// SPDX-License-Identifier: GPL-2.0
/*
 * MUSB OTG driver core code
 *
 * Copyright 2005 Mentor Graphics Corporation
 * Copyright (C) 2005-2006 by Texas Instruments
 * Copyright (C) 2006-2007 Nokia Corporation
 */

/*
 * Inventra (Multipoint) Dual-Role Controller Driver for Linux.
 *
 * This consists of a Host Controller Driver (HCD) and a peripheral
 * controller driver implementing the "Gadget" API; OTG support is
 * in the works.  These are normal Linux-USB controller drivers which
 * use IRQs and have no dedicated thread.
 *
 * This version of the driver has only been used with products from
 * Texas Instruments.  Those products integrate the Inventra logic
 * with other DMA, IRQ, and bus modules, as well as other logic that
 * needs to be reflected in this driver.
 *
 *
 * NOTE:  the original Mentor code here was pretty much a collection
 * of mechanisms that don't seem to have been fully integrated/working
 * for *any* Linux kernel version.  This version aims at Linux 2.6.now,
 * Key open issues include:
 *
 *  - Lack of host-side transaction scheduling, for all transfer types.
 *    The hardware doesn't do it; instead, software must.
 *
 *    This is not an issue for OTG devices that don't support external
 *    hubs, but for more "normal" USB hosts it's a user issue that the
 *    "multipoint" support doesn't scale in the expected ways.  That
 *    includes DaVinci EVM in a common non-OTG mode.
 *
 *      * Control and bulk use dedicated endpoints, and there's as
 *        yet no mechanism to either (a) reclaim the hardware when
 *        peripherals are NAKing, which gets complicated with bulk
 *        endpoints, or (b) use more than a single bulk endpoint in
 *        each direction.
 *
 *        RESULT:  one device may be perceived as blocking another one.
 *
 *      * Interrupt and isochronous will dynamically allocate endpoint
 *        hardware, but (a) there's no record keeping for bandwidth;
 *        (b) in the common case that few endpoints are available, there
 *        is no mechanism to reuse endpoints to talk to multiple devices.
 *
 *        RESULT:  At one extreme, bandwidth can be overcommitted in
 *        some hardware configurations, no faults will be reported.
 *        At the other extreme, the bandwidth capabilities which do
 *        exist tend to be severely undercommitted.  You can't yet hook
 *        up both a keyboard and a mouse to an external USB hub.
 */

/*
 * This gets many kinds of configuration information:
 *      - Kconfig for everything user-configurable
 *      - platform_device for addressing, irq, and platform_data
 *      - platform_data is mostly for board-specific information
 *        (plus recentrly, SOC or family details)
 *
 * Most of the conditional compilation will (someday) vanish.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/kobject.h>
#include <linux/prefetch.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/dma-mapping.h>
#include <linux/usb.h>
#include <linux/usb/of.h>

#include "musb_core.h"
#include "musb_trace.h"

#define TA_WAIT_BCON(m) max_t(int, (m)->a_wait_bcon, OTG_TIME_A_WAIT_BCON)


#define DRIVER_AUTHOR "Mentor Graphics, Texas Instruments, Nokia"
#define DRIVER_DESC "Inventra Dual-Role USB Controller Driver"

#define MUSB_VERSION "6.0"

#define DRIVER_INFO DRIVER_DESC ", v" MUSB_VERSION

#define MUSB_DRIVER_NAME "musb-hdrc"
const char musb_driver_name[] = MUSB_DRIVER_NAME;

MODULE_DESCRIPTION(DRIVER_INFO);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" MUSB_DRIVER_NAME);


/*-------------------------------------------------------------------------*/

static inline struct musb *dev_to_musb(struct device *dev)
{
        return dev_get_drvdata(dev);
}

enum musb_mode musb_get_mode(struct device *dev)
{
        enum usb_dr_mode mode;

        mode = usb_get_dr_mode(dev);
        switch (mode) {
        case USB_DR_MODE_HOST:
                return MUSB_HOST;
        case USB_DR_MODE_PERIPHERAL:
                return MUSB_PERIPHERAL;
        case USB_DR_MODE_OTG:
        case USB_DR_MODE_UNKNOWN:
        default:
                return MUSB_OTG;
        }
}
EXPORT_SYMBOL_GPL(musb_get_mode);

