ep->parent;
        unsigned long flags = 0;
        int ret = 0;

        spin_lock_irqsave(&hs->lock, flags);
        ret = dwc2_hsotg_ep_queue(ep, req, gfp_flags);
        spin_unlock_irqrestore(&hs->lock, flags);

        return ret;
}

static void dwc2_hsotg_ep_free_request(struct usb_ep *ep,
                                       struct usb_request *req)
{
        struct dwc2_hsotg_req *hs_req = our_req(req);

        kfree(hs_req);
}

/**
 * dwc2_hsotg_complete_oursetup - setup completion callback
 * @ep: The endpoint the request was on.
 * @req: The request completed.
 *
 * Called on completion of any requests the driver itself
 * submitted that need cleaning up.
 */
static void dwc2_hsotg_complete_oursetup(struct usb_ep *ep,
                                         struct usb_request *req)
{
        struct dwc2_hsotg_ep *hs_ep = our_ep(ep);
        struct dwc2_hsotg *hsotg = hs_ep->parent;

        dev_dbg(hsotg->dev, "%s: ep %p, req %p\n", __func__, ep, req);

        dwc2_hsotg_ep_free_request(ep, req);
}

/**
 * ep_from_windex - convert control wIndex value to endpoint
 * @hsotg: The driver state.
 * @windex: The control request wIndex field (in host order).
 *
 * Convert the given wIndex into a pointer to an driver endpoint
 * structure, or return NULL if it is not a valid endpoint.
 */
static struct dwc2_hsotg_ep *ep_from_windex(struct dwc2_hsotg *hsotg,
                                            u32 windex)
{
        struct dwc2_hsotg_ep *ep;
        int dir = (windex & USB_DIR_IN) ? 1 : 0;
        int idx = windex & 0x7F;

        if (windex >= 0x100)
                return NULL;

        if (idx > hsotg->num_of_eps)
                return NULL;

        ep = index_to_ep(hsotg, idx, dir);

        if (idx && ep->dir_in != dir)
                return NULL;

        return ep;
}

/**
 * dwc2_hsotg_set_test_mode - Enable usb Test Modes
 * @hsotg: The driver state.
 * @testmode: requested usb test mode
 * Enable usb Test Mode requested by the Host.
 */
int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode)
{
        int dctl = dwc2_readl(hsotg, DCTL);

        dctl &= ~DCTL_TSTCTL_MASK;
        switch (testmode) {
        case TEST_J:
        case TEST_K:
        case TEST_SE0_NAK:
        case TEST_PACKET:
        case TEST_FORCE_EN:
                dctl |= testmode << DCTL_TSTCTL_SHIFT;
                break;
        default:
                return -EINVAL;
        }
        dwc2_writel(hsotg, dctl, DCTL);
        return 0;
}

/**
 * dwc2_hsotg_send_reply - send reply to control request
 * @hsotg: The device state
 * @ep: Endpoint 0
 * @buff: Buffer for request
 * @length: Length of reply.
 *
 * Create a request and queue it on the given endpoint. This is useful as
 * an internal method of sending replies to certain control requests, etc.
 */
static int dwc2_hsotg_send_reply(struct dwc2_hsotg *hsotg,
                                 struct dwc2_hsotg_ep *ep,
                                void *buff,
                                int length)
{
        struct usb_request *req;
        int ret;

        dev_dbg(hsotg->dev, "%s: buff %p, len %d\n", __func__, buff, length);

        req = dwc2_hsotg_ep_alloc_request(&ep->ep, GFP_ATOMIC);
        hsotg->ep0_reply = req;
        if (!req) {
                dev_warn(hsotg->dev, "%s: cannot alloc req\n", __func__);
                return -ENOMEM;
        }

        req->buf = hsotg->ep0_buff;
        req->length = length;
        /*
         * zero flag is for sending zlp in DATA IN stage. It has no impact on
         * STATUS stage.
         */
        req->zero = 0;
        req->complete = dwc2_hsotg_complete_oursetup;

        if (length)
                memcpy(req->buf, buff, length);

        ret = dwc2_hsotg_ep_queue(&ep->ep, req, GFP_ATOMIC);
        if (ret) {
                dev_warn(hsotg->dev, "%s: cannot queue req\n", __func__);
                return ret;
        }

        return 0;
}

/**
 * dwc2_hsotg_process_req_status - process request GET_STATUS
 * @hsotg: The device state
 * @ctrl: USB control request
 */
static int dwc2_hsotg_process_req_status(struct dwc2_hsotg *hsotg,
                                         struct usb_ctrlrequest *ctrl)
{
        struct dwc2_hsotg_ep *ep0 = hsotg->eps_out[0];
        struct dwc2_hsotg_ep *ep;
        __le16 reply;
        int ret;

        dev_dbg(hsotg->dev, "%s: USB_REQ_GET_STATUS\n", __func__);

        if (!ep0->dir_in) {
                dev_warn(hsotg->dev, "%s: direction out?\n", __func__);
                return -EINVAL;
        }

        switch (ctrl->bRequestType & USB_RECIP_MASK) {
        case USB_RECIP_DEVICE:
                /*
                 * bit 0 => self powered
                 * bit 1 => remote wakeup
                 */
                reply = cpu_to_le16(0);
                break;

        case USB_RECIP_INTERFACE:
                /* currently, the data result should be zero */
                reply = cpu_to_le16(0);
                break;

        case USB_RECIP_ENDPOINT:
                ep = ep_from_windex(hsotg, le16_to_cpu(ctrl->wIndex));
                if (!ep)
                        return -ENOENT;

                reply = cpu_to_le16(ep->halted ? 1 : 0);
                break;

        default:
                return 0;
        }

        if (le16_to_cpu(ctrl->wLength) != 2)
                return -EINVAL;

        ret = dwc2_hsotg_send_reply(hsotg, ep0, &reply, 2);
        if (ret) {
                dev_err(hsotg->dev, "%s: failed to send reply\n", __func__);
                return ret;
        }

        return 1;
}

static int dwc2_hsotg_ep_sethalt(struct usb_ep *ep, int value, bool now);

/**
 * get_ep_head - return the first request on the endpoint
 * @hs_ep: The controller endpoint to get
 *
 * Get the first request on the endpoint.
 */
static struct dwc2_hsotg_req *get_ep_head(struct dwc2_hsotg_ep *hs_ep)
{
        return list_first_entry_or_null(&hs_ep->queue, struct dwc2_hsotg_req,
                                        queue);
}

/**
 * dwc2_gadget_start_next_request - Starts next request from ep queue
 * @hs_ep: Endpoint structure
 *
 * If queue is empty and EP is ISOC-OUT - unmasks OUTTKNEPDIS which is masked
 * in its handler. Hence we need to unmask it here to be able to do
 * resynchronization.
 */
static void dwc2_gadget_start_next_request(struct dwc2_hsotg_ep *hs_ep)
{
        u32 mask;
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        int dir_in = hs_ep->dir_in;
        struct dwc2_hsotg_req *hs_req;
        u32 epmsk_reg = dir_in ? DIEPMSK : DOEPMSK;

        if (!list_empty(&hs_ep->queue)) {
                hs_req = get_ep_head(hs_ep);
                dwc2_hsotg_start_req(hsotg, hs_ep, hs_req, false);
                return;
        }
        if (!hs_ep->isochronous)
                return;

        if (dir_in) {
                dev_dbg(hsotg->dev, "%s: No more ISOC-IN requests\n",
                        __func__);
        } else {
                dev_dbg(hsotg->dev, "%s: No more ISOC-OUT requests\n",
                        __func__);
                mask = dwc2_readl(hsotg, epmsk_reg);
                mask |= DOEPMSK_OUTTKNEPDISMSK;
                dwc2_writel(hsotg, mask, epmsk_reg);
        }
}

/**
 * dwc2_hsotg_process_req_feature - process request {SET,CLEAR}_FEATURE
 * @hsotg: The device state
 * @ctrl: USB control request
 */
static int dwc2_hsotg_process_req_feature(struct dwc2_hsotg *hsotg,
                                          struct usb_ctrlrequest *ctrl)
{
        struct dwc2_hsotg_ep *ep0 = hsotg->eps_out[0];
        struct dwc2_hsotg_req *hs_req;
        bool set = (ctrl->bRequest == USB_REQ_SET_FEATURE);
        struct dwc2_hsotg_ep *ep;
        int ret;
        bool halted;
        u32 recip;
        u32 wValue;
        u32 wIndex;

        dev_dbg(hsotg->dev, "%s: %s_FEATURE\n",
                __func__, set ? "SET" : "CLEAR");

        wValue = le16_to_cpu(ctrl->wValue);
        wIndex = le16_to_cpu(ctrl->wIndex);
        recip = ctrl->bRequestType & USB_RECIP_MASK;

        switch (recip) {
        case USB_RECIP_DEVICE:
                switch (wValue) {
                case USB_DEVICE_REMOTE_WAKEUP:
                        hsotg->remote_wakeup_allowed = 1;
                        break;

                case USB_DEVICE_TEST_MODE:
                        if ((wIndex & 0xff) != 0)
                                return -EINVAL;
                        if (!set)
                                return -EINVAL;

                        hsotg->test_mode = wIndex >> 8;
                        ret = dwc2_hsotg_send_reply(hsotg, ep0, NULL, 0);
                        if (ret) {
                                dev_err(hsotg->dev,
                                        "%s: failed to send reply\n", __func__);
                                return ret;
                        }
                        break;
                default:
                        return -ENOENT;
                }
                break;

        case USB_RECIP_ENDPOINT:
                ep = ep_from_windex(hsotg, wIndex);
                if (!ep) {
                        dev_dbg(hsotg->dev, "%s: no endpoint for 0x%04x\n",
                                __func__, wIndex);
                        return -ENOENT;
                }

                switch (wValue) {
                case USB_ENDPOINT_HALT:
                        halted = ep->halted;

                        dwc2_hsotg_ep_sethalt(&ep->ep, set, true);

                        ret = dwc2_hsotg_send_reply(hsotg, ep0, NULL, 0);
                        if (ret) {
                                dev_err(hsotg->dev,
                                        "%s: failed to send reply\n", __func__);
                                return ret;
                        }

                        /*
                         * we have to complete all requests for ep if it was
                         * halted, and the halt was cleared by CLEAR_FEATURE
                         */

                        if (!set && halted) {
                                /*
                                 * If we have request in progress,
                                 * then complete it
                                 */
                                if (ep->req) {
                                        hs_req = ep->req;
                                        ep->req = NULL;
                                        list_del_init(&hs_req->queue);
                                        if (hs_req->req.complete) {
                                                spin_unlock(&hsotg->lock);
                                                usb_gadget_giveback_request(
                                                        &ep->ep, &hs_req->req);
                                                spin_lock(&hsotg->lock);
                                        }
                                }

                                /* If we have pending request, then start it */
                                if (!ep->req)
                                        dwc2_gadget_start_next_request(ep);
                        }

                        break;

                default:
                        return -ENOENT;
                }
                break;
        default:
                return -ENOENT;
        }
        return 1;
}

static void dwc2_hsotg_enqueue_setup(struct dwc2_hsotg *hsotg);

/**
 * dwc2_hsotg_stall_ep0 - stall ep0
 * @hsotg: The device state
 *
 * Set stall for ep0 as response for setup request.
 */
static void dwc2_hsotg_stall_ep0(struct dwc2_hsotg *hsotg)
{
        struct dwc2_hsotg_ep *ep0 = hsotg->eps_out[0];
        u32 reg;
        u32 ctrl;

        dev_dbg(hsotg->dev, "ep0 stall (dir=%d)\n", ep0->dir_in);
        reg = (ep0->dir_in) ? DIEPCTL0 : DOEPCTL0;

        /*
         * DxEPCTL_Stall will be cleared by EP once it has
         * taken effect, so no need to clear later.
         */

        ctrl = dwc2_readl(hsotg, reg);
        ctrl |= DXEPCTL_STALL;
        ctrl |= DXEPCTL_CNAK;
        dwc2_writel(hsotg, ctrl, reg);

        dev_dbg(hsotg->dev,
                "written DXEPCTL=0x%08x to %08x (DXEPCTL=0x%08x)\n",
                ctrl, reg, dwc2_readl(hsotg, reg));

