/*
 * bdc_ep.c - BRCM BDC USB3.0 device controller endpoint related functions
 *
 * Copyright (C) 2014 Broadcom Corporation
 *
 * Author: Ashwini Pahuja
 *
 * Based on drivers under drivers/usb/
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 */
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/dmapool.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/otg.h>
#include <linux/pm.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <asm/unaligned.h>
#include <linux/platform_device.h>
#include <linux/usb/composite.h>

#include "bdc.h"
#include "bdc_ep.h"
#include "bdc_cmd.h"
#include "bdc_dbg.h"

static const char * const ep0_state_string[] =  {
        "WAIT_FOR_SETUP",
        "WAIT_FOR_DATA_START",
        "WAIT_FOR_DATA_XMIT",
        "WAIT_FOR_STATUS_START",
        "WAIT_FOR_STATUS_XMIT",
        "STATUS_PENDING"
};

/* Free the bdl during ep disable */
static void ep_bd_list_free(struct bdc_ep *ep, u32 num_tabs)
{
        struct bd_list *bd_list = &ep->bd_list;
        struct bdc *bdc = ep->bdc;
        struct bd_table *bd_table;
        int index;

        dev_dbg(bdc->dev, "%s ep:%s num_tabs:%d\n",
                                 __func__, ep->name, num_tabs);

        if (!bd_list->bd_table_array) {
                dev_dbg(bdc->dev, "%s already freed\n", ep->name);
                return;
        }
        for (index = 0; index < num_tabs; index++) {
                /*
                 * check if the bd_table struct is allocated ?
                 * if yes, then check if bd memory has been allocated, then
                 * free the dma_pool and also the bd_table struct memory
                */
                bd_table = bd_list->bd_table_array[index];
                dev_dbg(bdc->dev, "bd_table:%p index:%d\n", bd_table, index);
                if (!bd_table) {
                        dev_dbg(bdc->dev, "bd_table not allocated\n");
                        continue;
                }
                if (!bd_table->start_bd) {
                        dev_dbg(bdc->dev, "bd dma pool not allocated\n");
                        continue;
                }

                dev_dbg(bdc->dev,
                                "Free dma pool start_bd:%p dma:%llx\n",
                                bd_table->start_bd,
                                (unsigned long long)bd_table->dma);

                dma_pool_free(bdc->bd_table_pool,
                                bd_table->start_bd,
                                bd_table->dma);
                /* Free the bd_table structure */
                kfree(bd_table);
        }
        /* Free the bd table array */
        kfree(ep->bd_list.bd_table_array);
}

/*
 * chain the tables, by insteting a chain bd at the end of prev_table, pointing
 * to next_table
 */
static inline void chain_table(struct bd_table *prev_table,
                                        struct bd_table *next_table,
                                        u32 bd_p_tab)
{
        /* Chain the prev table to next table */
        prev_table->start_bd[bd_p_tab-1].offset[0] =
                                cpu_to_le32(lower_32_bits(next_table->dma));

        prev_table->start_bd[bd_p_tab-1].offset[1] =
                                cpu_to_le32(upper_32_bits(next_table->dma));

        prev_table->start_bd[bd_p_tab-1].offset[2] =
                                0x0;

        prev_table->start_bd[bd_p_tab-1].offset[3] =
                                cpu_to_le32(MARK_CHAIN_BD);
}

/* Allocate the bdl for ep, during config ep */
static int ep_bd_list_alloc(struct bdc_ep *ep)
{
        struct bd_table *prev_table = NULL;
        int index, num_tabs, bd_p_tab;
        struct bdc *bdc = ep->bdc;
        struct bd_table *bd_table;
        dma_addr_t dma;

        if (usb_endpoint_xfer_isoc(ep->desc))
                num_tabs = NUM_TABLES_ISOCH;
        else
                num_tabs = NUM_TABLES;

        bd_p_tab = NUM_BDS_PER_TABLE;
        /* if there is only 1 table in bd list then loop chain to self */
        dev_dbg(bdc->dev,
                "%s ep:%p num_tabs:%d\n",
                __func__, ep, num_tabs);

        /* Allocate memory for table array */
        ep->bd_list.bd_table_array = kzalloc(
                                        num_tabs * sizeof(struct bd_table *),
                                        GFP_ATOMIC);
        if (!ep->bd_list.bd_table_array)
                return -ENOMEM;

        /* Allocate memory for each table */
        for (index = 0; index < num_tabs; index++) {
                /* Allocate memory for bd_table structure */
                bd_table = kzalloc(sizeof(struct bd_table), GFP_ATOMIC);
                if (!bd_table)
                        goto fail;

                bd_table->start_bd = dma_pool_alloc(bdc->bd_table_pool,
                                                        GFP_ATOMIC,
                                                        &dma);
                if (!bd_table->start_bd) {
                        kfree(bd_table);
                        goto fail;
                }

                bd_table->dma = dma;

                dev_dbg(bdc->dev,
                        "index:%d start_bd:%p dma=%08llx prev_table:%p\n",
                        index, bd_table->start_bd,
                        (unsigned long long)bd_table->dma, prev_table);

                ep->bd_list.bd_table_array[index] = bd_table;
                memset(bd_table->start_bd, 0, bd_p_tab * sizeof(struct bdc_bd));
                if (prev_table)
                        chain_table(prev_table, bd_table, bd_p_tab);

                prev_table = bd_table;
        }
        chain_table(prev_table, ep->bd_list.bd_table_array[0], bd_p_tab);
        /* Memory allocation is successful, now init the internal fields */
        ep->bd_list.num_tabs = num_tabs;
        ep->bd_list.max_bdi  = (num_tabs * bd_p_tab) - 1;
        ep->bd_list.num_tabs = num_tabs;
        ep->bd_list.num_bds_table = bd_p_tab;
        ep->bd_list.eqp_bdi = 0;
        ep->bd_list.hwd_bdi = 0;

        return 0;
fail:
        /* Free the bd_table_array, bd_table struct, bd's */
        ep_bd_list_free(ep, num_tabs);

        return -ENOMEM;
}

/* returns how many bd's are need for this transfer */
static inline int bd_needed_req(struct bdc_req *req)
{
        int bd_needed = 0;
        int remaining;

        /* 1 bd needed for 0 byte transfer */
        if (req->usb_req.length == 0)
                return 1;

        /* remaining bytes after tranfering all max BD size BD's */
        remaining = req->usb_req.length % BD_MAX_BUFF_SIZE;
        if (remaining)
                bd_needed++;

        /* How many maximum BUFF size BD's ? */
        remaining = req->usb_req.length / BD_MAX_BUFF_SIZE;
        bd_needed += remaining;

        return bd_needed;
}

/* returns the bd index(bdi) corresponding to bd dma address */
static int bd_add_to_bdi(struct bdc_ep *ep, dma_addr_t bd_dma_addr)
{
        struct bd_list *bd_list = &ep->bd_list;
        dma_addr_t dma_first_bd, dma_last_bd;
        struct bdc *bdc = ep->bdc;
        struct bd_table *bd_table;
        bool found = false;
        int tbi, bdi;

        dma_first_bd = dma_last_bd = 0;
        dev_dbg(bdc->dev, "%s  %llx\n",
                        __func__, (unsigned long long)bd_dma_addr);
        /*
         * Find in which table this bd_dma_addr belongs?, go through the table
         * array and compare addresses of first and last address of bd of each
         * table
         */
        for (tbi = 0; tbi < bd_list->num_tabs; tbi++) {
                bd_table = bd_list->bd_table_array[tbi];
                dma_first_bd = bd_table->dma;
                dma_last_bd = bd_table->dma +
                                        (sizeof(struct bdc_bd) *
                                        (bd_list->num_bds_table - 1));
                dev_dbg(bdc->dev, "dma_first_bd:%llx dma_last_bd:%llx\n",
                                        (unsigned long long)dma_first_bd,
                                        (unsigned long long)dma_last_bd);
                if (bd_dma_addr >= dma_first_bd && bd_dma_addr <= dma_last_bd) {
                        found = true;
                        break;
                }
        }
        if (unlikely(!found)) {
                dev_err(bdc->dev, "%s FATAL err, bd not found\n", __func__);
                return -EINVAL;
        }
        /* Now we know the table, find the bdi */
        bdi = (bd_dma_addr - dma_first_bd) / sizeof(struct bdc_bd);

        /* return the global bdi, to compare with ep eqp_bdi */
        return (bdi + (tbi * bd_list->num_bds_table));
}