/*-------------------------------------------------------------------------*/

static int musb_ulpi_read(struct usb_phy *phy, u32 reg)
{
        void __iomem *addr = phy->io_priv;
        int     i = 0;
        u8      r;
        u8      power;
        int     ret;

        pm_runtime_get_sync(phy->io_dev);

        /* Make sure the transceiver is not in low power mode */
        power = musb_readb(addr, MUSB_POWER);
        power &= ~MUSB_POWER_SUSPENDM;
        musb_writeb(addr, MUSB_POWER, power);

        /* REVISIT: musbhdrc_ulpi_an.pdf recommends setting the
         * ULPICarKitControlDisableUTMI after clearing POWER_SUSPENDM.
         */

        musb_writeb(addr, MUSB_ULPI_REG_ADDR, (u8)reg);
        musb_writeb(addr, MUSB_ULPI_REG_CONTROL,
                        MUSB_ULPI_REG_REQ | MUSB_ULPI_RDN_WR);

        while (!(musb_readb(addr, MUSB_ULPI_REG_CONTROL)
                                & MUSB_ULPI_REG_CMPLT)) {
                i++;
                if (i == 10000) {
                        ret = -ETIMEDOUT;
                        goto out;
                }

        }
        r = musb_readb(addr, MUSB_ULPI_REG_CONTROL);
        r &= ~MUSB_ULPI_REG_CMPLT;
        musb_writeb(addr, MUSB_ULPI_REG_CONTROL, r);

        ret = musb_readb(addr, MUSB_ULPI_REG_DATA);

out:
        pm_runtime_put(phy->io_dev);

        return ret;
}

static int musb_ulpi_write(struct usb_phy *phy, u32 val, u32 reg)
{
        void __iomem *addr = phy->io_priv;
        int     i = 0;
        u8      r = 0;
        u8      power;
        int     ret = 0;

        pm_runtime_get_sync(phy->io_dev);

        /* Make sure the transceiver is not in low power mode */
        power = musb_readb(addr, MUSB_POWER);
        power &= ~MUSB_POWER_SUSPENDM;
        musb_writeb(addr, MUSB_POWER, power);

        musb_writeb(addr, MUSB_ULPI_REG_ADDR, (u8)reg);
        musb_writeb(addr, MUSB_ULPI_REG_DATA, (u8)val);
        musb_writeb(addr, MUSB_ULPI_REG_CONTROL, MUSB_ULPI_REG_REQ);

        while (!(musb_readb(addr, MUSB_ULPI_REG_CONTROL)
                                & MUSB_ULPI_REG_CMPLT)) {
                i++;
                if (i == 10000) {
                        ret = -ETIMEDOUT;
                        goto out;
                }
        }

        r = musb_readb(addr, MUSB_ULPI_REG_CONTROL);
        r &= ~MUSB_ULPI_REG_CMPLT;
        musb_writeb(addr, MUSB_ULPI_REG_CONTROL, r);

out:
        pm_runtime_put(phy->io_dev);

        return ret;
}

static struct usb_phy_io_ops musb_ulpi_access = {
        .read = musb_ulpi_read,
        .write = musb_ulpi_write,
};

/*-------------------------------------------------------------------------*/

static u32 musb_default_fifo_offset(u8 epnum)
{
        return 0x20 + (epnum * 4);
}

/* "flat" mapping: each endpoint has its own i/o address */
static void musb_flat_ep_select(void __iomem *mbase, u8 epnum)
{
}

static u32 musb_flat_ep_offset(u8 epnum, u16 offset)
{
        return 0x100 + (0x10 * epnum) + offset;
}