         /*
          * complete won't be called, so we enqueue
          * setup request here
          */
         dwc2_hsotg_enqueue_setup(hsotg);
}

/**
 * dwc2_hsotg_process_control - process a control request
 * @hsotg: The device state
 * @ctrl: The control request received
 *
 * The controller has received the SETUP phase of a control request, and
 * needs to work out what to do next (and whether to pass it on to the
 * gadget driver).
 */
static void dwc2_hsotg_process_control(struct dwc2_hsotg *hsotg,
                                       struct usb_ctrlrequest *ctrl)
{
        struct dwc2_hsotg_ep *ep0 = hsotg->eps_out[0];
        int ret = 0;
        u32 dcfg;

        dev_dbg(hsotg->dev,
                "ctrl Type=%02x, Req=%02x, V=%04x, I=%04x, L=%04x\n",
                ctrl->bRequestType, ctrl->bRequest, ctrl->wValue,
                ctrl->wIndex, ctrl->wLength);

        if (ctrl->wLength == 0) {
                ep0->dir_in = 1;
                hsotg->ep0_state = DWC2_EP0_STATUS_IN;
        } else if (ctrl->bRequestType & USB_DIR_IN) {
                ep0->dir_in = 1;
                hsotg->ep0_state = DWC2_EP0_DATA_IN;
        } else {
                ep0->dir_in = 0;
                hsotg->ep0_state = DWC2_EP0_DATA_OUT;
        }

        if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
                switch (ctrl->bRequest) {
                case USB_REQ_SET_ADDRESS:
                        hsotg->connected = 1;
                        dcfg = dwc2_readl(hsotg, DCFG);
                        dcfg &= ~DCFG_DEVADDR_MASK;
                        dcfg |= (le16_to_cpu(ctrl->wValue) <<
                                 DCFG_DEVADDR_SHIFT) & DCFG_DEVADDR_MASK;
                        dwc2_writel(hsotg, dcfg, DCFG);

                        dev_info(hsotg->dev, "new address %d\n", ctrl->wValue);

                        ret = dwc2_hsotg_send_reply(hsotg, ep0, NULL, 0);
                        return;

                case USB_REQ_GET_STATUS:
                        ret = dwc2_hsotg_process_req_status(hsotg, ctrl);
                        break;

                case USB_REQ_CLEAR_FEATURE:
                case USB_REQ_SET_FEATURE:
                        ret = dwc2_hsotg_process_req_feature(hsotg, ctrl);
                        break;
                }
        }

        /* as a fallback, try delivering it to the driver to deal with */

        if (ret == 0 && hsotg->driver) {
                spin_unlock(&hsotg->lock);
                ret = hsotg->driver->setup(&hsotg->gadget, ctrl);
                spin_lock(&hsotg->lock);
                if (ret < 0)
                        dev_dbg(hsotg->dev, "driver->setup() ret %d\n", ret);
        }

        /*
         * the request is either unhandlable, or is not formatted correctly
         * so respond with a STALL for the status stage to indicate failure.
         */

        if (ret < 0)
                dwc2_hsotg_stall_ep0(hsotg);
}

/**
 * dwc2_hsotg_complete_setup - completion of a setup transfer
 * @ep: The endpoint the request was on.
 * @req: The request completed.
 *
 * Called on completion of any requests the driver itself submitted for
 * EP0 setup packets
 */
static void dwc2_hsotg_complete_setup(struct usb_ep *ep,
                                      struct usb_request *req)
{
        struct dwc2_hsotg_ep *hs_ep = our_ep(ep);
        struct dwc2_hsotg *hsotg = hs_ep->parent;

        if (req->status < 0) {
                dev_dbg(hsotg->dev, "%s: failed %d\n", __func__, req->status);
                return;
        }

        spin_lock(&hsotg->lock);
        if (req->actual == 0)
                dwc2_hsotg_enqueue_setup(hsotg);
        else
                dwc2_hsotg_process_control(hsotg, req->buf);
        spin_unlock(&hsotg->lock);
}

/**
 * dwc2_hsotg_enqueue_setup - start a request for EP0 packets
 * @hsotg: The device state.
 *
 * Enqueue a request on EP0 if necessary to received any SETUP packets
 * received from the host.
 */
static void dwc2_hsotg_enqueue_setup(struct dwc2_hsotg *hsotg)
{
        struct usb_request *req = hsotg->ctrl_req;
        struct dwc2_hsotg_req *hs_req = our_req(req);
        int ret;

        dev_dbg(hsotg->dev, "%s: queueing setup request\n", __func__);

        req->zero = 0;
        req->length = 8;
        req->buf = hsotg->ctrl_buff;
        req->complete = dwc2_hsotg_complete_setup;

        if (!list_empty(&hs_req->queue)) {
                dev_dbg(hsotg->dev, "%s already queued???\n", __func__);
                return;
        }

        hsotg->eps_out[0]->dir_in = 0;
        hsotg->eps_out[0]->send_zlp = 0;
        hsotg->ep0_state = DWC2_EP0_SETUP;

        ret = dwc2_hsotg_ep_queue(&hsotg->eps_out[0]->ep, req, GFP_ATOMIC);
        if (ret < 0) {
                dev_err(hsotg->dev, "%s: failed queue (%d)\n", __func__, ret);
                /*
                 * Don't think there's much we can do other than watch the
                 * driver fail.
                 */
        }
}

static void dwc2_hsotg_program_zlp(struct dwc2_hsotg *hsotg,
                                   struct dwc2_hsotg_ep *hs_ep)
{
        u32 ctrl;
        u8 index = hs_ep->index;
        u32 epctl_reg = hs_ep->dir_in ? DIEPCTL(index) : DOEPCTL(index);
        u32 epsiz_reg = hs_ep->dir_in ? DIEPTSIZ(index) : DOEPTSIZ(index);

        if (hs_ep->dir_in)
                dev_dbg(hsotg->dev, "Sending zero-length packet on ep%d\n",
                        index);
        else
                dev_dbg(hsotg->dev, "Receiving zero-length packet on ep%d\n",
                        index);
        if (using_desc_dma(hsotg)) {
                /* Not specific buffer needed for ep0 ZLP */
                dma_addr_t dma = hs_ep->desc_list_dma;

                if (!index)
                        dwc2_gadget_set_ep0_desc_chain(hsotg, hs_ep);

                dwc2_gadget_config_nonisoc_xfer_ddma(hs_ep, dma, 0);
        } else {
                dwc2_writel(hsotg, DXEPTSIZ_MC(1) | DXEPTSIZ_PKTCNT(1) |
                            DXEPTSIZ_XFERSIZE(0),
                            epsiz_reg);
        }

        ctrl = dwc2_readl(hsotg, epctl_reg);
        ctrl |= DXEPCTL_CNAK;  /* clear NAK set by core */
        ctrl |= DXEPCTL_EPENA; /* ensure ep enabled */
        ctrl |= DXEPCTL_USBACTEP;
        dwc2_writel(hsotg, ctrl, epctl_reg);
}

/**
 * dwc2_hsotg_complete_request - complete a request given to us
 * @hsotg: The device state.
 * @hs_ep: The endpoint the request was on.
 * @hs_req: The request to complete.
 * @result: The result code (0 => Ok, otherwise errno)
 *
 * The given request has finished, so call the necessary completion
 * if it has one and then look to see if we can start a new request
 * on the endpoint.
 *
 * Note, expects the ep to already be locked as appropriate.
 */
static void dwc2_hsotg_complete_request(struct dwc2_hsotg *hsotg,
                                        struct dwc2_hsotg_ep *hs_ep,
                                       struct dwc2_hsotg_req *hs_req,
                                       int result)
{
        if (!hs_req) {
                dev_dbg(hsotg->dev, "%s: nothing to complete?\n", __func__);
                return;
        }

        dev_dbg(hsotg->dev, "complete: ep %p %s, req %p, %d => %p\n",
                hs_ep, hs_ep->ep.name, hs_req, result, hs_req->req.complete);

        /*
         * only replace the status if we've not already set an error
         * from a previous transaction
         */

        if (hs_req->req.status == -EINPROGRESS)
                hs_req->req.status = result;

        if (using_dma(hsotg))
                dwc2_hsotg_unmap_dma(hsotg, hs_ep, hs_req);

        dwc2_hsotg_handle_unaligned_buf_complete(hsotg, hs_ep, hs_req);

        hs_ep->req = NULL;
        list_del_init(&hs_req->queue);

        /*
         * call the complete request with the locks off, just in case the
         * request tries to queue more work for this endpoint.
         */

        if (hs_req->req.complete) {
                spin_unlock(&hsotg->lock);
                usb_gadget_giveback_request(&hs_ep->ep, &hs_req->req);
                spin_lock(&hsotg->lock);
        }

        /* In DDMA don't need to proceed to starting of next ISOC request */
        if (using_desc_dma(hsotg) && hs_ep->isochronous)
                return;

        /*
         * Look to see if there is anything else to do. Note, the completion
         * of the previous request may have caused a new request to be started
         * so be careful when doing this.
         */

        if (!hs_ep->req && result >= 0)
                dwc2_gadget_start_next_request(hs_ep);
}

/*
 * dwc2_gadget_complete_isoc_request_ddma - complete an isoc request in DDMA
 * @hs_ep: The endpoint the request was on.
 *
 * Get first request from the ep queue, determine descriptor on which complete
 * happened. SW discovers which descriptor currently in use by HW, adjusts
 * dma_address and calculates index of completed descriptor based on the value
 * of DEPDMA register. Update actual length of request, giveback to gadget.
 */
static void dwc2_gadget_complete_isoc_request_ddma(struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        struct dwc2_hsotg_req *hs_req;
        struct usb_request *ureq;
        u32 desc_sts;
        u32 mask;

        desc_sts = hs_ep->desc_list[hs_ep->compl_desc].status;

        /* Process only descriptors with buffer status set to DMA done */
        while ((desc_sts & DEV_DMA_BUFF_STS_MASK) >>
                DEV_DMA_BUFF_STS_SHIFT == DEV_DMA_BUFF_STS_DMADONE) {

                hs_req = get_ep_head(hs_ep);
                if (!hs_req) {
                        dev_warn(hsotg->dev, "%s: ISOC EP queue empty\n", __func__);
                        return;
                }
                ureq = &hs_req->req;

                /* Check completion status */
                if ((desc_sts & DEV_DMA_STS_MASK) >> DEV_DMA_STS_SHIFT ==
                        DEV_DMA_STS_SUCC) {
                        mask = hs_ep->dir_in ? DEV_DMA_ISOC_TX_NBYTES_MASK :
                                DEV_DMA_ISOC_RX_NBYTES_MASK;
                        ureq->actual = ureq->length - ((desc_sts & mask) >>
                                DEV_DMA_ISOC_NBYTES_SHIFT);

                        /* Adjust actual len for ISOC Out if len is
                         * not align of 4
                         */
                        if (!hs_ep->dir_in && ureq->length & 0x3)
                                ureq->actual += 4 - (ureq->length & 0x3);
                }

                dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req, 0);

                hs_ep->compl_desc++;
                if (hs_ep->compl_desc > (MAX_DMA_DESC_NUM_GENERIC - 1))
                        hs_ep->compl_desc = 0;
                desc_sts = hs_ep->desc_list[hs_ep->compl_desc].status;
        }
}

/*
 * dwc2_gadget_handle_isoc_bna - handle BNA interrupt for ISOC.
 * @hs_ep: The isochronous endpoint.
 *
 * If EP ISOC OUT then need to flush RX FIFO to remove source of BNA
 * interrupt. Reset target frame and next_desc to allow to start
 * ISOC's on NAK interrupt for IN direction or on OUTTKNEPDIS
 * interrupt for OUT direction.
 */
static void dwc2_gadget_handle_isoc_bna(struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;

        if (!hs_ep->dir_in)
                dwc2_flush_rx_fifo(hsotg);
        dwc2_hsotg_complete_request(hsotg, hs_ep, get_ep_head(hs_ep), 0);

        hs_ep->target_frame = TARGET_FRAME_INITIAL;
        hs_ep->next_desc = 0;
        hs_ep->compl_desc = 0;
}