/* returns the table index(tbi) of the given bdi */
static int bdi_to_tbi(struct bdc_ep *ep, int bdi)
{
        int tbi;

        tbi = bdi / ep->bd_list.num_bds_table;
        dev_vdbg(ep->bdc->dev,
                "bdi:%d num_bds_table:%d tbi:%d\n",
                bdi, ep->bd_list.num_bds_table, tbi);

        return tbi;
}

/* Find the bdi last bd in the transfer */
static inline int find_end_bdi(struct bdc_ep *ep, int next_hwd_bdi)
{
        int end_bdi;

        end_bdi = next_hwd_bdi - 1;
        if (end_bdi < 0)
                end_bdi = ep->bd_list.max_bdi - 1;
         else if ((end_bdi % (ep->bd_list.num_bds_table-1)) == 0)
                end_bdi--;

        return end_bdi;
}

/*
 * How many transfer bd's are available on this ep bdl, chain bds are not
 * counted in available bds
 */
static int bd_available_ep(struct bdc_ep *ep)
{
        struct bd_list *bd_list = &ep->bd_list;
        int available1, available2;
        struct bdc *bdc = ep->bdc;
        int chain_bd1, chain_bd2;
        int available_bd = 0;

        available1 = available2 = chain_bd1 = chain_bd2 = 0;
        /* if empty then we have all bd's available - number of chain bd's */
        if (bd_list->eqp_bdi == bd_list->hwd_bdi)
                return bd_list->max_bdi - bd_list->num_tabs;

        /*
         * Depending upon where eqp and dqp pointers are, caculate number
         * of avaialble bd's
         */
        if (bd_list->hwd_bdi < bd_list->eqp_bdi) {
                /* available bd's are from eqp..max_bds + 0..dqp - chain_bds */
                available1 = bd_list->max_bdi - bd_list->eqp_bdi;
                available2 = bd_list->hwd_bdi;
                chain_bd1 = available1 / bd_list->num_bds_table;
                chain_bd2 = available2 / bd_list->num_bds_table;
                dev_vdbg(bdc->dev, "chain_bd1:%d chain_bd2:%d\n",
                                                chain_bd1, chain_bd2);
                available_bd = available1 + available2 - chain_bd1 - chain_bd2;
        } else {
                /* available bd's are from eqp..dqp - number of chain bd's */
                available1 = bd_list->hwd_bdi -  bd_list->eqp_bdi;
                /* if gap between eqp and dqp is less than NUM_BDS_PER_TABLE */
                if ((bd_list->hwd_bdi - bd_list->eqp_bdi)
                                        <= bd_list->num_bds_table) {
                        /* If there any chain bd in between */
                        if (!(bdi_to_tbi(ep, bd_list->hwd_bdi)
                                        == bdi_to_tbi(ep, bd_list->eqp_bdi))) {
                                available_bd = available1 - 1;
                        }
                } else {
                        chain_bd1 = available1 / bd_list->num_bds_table;
                        available_bd = available1 - chain_bd1;
                }
        }
        /*
         * we need to keep one extra bd to check if ring is full or empty so
         * reduce by 1
         */
        available_bd--;
        dev_vdbg(bdc->dev, "available_bd:%d\n", available_bd);

        return available_bd;
}

/* Notify the hardware after queueing the bd to bdl */
void bdc_notify_xfr(struct bdc *bdc, u32 epnum)
{
        struct bdc_ep *ep = bdc->bdc_ep_array[epnum];

        dev_vdbg(bdc->dev, "%s epnum:%d\n", __func__, epnum);
        /*
         * We don't have anyway to check if ep state is running,
         * except the software flags.
         */
        if (unlikely(ep->flags & BDC_EP_STOP))
                ep->flags &= ~BDC_EP_STOP;

        bdc_writel(bdc->regs, BDC_XSFNTF, epnum);
}

/* returns the bd corresponding to bdi */
static struct bdc_bd *bdi_to_bd(struct bdc_ep *ep, int bdi)
{
        int tbi = bdi_to_tbi(ep, bdi);
        int local_bdi = 0;

        local_bdi = bdi - (tbi * ep->bd_list.num_bds_table);
        dev_vdbg(ep->bdc->dev,
                "%s bdi:%d local_bdi:%d\n",
                 __func__, bdi, local_bdi);

        return (ep->bd_list.bd_table_array[tbi]->start_bd + local_bdi);
}

/* Advance the enqueue pointer */
static void ep_bdlist_eqp_adv(struct bdc_ep *ep)
{
        ep->bd_list.eqp_bdi++;
        /* if it's chain bd, then move to next */
        if (((ep->bd_list.eqp_bdi + 1) % ep->bd_list.num_bds_table) == 0)
                ep->bd_list.eqp_bdi++;

        /* if the eqp is pointing to last + 1 then move back to 0 */
        if (ep->bd_list.eqp_bdi == (ep->bd_list.max_bdi + 1))
                ep->bd_list.eqp_bdi = 0;
}

/* Setup the first bd for ep0 transfer */
static int setup_first_bd_ep0(struct bdc *bdc, struct bdc_req *req, u32 *dword3)
{
        u16 wValue;
        u32 req_len;

        req->ep->dir = 0;
        req_len = req->usb_req.length;
        switch (bdc->ep0_state) {
        case WAIT_FOR_DATA_START:
                *dword3 |= BD_TYPE_DS;
                if (bdc->setup_pkt.bRequestType & USB_DIR_IN)
                        *dword3 |= BD_DIR_IN;

                /* check if zlp will be needed */
                wValue = le16_to_cpu(bdc->setup_pkt.wValue);
                if ((wValue > req_len) &&
                                (req_len % bdc->gadget.ep0->maxpacket == 0)) {
                        dev_dbg(bdc->dev, "ZLP needed wVal:%d len:%d MaxP:%d\n",
                                        wValue, req_len,
                                        bdc->gadget.ep0->maxpacket);
                        bdc->zlp_needed = true;
                }
                break;

        case WAIT_FOR_STATUS_START:
                *dword3 |= BD_TYPE_SS;
                if (!le16_to_cpu(bdc->setup_pkt.wLength) ||
                                !(bdc->setup_pkt.bRequestType & USB_DIR_IN))
                        *dword3 |= BD_DIR_IN;
                break;
        default:
                dev_err(bdc->dev,
                        "Unknown ep0 state for queueing bd ep0_state:%s\n",
                        ep0_state_string[bdc->ep0_state]);
                return -EINVAL;
        }

        return 0;
}

/* Setup the bd dma descriptor for a given request */
static int setup_bd_list_xfr(struct bdc *bdc, struct bdc_req *req, int num_bds)
{
        dma_addr_t buf_add = req->usb_req.dma;
        u32 maxp, tfs, dword2, dword3;
        struct bd_transfer *bd_xfr;
        struct bd_list *bd_list;
        struct bdc_ep *ep;
        struct bdc_bd *bd;
        int ret, bdnum;
        u32 req_len;

        ep = req->ep;
        bd_list = &ep->bd_list;
        bd_xfr = &req->bd_xfr;
        bd_xfr->req = req;
        bd_xfr->start_bdi = bd_list->eqp_bdi;
        bd = bdi_to_bd(ep, bd_list->eqp_bdi);
        req_len = req->usb_req.length;
        maxp = usb_endpoint_maxp(ep->desc);
        tfs = roundup(req->usb_req.length, maxp);
        tfs = tfs/maxp;
        dev_vdbg(bdc->dev, "%s ep:%s num_bds:%d tfs:%d r_len:%d bd:%p\n",
                                __func__, ep->name, num_bds, tfs, req_len, bd);

        for (bdnum = 0; bdnum < num_bds; bdnum++) {
                dword2 = dword3 = 0;
                /* First bd */
                if (!bdnum) {
                        dword3 |= BD_SOT|BD_SBF|(tfs<<BD_TFS_SHIFT);
                        dword2 |= BD_LTF;
                        /* format of first bd for ep0 is different than other */
                        if (ep->ep_num == 1) {
                                ret = setup_first_bd_ep0(bdc, req, &dword3);
                                if (ret)
                                        return ret;
                        }
                }
                if (!req->ep->dir)
                        dword3 |= BD_ISP;

                if (req_len > BD_MAX_BUFF_SIZE) {
                        dword2 |= BD_MAX_BUFF_SIZE;
                        req_len -= BD_MAX_BUFF_SIZE;
                } else {
                        /* this should be the last bd */
                        dword2 |= req_len;
                        dword3 |= BD_IOC;
                        dword3 |= BD_EOT;
                }
                /* Currently only 1 INT target is supported */
                dword2 |= BD_INTR_TARGET(0);
                bd = bdi_to_bd(ep, ep->bd_list.eqp_bdi);
                if (unlikely(!bd)) {
                        dev_err(bdc->dev, "Err bd pointing to wrong addr\n");
                        return -EINVAL;
                }
                /* write bd */
                bd->offset[0] = cpu_to_le32(lower_32_bits(buf_add));
                bd->offset[1] = cpu_to_le32(upper_32_bits(buf_add));
                bd->offset[2] = cpu_to_le32(dword2);
                bd->offset[3] = cpu_to_le32(dword3);
                /* advance eqp pointer */
                ep_bdlist_eqp_adv(ep);
                /* advance the buff pointer */
                buf_add += BD_MAX_BUFF_SIZE;
                dev_vdbg(bdc->dev, "buf_add:%08llx req_len:%d bd:%p eqp:%d\n",
                                (unsigned long long)buf_add, req_len, bd,
                                                        ep->bd_list.eqp_bdi);
                bd = bdi_to_bd(ep, ep->bd_list.eqp_bdi);
                bd->offset[3] = cpu_to_le32(BD_SBF);
        }
        /* clear the STOP BD fetch bit from the first bd of this xfr */
        bd = bdi_to_bd(ep, bd_xfr->start_bdi);
        bd->offset[3] &= cpu_to_le32(~BD_SBF);
        /* the new eqp will be next hw dqp */
        bd_xfr->num_bds  = num_bds;
        bd_xfr->next_hwd_bdi = ep->bd_list.eqp_bdi;
        /* everything is written correctly before notifying the HW */
        wmb();

        return 0;
}

/* Queue the xfr */
static int bdc_queue_xfr(struct bdc *bdc, struct bdc_req *req)
{
        int num_bds, bd_available;
        struct bdc_ep *ep;
        int ret;

        ep = req->ep;
        dev_dbg(bdc->dev, "%s req:%p\n", __func__, req);
        dev_dbg(bdc->dev, "eqp_bdi:%d hwd_bdi:%d\n",
                        ep->bd_list.eqp_bdi, ep->bd_list.hwd_bdi);

        num_bds =  bd_needed_req(req);
        bd_available = bd_available_ep(ep);