/* "indexed" mapping: INDEX register controls register bank select */
static void musb_indexed_ep_select(void __iomem *mbase, u8 epnum)
{
        musb_writeb(mbase, MUSB_INDEX, epnum);
}

static u32 musb_indexed_ep_offset(u8 epnum, u16 offset)
{
        return 0x10 + offset;
}

static u32 musb_default_busctl_offset(u8 epnum, u16 offset)
{
        return 0x80 + (0x08 * epnum) + offset;
}

static u8 musb_default_readb(const void __iomem *addr, unsigned offset)
{
        u8 data =  __raw_readb(addr + offset);

        trace_musb_readb(__builtin_return_address(0), addr, offset, data);
        return data;
}

static void musb_default_writeb(void __iomem *addr, unsigned offset, u8 data)
{
        trace_musb_writeb(__builtin_return_address(0), addr, offset, data);
        __raw_writeb(data, addr + offset);
}

static u16 musb_default_readw(const void __iomem *addr, unsigned offset)
{
        u16 data = __raw_readw(addr + offset);

        trace_musb_readw(__builtin_return_address(0), addr, offset, data);
        return data;
}

static void musb_default_writew(void __iomem *addr, unsigned offset, u16 data)
{
        trace_musb_writew(__builtin_return_address(0), addr, offset, data);
        __raw_writew(data, addr + offset);
}

/*
 * Load an endpoint's FIFO
 */
static void musb_default_write_fifo(struct musb_hw_ep *hw_ep, u16 len,
                                    const u8 *src)
{
        struct musb *musb = hw_ep->musb;
        void __iomem *fifo = hw_ep->fifo;

        if (unlikely(len == 0))
                return;

        prefetch((u8 *)src);

        dev_dbg(musb->controller, "%cX ep%d fifo %p count %d buf %p\n",
                        'T', hw_ep->epnum, fifo, len, src);

        /* we can't assume unaligned reads work */
        if (likely((0x01 & (unsigned long) src) == 0)) {
                u16     index = 0;

                /* best case is 32bit-aligned source address */
                if ((0x02 & (unsigned long) src) == 0) {
                        if (len >= 4) {
                                iowrite32_rep(fifo, src + index, len >> 2);
                                index += len & ~0x03;
                        }
                        if (len & 0x02) {
                                __raw_writew(*(u16 *)&src[index], fifo);
                                index += 2;
                        }
                } else {
                        if (len >= 2) {
                                iowrite16_rep(fifo, src + index, len >> 1);
                                index += len & ~0x01;
                        }
                }
                if (len & 0x01)
                        __raw_writeb(src[index], fifo);
        } else  {
                /* byte aligned */
                iowrite8_rep(fifo, src, len);
        }
}

/*
 * Unload an endpoint's FIFO
 */
static void musb_default_read_fifo(struct musb_hw_ep *hw_ep, u16 len, u8 *dst)
{
        struct musb *musb = hw_ep->musb;
        void __iomem *fifo = hw_ep->fifo;

        if (unlikely(len == 0))
                return;

        dev_dbg(musb->controller, "%cX ep%d fifo %p count %d buf %p\n",
                        'R', hw_ep->epnum, fifo, len, dst);

        /* we can't assume unaligned writes work */
        if (likely((0x01 & (unsigned long) dst) == 0)) {
                u16     index = 0;

                /* best case is 32bit-aligned destination address */
                if ((0x02 & (unsigned long) dst) == 0) {
                        if (len >= 4) {
                                ioread32_rep(fifo, dst, len >> 2);
                                index = len & ~0x03;
                        }
                        if (len & 0x02) {
                                *(u16 *)&dst[index] = __raw_readw(fifo);
                                index += 2;
                        }
                } else {
                        if (len >= 2) {
                                ioread16_rep(fifo, dst, len >> 1);
                                index = len & ~0x01;
                        }
                }
                if (len & 0x01)
                        dst[index] = __raw_readb(fifo);
        } else  {
                /* byte aligned */
                ioread8_rep(fifo, dst, len);
        }
}