/**
 * dwc2_hsotg_rx_data - receive data from the FIFO for an endpoint
 * @hsotg: The device state.
 * @ep_idx: The endpoint index for the data
 * @size: The size of data in the fifo, in bytes
 *
 * The FIFO status shows there is data to read from the FIFO for a given
 * endpoint, so sort out whether we need to read the data into a request
 * that has been made for that endpoint.
 */
static void dwc2_hsotg_rx_data(struct dwc2_hsotg *hsotg, int ep_idx, int size)
{
        struct dwc2_hsotg_ep *hs_ep = hsotg->eps_out[ep_idx];
        struct dwc2_hsotg_req *hs_req = hs_ep->req;
        int to_read;
        int max_req;
        int read_ptr;

        if (!hs_req) {
                u32 epctl = dwc2_readl(hsotg, DOEPCTL(ep_idx));
                int ptr;

                dev_dbg(hsotg->dev,
                        "%s: FIFO %d bytes on ep%d but no req (DXEPCTl=0x%08x)\n",
                         __func__, size, ep_idx, epctl);

                /* dump the data from the FIFO, we've nothing we can do */
                for (ptr = 0; ptr < size; ptr += 4)
                        (void)dwc2_readl(hsotg, EPFIFO(ep_idx));

                return;
        }

        to_read = size;
        read_ptr = hs_req->req.actual;
        max_req = hs_req->req.length - read_ptr;

        dev_dbg(hsotg->dev, "%s: read %d/%d, done %d/%d\n",
                __func__, to_read, max_req, read_ptr, hs_req->req.length);

        if (to_read > max_req) {
                /*
                 * more data appeared than we where willing
                 * to deal with in this request.
                 */

                /* currently we don't deal this */
                WARN_ON_ONCE(1);
        }

        hs_ep->total_data += to_read;
        hs_req->req.actual += to_read;
        to_read = DIV_ROUND_UP(to_read, 4);

        /*
         * note, we might over-write the buffer end by 3 bytes depending on
         * alignment of the data.
         */
        dwc2_readl_rep(hsotg, EPFIFO(ep_idx),
                       hs_req->req.buf + read_ptr, to_read);
}

/**
 * dwc2_hsotg_ep0_zlp - send/receive zero-length packet on control endpoint
 * @hsotg: The device instance
 * @dir_in: If IN zlp
 *
 * Generate a zero-length IN packet request for terminating a SETUP
 * transaction.
 *
 * Note, since we don't write any data to the TxFIFO, then it is
 * currently believed that we do not need to wait for any space in
 * the TxFIFO.
 */
static void dwc2_hsotg_ep0_zlp(struct dwc2_hsotg *hsotg, bool dir_in)
{
        /* eps_out[0] is used in both directions */
        hsotg->eps_out[0]->dir_in = dir_in;
        hsotg->ep0_state = dir_in ? DWC2_EP0_STATUS_IN : DWC2_EP0_STATUS_OUT;

        dwc2_hsotg_program_zlp(hsotg, hsotg->eps_out[0]);
}

static void dwc2_hsotg_change_ep_iso_parity(struct dwc2_hsotg *hsotg,
                                            u32 epctl_reg)
{
        u32 ctrl;

        ctrl = dwc2_readl(hsotg, epctl_reg);
        if (ctrl & DXEPCTL_EOFRNUM)
                ctrl |= DXEPCTL_SETEVENFR;
        else
                ctrl |= DXEPCTL_SETODDFR;
        dwc2_writel(hsotg, ctrl, epctl_reg);
}

/*
 * dwc2_gadget_get_xfersize_ddma - get transferred bytes amount from desc
 * @hs_ep - The endpoint on which transfer went
 *
 * Iterate over endpoints descriptor chain and get info on bytes remained
 * in DMA descriptors after transfer has completed. Used for non isoc EPs.
 */
static unsigned int dwc2_gadget_get_xfersize_ddma(struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        unsigned int bytes_rem = 0;
        struct dwc2_dma_desc *desc = hs_ep->desc_list;
        int i;
        u32 status;

        if (!desc)
                return -EINVAL;

        for (i = 0; i < hs_ep->desc_count; ++i) {
                status = desc->status;
                bytes_rem += status & DEV_DMA_NBYTES_MASK;

                if (status & DEV_DMA_STS_MASK)
                        dev_err(hsotg->dev, "descriptor %d closed with %x\n",
                                i, status & DEV_DMA_STS_MASK);
        }

        return bytes_rem;
}

/**
 * dwc2_hsotg_handle_outdone - handle receiving OutDone/SetupDone from RXFIFO
 * @hsotg: The device instance
 * @epnum: The endpoint received from
 *
 * The RXFIFO has delivered an OutDone event, which means that the data
 * transfer for an OUT endpoint has been completed, either by a short
 * packet or by the finish of a transfer.
 */
static void dwc2_hsotg_handle_outdone(struct dwc2_hsotg *hsotg, int epnum)
{
        u32 epsize = dwc2_readl(hsotg, DOEPTSIZ(epnum));
        struct dwc2_hsotg_ep *hs_ep = hsotg->eps_out[epnum];
        struct dwc2_hsotg_req *hs_req = hs_ep->req;
        struct usb_request *req = &hs_req->req;
        unsigned int size_left = DXEPTSIZ_XFERSIZE_GET(epsize);
        int result = 0;

        if (!hs_req) {
                dev_dbg(hsotg->dev, "%s: no request active\n", __func__);
                return;
        }

        if (epnum == 0 && hsotg->ep0_state == DWC2_EP0_STATUS_OUT) {
                dev_dbg(hsotg->dev, "zlp packet received\n");
                dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req, 0);
                dwc2_hsotg_enqueue_setup(hsotg);
                return;
        }

        if (using_desc_dma(hsotg))
                size_left = dwc2_gadget_get_xfersize_ddma(hs_ep);

        if (using_dma(hsotg)) {
                unsigned int size_done;

                /*
                 * Calculate the size of the transfer by checking how much
                 * is left in the endpoint size register and then working it
                 * out from the amount we loaded for the transfer.
                 *
                 * We need to do this as DMA pointers are always 32bit aligned
                 * so may overshoot/undershoot the transfer.
                 */

                size_done = hs_ep->size_loaded - size_left;
                size_done += hs_ep->last_load;

                req->actual = size_done;
        }

        /* if there is more request to do, schedule new transfer */
        if (req->actual < req->length && size_left == 0) {
                dwc2_hsotg_start_req(hsotg, hs_ep, hs_req, true);
                return;
        }

        if (req->actual < req->length && req->short_not_ok) {
                dev_dbg(hsotg->dev, "%s: got %d/%d (short not ok) => error\n",
                        __func__, req->actual, req->length);

                /*
                 * todo - what should we return here? there's no one else
                 * even bothering to check the status.
                 */
        }

        /* DDMA IN status phase will start from StsPhseRcvd interrupt */
        if (!using_desc_dma(hsotg) && epnum == 0 &&
            hsotg->ep0_state == DWC2_EP0_DATA_OUT) {
                /* Move to STATUS IN */
                dwc2_hsotg_ep0_zlp(hsotg, true);
                return;
        }

        /*
         * Slave mode OUT transfers do not go through XferComplete so
         * adjust the ISOC parity here.
         */
        if (!using_dma(hsotg)) {
                if (hs_ep->isochronous && hs_ep->interval == 1)
                        dwc2_hsotg_change_ep_iso_parity(hsotg, DOEPCTL(epnum));
                else if (hs_ep->isochronous && hs_ep->interval > 1)
                        dwc2_gadget_incr_frame_num(hs_ep);
        }

        dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req, result);
}

/**
 * dwc2_hsotg_handle_rx - RX FIFO has data
 * @hsotg: The device instance
 *
 * The IRQ handler has detected that the RX FIFO has some data in it
 * that requires processing, so find out what is in there and do the
 * appropriate read.
 *
 * The RXFIFO is a true FIFO, the packets coming out are still in packet
 * chunks, so if you have x packets received on an endpoint you'll get x
 * FIFO events delivered, each with a packet's worth of data in it.
 *
 * When using DMA, we should not be processing events from the RXFIFO
 * as the actual data should be sent to the memory directly and we turn
 * on the completion interrupts to get notifications of transfer completion.
 */
static void dwc2_hsotg_handle_rx(struct dwc2_hsotg *hsotg)
{
        u32 grxstsr = dwc2_readl(hsotg, GRXSTSP);
        u32 epnum, status, size;

        WARN_ON(using_dma(hsotg));

        epnum = grxstsr & GRXSTS_EPNUM_MASK;
        status = grxstsr & GRXSTS_PKTSTS_MASK;

        size = grxstsr & GRXSTS_BYTECNT_MASK;
        size >>= GRXSTS_BYTECNT_SHIFT;

        dev_dbg(hsotg->dev, "%s: GRXSTSP=0x%08x (%d@%d)\n",
                __func__, grxstsr, size, epnum);

        switch ((status & GRXSTS_PKTSTS_MASK) >> GRXSTS_PKTSTS_SHIFT) {
        case GRXSTS_PKTSTS_GLOBALOUTNAK:
                dev_dbg(hsotg->dev, "GLOBALOUTNAK\n");
                break;

        case GRXSTS_PKTSTS_OUTDONE:
                dev_dbg(hsotg->dev, "OutDone (Frame=0x%08x)\n",
                        dwc2_hsotg_read_frameno(hsotg));

                if (!using_dma(hsotg))
                        dwc2_hsotg_handle_outdone(hsotg, epnum);
                break;

        case GRXSTS_PKTSTS_SETUPDONE:
                dev_dbg(hsotg->dev,
                        "SetupDone (Frame=0x%08x, DOPEPCTL=0x%08x)\n",
                        dwc2_hsotg_read_frameno(hsotg),
                        dwc2_readl(hsotg, DOEPCTL(0)));
                /*
                 * Call dwc2_hsotg_handle_outdone here if it was not called from
                 * GRXSTS_PKTSTS_OUTDONE. That is, if the core didn't
                 * generate GRXSTS_PKTSTS_OUTDONE for setup packet.
                 */
                if (hsotg->ep0_state == DWC2_EP0_SETUP)
                        dwc2_hsotg_handle_outdone(hsotg, epnum);
                break;

        case GRXSTS_PKTSTS_OUTRX:
                dwc2_hsotg_rx_data(hsotg, epnum, size);
                break;

        case GRXSTS_PKTSTS_SETUPRX:
                dev_dbg(hsotg->dev,
                        "SetupRX (Frame=0x%08x, DOPEPCTL=0x%08x)\n",
                        dwc2_hsotg_read_frameno(hsotg),
                        dwc2_readl(hsotg, DOEPCTL(0)));

                WARN_ON(hsotg->ep0_state != DWC2_EP0_SETUP);

                dwc2_hsotg_rx_data(hsotg, epnum, size);
                break;

        default:
                dev_warn(hsotg->dev, "%s: unknown status %08x\n",
                         __func__, grxstsr);

                dwc2_hsotg_dump(hsotg);
                break;
        }
}

/**
 * dwc2_hsotg_ep0_mps - turn max packet size into register setting
 * @mps: The maximum packet size in bytes.
 */
static u32 dwc2_hsotg_ep0_mps(unsigned int mps)
{
        switch (mps) {
        case 64:
                return D0EPCTL_MPS_64;
        case 32:
                return D0EPCTL_MPS_32;
        case 16:
                return D0EPCTL_MPS_16;
        case 8:
                return D0EPCTL_MPS_8;
        }

        /* bad max packet size, warn and return invalid result */
        WARN_ON(1);
        return (u32)-1;
}