        /* how many bd's are avaialble on ep */
        if (num_bds > bd_available)
                return -ENOMEM;

        ret = setup_bd_list_xfr(bdc, req, num_bds);
        if (ret)
                return ret;
        list_add_tail(&req->queue, &ep->queue);
        bdc_dbg_bd_list(bdc, ep);
        bdc_notify_xfr(bdc, ep->ep_num);

        return 0;
}

/* callback to gadget layer when xfr completes */
static void bdc_req_complete(struct bdc_ep *ep, struct bdc_req *req,
                                                int status)
{
        struct bdc *bdc = ep->bdc;

        if (req == NULL  || &req->queue == NULL || &req->usb_req == NULL)
                return;

        dev_dbg(bdc->dev, "%s ep:%s status:%d\n", __func__, ep->name, status);
        list_del(&req->queue);
        req->usb_req.status = status;
        usb_gadget_unmap_request(&bdc->gadget, &req->usb_req, ep->dir);
        if (req->usb_req.complete) {
                spin_unlock(&bdc->lock);
                usb_gadget_giveback_request(&ep->usb_ep, &req->usb_req);
                spin_lock(&bdc->lock);
        }
}

/* Disable the endpoint */
int bdc_ep_disable(struct bdc_ep *ep)
{
        struct bdc_req *req;
        struct bdc *bdc;
        int ret;

        ret = 0;
        bdc = ep->bdc;
        dev_dbg(bdc->dev, "%s() ep->ep_num=%d\n", __func__, ep->ep_num);
        /* Stop the endpoint */
        ret = bdc_stop_ep(bdc, ep->ep_num);

        /*
         * Intentionally don't check the ret value of stop, it can fail in
         * disconnect scenarios, continue with dconfig
         */
        /* de-queue any pending requests */
        while (!list_empty(&ep->queue)) {
                req = list_entry(ep->queue.next, struct bdc_req,
                                queue);
                bdc_req_complete(ep, req, -ESHUTDOWN);
        }
        /* deconfigure the endpoint */
        ret = bdc_dconfig_ep(bdc, ep);
        if (ret)
                dev_warn(bdc->dev,
                        "dconfig fail but continue with memory free");

        ep->flags = 0;
        /* ep0 memory is not freed, but reused on next connect sr */
        if (ep->ep_num == 1)
                return 0;

        /* Free the bdl memory */
        ep_bd_list_free(ep, ep->bd_list.num_tabs);
        ep->desc = NULL;
        ep->comp_desc = NULL;
        ep->usb_ep.desc = NULL;
        ep->ep_type = 0;

        return ret;
}

/* Enable the ep */
int bdc_ep_enable(struct bdc_ep *ep)
{
        struct bdc *bdc;
        int ret = 0;

        bdc = ep->bdc;
        dev_dbg(bdc->dev, "%s NUM_TABLES:%d %d\n",
                                        __func__, NUM_TABLES, NUM_TABLES_ISOCH);

        ret = ep_bd_list_alloc(ep);
        if (ret) {
                dev_err(bdc->dev, "ep bd list allocation failed:%d\n", ret);
                return -ENOMEM;
        }
        bdc_dbg_bd_list(bdc, ep);
        /* only for ep0: config ep is called for ep0 from connect event */
        ep->flags |= BDC_EP_ENABLED;
        if (ep->ep_num == 1)
                return ret;

        /* Issue a configure endpoint command */
        ret = bdc_config_ep(bdc, ep);
        if (ret)
                return ret;

        ep->usb_ep.maxpacket = usb_endpoint_maxp(ep->desc);
        ep->usb_ep.desc = ep->desc;
        ep->usb_ep.comp_desc = ep->comp_desc;
        ep->ep_type = usb_endpoint_type(ep->desc);
        ep->flags |= BDC_EP_ENABLED;

        return 0;
}

/* EP0 related code */

/* Queue a status stage BD */
static int ep0_queue_status_stage(struct bdc *bdc)
{
        struct bdc_req *status_req;
        struct bdc_ep *ep;

        status_req = &bdc->status_req;
        ep = bdc->bdc_ep_array[1];
        status_req->ep = ep;
        status_req->usb_req.length = 0;
        status_req->usb_req.status = -EINPROGRESS;
        status_req->usb_req.actual = 0;
        status_req->usb_req.complete = NULL;
        bdc_queue_xfr(bdc, status_req);

        return 0;
}

/* Queue xfr on ep0 */
static int ep0_queue(struct bdc_ep *ep, struct bdc_req *req)
{
        struct bdc *bdc;
        int ret;

        bdc = ep->bdc;
        dev_dbg(bdc->dev, "%s()\n", __func__);
        req->usb_req.actual = 0;
        req->usb_req.status = -EINPROGRESS;
        req->epnum = ep->ep_num;

        if (bdc->delayed_status) {
                bdc->delayed_status = false;
                /* if status stage was delayed? */
                if (bdc->ep0_state == WAIT_FOR_STATUS_START) {
                        /* Queue a status stage BD */
                        ep0_queue_status_stage(bdc);
                        bdc->ep0_state = WAIT_FOR_STATUS_XMIT;
                        return 0;
                }
        } else {
                /*
                 * if delayed status is false and 0 length transfer is requested
                 * i.e. for status stage of some setup request, then just
                 * return from here the status stage is queued independently
                 */
                if (req->usb_req.length == 0)
                        return 0;

        }
        ret = usb_gadget_map_request(&bdc->gadget, &req->usb_req, ep->dir);
        if (ret) {
                dev_err(bdc->dev, "dma mapping failed %s\n", ep->name);
                return ret;
        }

        return bdc_queue_xfr(bdc, req);
}

/* Queue data stage */
static int ep0_queue_data_stage(struct bdc *bdc)
{
        struct bdc_ep *ep;

        dev_dbg(bdc->dev, "%s\n", __func__);
        ep = bdc->bdc_ep_array[1];
        bdc->ep0_req.ep = ep;
        bdc->ep0_req.usb_req.complete = NULL;

        return ep0_queue(ep, &bdc->ep0_req);
}

/* Queue req on ep */
static int ep_queue(struct bdc_ep *ep, struct bdc_req *req)
{
        struct bdc *bdc;
        int ret = 0;

        if (!req || !ep->usb_ep.desc)
                return -EINVAL;

        bdc = ep->bdc;

        req->usb_req.actual = 0;
        req->usb_req.status = -EINPROGRESS;
        req->epnum = ep->ep_num;

        ret = usb_gadget_map_request(&bdc->gadget, &req->usb_req, ep->dir);
        if (ret) {
                dev_err(bdc->dev, "dma mapping failed\n");
                return ret;
        }

        return bdc_queue_xfr(bdc, req);
}

/* Dequeue a request from ep */
static int ep_dequeue(struct bdc_ep *ep, struct bdc_req *req)
{
        int start_bdi, end_bdi, tbi, eqp_bdi, curr_hw_dqpi;
        bool start_pending, end_pending;
        bool first_remove = false;
        struct bdc_req *first_req;
        struct bdc_bd *bd_start;
        struct bd_table *table;
        dma_addr_t next_bd_dma;
        u64   deq_ptr_64 = 0;
        struct bdc  *bdc;
        u32    tmp_32;
        int ret;

        bdc = ep->bdc;
        start_pending = end_pending = false;
        eqp_bdi = ep->bd_list.eqp_bdi - 1;

        if (eqp_bdi < 0)
                eqp_bdi = ep->bd_list.max_bdi;

        start_bdi = req->bd_xfr.start_bdi;
        end_bdi = find_end_bdi(ep, req->bd_xfr.next_hwd_bdi);

        dev_dbg(bdc->dev, "%s ep:%s start:%d end:%d\n",
                                        __func__, ep->name, start_bdi, end_bdi);
        dev_dbg(bdc->dev, "ep_dequeue ep=%p ep->desc=%p\n",
                                                ep, (void *)ep->usb_ep.desc);
        /* Stop the ep to see where the HW is ? */
        ret = bdc_stop_ep(bdc, ep->ep_num);
        /* if there is an issue with stopping ep, then no need to go further */
        if (ret)
                return 0;