/*
 * Old style IO functions
 */
u8 (*musb_readb)(const void __iomem *addr, unsigned offset);
EXPORT_SYMBOL_GPL(musb_readb);

void (*musb_writeb)(void __iomem *addr, unsigned offset, u8 data);
EXPORT_SYMBOL_GPL(musb_writeb);

u16 (*musb_readw)(const void __iomem *addr, unsigned offset);
EXPORT_SYMBOL_GPL(musb_readw);

void (*musb_writew)(void __iomem *addr, unsigned offset, u16 data);
EXPORT_SYMBOL_GPL(musb_writew);

u32 musb_readl(const void __iomem *addr, unsigned offset)
{
        u32 data = __raw_readl(addr + offset);

        trace_musb_readl(__builtin_return_address(0), addr, offset, data);
        return data;
}
EXPORT_SYMBOL_GPL(musb_readl);

void musb_writel(void __iomem *addr, unsigned offset, u32 data)
{
        trace_musb_writel(__builtin_return_address(0), addr, offset, data);
        __raw_writel(data, addr + offset);
}
EXPORT_SYMBOL_GPL(musb_writel);

#ifndef CONFIG_MUSB_PIO_ONLY
struct dma_controller *
(*musb_dma_controller_create)(struct musb *musb, void __iomem *base);
EXPORT_SYMBOL(musb_dma_controller_create);

void (*musb_dma_controller_destroy)(struct dma_controller *c);
EXPORT_SYMBOL(musb_dma_controller_destroy);
#endif

/*
 * New style IO functions
 */
void musb_read_fifo(struct musb_hw_ep *hw_ep, u16 len, u8 *dst)
{
        return hw_ep->musb->io.read_fifo(hw_ep, len, dst);
}

void musb_write_fifo(struct musb_hw_ep *hw_ep, u16 len, const u8 *src)
{
        return hw_ep->musb->io.write_fifo(hw_ep, len, src);
}

/*-------------------------------------------------------------------------*/

/* for high speed test mode; see USB 2.0 spec 7.1.20 */
static const u8 musb_test_packet[53] = {
        /* implicit SYNC then DATA0 to start */

        /* JKJKJKJK x9 */
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        /* JJKKJJKK x8 */
        0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
        /* JJJJKKKK x8 */
        0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee,
        /* JJJJJJJKKKKKKK x8 */
        0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        /* JJJJJJJK x8 */
        0x7f, 0xbf, 0xdf, 0xef, 0xf7, 0xfb, 0xfd,
        /* JKKKKKKK x10, JK */
        0xfc, 0x7e, 0xbf, 0xdf, 0xef, 0xf7, 0xfb, 0xfd, 0x7e

        /* implicit CRC16 then EOP to end */
};

void musb_load_testpacket(struct musb *musb)
{
        void __iomem    *regs = musb->endpoints[0].regs;

        musb_ep_select(musb->mregs, 0);
        musb_write_fifo(musb->control_ep,
                        sizeof(musb_test_packet), musb_test_packet);
        musb_writew(regs, MUSB_CSR0, MUSB_CSR0_TXPKTRDY);
}

/*-------------------------------------------------------------------------*/

/*
 * Handles OTG hnp timeouts, such as b_ase0_brst
 */
static void musb_otg_timer_func(struct timer_list *t)
{
        struct musb     *musb = from_timer(musb, t, otg_timer);
        unsigned long   flags;

        spin_lock_irqsave(&musb->lock, flags);
        switch (musb->xceiv->otg->state) {
        case OTG_STATE_B_WAIT_ACON:
                musb_dbg(musb,
                        "HNP: b_wait_acon timeout; back to b_peripheral");
                musb_g_disconnect(musb);
                musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
                musb->is_active = 0;
                break;
        case OTG_STATE_A_SUSPEND:
        case OTG_STATE_A_WAIT_BCON:
                musb_dbg(musb, "HNP: %s timeout",
                        usb_otg_state_string(musb->xceiv->otg->state));
                musb_platform_set_vbus(musb, 0);
                musb->xceiv->otg->state = OTG_STATE_A_WAIT_VFALL;
                break;
        default:
                musb_dbg(musb, "HNP: Unhandled mode %s",
                        usb_otg_state_string(musb->xceiv->otg->state));
        }
        spin_unlock_irqrestore(&musb->lock, flags);
}