/**
 * dwc2_hsotg_set_ep_maxpacket - set endpoint's max-packet field
 * @hsotg: The driver state.
 * @ep: The index number of the endpoint
 * @mps: The maximum packet size in bytes
 * @mc: The multicount value
 * @dir_in: True if direction is in.
 *
 * Configure the maximum packet size for the given endpoint, updating
 * the hardware control registers to reflect this.
 */
static void dwc2_hsotg_set_ep_maxpacket(struct dwc2_hsotg *hsotg,
                                        unsigned int ep, unsigned int mps,
                                        unsigned int mc, unsigned int dir_in)
{
        struct dwc2_hsotg_ep *hs_ep;
        u32 reg;

        hs_ep = index_to_ep(hsotg, ep, dir_in);
        if (!hs_ep)
                return;

        if (ep == 0) {
                u32 mps_bytes = mps;

                /* EP0 is a special case */
                mps = dwc2_hsotg_ep0_mps(mps_bytes);
                if (mps > 3)
                        goto bad_mps;
                hs_ep->ep.maxpacket = mps_bytes;
                hs_ep->mc = 1;
        } else {
                if (mps > 1024)
                        goto bad_mps;
                hs_ep->mc = mc;
                if (mc > 3)
                        goto bad_mps;
                hs_ep->ep.maxpacket = mps;
        }

        if (dir_in) {
                reg = dwc2_readl(hsotg, DIEPCTL(ep));
                reg &= ~DXEPCTL_MPS_MASK;
                reg |= mps;
                dwc2_writel(hsotg, reg, DIEPCTL(ep));
        } else {
                reg = dwc2_readl(hsotg, DOEPCTL(ep));
                reg &= ~DXEPCTL_MPS_MASK;
                reg |= mps;
                dwc2_writel(hsotg, reg, DOEPCTL(ep));
        }

        return;

bad_mps:
        dev_err(hsotg->dev, "ep%d: bad mps of %d\n", ep, mps);
}

/**
 * dwc2_hsotg_txfifo_flush - flush Tx FIFO
 * @hsotg: The driver state
 * @idx: The index for the endpoint (0..15)
 */
static void dwc2_hsotg_txfifo_flush(struct dwc2_hsotg *hsotg, unsigned int idx)
{
        dwc2_writel(hsotg, GRSTCTL_TXFNUM(idx) | GRSTCTL_TXFFLSH,
                    GRSTCTL);

        /* wait until the fifo is flushed */
        if (dwc2_hsotg_wait_bit_clear(hsotg, GRSTCTL, GRSTCTL_TXFFLSH, 100))
                dev_warn(hsotg->dev, "%s: timeout flushing fifo GRSTCTL_TXFFLSH\n",
                         __func__);
}

/**
 * dwc2_hsotg_trytx - check to see if anything needs transmitting
 * @hsotg: The driver state
 * @hs_ep: The driver endpoint to check.
 *
 * Check to see if there is a request that has data to send, and if so
 * make an attempt to write data into the FIFO.
 */
static int dwc2_hsotg_trytx(struct dwc2_hsotg *hsotg,
                            struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg_req *hs_req = hs_ep->req;

        if (!hs_ep->dir_in || !hs_req) {
                /**
                 * if request is not enqueued, we disable interrupts
                 * for endpoints, excepting ep0
                 */
                if (hs_ep->index != 0)
                        dwc2_hsotg_ctrl_epint(hsotg, hs_ep->index,
                                              hs_ep->dir_in, 0);
                return 0;
        }

        if (hs_req->req.actual < hs_req->req.length) {
                dev_dbg(hsotg->dev, "trying to write more for ep%d\n",
                        hs_ep->index);
                return dwc2_hsotg_write_fifo(hsotg, hs_ep, hs_req);
        }

        return 0;
}

/**
 * dwc2_hsotg_complete_in - complete IN transfer
 * @hsotg: The device state.
 * @hs_ep: The endpoint that has just completed.
 *
 * An IN transfer has been completed, update the transfer's state and then
 * call the relevant completion routines.
 */
static void dwc2_hsotg_complete_in(struct dwc2_hsotg *hsotg,
                                   struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg_req *hs_req = hs_ep->req;
        u32 epsize = dwc2_readl(hsotg, DIEPTSIZ(hs_ep->index));
        int size_left, size_done;

        if (!hs_req) {
                dev_dbg(hsotg->dev, "XferCompl but no req\n");
                return;
        }

        /* Finish ZLP handling for IN EP0 transactions */
        if (hs_ep->index == 0 && hsotg->ep0_state == DWC2_EP0_STATUS_IN) {
                dev_dbg(hsotg->dev, "zlp packet sent\n");

                /*
                 * While send zlp for DWC2_EP0_STATUS_IN EP direction was
                 * changed to IN. Change back to complete OUT transfer request
                 */
                hs_ep->dir_in = 0;

                dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req, 0);
                if (hsotg->test_mode) {
                        int ret;

                        ret = dwc2_hsotg_set_test_mode(hsotg, hsotg->test_mode);
                        if (ret < 0) {
                                dev_dbg(hsotg->dev, "Invalid Test #%d\n",
                                        hsotg->test_mode);
                                dwc2_hsotg_stall_ep0(hsotg);
                                return;
                        }
                }
                dwc2_hsotg_enqueue_setup(hsotg);
                return;
        }

        /*
         * Calculate the size of the transfer by checking how much is left
         * in the endpoint size register and then working it out from
         * the amount we loaded for the transfer.
         *
         * We do this even for DMA, as the transfer may have incremented
         * past the end of the buffer (DMA transfers are always 32bit
         * aligned).
         */
        if (using_desc_dma(hsotg)) {
                size_left = dwc2_gadget_get_xfersize_ddma(hs_ep);
                if (size_left < 0)
                        dev_err(hsotg->dev, "error parsing DDMA results %d\n",
                                size_left);
        } else {
                size_left = DXEPTSIZ_XFERSIZE_GET(epsize);
        }

        size_done = hs_ep->size_loaded - size_left;
        size_done += hs_ep->last_load;

        if (hs_req->req.actual != size_done)
                dev_dbg(hsotg->dev, "%s: adjusting size done %d => %d\n",
                        __func__, hs_req->req.actual, size_done);

        hs_req->req.actual = size_done;
        dev_dbg(hsotg->dev, "req->length:%d req->actual:%d req->zero:%d\n",
                hs_req->req.length, hs_req->req.actual, hs_req->req.zero);

        if (!size_left && hs_req->req.actual < hs_req->req.length) {
                dev_dbg(hsotg->dev, "%s trying more for req...\n", __func__);
                dwc2_hsotg_start_req(hsotg, hs_ep, hs_req, true);
                return;
        }

        /* Zlp for all endpoints, for ep0 only in DATA IN stage */
        if (hs_ep->send_zlp) {
                dwc2_hsotg_program_zlp(hsotg, hs_ep);
                hs_ep->send_zlp = 0;
                /* transfer will be completed on next complete interrupt */
                return;
        }

        if (hs_ep->index == 0 && hsotg->ep0_state == DWC2_EP0_DATA_IN) {
                /* Move to STATUS OUT */
                dwc2_hsotg_ep0_zlp(hsotg, false);
                return;
        }

        dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req, 0);
}

/**
 * dwc2_gadget_read_ep_interrupts - reads interrupts for given ep
 * @hsotg: The device state.
 * @idx: Index of ep.
 * @dir_in: Endpoint direction 1-in 0-out.
 *
 * Reads for endpoint with given index and direction, by masking
 * epint_reg with coresponding mask.
 */
static u32 dwc2_gadget_read_ep_interrupts(struct dwc2_hsotg *hsotg,
                                          unsigned int idx, int dir_in)
{
        u32 epmsk_reg = dir_in ? DIEPMSK : DOEPMSK;
        u32 epint_reg = dir_in ? DIEPINT(idx) : DOEPINT(idx);
        u32 ints;
        u32 mask;
        u32 diepempmsk;

        mask = dwc2_readl(hsotg, epmsk_reg);
        diepempmsk = dwc2_readl(hsotg, DIEPEMPMSK);
        mask |= ((diepempmsk >> idx) & 0x1) ? DIEPMSK_TXFIFOEMPTY : 0;
        mask |= DXEPINT_SETUP_RCVD;

        ints = dwc2_readl(hsotg, epint_reg);
        ints &= mask;
        return ints;
}

/**
 * dwc2_gadget_handle_ep_disabled - handle DXEPINT_EPDISBLD
 * @hs_ep: The endpoint on which interrupt is asserted.
 *
 * This interrupt indicates that the endpoint has been disabled per the
 * application's request.
 *
 * For IN endpoints flushes txfifo, in case of BULK clears DCTL_CGNPINNAK,
 * in case of ISOC completes current request.
 *
 * For ISOC-OUT endpoints completes expired requests. If there is remaining
 * request starts it.
 */
static void dwc2_gadget_handle_ep_disabled(struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        struct dwc2_hsotg_req *hs_req;
        unsigned char idx = hs_ep->index;
        int dir_in = hs_ep->dir_in;
        u32 epctl_reg = dir_in ? DIEPCTL(idx) : DOEPCTL(idx);
        int dctl = dwc2_readl(hsotg, DCTL);

        dev_dbg(hsotg->dev, "%s: EPDisbld\n", __func__);

        if (dir_in) {
                int epctl = dwc2_readl(hsotg, epctl_reg);

                dwc2_hsotg_txfifo_flush(hsotg, hs_ep->fifo_index);

                if (hs_ep->isochronous) {
                        dwc2_hsotg_complete_in(hsotg, hs_ep);
                        return;
                }

                if ((epctl & DXEPCTL_STALL) && (epctl & DXEPCTL_EPTYPE_BULK)) {
                        int dctl = dwc2_readl(hsotg, DCTL);

                        dctl |= DCTL_CGNPINNAK;
                        dwc2_writel(hsotg, dctl, DCTL);
                }
                return;
        }

        if (dctl & DCTL_GOUTNAKSTS) {
                dctl |= DCTL_CGOUTNAK;
                dwc2_writel(hsotg, dctl, DCTL);
        }

        if (!hs_ep->isochronous)
                return;

        if (list_empty(&hs_ep->queue)) {
                dev_dbg(hsotg->dev, "%s: complete_ep 0x%p, ep->queue empty!\n",
                        __func__, hs_ep);
                return;
        }

        do {
                hs_req = get_ep_head(hs_ep);
                if (hs_req)
                        dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req,
                                                    -ENODATA);
                dwc2_gadget_incr_frame_num(hs_ep);
                /* Update current frame number value. */
                hsotg->frame_number = dwc2_hsotg_read_frameno(hsotg);
        } while (dwc2_gadget_target_frame_elapsed(hs_ep));

        dwc2_gadget_start_next_request(hs_ep);
}

/**
 * dwc2_gadget_handle_out_token_ep_disabled - handle DXEPINT_OUTTKNEPDIS
 * @ep: The endpoint on which interrupt is asserted.
 *
 * This is starting point for ISOC-OUT transfer, synchronization done with
 * first out token received from host while corresponding EP is disabled.
 *
 * Device does not know initial frame in which out token will come. For this
 * HW generates OUTTKNEPDIS - out token is received while EP is disabled. Upon
 * getting this interrupt SW starts calculation for next transfer frame.
 */
static void dwc2_gadget_handle_out_token_ep_disabled(struct dwc2_hsotg_ep *ep)
{
        struct dwc2_hsotg *hsotg = ep->parent;
        int dir_in = ep->dir_in;
        u32 doepmsk;

        if (dir_in || !ep->isochronous)
                return;

        if (using_desc_dma(hsotg)) {
                if (ep->target_frame == TARGET_FRAME_INITIAL) {
                        /* Start first ISO Out */
                        ep->target_frame = hsotg->frame_number;
                        dwc2_gadget_start_isoc_ddma(ep);
                }
                return;
        }

        if (ep->interval > 1 &&
            ep->target_frame == TARGET_FRAME_INITIAL) {
                u32 ctrl;

                ep->target_frame = hsotg->frame_number;
                dwc2_gadget_incr_frame_num(ep);

                ctrl = dwc2_readl(hsotg, DOEPCTL(ep->index));
                if (ep->target_frame & 0x1)
                        ctrl |= DXEPCTL_SETODDFR;
                else
                        ctrl |= DXEPCTL_SETEVENFR;

                dwc2_writel(hsotg, ctrl, DOEPCTL(ep->index));
        }

        dwc2_gadget_start_next_request(ep);
        doepmsk = dwc2_readl(hsotg, DOEPMSK);
        doepmsk &= ~DOEPMSK_OUTTKNEPDISMSK;
        dwc2_writel(hsotg, doepmsk, DOEPMSK);
}