        /*
         * After endpoint is stopped, there can be 3 cases, the request
         * is processed, pending or in the middle of processing
         */

        /* The current hw dequeue pointer */
        tmp_32 = bdc_readl(bdc->regs, BDC_EPSTS0);
        deq_ptr_64 = tmp_32;
        tmp_32 = bdc_readl(bdc->regs, BDC_EPSTS1);
        deq_ptr_64 |= ((u64)tmp_32 << 32);

        /* we have the dma addr of next bd that will be fetched by hardware */
        curr_hw_dqpi = bd_add_to_bdi(ep, deq_ptr_64);
        if (curr_hw_dqpi < 0)
                return curr_hw_dqpi;

        /*
         * curr_hw_dqpi points to actual dqp of HW and HW owns bd's from
         * curr_hw_dqbdi..eqp_bdi.
         */

        /* Check if start_bdi and end_bdi are in range of HW owned BD's */
        if (curr_hw_dqpi > eqp_bdi) {
                /* there is a wrap from last to 0 */
                if (start_bdi >= curr_hw_dqpi || start_bdi <= eqp_bdi) {
                        start_pending = true;
                        end_pending = true;
                } else if (end_bdi >= curr_hw_dqpi || end_bdi <= eqp_bdi) {
                                end_pending = true;
                }
        } else {
                if (start_bdi >= curr_hw_dqpi) {
                        start_pending = true;
                        end_pending = true;
                } else if (end_bdi >= curr_hw_dqpi) {
                        end_pending = true;
                }
        }
        dev_dbg(bdc->dev,
                "start_pending:%d end_pending:%d speed:%d\n",
                start_pending, end_pending, bdc->gadget.speed);

        /* If both start till end are processes, we cannot deq req */
        if (!start_pending && !end_pending)
                return -EINVAL;

        /*
         * if ep_dequeue is called after disconnect then just return
         * success from here
         */
        if (bdc->gadget.speed == USB_SPEED_UNKNOWN)
                return 0;
        tbi = bdi_to_tbi(ep, req->bd_xfr.next_hwd_bdi);
        table = ep->bd_list.bd_table_array[tbi];
        next_bd_dma =  table->dma +
                        sizeof(struct bdc_bd)*(req->bd_xfr.next_hwd_bdi -
                                        tbi * ep->bd_list.num_bds_table);

        first_req = list_first_entry(&ep->queue, struct bdc_req,
                        queue);

        if (req == first_req)
                first_remove = true;

        /*
         * Due to HW limitation we need to bypadd chain bd's and issue ep_bla,
         * incase if start is pending this is the first request in the list
         * then issue ep_bla instead of marking as chain bd
         */
        if (start_pending && !first_remove) {
                /*
                 * Mark the start bd as Chain bd, and point the chain
                 * bd to next_bd_dma
                 */
                bd_start = bdi_to_bd(ep, start_bdi);
                bd_start->offset[0] = cpu_to_le32(lower_32_bits(next_bd_dma));
                bd_start->offset[1] = cpu_to_le32(upper_32_bits(next_bd_dma));
                bd_start->offset[2] = 0x0;
                bd_start->offset[3] = cpu_to_le32(MARK_CHAIN_BD);
                bdc_dbg_bd_list(bdc, ep);
        } else if (end_pending) {
                /*
                 * The transfer is stopped in the middle, move the
                 * HW deq pointer to next_bd_dma
                 */
                ret = bdc_ep_bla(bdc, ep, next_bd_dma);
                if (ret) {
                        dev_err(bdc->dev, "error in ep_bla:%d\n", ret);
                        return ret;
                }
        }

        return 0;
}

/* Halt/Clear the ep based on value */
static int ep_set_halt(struct bdc_ep *ep, u32 value)
{
        struct bdc *bdc;
        int ret;

        bdc = ep->bdc;
        dev_dbg(bdc->dev, "%s ep:%s value=%d\n", __func__, ep->name, value);

        if (value) {
                dev_dbg(bdc->dev, "Halt\n");
                if (ep->ep_num == 1)
                        bdc->ep0_state = WAIT_FOR_SETUP;

                ret = bdc_ep_set_stall(bdc, ep->ep_num);
                if (ret)
                        dev_err(bdc->dev, "failed to set STALL on %s\n",
                                ep->name);
                else
                        ep->flags |= BDC_EP_STALL;
        } else {
                /* Clear */
                dev_dbg(bdc->dev, "Before Clear\n");
                ret = bdc_ep_clear_stall(bdc, ep->ep_num);
                if (ret)
                        dev_err(bdc->dev, "failed to clear STALL on %s\n",
                                ep->name);
                else
                        ep->flags &= ~BDC_EP_STALL;
                dev_dbg(bdc->dev, "After  Clear\n");
        }

        return ret;
}

/* Free all the ep */
void bdc_free_ep(struct bdc *bdc)
{
        struct bdc_ep *ep;
        u8      epnum;

        dev_dbg(bdc->dev, "%s\n", __func__);
        for (epnum = 1; epnum < bdc->num_eps; epnum++) {
                ep = bdc->bdc_ep_array[epnum];
                if (!ep)
                        continue;

                if (ep->flags & BDC_EP_ENABLED)
                        ep_bd_list_free(ep, ep->bd_list.num_tabs);

                /* ep0 is not in this gadget list */
                if (epnum != 1)
                        list_del(&ep->usb_ep.ep_list);

                kfree(ep);
        }
}

/* USB2 spec, section 7.1.20 */
static int bdc_set_test_mode(struct bdc *bdc)
{
        u32 usb2_pm;

        usb2_pm = bdc_readl(bdc->regs, BDC_USPPM2);
        usb2_pm &= ~BDC_PTC_MASK;
        dev_dbg(bdc->dev, "%s\n", __func__);
        switch (bdc->test_mode) {
        case TEST_J:
        case TEST_K:
        case TEST_SE0_NAK:
        case TEST_PACKET:
        case TEST_FORCE_EN:
                usb2_pm |= bdc->test_mode << 28;
                break;
        default:
                return -EINVAL;
        }
        dev_dbg(bdc->dev, "usb2_pm=%08x", usb2_pm);
        bdc_writel(bdc->regs, BDC_USPPM2, usb2_pm);

        return 0;
}

/*
 * Helper function to handle Transfer status report with status as either
 * success or short
 */
static void handle_xsr_succ_status(struct bdc *bdc, struct bdc_ep *ep,
                                                        struct bdc_sr *sreport)
{
        int short_bdi, start_bdi, end_bdi, max_len_bds, chain_bds;
        struct bd_list *bd_list = &ep->bd_list;
        int actual_length, length_short;
        struct bd_transfer *bd_xfr;
        struct bdc_bd *short_bd;
        struct bdc_req *req;
        u64   deq_ptr_64 = 0;
        int status = 0;
        int sr_status;
        u32    tmp_32;

        dev_dbg(bdc->dev, "%s  ep:%p\n", __func__, ep);
        bdc_dbg_srr(bdc, 0);
        /* do not process thie sr if ignore flag is set */
        if (ep->ignore_next_sr) {
                ep->ignore_next_sr = false;
                return;
        }

        if (unlikely(list_empty(&ep->queue))) {
                dev_warn(bdc->dev, "xfr srr with no BD's queued\n");
                return;
        }
        req = list_entry(ep->queue.next, struct bdc_req,
                        queue);

        bd_xfr = &req->bd_xfr;
        sr_status = XSF_STS(le32_to_cpu(sreport->offset[3]));

        /*
         * sr_status is short and this transfer has more than 1 bd then it needs
         * special handling,  this is only applicable for bulk and ctrl
         */
        if (sr_status == XSF_SHORT &&  bd_xfr->num_bds > 1) {
                /*
                 * This is multi bd xfr, lets see which bd
                 * caused short transfer and how many bytes have been
                 * transferred so far.
                 */
                tmp_32 = le32_to_cpu(sreport->offset[0]);
                deq_ptr_64 = tmp_32;
                tmp_32 = le32_to_cpu(sreport->offset[1]);

                deq_ptr_64 |= ((u64)tmp_32 << 32);
                short_bdi = bd_add_to_bdi(ep, deq_ptr_64);
                if (unlikely(short_bdi < 0))
                        dev_warn(bdc->dev, "bd doesn't exist?\n");

                start_bdi =  bd_xfr->start_bdi;
                /*
                 * We know the start_bdi and short_bdi, how many xfr
                 * bds in between
                 */
                if (start_bdi <= short_bdi) {
                        max_len_bds = short_bdi - start_bdi;
                        if (max_len_bds <= bd_list->num_bds_table) {
                                if (!(bdi_to_tbi(ep, start_bdi) ==
                                                bdi_to_tbi(ep, short_bdi)))
                                        max_len_bds--;
                        } else {
                                chain_bds = max_len_bds/bd_list->num_bds_table;
                                max_len_bds -= chain_bds;
                        }
                } else {
                        /* there is a wrap in the ring within a xfr */
                        chain_bds = (bd_list->max_bdi - start_bdi)/
                                                        bd_list->num_bds_table;
                        chain_bds += short_bdi/bd_list->num_bds_table;
                        max_len_bds = bd_list->max_bdi - start_bdi;
                        max_len_bds += short_bdi;
                        max_len_bds -= chain_bds;
                }
                /* max_len_bds is the number of full length bds */
                end_bdi = find_end_bdi(ep, bd_xfr->next_hwd_bdi);
                if (!(end_bdi == short_bdi))
                        ep->ignore_next_sr = true;

                actual_length = max_len_bds * BD_MAX_BUFF_SIZE;
                short_bd = bdi_to_bd(ep, short_bdi);
                /* length queued */
                length_short = le32_to_cpu(short_bd->offset[2]) & 0x1FFFFF;
                /* actual length trensfered */
                length_short -= SR_BD_LEN(le32_to_cpu(sreport->offset[2]));
                actual_length += length_short;
                req->usb_req.actual = actual_length;
        } else {
                req->usb_req.actual = req->usb_req.length -
                        SR_BD_LEN(le32_to_cpu(sreport->offset[2]));
                dev_dbg(bdc->dev,
                        "len=%d actual=%d bd_xfr->next_hwd_bdi:%d\n",
                        req->usb_req.length, req->usb_req.actual,
                        bd_xfr->next_hwd_bdi);
        }

        /* Update the dequeue pointer */
        ep->bd_list.hwd_bdi = bd_xfr->next_hwd_bdi;
        if (req->usb_req.actual < req->usb_req.length) {
                dev_dbg(bdc->dev, "short xfr on %d\n", ep->ep_num);
                if (req->usb_req.short_not_ok)
                        status = -EREMOTEIO;
        }
        bdc_req_complete(ep, bd_xfr->req, status);
}

/* EP0 setup related packet handlers */

/*
 * Setup packet received, just store the packet and process on next DS or SS
 * started SR
 */
void bdc_xsf_ep0_setup_recv(struct bdc *bdc, struct bdc_sr *sreport)
{
        struct usb_ctrlrequest *setup_pkt;
        u32 len;

        dev_dbg(bdc->dev,
                "%s ep0_state:%s\n",
                __func__, ep0_state_string[bdc->ep0_state]);
        /* Store received setup packet */
        setup_pkt = &bdc->setup_pkt;
        memcpy(setup_pkt, &sreport->offset[0], sizeof(*setup_pkt));
        len = le16_to_cpu(setup_pkt->wLength);
        if (!len)
                bdc->ep0_state = WAIT_FOR_STATUS_START;
        else
                bdc->ep0_state = WAIT_FOR_DATA_START;


        dev_dbg(bdc->dev,
                "%s exit ep0_state:%s\n",
                __func__, ep0_state_string[bdc->ep0_state]);
}

/* Stall ep0 */
static void ep0_stall(struct bdc *bdc)
{
        struct bdc_ep   *ep = bdc->bdc_ep_array[1];
        struct bdc_req *req;

        dev_dbg(bdc->dev, "%s\n", __func__);
        bdc->delayed_status = false;
        ep_set_halt(ep, 1);

        /* de-queue any pendig requests */
        while (!list_empty(&ep->queue)) {
                req = list_entry(ep->queue.next, struct bdc_req,
                                queue);
                bdc_req_complete(ep, req, -ESHUTDOWN);
        }
}

/* SET_ADD handlers */
static int ep0_set_address(struct bdc *bdc, struct usb_ctrlrequest *ctrl)
{
        enum usb_device_state state = bdc->gadget.state;
        int ret = 0;
        u32 addr;

        addr = le16_to_cpu(ctrl->wValue);
        dev_dbg(bdc->dev,
                "%s addr:%d dev state:%d\n",
                __func__, addr, state);

        if (addr > 127)
                return -EINVAL;

        switch (state) {
        case USB_STATE_DEFAULT:
        case USB_STATE_ADDRESS:
                /* Issue Address device command */
                ret = bdc_address_device(bdc, addr);
                if (ret)
                        return ret;

                if (addr)
                        usb_gadget_set_state(&bdc->gadget, USB_STATE_ADDRESS);
                else
                        usb_gadget_set_state(&bdc->gadget, USB_STATE_DEFAULT);

                bdc->dev_addr = addr;
                break;
        default:
                dev_warn(bdc->dev,
                        "SET Address in wrong device state %d\n",
                        state);
                ret = -EINVAL;
        }

        return ret;
}

/* Handler for SET/CLEAR FEATURE requests for device */
static int ep0_handle_feature_dev(struct bdc *bdc, u16 wValue,
                                                        u16 wIndex, bool set)
{
        enum usb_device_state state = bdc->gadget.state;
        u32     usppms = 0;

        dev_dbg(bdc->dev, "%s set:%d dev state:%d\n",
                                        __func__, set, state);
        switch (wValue) {
        case USB_DEVICE_REMOTE_WAKEUP:
                dev_dbg(bdc->dev, "USB_DEVICE_REMOTE_WAKEUP\n");
                if (set)
                        bdc->devstatus |= REMOTE_WAKE_ENABLE;
                else
                        bdc->devstatus &= ~REMOTE_WAKE_ENABLE;
                break;

        case USB_DEVICE_TEST_MODE:
                dev_dbg(bdc->dev, "USB_DEVICE_TEST_MODE\n");
                if ((wIndex & 0xFF) ||
                                (bdc->gadget.speed != USB_SPEED_HIGH) || !set)
                        return -EINVAL;

                bdc->test_mode = wIndex >> 8;
                break;

        case USB_DEVICE_U1_ENABLE:
                dev_dbg(bdc->dev, "USB_DEVICE_U1_ENABLE\n");

                if (bdc->gadget.speed != USB_SPEED_SUPER ||
                                                state != USB_STATE_CONFIGURED)
                        return -EINVAL;

                usppms =  bdc_readl(bdc->regs, BDC_USPPMS);
                if (set) {
                        /* clear previous u1t */
                        usppms &= ~BDC_U1T(BDC_U1T_MASK);
                        usppms |= BDC_U1T(U1_TIMEOUT);
                        usppms |= BDC_U1E | BDC_PORT_W1S;
                        bdc->devstatus |= (1 << USB_DEV_STAT_U1_ENABLED);
                } else {
                        usppms &= ~BDC_U1E;
                        usppms |= BDC_PORT_W1S;
                        bdc->devstatus &= ~(1 << USB_DEV_STAT_U1_ENABLED);
                }
                bdc_writel(bdc->regs, BDC_USPPMS, usppms);
                break;

        case USB_DEVICE_U2_ENABLE:
                dev_dbg(bdc->dev, "USB_DEVICE_U2_ENABLE\n");

                if (bdc->gadget.speed != USB_SPEED_SUPER ||
                                                state != USB_STATE_CONFIGURED)
                        return -EINVAL;

                usppms = bdc_readl(bdc->regs, BDC_USPPMS);
                if (set) {
                        usppms |= BDC_U2E;
                        usppms |= BDC_U2A;
                        bdc->devstatus |= (1 << USB_DEV_STAT_U2_ENABLED);
                } else {
                        usppms &= ~BDC_U2E;
                        usppms &= ~BDC_U2A;
                        bdc->devstatus &= ~(1 << USB_DEV_STAT_U2_ENABLED);
                }
                bdc_writel(bdc->regs, BDC_USPPMS, usppms);
                break;

        case USB_DEVICE_LTM_ENABLE:
                dev_dbg(bdc->dev, "USB_DEVICE_LTM_ENABLE?\n");
                if (bdc->gadget.speed != USB_SPEED_SUPER ||
                                                state != USB_STATE_CONFIGURED)
                        return -EINVAL;
                break;
        default:
                dev_err(bdc->dev, "Unknown wValue:%d\n", wValue);
                return -EOPNOTSUPP;
        } /* USB_RECIP_DEVICE end */

        return 0;
}

/* SET/CLEAR FEATURE handler */
static int ep0_handle_feature(struct bdc *bdc,
                              struct usb_ctrlrequest *setup_pkt, bool set)
{
        enum usb_device_state state = bdc->gadget.state;
        struct bdc_ep *ep;
        u16 wValue;
        u16 wIndex;
        int epnum;

        wValue = le16_to_cpu(setup_pkt->wValue);
        wIndex = le16_to_cpu(setup_pkt->wIndex);

        dev_dbg(bdc->dev,
                "%s wValue=%d wIndex=%d devstate=%08x speed=%d set=%d",
                __func__, wValue, wIndex, state,
                bdc->gadget.speed, set);