/**
 * dwc2_gadget_handle_nak - handle NAK interrupt
 * @hs_ep: The endpoint on which interrupt is asserted.
 *
 * This is starting point for ISOC-IN transfer, synchronization done with
 * first IN token received from host while corresponding EP is disabled.
 *
 * Device does not know when first one token will arrive from host. On first
 * token arrival HW generates 2 interrupts: 'in token received while FIFO empty'
 * and 'NAK'. NAK interrupt for ISOC-IN means that token has arrived and ZLP was
 * sent in response to that as there was no data in FIFO. SW is basing on this
 * interrupt to obtain frame in which token has come and then based on the
 * interval calculates next frame for transfer.
 */
static void dwc2_gadget_handle_nak(struct dwc2_hsotg_ep *hs_ep)
{
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        int dir_in = hs_ep->dir_in;

        if (!dir_in || !hs_ep->isochronous)
                return;

        if (hs_ep->target_frame == TARGET_FRAME_INITIAL) {

                if (using_desc_dma(hsotg)) {
                        hs_ep->target_frame = hsotg->frame_number;
                        dwc2_gadget_incr_frame_num(hs_ep);
                        dwc2_gadget_start_isoc_ddma(hs_ep);
                        return;
                }

                hs_ep->target_frame = hsotg->frame_number;
                if (hs_ep->interval > 1) {
                        u32 ctrl = dwc2_readl(hsotg,
                                              DIEPCTL(hs_ep->index));
                        if (hs_ep->target_frame & 0x1)
                                ctrl |= DXEPCTL_SETODDFR;
                        else
                                ctrl |= DXEPCTL_SETEVENFR;

                        dwc2_writel(hsotg, ctrl, DIEPCTL(hs_ep->index));
                }

                dwc2_hsotg_complete_request(hsotg, hs_ep,
                                            get_ep_head(hs_ep), 0);
        }

        if (!using_desc_dma(hsotg))
                dwc2_gadget_incr_frame_num(hs_ep);
}

/**
 * dwc2_hsotg_epint - handle an in/out endpoint interrupt
 * @hsotg: The driver state
 * @idx: The index for the endpoint (0..15)
 * @dir_in: Set if this is an IN endpoint
 *
 * Process and clear any interrupt pending for an individual endpoint
 */
static void dwc2_hsotg_epint(struct dwc2_hsotg *hsotg, unsigned int idx,
                             int dir_in)
{
        struct dwc2_hsotg_ep *hs_ep = index_to_ep(hsotg, idx, dir_in);
        u32 epint_reg = dir_in ? DIEPINT(idx) : DOEPINT(idx);
        u32 epctl_reg = dir_in ? DIEPCTL(idx) : DOEPCTL(idx);
        u32 epsiz_reg = dir_in ? DIEPTSIZ(idx) : DOEPTSIZ(idx);
        u32 ints;
        u32 ctrl;

        ints = dwc2_gadget_read_ep_interrupts(hsotg, idx, dir_in);
        ctrl = dwc2_readl(hsotg, epctl_reg);

        /* Clear endpoint interrupts */
        dwc2_writel(hsotg, ints, epint_reg);

        if (!hs_ep) {
                dev_err(hsotg->dev, "%s:Interrupt for unconfigured ep%d(%s)\n",
                        __func__, idx, dir_in ? "in" : "out");
                return;
        }

        dev_dbg(hsotg->dev, "%s: ep%d(%s) DxEPINT=0x%08x\n",
                __func__, idx, dir_in ? "in" : "out", ints);

        /* Don't process XferCompl interrupt if it is a setup packet */
        if (idx == 0 && (ints & (DXEPINT_SETUP | DXEPINT_SETUP_RCVD)))
                ints &= ~DXEPINT_XFERCOMPL;

        /*
         * Don't process XferCompl interrupt in DDMA if EP0 is still in SETUP
         * stage and xfercomplete was generated without SETUP phase done
         * interrupt. SW should parse received setup packet only after host's
         * exit from setup phase of control transfer.
         */
        if (using_desc_dma(hsotg) && idx == 0 && !hs_ep->dir_in &&
            hsotg->ep0_state == DWC2_EP0_SETUP && !(ints & DXEPINT_SETUP))
                ints &= ~DXEPINT_XFERCOMPL;

        if (ints & DXEPINT_XFERCOMPL) {
                dev_dbg(hsotg->dev,
                        "%s: XferCompl: DxEPCTL=0x%08x, DXEPTSIZ=%08x\n",
                        __func__, dwc2_readl(hsotg, epctl_reg),
                        dwc2_readl(hsotg, epsiz_reg));

                /* In DDMA handle isochronous requests separately */
                if (using_desc_dma(hsotg) && hs_ep->isochronous) {
                        /* XferCompl set along with BNA */
                        if (!(ints & DXEPINT_BNAINTR))
                                dwc2_gadget_complete_isoc_request_ddma(hs_ep);
                } else if (dir_in) {
                        /*
                         * We get OutDone from the FIFO, so we only
                         * need to look at completing IN requests here
                         * if operating slave mode
                         */
                        if (hs_ep->isochronous && hs_ep->interval > 1)
                                dwc2_gadget_incr_frame_num(hs_ep);

                        dwc2_hsotg_complete_in(hsotg, hs_ep);
                        if (ints & DXEPINT_NAKINTRPT)
                                ints &= ~DXEPINT_NAKINTRPT;

                        if (idx == 0 && !hs_ep->req)
                                dwc2_hsotg_enqueue_setup(hsotg);
                } else if (using_dma(hsotg)) {
                        /*
                         * We're using DMA, we need to fire an OutDone here
                         * as we ignore the RXFIFO.
                         */
                        if (hs_ep->isochronous && hs_ep->interval > 1)
                                dwc2_gadget_incr_frame_num(hs_ep);

                        dwc2_hsotg_handle_outdone(hsotg, idx);
                }
        }

        if (ints & DXEPINT_EPDISBLD)
                dwc2_gadget_handle_ep_disabled(hs_ep);

        if (ints & DXEPINT_OUTTKNEPDIS)
                dwc2_gadget_handle_out_token_ep_disabled(hs_ep);

        if (ints & DXEPINT_NAKINTRPT)
                dwc2_gadget_handle_nak(hs_ep);

        if (ints & DXEPINT_AHBERR)
                dev_dbg(hsotg->dev, "%s: AHBErr\n", __func__);

        if (ints & DXEPINT_SETUP) {  /* Setup or Timeout */
                dev_dbg(hsotg->dev, "%s: Setup/Timeout\n",  __func__);

                if (using_dma(hsotg) && idx == 0) {
                        /*
                         * this is the notification we've received a
                         * setup packet. In non-DMA mode we'd get this
                         * from the RXFIFO, instead we need to process
                         * the setup here.
                         */

                        if (dir_in)
                                WARN_ON_ONCE(1);
                        else
                                dwc2_hsotg_handle_outdone(hsotg, 0);
                }
        }

        if (ints & DXEPINT_STSPHSERCVD) {
                dev_dbg(hsotg->dev, "%s: StsPhseRcvd\n", __func__);

                /* Safety check EP0 state when STSPHSERCVD asserted */
                if (hsotg->ep0_state == DWC2_EP0_DATA_OUT) {
                        /* Move to STATUS IN for DDMA */
                        if (using_desc_dma(hsotg))
                                dwc2_hsotg_ep0_zlp(hsotg, true);
                }

        }

        if (ints & DXEPINT_BACK2BACKSETUP)
                dev_dbg(hsotg->dev, "%s: B2BSetup/INEPNakEff\n", __func__);

        if (ints & DXEPINT_BNAINTR) {
                dev_dbg(hsotg->dev, "%s: BNA interrupt\n", __func__);
                if (hs_ep->isochronous)
                        dwc2_gadget_handle_isoc_bna(hs_ep);
        }

        if (dir_in && !hs_ep->isochronous) {
                /* not sure if this is important, but we'll clear it anyway */
                if (ints & DXEPINT_INTKNTXFEMP) {
                        dev_dbg(hsotg->dev, "%s: ep%d: INTknTXFEmpMsk\n",
                                __func__, idx);
                }

                /* this probably means something bad is happening */
                if (ints & DXEPINT_INTKNEPMIS) {
                        dev_warn(hsotg->dev, "%s: ep%d: INTknEP\n",
                                 __func__, idx);
                }

                /* FIFO has space or is empty (see GAHBCFG) */
                if (hsotg->dedicated_fifos &&
                    ints & DXEPINT_TXFEMP) {
                        dev_dbg(hsotg->dev, "%s: ep%d: TxFIFOEmpty\n",
                                __func__, idx);
                        if (!using_dma(hsotg))
                                dwc2_hsotg_trytx(hsotg, hs_ep);
                }
        }
}

/**
 * dwc2_hsotg_irq_enumdone - Handle EnumDone interrupt (enumeration done)

 * @hsotg: The device state.
 *
 * Handle updating the device settings after the enumeration phase has
 * been completed.
 */
static void dwc2_hsotg_irq_enumdone(struct dwc2_hsotg *hsotg)
{
        u32 dsts = dwc2_readl(hsotg, DSTS);
        int ep0_mps = 0, ep_mps = 8;

        /*
         * This should signal the finish of the enumeration phase
         * of the USB handshaking, so we should now know what rate
         * we connected at.
         */

        dev_dbg(hsotg->dev, "EnumDone (DSTS=0x%08x)\n", dsts);

        /*
         * note, since we're limited by the size of transfer on EP0, and
         * it seems IN transfers must be a even number of packets we do
         * not advertise a 64byte MPS on EP0.
         */

        /* catch both EnumSpd_FS and EnumSpd_FS48 */
        switch ((dsts & DSTS_ENUMSPD_MASK) >> DSTS_ENUMSPD_SHIFT) {
        case DSTS_ENUMSPD_FS:
        case DSTS_ENUMSPD_FS48:
                hsotg->gadget.speed = USB_SPEED_FULL;
                ep0_mps = EP0_MPS_LIMIT;
                ep_mps = 1023;
                break;

        case DSTS_ENUMSPD_HS:
                hsotg->gadget.speed = USB_SPEED_HIGH;
                ep0_mps = EP0_MPS_LIMIT;
                ep_mps = 1024;
                break;

        case DSTS_ENUMSPD_LS:
                hsotg->gadget.speed = USB_SPEED_LOW;
                ep0_mps = 8;
                ep_mps = 8;
                /*
                 * note, we don't actually support LS in this driver at the
                 * moment, and the documentation seems to imply that it isn't
                 * supported by the PHYs on some of the devices.
                 */
                break;
        }
        dev_info(hsotg->dev, "new device is %s\n",
                 usb_speed_string(hsotg->gadget.speed));

        /*
         * we should now know the maximum packet size for an
         * endpoint, so set the endpoints to a default value.
         */

        if (ep0_mps) {
                int i;
                /* Initialize ep0 for both in and out directions */
                dwc2_hsotg_set_ep_maxpacket(hsotg, 0, ep0_mps, 0, 1);
                dwc2_hsotg_set_ep_maxpacket(hsotg, 0, ep0_mps, 0, 0);
                for (i = 1; i < hsotg->num_of_eps; i++) {
                        if (hsotg->eps_in[i])
                                dwc2_hsotg_set_ep_maxpacket(hsotg, i, ep_mps,
                                                            0, 1);
                        if (hsotg->eps_out[i])
                                dwc2_hsotg_set_ep_maxpacket(hsotg, i, ep_mps,
                                                            0, 0);
                }
        }

        /* ensure after enumeration our EP0 is active */

        dwc2_hsotg_enqueue_setup(hsotg);

        dev_dbg(hsotg->dev, "EP0: DIEPCTL0=0x%08x, DOEPCTL0=0x%08x\n",
                dwc2_readl(hsotg, DIEPCTL0),
                dwc2_readl(hsotg, DOEPCTL0));
}