        switch (setup_pkt->bRequestType & USB_RECIP_MASK) {
        case USB_RECIP_DEVICE:
                return ep0_handle_feature_dev(bdc, wValue, wIndex, set);
        case USB_RECIP_INTERFACE:
                dev_dbg(bdc->dev, "USB_RECIP_INTERFACE\n");
                /* USB3 spec, sec 9.4.9 */
                if (wValue != USB_INTRF_FUNC_SUSPEND)
                        return -EINVAL;
                /* USB3 spec, Table 9-8 */
                if (set) {
                        if (wIndex & USB_INTRF_FUNC_SUSPEND_RW) {
                                dev_dbg(bdc->dev, "SET REMOTE_WAKEUP\n");
                                bdc->devstatus |= REMOTE_WAKE_ENABLE;
                        } else {
                                dev_dbg(bdc->dev, "CLEAR REMOTE_WAKEUP\n");
                                bdc->devstatus &= ~REMOTE_WAKE_ENABLE;
                        }
                }
                break;

        case USB_RECIP_ENDPOINT:
                dev_dbg(bdc->dev, "USB_RECIP_ENDPOINT\n");
                if (wValue != USB_ENDPOINT_HALT)
                        return -EINVAL;

                epnum = wIndex & USB_ENDPOINT_NUMBER_MASK;
                if (epnum) {
                        if ((wIndex & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN)
                                epnum = epnum * 2 + 1;
                        else
                                epnum *= 2;
                } else {
                        epnum = 1; /*EP0*/
                }
                /*
                 * If CLEAR_FEATURE on ep0 then don't do anything as the stall
                 * condition on ep0 has already been cleared when SETUP packet
                 * was received.
                 */
                if (epnum == 1 && !set) {
                        dev_dbg(bdc->dev, "ep0 stall already cleared\n");
                        return 0;
                }
                dev_dbg(bdc->dev, "epnum=%d\n", epnum);
                ep = bdc->bdc_ep_array[epnum];
                if (!ep)
                        return -EINVAL;

                return ep_set_halt(ep, set);
        default:
                dev_err(bdc->dev, "Unknown recipient\n");
                return -EINVAL;
        }

        return 0;
}

/* GET_STATUS request handler */
static int ep0_handle_status(struct bdc *bdc,
                             struct usb_ctrlrequest *setup_pkt)
{
        enum usb_device_state state = bdc->gadget.state;
        struct bdc_ep *ep;
        u16 usb_status = 0;
        u32 epnum;
        u16 wIndex;

        /* USB2.0 spec sec 9.4.5 */
        if (state == USB_STATE_DEFAULT)
                return -EINVAL;
        wIndex = le16_to_cpu(setup_pkt->wIndex);
        dev_dbg(bdc->dev, "%s\n", __func__);
        usb_status = bdc->devstatus;
        switch (setup_pkt->bRequestType & USB_RECIP_MASK) {
        case USB_RECIP_DEVICE:
                dev_dbg(bdc->dev,
                        "USB_RECIP_DEVICE devstatus:%08x\n",
                        bdc->devstatus);
                /* USB3 spec, sec 9.4.5 */
                if (bdc->gadget.speed == USB_SPEED_SUPER)
                        usb_status &= ~REMOTE_WAKE_ENABLE;
                break;

        case USB_RECIP_INTERFACE:
                dev_dbg(bdc->dev, "USB_RECIP_INTERFACE\n");
                if (bdc->gadget.speed == USB_SPEED_SUPER) {
                        /*
                         * This should come from func for Func remote wkup
                         * usb_status |=1;
                         */
                        if (bdc->devstatus & REMOTE_WAKE_ENABLE)
                                usb_status |= REMOTE_WAKE_ENABLE;
                } else {
                        usb_status = 0;
                }

                break;

        case USB_RECIP_ENDPOINT:
                dev_dbg(bdc->dev, "USB_RECIP_ENDPOINT\n");
                epnum = wIndex & USB_ENDPOINT_NUMBER_MASK;
                if (epnum) {
                        if ((wIndex & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN)
                                epnum = epnum*2 + 1;
                        else
                                epnum *= 2;
                } else {
                        epnum = 1; /* EP0 */
                }

                ep = bdc->bdc_ep_array[epnum];
                if (!ep) {
                        dev_err(bdc->dev, "ISSUE, GET_STATUS for invalid EP ?");
                        return -EINVAL;
                }
                if (ep->flags & BDC_EP_STALL)
                        usb_status |= 1 << USB_ENDPOINT_HALT;

                break;
        default:
                dev_err(bdc->dev, "Unknown recipient for get_status\n");
                return -EINVAL;
        }
        /* prepare a data stage for GET_STATUS */
        dev_dbg(bdc->dev, "usb_status=%08x\n", usb_status);
        *(__le16 *)bdc->ep0_response_buff = cpu_to_le16(usb_status);
        bdc->ep0_req.usb_req.length = 2;
        bdc->ep0_req.usb_req.buf = &bdc->ep0_response_buff;
        ep0_queue_data_stage(bdc);

        return 0;
}

static void ep0_set_sel_cmpl(struct usb_ep *_ep, struct usb_request *_req)
{
        /* ep0_set_sel_cmpl */
}

/* Queue data stage to handle 6 byte SET_SEL request */
static int ep0_set_sel(struct bdc *bdc,
                             struct usb_ctrlrequest *setup_pkt)
{
        struct bdc_ep   *ep;
        u16     wLength;

        dev_dbg(bdc->dev, "%s\n", __func__);
        wLength = le16_to_cpu(setup_pkt->wLength);
        if (unlikely(wLength != 6)) {
                dev_err(bdc->dev, "%s Wrong wLength:%d\n", __func__, wLength);
                return -EINVAL;
        }
        ep = bdc->bdc_ep_array[1];
        bdc->ep0_req.ep = ep;
        bdc->ep0_req.usb_req.length = 6;
        bdc->ep0_req.usb_req.buf = bdc->ep0_response_buff;
        bdc->ep0_req.usb_req.complete = ep0_set_sel_cmpl;
        ep0_queue_data_stage(bdc);

        return 0;
}

/*
 * Queue a 0 byte bd only if wLength is more than the length and and length is
 * a multiple of MaxPacket then queue 0 byte BD
 */
static int ep0_queue_zlp(struct bdc *bdc)
{
        int ret;

        dev_dbg(bdc->dev, "%s\n", __func__);
        bdc->ep0_req.ep = bdc->bdc_ep_array[1];
        bdc->ep0_req.usb_req.length = 0;
        bdc->ep0_req.usb_req.complete = NULL;
        bdc->ep0_state = WAIT_FOR_DATA_START;
        ret = bdc_queue_xfr(bdc, &bdc->ep0_req);
        if (ret) {
                dev_err(bdc->dev, "err queueing zlp :%d\n", ret);
                return ret;
        }
        bdc->ep0_state = WAIT_FOR_DATA_XMIT;

        return 0;
}

/* Control request handler */
static int handle_control_request(struct bdc *bdc)
{
        enum usb_device_state state = bdc->gadget.state;
        struct usb_ctrlrequest *setup_pkt;
        int delegate_setup = 0;
        int ret = 0;
        int config = 0;

        setup_pkt = &bdc->setup_pkt;
        dev_dbg(bdc->dev, "%s\n", __func__);
        if ((setup_pkt->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
                switch (setup_pkt->bRequest) {
                case USB_REQ_SET_ADDRESS:
                        dev_dbg(bdc->dev, "USB_REQ_SET_ADDRESS\n");
                        ret = ep0_set_address(bdc, setup_pkt);
                        bdc->devstatus &= DEVSTATUS_CLEAR;
                        break;

                case USB_REQ_SET_CONFIGURATION:
                        dev_dbg(bdc->dev, "USB_REQ_SET_CONFIGURATION\n");
                        if (state == USB_STATE_ADDRESS) {
                                usb_gadget_set_state(&bdc->gadget,
                                                        USB_STATE_CONFIGURED);
                        } else if (state == USB_STATE_CONFIGURED) {
                                /*
                                 * USB2 spec sec 9.4.7, if wValue is 0 then dev
                                 * is moved to addressed state
                                 */
                                config = le16_to_cpu(setup_pkt->wValue);
                                if (!config)
                                        usb_gadget_set_state(
                                                        &bdc->gadget,
                                                        USB_STATE_ADDRESS);
                        }
                        delegate_setup = 1;
                        break;

                case USB_REQ_SET_FEATURE:
                        dev_dbg(bdc->dev, "USB_REQ_SET_FEATURE\n");
                        ret = ep0_handle_feature(bdc, setup_pkt, 1);
                        break;

                case USB_REQ_CLEAR_FEATURE:
                        dev_dbg(bdc->dev, "USB_REQ_CLEAR_FEATURE\n");
                        ret = ep0_handle_feature(bdc, setup_pkt, 0);
                        break;

                case USB_REQ_GET_STATUS:
                        dev_dbg(bdc->dev, "USB_REQ_GET_STATUS\n");
                        ret = ep0_handle_status(bdc, setup_pkt);
                        break;

                case USB_REQ_SET_SEL:
                        dev_dbg(bdc->dev, "USB_REQ_SET_SEL\n");
                        ret = ep0_set_sel(bdc, setup_pkt);
                        break;

                case USB_REQ_SET_ISOCH_DELAY:
                        dev_warn(bdc->dev,
                        "USB_REQ_SET_ISOCH_DELAY not handled\n");
                        ret = 0;
                        break;
                default:
                        delegate_setup = 1;
                }
        } else {
                delegate_setup = 1;
        }

        if (delegate_setup) {
                spin_unlock(&bdc->lock);
                ret = bdc->gadget_driver->setup(&bdc->gadget, setup_pkt);
                spin_lock(&bdc->lock);
        }

        return ret;
}

/* EP0: Data stage started */
void bdc_xsf_ep0_data_start(struct bdc *bdc, struct bdc_sr *sreport)
{
        struct bdc_ep *ep;
        int ret = 0;

        dev_dbg(bdc->dev, "%s\n", __func__);
        ep = bdc->bdc_ep_array[1];
        /* If ep0 was stalled, the clear it first */
        if (ep->flags & BDC_EP_STALL) {
                ret = ep_set_halt(ep, 0);
                if (ret)
                        goto err;
        }
        if (bdc->ep0_state != WAIT_FOR_DATA_START)
                dev_warn(bdc->dev,
                        "Data stage not expected ep0_state:%s\n",
                        ep0_state_string[bdc->ep0_state]);

        ret = handle_control_request(bdc);
        if (ret == USB_GADGET_DELAYED_STATUS) {
                /*
                 * The ep0 state will remain WAIT_FOR_DATA_START till
                 * we received ep_queue on ep0
                 */
                bdc->delayed_status = true;
                return;
        }
        if (!ret) {
                bdc->ep0_state = WAIT_FOR_DATA_XMIT;
                dev_dbg(bdc->dev,
                        "ep0_state:%s", ep0_state_string[bdc->ep0_state]);
                return;
        }
err:
        ep0_stall(bdc);
}

/* EP0: status stage started */
void bdc_xsf_ep0_status_start(struct bdc *bdc, struct bdc_sr *sreport)
{
        struct usb_ctrlrequest *setup_pkt;
        struct bdc_ep *ep;
        int ret = 0;

        dev_dbg(bdc->dev,
                "%s ep0_state:%s",
                __func__, ep0_state_string[bdc->ep0_state]);
        ep = bdc->bdc_ep_array[1];

        /* check if ZLP was queued? */
        if (bdc->zlp_needed)
                bdc->zlp_needed = false;

        if (ep->flags & BDC_EP_STALL) {
                ret = ep_set_halt(ep, 0);
                if (ret)
                        goto err;
        }

        if ((bdc->ep0_state != WAIT_FOR_STATUS_START) &&
                                (bdc->ep0_state != WAIT_FOR_DATA_XMIT))
                dev_err(bdc->dev,
                        "Status stage recv but ep0_state:%s\n",
                        ep0_state_string[bdc->ep0_state]);

        /* check if data stage is in progress ? */
        if (bdc->ep0_state == WAIT_FOR_DATA_XMIT) {
                bdc->ep0_state = STATUS_PENDING;
                /* Status stage will be queued upon Data stage transmit event */
                dev_dbg(bdc->dev,
                        "status started but data  not transmitted yet\n");
                return;
        }
        setup_pkt = &bdc->setup_pkt;

        /*
         * 2 stage setup then only process the setup, for 3 stage setup the date
         * stage is already handled
         */
        if (!le16_to_cpu(setup_pkt->wLength)) {
                ret = handle_control_request(bdc);
                if (ret == USB_GADGET_DELAYED_STATUS) {
                        bdc->delayed_status = true;
                        /* ep0_state will remain WAIT_FOR_STATUS_START */
                        return;
                }
        }
        if (!ret) {
                /* Queue a status stage BD */
                ep0_queue_status_stage(bdc);
                bdc->ep0_state = WAIT_FOR_STATUS_XMIT;
                dev_dbg(bdc->dev,
                        "ep0_state:%s", ep0_state_string[bdc->ep0_state]);
                return;
        }
err:
        ep0_stall(bdc);
}

/* Helper function to update ep0 upon SR with xsf_succ or xsf_short */
static void ep0_xsf_complete(struct bdc *bdc, struct bdc_sr *sreport)
{
        dev_dbg(bdc->dev, "%s\n", __func__);
        switch (bdc->ep0_state) {
        case WAIT_FOR_DATA_XMIT:
                bdc->ep0_state = WAIT_FOR_STATUS_START;
                break;
        case WAIT_FOR_STATUS_XMIT:
                bdc->ep0_state = WAIT_FOR_SETUP;
                if (bdc->test_mode) {
                        int ret;

                        dev_dbg(bdc->dev, "test_mode:%d\n", bdc->test_mode);
                        ret = bdc_set_test_mode(bdc);
                        if (ret < 0) {
                                dev_err(bdc->dev, "Err in setting Test mode\n");
                                return;
                        }
                        bdc->test_mode = 0;
                }
                break;
        case STATUS_PENDING:
                bdc_xsf_ep0_status_start(bdc, sreport);
                break;

        default:
                dev_err(bdc->dev,
                        "Unknown ep0_state:%s\n",
                        ep0_state_string[bdc->ep0_state]);

        }
}

/* xfr completion status report handler */
void bdc_sr_xsf(struct bdc *bdc, struct bdc_sr *sreport)
{
        struct bdc_ep *ep;
        u32 sr_status;
        u8 ep_num;

        ep_num = (le32_to_cpu(sreport->offset[3])>>4) & 0x1f;
        ep = bdc->bdc_ep_array[ep_num];
        if (!ep || !(ep->flags & BDC_EP_ENABLED)) {
                dev_err(bdc->dev, "xsf for ep not enabled\n");
                return;
        }
        /*
         * check if this transfer is after link went from U3->U0 due
         * to remote wakeup
         */
        if (bdc->devstatus & FUNC_WAKE_ISSUED) {
                bdc->devstatus &= ~(FUNC_WAKE_ISSUED);
                dev_dbg(bdc->dev, "%s clearing FUNC_WAKE_ISSUED flag\n",
                                                                __func__);
        }
        sr_status = XSF_STS(le32_to_cpu(sreport->offset[3]));
        dev_dbg_ratelimited(bdc->dev, "%s sr_status=%d ep:%s\n",
                                        __func__, sr_status, ep->name);

        switch (sr_status) {
        case XSF_SUCC:
        case XSF_SHORT:
                handle_xsr_succ_status(bdc, ep, sreport);
                if (ep_num == 1)
                        ep0_xsf_complete(bdc, sreport);
                break;

        case XSF_SETUP_RECV:
        case XSF_DATA_START:
        case XSF_STATUS_START:
                if (ep_num != 1) {
                        dev_err(bdc->dev,
                                "ep0 related packets on non ep0 endpoint");
                        return;
                }
                bdc->sr_xsf_ep0[sr_status - XSF_SETUP_RECV](bdc, sreport);
                break;

        case XSF_BABB:
                if (ep_num == 1) {
                        dev_dbg(bdc->dev, "Babble on ep0 zlp_need:%d\n",
                                                        bdc->zlp_needed);
                        /*
                         * If the last completed transfer had wLength >Data Len,
                         * and Len is multiple of MaxPacket,then queue ZLP
                         */
                        if (bdc->zlp_needed) {
                                /* queue 0 length bd */
                                ep0_queue_zlp(bdc);
                                return;
                        }
                }
                dev_warn(bdc->dev, "Babble on ep not handled\n");
                break;
        default:
                dev_warn(bdc->dev, "sr status not handled:%x\n", sr_status);
                break;
        }
}

static int bdc_gadget_ep_queue(struct usb_ep *_ep,
                                struct usb_request *_req, gfp_t gfp_flags)
{
        struct bdc_req *req;
        unsigned long flags;
        struct bdc_ep *ep;
        struct bdc *bdc;
        int ret;

        if (!_ep || !_ep->desc)
                return -ESHUTDOWN;

        if (!_req || !_req->complete || !_req->buf)
                return -EINVAL;

        ep = to_bdc_ep(_ep);
        req = to_bdc_req(_req);
        bdc = ep->bdc;
        dev_dbg(bdc->dev, "%s ep:%p req:%p\n", __func__, ep, req);
        dev_dbg(bdc->dev, "queuing request %p to %s length %d zero:%d\n",
                                _req, ep->name, _req->length, _req->zero);

        if (!ep->usb_ep.desc) {
                dev_warn(bdc->dev,
                        "trying to queue req %p to disabled %s\n",
                        _req, ep->name);
                return -ESHUTDOWN;
        }

        if (_req->length > MAX_XFR_LEN) {
                dev_warn(bdc->dev,
                        "req length > supported MAX:%d requested:%d\n",
                        MAX_XFR_LEN, _req->length);
                return -EOPNOTSUPP;
        }
        spin_lock_irqsave(&bdc->lock, flags);
        if (ep == bdc->bdc_ep_array[1])
                ret = ep0_queue(ep, req);
        else
                ret = ep_queue(ep, req);

        spin_unlock_irqrestore(&bdc->lock, flags);