/**
 * kill_all_requests - remove all requests from the endpoint's queue
 * @hsotg: The device state.
 * @ep: The endpoint the requests may be on.
 * @result: The result code to use.
 *
 * Go through the requests on the given endpoint and mark them
 * completed with the given result code.
 */
static void kill_all_requests(struct dwc2_hsotg *hsotg,
                              struct dwc2_hsotg_ep *ep,
                              int result)
{
        struct dwc2_hsotg_req *req, *treq;
        unsigned int size;

        ep->req = NULL;

        list_for_each_entry_safe(req, treq, &ep->queue, queue)
                dwc2_hsotg_complete_request(hsotg, ep, req,
                                            result);

        if (!hsotg->dedicated_fifos)
                return;
        size = (dwc2_readl(hsotg, DTXFSTS(ep->fifo_index)) & 0xffff) * 4;
        if (size < ep->fifo_size)
                dwc2_hsotg_txfifo_flush(hsotg, ep->fifo_index);
}

/**
 * dwc2_hsotg_disconnect - disconnect service
 * @hsotg: The device state.
 *
 * The device has been disconnected. Remove all current
 * transactions and signal the gadget driver that this
 * has happened.
 */
void dwc2_hsotg_disconnect(struct dwc2_hsotg *hsotg)
{
        unsigned int ep;

        if (!hsotg->connected)
                return;

        hsotg->connected = 0;
        hsotg->test_mode = 0;

        for (ep = 0; ep < hsotg->num_of_eps; ep++) {
                if (hsotg->eps_in[ep])
                        kill_all_requests(hsotg, hsotg->eps_in[ep],
                                          -ESHUTDOWN);
                if (hsotg->eps_out[ep])
                        kill_all_requests(hsotg, hsotg->eps_out[ep],
                                          -ESHUTDOWN);
        }

        call_gadget(hsotg, disconnect);
        hsotg->lx_state = DWC2_L3;

        usb_gadget_set_state(&hsotg->gadget, USB_STATE_NOTATTACHED);
}

/**
 * dwc2_hsotg_irq_fifoempty - TX FIFO empty interrupt handler
 * @hsotg: The device state:
 * @periodic: True if this is a periodic FIFO interrupt
 */
static void dwc2_hsotg_irq_fifoempty(struct dwc2_hsotg *hsotg, bool periodic)
{
        struct dwc2_hsotg_ep *ep;
        int epno, ret;

        /* look through for any more data to transmit */
        for (epno = 0; epno < hsotg->num_of_eps; epno++) {
                ep = index_to_ep(hsotg, epno, 1);

                if (!ep)
                        continue;

                if (!ep->dir_in)
                        continue;

                if ((periodic && !ep->periodic) ||
                    (!periodic && ep->periodic))
                        continue;

                ret = dwc2_hsotg_trytx(hsotg, ep);
                if (ret < 0)
                        break;
        }
}

/* IRQ flags which will trigger a retry around the IRQ loop */
#define IRQ_RETRY_MASK (GINTSTS_NPTXFEMP | \
                        GINTSTS_PTXFEMP |  \
                        GINTSTS_RXFLVL)

/**
 * dwc2_hsotg_core_init - issue softreset to the core
 * @hsotg: The device state
 * @is_usb_reset: Usb resetting flag
 *
 * Issue a soft reset to the core, and await the core finishing it.
 */
void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
                                       bool is_usb_reset)
{
        u32 intmsk;
        u32 val;
        u32 usbcfg;
        u32 dcfg = 0;

        /* Kill any ep0 requests as controller will be reinitialized */
        kill_all_requests(hsotg, hsotg->eps_out[0], -ECONNRESET);

        if (!is_usb_reset)
                if (dwc2_core_reset(hsotg, true))
                        return;

        /*
         * we must now enable ep0 ready for host detection and then
         * set configuration.
         */

        /* keep other bits untouched (so e.g. forced modes are not lost) */
        usbcfg = dwc2_readl(hsotg, GUSBCFG);
        usbcfg &= ~(GUSBCFG_TOUTCAL_MASK | GUSBCFG_PHYIF16 | GUSBCFG_SRPCAP |
                GUSBCFG_HNPCAP | GUSBCFG_USBTRDTIM_MASK);

        if (hsotg->params.phy_type == DWC2_PHY_TYPE_PARAM_FS &&
            (hsotg->params.speed == DWC2_SPEED_PARAM_FULL ||
             hsotg->params.speed == DWC2_SPEED_PARAM_LOW)) {
                /* FS/LS Dedicated Transceiver Interface */
                usbcfg |= GUSBCFG_PHYSEL;
        } else {
                /* set the PLL on, remove the HNP/SRP and set the PHY */
                val = (hsotg->phyif == GUSBCFG_PHYIF8) ? 9 : 5;
                usbcfg |= hsotg->phyif | GUSBCFG_TOUTCAL(7) |
                        (val << GUSBCFG_USBTRDTIM_SHIFT);
        }
        dwc2_writel(hsotg, usbcfg, GUSBCFG);

        dwc2_hsotg_init_fifo(hsotg);

        if (!is_usb_reset)
                dwc2_set_bit(hsotg, DCTL, DCTL_SFTDISCON);

        dcfg |= DCFG_EPMISCNT(1);

        switch (hsotg->params.speed) {
        case DWC2_SPEED_PARAM_LOW:
                dcfg |= DCFG_DEVSPD_LS;
                break;
        case DWC2_SPEED_PARAM_FULL:
                if (hsotg->params.phy_type == DWC2_PHY_TYPE_PARAM_FS)
                        dcfg |= DCFG_DEVSPD_FS48;
                else
                        dcfg |= DCFG_DEVSPD_FS;
                break;
        default:
                dcfg |= DCFG_DEVSPD_HS;
        }

        if (hsotg->params.ipg_isoc_en)
                dcfg |= DCFG_IPG_ISOC_SUPPORDED;

        dwc2_writel(hsotg, dcfg,  DCFG);

        /* Clear any pending OTG interrupts */
        dwc2_writel(hsotg, 0xffffffff, GOTGINT);

        /* Clear any pending interrupts */
        dwc2_writel(hsotg, 0xffffffff, GINTSTS);
        intmsk = GINTSTS_ERLYSUSP | GINTSTS_SESSREQINT |
                GINTSTS_GOUTNAKEFF | GINTSTS_GINNAKEFF |
                GINTSTS_USBRST | GINTSTS_RESETDET |
                GINTSTS_ENUMDONE | GINTSTS_OTGINT |
                GINTSTS_USBSUSP | GINTSTS_WKUPINT |
                GINTSTS_LPMTRANRCVD;

        if (!using_desc_dma(hsotg))
                intmsk |= GINTSTS_INCOMPL_SOIN | GINTSTS_INCOMPL_SOOUT;

        if (!hsotg->params.external_id_pin_ctl)
                intmsk |= GINTSTS_CONIDSTSCHNG;

        dwc2_writel(hsotg, intmsk, GINTMSK);

        if (using_dma(hsotg)) {
                dwc2_writel(hsotg, GAHBCFG_GLBL_INTR_EN | GAHBCFG_DMA_EN |
                            hsotg->params.ahbcfg,
                            GAHBCFG);

                /* Set DDMA mode support in the core if needed */
                if (using_desc_dma(hsotg))
                        dwc2_set_bit(hsotg, DCFG, DCFG_DESCDMA_EN);

        } else {
                dwc2_writel(hsotg, ((hsotg->dedicated_fifos) ?
                                                (GAHBCFG_NP_TXF_EMP_LVL |
                                                 GAHBCFG_P_TXF_EMP_LVL) : 0) |
                            GAHBCFG_GLBL_INTR_EN, GAHBCFG);
        }

        /*
         * If INTknTXFEmpMsk is enabled, it's important to disable ep interrupts
         * when we have no data to transfer. Otherwise we get being flooded by
         * interrupts.
         */

        dwc2_writel(hsotg, ((hsotg->dedicated_fifos && !using_dma(hsotg)) ?
                DIEPMSK_TXFIFOEMPTY | DIEPMSK_INTKNTXFEMPMSK : 0) |
                DIEPMSK_EPDISBLDMSK | DIEPMSK_XFERCOMPLMSK |
                DIEPMSK_TIMEOUTMSK | DIEPMSK_AHBERRMSK,
                DIEPMSK);

        /*
         * don't need XferCompl, we get that from RXFIFO in slave mode. In
         * DMA mode we may need this and StsPhseRcvd.
         */
        dwc2_writel(hsotg, (using_dma(hsotg) ? (DIEPMSK_XFERCOMPLMSK |
                DOEPMSK_STSPHSERCVDMSK) : 0) |
                DOEPMSK_EPDISBLDMSK | DOEPMSK_AHBERRMSK |
                DOEPMSK_SETUPMSK,
                DOEPMSK);

        /* Enable BNA interrupt for DDMA */
        if (using_desc_dma(hsotg)) {
                dwc2_set_bit(hsotg, DOEPMSK, DOEPMSK_BNAMSK);
                dwc2_set_bit(hsotg, DIEPMSK, DIEPMSK_BNAININTRMSK);
        }

        dwc2_writel(hsotg, 0, DAINTMSK);

        dev_dbg(hsotg->dev, "EP0: DIEPCTL0=0x%08x, DOEPCTL0=0x%08x\n",
                dwc2_readl(hsotg, DIEPCTL0),
                dwc2_readl(hsotg, DOEPCTL0));

        /* enable in and out endpoint interrupts */
        dwc2_hsotg_en_gsint(hsotg, GINTSTS_OEPINT | GINTSTS_IEPINT);

        /*
         * Enable the RXFIFO when in slave mode, as this is how we collect
         * the data. In DMA mode, we get events from the FIFO but also
         * things we cannot process, so do not use it.
         */
        if (!using_dma(hsotg))
                dwc2_hsotg_en_gsint(hsotg, GINTSTS_RXFLVL);

        /* Enable interrupts for EP0 in and out */
        dwc2_hsotg_ctrl_epint(hsotg, 0, 0, 1);
        dwc2_hsotg_ctrl_epint(hsotg, 0, 1, 1);

        if (!is_usb_reset) {
                dwc2_set_bit(hsotg, DCTL, DCTL_PWRONPRGDONE);
                udelay(10);  /* see openiboot */
                dwc2_clear_bit(hsotg, DCTL, DCTL_PWRONPRGDONE);
        }

        dev_dbg(hsotg->dev, "DCTL=0x%08x\n", dwc2_readl(hsotg, DCTL));

        /*
         * DxEPCTL_USBActEp says RO in manual, but seems to be set by
         * writing to the EPCTL register..
         */

        /* set to read 1 8byte packet */
        dwc2_writel(hsotg, DXEPTSIZ_MC(1) | DXEPTSIZ_PKTCNT(1) |
               DXEPTSIZ_XFERSIZE(8), DOEPTSIZ0);

        dwc2_writel(hsotg, dwc2_hsotg_ep0_mps(hsotg->eps_out[0]->ep.maxpacket) |
               DXEPCTL_CNAK | DXEPCTL_EPENA |
               DXEPCTL_USBACTEP,
               DOEPCTL0);

        /* enable, but don't activate EP0in */
        dwc2_writel(hsotg, dwc2_hsotg_ep0_mps(hsotg->eps_out[0]->ep.maxpacket) |
               DXEPCTL_USBACTEP, DIEPCTL0);

        /* clear global NAKs */
        val = DCTL_CGOUTNAK | DCTL_CGNPINNAK;
        if (!is_usb_reset)
                val |= DCTL_SFTDISCON;
        dwc2_set_bit(hsotg, DCTL, val);

        /* configure the core to support LPM */
        dwc2_gadget_init_lpm(hsotg);

        /* must be at-least 3ms to allow bus to see disconnect */
        mdelay(3);

        hsotg->lx_state = DWC2_L0;

        dwc2_hsotg_enqueue_setup(hsotg);

        dev_dbg(hsotg->dev, "EP0: DIEPCTL0=0x%08x, DOEPCTL0=0x%08x\n",
                dwc2_readl(hsotg, DIEPCTL0),
                dwc2_readl(hsotg, DOEPCTL0));
}

static void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
{
        /* set the soft-disconnect bit */
        dwc2_set_bit(hsotg, DCTL, DCTL_SFTDISCON);
}

void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg)
{
        /* remove the soft-disconnect and let's go */
        dwc2_clear_bit(hsotg, DCTL, DCTL_SFTDISCON);
}

/**
 * dwc2_gadget_handle_incomplete_isoc_in - handle incomplete ISO IN Interrupt.
 * @hsotg: The device state:
 *
 * This interrupt indicates one of the following conditions occurred while
 * transmitting an ISOC transaction.
 * - Corrupted IN Token for ISOC EP.
 * - Packet not complete in FIFO.
 *
 * The following actions will be taken:
 * - Determine the EP
 * - Disable EP; when 'Endpoint Disabled' interrupt is received Flush FIFO
 */
static void dwc2_gadget_handle_incomplete_isoc_in(struct dwc2_hsotg *hsotg)
{
        struct dwc2_hsotg_ep *hs_ep;
        u32 epctrl;
        u32 daintmsk;
        u32 idx;

        dev_dbg(hsotg->dev, "Incomplete isoc in interrupt received:\n");

        daintmsk = dwc2_readl(hsotg, DAINTMSK);

        for (idx = 1; idx < hsotg->num_of_eps; idx++) {
                hs_ep = hsotg->eps_in[idx];
                /* Proceed only unmasked ISOC EPs */
                if ((BIT(idx) & ~daintmsk) || !hs_ep->isochronous)
                        continue;

                epctrl = dwc2_readl(hsotg, DIEPCTL(idx));
                if ((epctrl & DXEPCTL_EPENA) &&
                    dwc2_gadget_target_frame_elapsed(hs_ep)) {
                        epctrl |= DXEPCTL_SNAK;
                        epctrl |= DXEPCTL_EPDIS;
                        dwc2_writel(hsotg, epctrl, DIEPCTL(idx));
                }
        }

        /* Clear interrupt */
        dwc2_writel(hsotg, GINTSTS_INCOMPL_SOIN, GINTSTS);
}

/**
 * dwc2_gadget_handle_incomplete_isoc_out - handle incomplete ISO OUT Interrupt
 * @hsotg: The device state:
 *
 * This interrupt indicates one of the following conditions occurred while
 * transmitting an ISOC transaction.
 * - Corrupted OUT Token for ISOC EP.
 * - Packet not complete in FIFO.
 *
 * The following actions will be taken:
 * - Determine the EP
 * - Set DCTL_SGOUTNAK and unmask GOUTNAKEFF if target frame elapsed.
 */
static void dwc2_gadget_handle_incomplete_isoc_out(struct dwc2_hsotg *hsotg)
{
        u32 gintsts;
        u32 gintmsk;
        u32 daintmsk;
        u32 epctrl;
        struct dwc2_hsotg_ep *hs_ep;
        int idx;

        dev_dbg(hsotg->dev, "%s: GINTSTS_INCOMPL_SOOUT\n", __func__);

        daintmsk = dwc2_readl(hsotg, DAINTMSK);
        daintmsk >>= DAINT_OUTEP_SHIFT;

        for (idx = 1; idx < hsotg->num_of_eps; idx++) {
                hs_ep = hsotg->eps_out[idx];
                /* Proceed only unmasked ISOC EPs */
                if ((BIT(idx) & ~daintmsk) || !hs_ep->isochronous)
                        continue;

                epctrl = dwc2_readl(hsotg, DOEPCTL(idx));
                if ((epctrl & DXEPCTL_EPENA) &&
                    dwc2_gadget_target_frame_elapsed(hs_ep)) {
                        /* Unmask GOUTNAKEFF interrupt */
                        gintmsk = dwc2_readl(hsotg, GINTMSK);
                        gintmsk |= GINTSTS_GOUTNAKEFF;
                        dwc2_writel(hsotg, gintmsk, GINTMSK);

                        gintsts = dwc2_readl(hsotg, GINTSTS);
                        if (!(gintsts & GINTSTS_GOUTNAKEFF)) {
                                dwc2_set_bit(hsotg, DCTL, DCTL_SGOUTNAK);
                                break;
                        }
                }
        }

        /* Clear interrupt */
        dwc2_writel(hsotg, GINTSTS_INCOMPL_SOOUT, GINTSTS);
}

/**
 * dwc2_hsotg_irq - handle device interrupt
 * @irq: The IRQ number triggered
 * @pw: The pw value when registered the handler.
 */
static irqreturn_t dwc2_hsotg_irq(int irq, void *pw)
{
        struct dwc2_hsotg *hsotg = pw;
        int retry_count = 8;
        u32 gintsts;
        u32 gintmsk;

        if (!dwc2_is_device_mode(hsotg))
                return IRQ_NONE;

        spin_lock(&hsotg->lock);
irq_retry:
        gintsts = dwc2_readl(hsotg, GINTSTS);
        gintmsk = dwc2_readl(hsotg, GINTMSK);

        dev_dbg(hsotg->dev, "%s: %08x %08x (%08x) retry %d\n",
                __func__, gintsts, gintsts & gintmsk, gintmsk, retry_count);

        gintsts &= gintmsk;

        if (gintsts & GINTSTS_RESETDET) {
                dev_dbg(hsotg->dev, "%s: USBRstDet\n", __func__);

                dwc2_writel(hsotg, GINTSTS_RESETDET, GINTSTS);

                /* This event must be used only if controller is suspended */
                if (hsotg->lx_state == DWC2_L2) {
                        dwc2_exit_partial_power_down(hsotg, true);
                        hsotg->lx_state = DWC2_L0;
                }
        }

        if (gintsts & (GINTSTS_USBRST | GINTSTS_RESETDET)) {
                u32 usb_status = dwc2_readl(hsotg, GOTGCTL);
                u32 connected = hsotg->connected;

                dev_dbg(hsotg->dev, "%s: USBRst\n", __func__);
                dev_dbg(hsotg->dev, "GNPTXSTS=%08x\n",
                        dwc2_readl(hsotg, GNPTXSTS));

                dwc2_writel(hsotg, GINTSTS_USBRST, GINTSTS);

                /* Report disconnection if it is not already done. */
                dwc2_hsotg_disconnect(hsotg);

                /* Reset device address to zero */
                dwc2_clear_bit(hsotg, DCFG, DCFG_DEVADDR_MASK);

                if (usb_status & GOTGCTL_BSESVLD && connected)
                        dwc2_hsotg_core_init_disconnected(hsotg, true);
        }

        if (gintsts & GINTSTS_ENUMDONE) {
                dwc2_writel(hsotg, GINTSTS_ENUMDONE, GINTSTS);

                dwc2_hsotg_irq_enumdone(hsotg);
        }

        if (gintsts & (GINTSTS_OEPINT | GINTSTS_IEPINT)) {
                u32 daint = dwc2_readl(hsotg, DAINT);
                u32 daintmsk = dwc2_readl(hsotg, DAINTMSK);
                u32 daint_out, daint_in;
                int ep;

                daint &= daintmsk;
                daint_out = daint >> DAINT_OUTEP_SHIFT;
                daint_in = daint & ~(daint_out << DAINT_OUTEP_SHIFT);

                dev_dbg(hsotg->dev, "%s: daint=%08x\n", __func__, daint);

                for (ep = 0; ep < hsotg->num_of_eps && daint_out;
                                                ep++, daint_out >>= 1) {
                        if (daint_out & 1)
                                dwc2_hsotg_epint(hsotg, ep, 0);
                }

                for (ep = 0; ep < hsotg->num_of_eps  && daint_in;
                                                ep++, daint_in >>= 1) {
                        if (daint_in & 1)
                                dwc2_hsotg_epint(hsotg, ep, 1);
                }
        }

        /* check both FIFOs */

        if (gintsts & GINTSTS_NPTXFEMP) {
                dev_dbg(hsotg->dev, "NPTxFEmp\n");

                /*
                 * Disable the interrupt to stop it happening again
                 * unless one of these endpoint routines decides that
                 * it needs re-enabling
                 */

                dwc2_hsotg_disable_gsint(hsotg, GINTSTS_NPTXFEMP);
                dwc2_hsotg_irq_fifoempty(hsotg, false);
        }

        if (gintsts & GINTSTS_PTXFEMP) {
                dev_dbg(hsotg->dev, "PTxFEmp\n");

                /* See note in GINTSTS_NPTxFEmp */

                dwc2_hsotg_disable_gsint(hsotg, GINTSTS_PTXFEMP);
                dwc2_hsotg_irq_fifoempty(hsotg, true);
        }

        if (gintsts & GINTSTS_RXFLVL) {
                /*
                 * note, since GINTSTS_RxFLvl doubles as FIFO-not-empty,
                 * we need to retry dwc2_hsotg_handle_rx if this is still
                 * set.
                 */

                dwc2_hsotg_handle_rx(hsotg);
        }

        if (gintsts & GINTSTS_ERLYSUSP) {
                dev_dbg(hsotg->dev, "GINTSTS_ErlySusp\n");
                dwc2_writel(hsotg, GINTSTS_ERLYSUSP, GINTSTS);
        }

        /*
         * these next two seem to crop-up occasionally causing the core
         * to shutdown the USB transfer, so try clearing them and logging
         * the occurrence.
         */

        if (gintsts & GINTSTS_GOUTNAKEFF) {
                u8 idx;
                u32 epctrl;
                u32 gintmsk;
                u32 daintmsk;
                struct dwc2_hsotg_ep *hs_ep;

                daintmsk = dwc2_readl(hsotg, DAINTMSK);
                daintmsk >>= DAINT_OUTEP_SHIFT;
                /* Mask this interrupt */
                gintmsk = dwc2_readl(hsotg, GINTMSK);
                gintmsk &= ~GINTSTS_GOUTNAKEFF;
                dwc2_writel(hsotg, gintmsk, GINTMSK);

                dev_dbg(hsotg->dev, "GOUTNakEff triggered\n");
                for (idx = 1; idx < hsotg->num_of_eps; idx++) {
                        hs_ep = hsotg->eps_out[idx];
                        /* Proceed only unmasked ISOC EPs */
                        if ((BIT(idx) & ~daintmsk) || !hs_ep->isochronous)
                                continue;

                        epctrl = dwc2_readl(hsotg, DOEPCTL(idx));

                        if (epctrl & DXEPCTL_EPENA) {
                                epctrl |= DXEPCTL_SNAK;
                                epctrl |= DXEPCTL_EPDIS;
                                dwc2_writel(hsotg, epctrl, DOEPCTL(idx));
                        }
                }

                /* This interrupt bit is cleared in DXEPINT_EPDISBLD handler */
        }

        if (gintsts & GINTSTS_GINNAKEFF) {
                dev_info(hsotg->dev, "GINNakEff triggered\n");

                dwc2_set_bit(hsotg, DCTL, DCTL_CGNPINNAK);

                dwc2_hsotg_dump(hsotg);
        }

        if (gintsts & GINTSTS_INCOMPL_SOIN)
                dwc2_gadget_handle_incomplete_isoc_in(hsotg);

        if (gintsts & GINTSTS_INCOMPL_SOOUT)
                dwc2_gadget_handle_incomplete_isoc_out(hsotg);

        /*
         * if we've had fifo events, we should try and go around the
         * loop again to see if there's any point in returning yet.
         */

        if (gintsts & IRQ_RETRY_MASK && --retry_count > 0)
                goto irq_retry;

        spin_unlock(&hsotg->lock);

        return IRQ_HANDLED;
}

static void dwc2_hsotg_ep_stop_xfr(struct dwc2_hsotg *hsotg,
                                   struct dwc2_hsotg_ep *hs_ep)
{
        u32 epctrl_reg;
        u32 epint_reg;

        epctrl_reg = hs_ep->dir_in ? DIEPCTL(hs_ep->index) :
                DOEPCTL(hs_ep->index);
        epint_reg = hs_ep->dir_in ? DIEPINT(hs_ep->index) :
                DOEPINT(hs_ep->index);

        dev_dbg(hsotg->dev, "%s: stopping transfer on %s\n", __func__,
                hs_ep->name);

        if (hs_ep->dir_in) {
                if (hsotg->dedicated_fifos || hs_ep->periodic) {
                        dwc2_set_bit(hsotg, epctrl_reg, DXEPCTL_SNAK);
                        /* Wait for Nak effect */
                        if (dwc2_hsotg_wait_bit_set(hsotg, epint_reg,
                                                    DXEPINT_INEPNAKEFF, 100))
                                dev_warn(hsotg->dev,
                                         "%s: timeout DIEPINT.NAKEFF\n",
                                         __func__);
                } else {
                        dwc2_set_bit(hsotg, DCTL, DCTL_SGNPINNAK);
                        /* Wait for Nak effect */
                        if (dwc2_hsotg_wait_bit_set(hsotg, GINTSTS,
                                                    GINTSTS_GINNAKEFF, 100))
                                dev_warn(hsotg->dev,
                                         "%s: timeout GINTSTS.GINNAKEFF\n",
                                         __func__);
                }
        } else {
                if (!(dwc2_readl(hsotg, GINTSTS) & GINTSTS_GOUTNAKEFF))
                        dwc2_set_bit(hsotg, DCTL, DCTL_SGOUTNAK);