        return ret;
}

static int bdc_gadget_ep_dequeue(struct usb_ep *_ep,
                                  struct usb_request *_req)
{
        struct bdc_req *req;
        unsigned long flags;
        struct bdc_ep *ep;
        struct bdc *bdc;
        int ret;

        if (!_ep || !_req)
                return -EINVAL;

        ep = to_bdc_ep(_ep);
        req = to_bdc_req(_req);
        bdc = ep->bdc;
        dev_dbg(bdc->dev, "%s ep:%s req:%p\n", __func__, ep->name, req);
        bdc_dbg_bd_list(bdc, ep);
        spin_lock_irqsave(&bdc->lock, flags);
        /* make sure it's still queued on this endpoint */
        list_for_each_entry(req, &ep->queue, queue) {
                if (&req->usb_req == _req)
                        break;
        }
        if (&req->usb_req != _req) {
                spin_unlock_irqrestore(&bdc->lock, flags);
                dev_err(bdc->dev, "usb_req !=req n");
                return -EINVAL;
        }
        ret = ep_dequeue(ep, req);
        if (ret) {
                ret = -EOPNOTSUPP;
                goto err;
        }
        bdc_req_complete(ep, req, -ECONNRESET);

err:
        bdc_dbg_bd_list(bdc, ep);
        spin_unlock_irqrestore(&bdc->lock, flags);

        return ret;
}

static int bdc_gadget_ep_set_halt(struct usb_ep *_ep, int value)
{
        unsigned long flags;
        struct bdc_ep *ep;
        struct bdc *bdc;
        int ret;

        ep = to_bdc_ep(_ep);
        bdc = ep->bdc;
        dev_dbg(bdc->dev, "%s ep:%s value=%d\n", __func__, ep->name, value);
        spin_lock_irqsave(&bdc->lock, flags);
        if (usb_endpoint_xfer_isoc(ep->usb_ep.desc))
                ret = -EINVAL;
        else if (!list_empty(&ep->queue))
                ret = -EAGAIN;
        else
                ret = ep_set_halt(ep, value);

        spin_unlock_irqrestore(&bdc->lock, flags);

        return ret;
}

static struct usb_request *bdc_gadget_alloc_request(struct usb_ep *_ep,
                                                     gfp_t gfp_flags)
{
        struct bdc_req *req;
        struct bdc_ep *ep;

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

        ep = to_bdc_ep(_ep);
        req->ep = ep;
        req->epnum = ep->ep_num;
        req->usb_req.dma = DMA_ADDR_INVALID;
        dev_dbg(ep->bdc->dev, "%s ep:%s req:%p\n", __func__, ep->name, req);

        return &req->usb_req;
}

static void bdc_gadget_free_request(struct usb_ep *_ep,
                                     struct usb_request *_req)
{
        struct bdc_req *req;

        req = to_bdc_req(_req);
        kfree(req);
}

/* endpoint operations */

/* configure endpoint and also allocate resources */
static int bdc_gadget_ep_enable(struct usb_ep *_ep,
                                 const struct usb_endpoint_descriptor *desc)
{
        unsigned long flags;
        struct bdc_ep *ep;
        struct bdc *bdc;
        int ret;

        if (!_ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
                pr_debug("bdc_gadget_ep_enable invalid parameters\n");
                return -EINVAL;
        }

        if (!desc->wMaxPacketSize) {
                pr_debug("bdc_gadget_ep_enable missing wMaxPacketSize\n");
                return -EINVAL;
        }

        ep = to_bdc_ep(_ep);
        bdc = ep->bdc;

        /* Sanity check, upper layer will not send enable for ep0 */
        if (ep == bdc->bdc_ep_array[1])
                return -EINVAL;

        if (!bdc->gadget_driver
            || bdc->gadget.speed == USB_SPEED_UNKNOWN) {
                return -ESHUTDOWN;
        }

        dev_dbg(bdc->dev, "%s Enabling %s\n", __func__, ep->name);
        spin_lock_irqsave(&bdc->lock, flags);
        ep->desc = desc;
        ep->comp_desc = _ep->comp_desc;
        ret = bdc_ep_enable(ep);
        spin_unlock_irqrestore(&bdc->lock, flags);

        return ret;
}

static int bdc_gadget_ep_disable(struct usb_ep *_ep)
{
        unsigned long flags;
        struct bdc_ep *ep;
        struct bdc *bdc;
        int ret;

        if (!_ep) {
                pr_debug("bdc: invalid parameters\n");
                return -EINVAL;
        }
        ep = to_bdc_ep(_ep);
        bdc = ep->bdc;

        /* Upper layer will not call this for ep0, but do a sanity check */
        if (ep == bdc->bdc_ep_array[1]) {
                dev_warn(bdc->dev, "%s called for ep0\n", __func__);
                return -EINVAL;
        }
        dev_dbg(bdc->dev,
                "%s() ep:%s ep->flags:%08x\n",
                __func__, ep->name, ep->flags);

        if (!(ep->flags & BDC_EP_ENABLED)) {
                dev_warn(bdc->dev, "%s is already disabled\n", ep->name);
                return 0;
        }
        spin_lock_irqsave(&bdc->lock, flags);
        ret = bdc_ep_disable(ep);
        spin_unlock_irqrestore(&bdc->lock, flags);

        return ret;
}

static const struct usb_ep_ops bdc_gadget_ep_ops = {
        .enable = bdc_gadget_ep_enable,
        .disable = bdc_gadget_ep_disable,
        .alloc_request = bdc_gadget_alloc_request,
        .free_request = bdc_gadget_free_request,
        .queue = bdc_gadget_ep_queue,
        .dequeue = bdc_gadget_ep_dequeue,
        .set_halt = bdc_gadget_ep_set_halt
};

/* dir = 1 is IN */
static int init_ep(struct bdc *bdc, u32 epnum, u32 dir)
{
        struct bdc_ep *ep;

        dev_dbg(bdc->dev, "%s epnum=%d dir=%d\n", __func__, epnum, dir);
        ep = kzalloc(sizeof(*ep), GFP_KERNEL);
        if (!ep)
                return -ENOMEM;

        ep->bdc = bdc;
        ep->dir = dir;

        if (dir)
                ep->usb_ep.caps.dir_in = true;
        else
                ep->usb_ep.caps.dir_out = true;

        /* ep->ep_num is the index inside bdc_ep */
        if (epnum == 1) {
                ep->ep_num = 1;
                bdc->bdc_ep_array[ep->ep_num] = ep;
                snprintf(ep->name, sizeof(ep->name), "ep%d", epnum - 1);
                usb_ep_set_maxpacket_limit(&ep->usb_ep, EP0_MAX_PKT_SIZE);
                ep->usb_ep.caps.type_control = true;
                ep->comp_desc = NULL;
                bdc->gadget.ep0 = &ep->usb_ep;
        } else {
                if (dir)
                        ep->ep_num = epnum * 2 - 1;
                else
                        ep->ep_num = epnum * 2 - 2;

                bdc->bdc_ep_array[ep->ep_num] = ep;
                snprintf(ep->name, sizeof(ep->name), "ep%d%s", epnum - 1,
                         dir & 1 ? "in" : "out");

                usb_ep_set_maxpacket_limit(&ep->usb_ep, 1024);
                ep->usb_ep.caps.type_iso = true;
                ep->usb_ep.caps.type_bulk = true;
                ep->usb_ep.caps.type_int = true;
                ep->usb_ep.max_streams = 0;
                list_add_tail(&ep->usb_ep.ep_list, &bdc->gadget.ep_list);
        }
        ep->usb_ep.ops = &bdc_gadget_ep_ops;
        ep->usb_ep.name = ep->name;
        ep->flags = 0;
        ep->ignore_next_sr = false;
        dev_dbg(bdc->dev, "ep=%p ep->usb_ep.name=%s epnum=%d ep->epnum=%d\n",
                                ep, ep->usb_ep.name, epnum, ep->ep_num);

        INIT_LIST_HEAD(&ep->queue);

        return 0;
}

/* Init all ep */
int bdc_init_ep(struct bdc *bdc)
{
        u8 epnum;
        int ret;

        dev_dbg(bdc->dev, "%s()\n", __func__);
        INIT_LIST_HEAD(&bdc->gadget.ep_list);
        /* init ep0 */
        ret = init_ep(bdc, 1, 0);
        if (ret) {
                dev_err(bdc->dev, "init ep ep0 fail %d\n", ret);
                return ret;
        }

        for (epnum = 2; epnum <= bdc->num_eps / 2; epnum++) {
                /* OUT */
                ret = init_ep(bdc, epnum, 0);
                if (ret) {
                        dev_err(bdc->dev,
                                "init ep failed for:%d error: %d\n",
                                epnum, ret);
                        return ret;
                }

                /* IN */
                ret = init_ep(bdc, epnum, 1);
                if (ret) {
                        dev_err(bdc->dev,
                                "init ep failed for:%d error: %d\n",
                                epnum, ret);
                        return ret;
                }
        }

        return 0;
}