                /* Wait for global nak to take effect */
                if (dwc2_hsotg_wait_bit_set(hsotg, GINTSTS,
                                            GINTSTS_GOUTNAKEFF, 100))
                        dev_warn(hsotg->dev, "%s: timeout GINTSTS.GOUTNAKEFF\n",
                                 __func__);
        }

        /* Disable ep */
        dwc2_set_bit(hsotg, epctrl_reg, DXEPCTL_EPDIS | DXEPCTL_SNAK);

        /* Wait for ep to be disabled */
        if (dwc2_hsotg_wait_bit_set(hsotg, epint_reg, DXEPINT_EPDISBLD, 100))
                dev_warn(hsotg->dev,
                         "%s: timeout DOEPCTL.EPDisable\n", __func__);

        /* Clear EPDISBLD interrupt */
        dwc2_set_bit(hsotg, epint_reg, DXEPINT_EPDISBLD);

        if (hs_ep->dir_in) {
                unsigned short fifo_index;

                if (hsotg->dedicated_fifos || hs_ep->periodic)
                        fifo_index = hs_ep->fifo_index;
                else
                        fifo_index = 0;

                /* Flush TX FIFO */
                dwc2_flush_tx_fifo(hsotg, fifo_index);

                /* Clear Global In NP NAK in Shared FIFO for non periodic ep */
                if (!hsotg->dedicated_fifos && !hs_ep->periodic)
                        dwc2_set_bit(hsotg, DCTL, DCTL_CGNPINNAK);

        } else {
                /* Remove global NAKs */
                dwc2_set_bit(hsotg, DCTL, DCTL_CGOUTNAK);
        }
}

/**
 * dwc2_hsotg_ep_enable - enable the given endpoint
 * @ep: The USB endpint to configure
 * @desc: The USB endpoint descriptor to configure with.
 *
 * This is called from the USB gadget code's usb_ep_enable().
 */
static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
                                const struct usb_endpoint_descriptor *desc)
{
        struct dwc2_hsotg_ep *hs_ep = our_ep(ep);
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        unsigned long flags;
        unsigned int index = hs_ep->index;
        u32 epctrl_reg;
        u32 epctrl;
        u32 mps;
        u32 mc;
        u32 mask;
        unsigned int dir_in;
        unsigned int i, val, size;
        int ret = 0;
        unsigned char ep_type;

        dev_dbg(hsotg->dev,
                "%s: ep %s: a 0x%02x, attr 0x%02x, mps 0x%04x, intr %d\n",
                __func__, ep->name, desc->bEndpointAddress, desc->bmAttributes,
                desc->wMaxPacketSize, desc->bInterval);

        /* not to be called for EP0 */
        if (index == 0) {
                dev_err(hsotg->dev, "%s: called for EP 0\n", __func__);
                return -EINVAL;
        }

        dir_in = (desc->bEndpointAddress & USB_ENDPOINT_DIR_MASK) ? 1 : 0;
        if (dir_in != hs_ep->dir_in) {
                dev_err(hsotg->dev, "%s: direction mismatch!\n", __func__);
                return -EINVAL;
        }

        ep_type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
        mps = usb_endpoint_maxp(desc);
        mc = usb_endpoint_maxp_mult(desc);

        /* ISOC IN in DDMA supported bInterval up to 10 */
        if (using_desc_dma(hsotg) && ep_type == USB_ENDPOINT_XFER_ISOC &&
            dir_in && desc->bInterval > 10) {
                dev_err(hsotg->dev,
                        "%s: ISOC IN, DDMA: bInterval>10 not supported!\n", __func__);
                return -EINVAL;
        }

        /* High bandwidth ISOC OUT in DDMA not supported */
        if (using_desc_dma(hsotg) && ep_type == USB_ENDPOINT_XFER_ISOC &&
            !dir_in && mc > 1) {
                dev_err(hsotg->dev,
                        "%s: ISOC OUT, DDMA: HB not supported!\n", __func__);
                return -EINVAL;
        }

        /* note, we handle this here instead of dwc2_hsotg_set_ep_maxpacket */

        epctrl_reg = dir_in ? DIEPCTL(index) : DOEPCTL(index);
        epctrl = dwc2_readl(hsotg, epctrl_reg);

        dev_dbg(hsotg->dev, "%s: read DxEPCTL=0x%08x from 0x%08x\n",
                __func__, epctrl, epctrl_reg);

        /* Allocate DMA descriptor chain for non-ctrl endpoints */
        if (using_desc_dma(hsotg) && !hs_ep->desc_list) {
                hs_ep->desc_list = dmam_alloc_coherent(hsotg->dev,
                        MAX_DMA_DESC_NUM_GENERIC *
                        sizeof(struct dwc2_dma_desc),
                        &hs_ep->desc_list_dma, GFP_ATOMIC);
                if (!hs_ep->desc_list) {
                        ret = -ENOMEM;
                        goto error2;
                }
        }

        spin_lock_irqsave(&hsotg->lock, flags);

        epctrl &= ~(DXEPCTL_EPTYPE_MASK | DXEPCTL_MPS_MASK);
        epctrl |= DXEPCTL_MPS(mps);

        /*
         * mark the endpoint as active, otherwise the core may ignore
         * transactions entirely for this endpoint
         */
        epctrl |= DXEPCTL_USBACTEP;

        /* update the endpoint state */
        dwc2_hsotg_set_ep_maxpacket(hsotg, hs_ep->index, mps, mc, dir_in);

        /* default, set to non-periodic */
        hs_ep->isochronous = 0;
        hs_ep->periodic = 0;
        hs_ep->halted = 0;
        hs_ep->interval = desc->bInterval;

        switch (ep_type) {
        case USB_ENDPOINT_XFER_ISOC:
                epctrl |= DXEPCTL_EPTYPE_ISO;
                epctrl |= DXEPCTL_SETEVENFR;
                hs_ep->isochronous = 1;
                hs_ep->interval = 1 << (desc->bInterval - 1);
                hs_ep->target_frame = TARGET_FRAME_INITIAL;
                hs_ep->next_desc = 0;
                hs_ep->compl_desc = 0;
                if (dir_in) {
                        hs_ep->periodic = 1;
                        mask = dwc2_readl(hsotg, DIEPMSK);
                        mask |= DIEPMSK_NAKMSK;
                        dwc2_writel(hsotg, mask, DIEPMSK);
                } else {
                        mask = dwc2_readl(hsotg, DOEPMSK);
                        mask |= DOEPMSK_OUTTKNEPDISMSK;
                        dwc2_writel(hsotg, mask, DOEPMSK);
                }
                break;

        case USB_ENDPOINT_XFER_BULK:
                epctrl |= DXEPCTL_EPTYPE_BULK;
                break;

        case USB_ENDPOINT_XFER_INT:
                if (dir_in)
                        hs_ep->periodic = 1;

                if (hsotg->gadget.speed == USB_SPEED_HIGH)
                        hs_ep->interval = 1 << (desc->bInterval - 1);

                epctrl |= DXEPCTL_EPTYPE_INTERRUPT;
                break;

        case USB_ENDPOINT_XFER_CONTROL:
                epctrl |= DXEPCTL_EPTYPE_CONTROL;
                break;
        }

        /*
         * if the hardware has dedicated fifos, we must give each IN EP
         * a unique tx-fifo even if it is non-periodic.
         */
        if (dir_in && hsotg->dedicated_fifos) {
                u32 fifo_index = 0;
                u32 fifo_size = UINT_MAX;

                size = hs_ep->ep.maxpacket * hs_ep->mc;
                for (i = 1; i < hsotg->num_of_eps; ++i) {
                        if (hsotg->fifo_map & (1 << i))
                                continue;
                        val = dwc2_readl(hsotg, DPTXFSIZN(i));
                        val = (val >> FIFOSIZE_DEPTH_SHIFT) * 4;
                        if (val < size)
                                continue;
                        /* Search for smallest acceptable fifo */
                        if (val < fifo_size) {
                                fifo_size = val;
                                fifo_index = i;
                        }
                }
                if (!fifo_index) {
                        dev_err(hsotg->dev,
                                "%s: No suitable fifo found\n", __func__);
                        ret = -ENOMEM;
                        goto error1;
                }
                hsotg->fifo_map |= 1 << fifo_index;
                epctrl |= DXEPCTL_TXFNUM(fifo_index);
                hs_ep->fifo_index = fifo_index;
                hs_ep->fifo_size = fifo_size;
        }

        /* for non control endpoints, set PID to D0 */
        if (index && !hs_ep->isochronous)
                epctrl |= DXEPCTL_SETD0PID;

        /* WA for Full speed ISOC IN in DDMA mode.
         * By Clear NAK status of EP, core will send ZLP
         * to IN token and assert NAK interrupt relying
         * on TxFIFO status only
         */

        if (hsotg->gadget.speed == USB_SPEED_FULL &&
            hs_ep->isochronous && dir_in) {
                /* The WA applies only to core versions from 2.72a
                 * to 4.00a (including both). Also for FS_IOT_1.00a
                 * and HS_IOT_1.00a.
                 */
                u32 gsnpsid = dwc2_readl(hsotg, GSNPSID);

                if ((gsnpsid >= DWC2_CORE_REV_2_72a &&
                     gsnpsid <= DWC2_CORE_REV_4_00a) ||
                     gsnpsid == DWC2_FS_IOT_REV_1_00a ||
                     gsnpsid == DWC2_HS_IOT_REV_1_00a)
                        epctrl |= DXEPCTL_CNAK;
        }

        dev_dbg(hsotg->dev, "%s: write DxEPCTL=0x%08x\n",
                __func__, epctrl);

        dwc2_writel(hsotg, epctrl, epctrl_reg);
        dev_dbg(hsotg->dev, "%s: read DxEPCTL=0x%08x\n",
                __func__, dwc2_readl(hsotg, epctrl_reg));

        /* enable the endpoint interrupt */
        dwc2_hsotg_ctrl_epint(hsotg, index, dir_in, 1);

error1:
        spin_unlock_irqrestore(&hsotg->lock, flags);

error2:
        if (ret && using_desc_dma(hsotg) && hs_ep->desc_list) {
                dmam_free_coherent(hsotg->dev, MAX_DMA_DESC_NUM_GENERIC *
                        sizeof(struct dwc2_dma_desc),
                        hs_ep->desc_list, hs_ep->desc_list_dma);
                hs_ep->desc_list = NULL;
        }

        return ret;
}

/**
 * dwc2_hsotg_ep_disable - disable given endpoint
 * @ep: The endpoint to disable.
 */
static int dwc2_hsotg_ep_disable(struct usb_ep *ep)
{
        struct dwc2_hsotg_ep *hs_ep = our_ep(ep);
        struct dwc2_hsotg *hsotg = hs_ep->parent;
        int dir_in = hs_ep->dir_in;
        int index = hs_ep->index;
        unsigned long flags;
        u32 epctrl_reg;
        u32 ctrl;

        dev_dbg(hsotg->dev, "%s(ep %p)\n", __func__, ep);

        if (ep == &hsotg->eps_out[0]->ep) {
                dev_err(hsotg->dev, "%s: called for ep0\n", __func__);