/*
 * Stops the HNP transition. Caller must take care of locking.
 */
void musb_hnp_stop(struct musb *musb)
{
        struct usb_hcd  *hcd = musb->hcd;
        void __iomem    *mbase = musb->mregs;
        u8      reg;

        musb_dbg(musb, "HNP: stop from %s",
                        usb_otg_state_string(musb->xceiv->otg->state));

        switch (musb->xceiv->otg->state) {
        case OTG_STATE_A_PERIPHERAL:
                musb_g_disconnect(musb);
                musb_dbg(musb, "HNP: back to %s",
                        usb_otg_state_string(musb->xceiv->otg->state));
                break;
        case OTG_STATE_B_HOST:
                musb_dbg(musb, "HNP: Disabling HR");
                if (hcd)
                        hcd->self.is_b_host = 0;
                musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
                MUSB_DEV_MODE(musb);
                reg = musb_readb(mbase, MUSB_POWER);
                reg |= MUSB_POWER_SUSPENDM;
                musb_writeb(mbase, MUSB_POWER, reg);
                /* REVISIT: Start SESSION_REQUEST here? */
                break;
        default:
                musb_dbg(musb, "HNP: Stopping in unknown state %s",
                        usb_otg_state_string(musb->xceiv->otg->state));
        }

        /*
         * When returning to A state after HNP, avoid hub_port_rebounce(),
         * which cause occasional OPT A "Did not receive reset after connect"
         * errors.
         */
        musb->port1_status &= ~(USB_PORT_STAT_C_CONNECTION << 16);
}

static void musb_recover_from_babble(struct musb *musb);

static void musb_handle_intr_resume(struct musb *musb, u8 devctl)
{
        musb_dbg(musb, "RESUME (%s)",
                        usb_otg_state_string(musb->xceiv->otg->state));

        if (devctl & MUSB_DEVCTL_HM) {
                switch (musb->xceiv->otg->state) {
                case OTG_STATE_A_SUSPEND:
                        /* remote wakeup? */
                        musb->port1_status |=
                                        (USB_PORT_STAT_C_SUSPEND << 16)
                                        | MUSB_PORT_STAT_RESUME;
                        musb->rh_timer = jiffies
                                + msecs_to_jiffies(USB_RESUME_TIMEOUT);
                        musb->xceiv->otg->state = OTG_STATE_A_HOST;
                        musb->is_active = 1;
                        musb_host_resume_root_hub(musb);
                        schedule_delayed_work(&musb->finish_resume_work,
                                msecs_to_jiffies(USB_RESUME_TIMEOUT));
                        break;
                case OTG_STATE_B_WAIT_ACON:
                        musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
                        musb->is_active = 1;
                        MUSB_DEV_MODE(musb);
                        break;
                default:
                        WARNING("bogus %s RESUME (%s)\n",
                                "host",
                                usb_otg_state_string(musb->xceiv->otg->state));
                }
        } else {
                switch (musb->xceiv->otg->state) {
                case OTG_STATE_A_SUSPEND:
                        /* possibly DISCONNECT is upcoming */
                        musb->xceiv->otg->state = OTG_STATE_A_HOST;
                        musb_host_resume_root_hub(musb);
                        break;
                case OTG_STATE_B_WAIT_ACON:
                case OTG_STATE_B_PERIPHERAL:
                        /* disconnect while suspended?  we may
                         * not get a disconnect irq...
                         */
                        if ((devctl & MUSB_DEVCTL_VBUS)
                                        != (3 << MUSB_DEVCTL_VBUS_SHIFT)
                                        ) {
                                musb->int_usb |= MUSB_INTR_DISCONNECT;
                                musb->int_usb &= ~MUSB_INTR_SUSPEND;
                                break;
                        }
                        musb_g_resume(musb);
                        break;
                case OTG_STATE_B_IDLE:
                        musb->int_usb &= ~MUSB_INTR_SUSPEND;
                        break;
                default:
                        WARNING("bogus %s RESUME (%s)\n",
                                "peripheral",
                                usb_otg_state_string(musb->xceiv->otg->state));
                }
        }
}

/* return IRQ_HANDLED to tell the caller to return immediately */
static irqreturn_t musb_handle_intr_sessreq(struct musb *musb, u8 devctl)
{
        void __iomem *mbase = musb->mregs;

        if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS
                        && (devctl & MUSB_DEVCTL_BDEVICE)) {
                musb_dbg(musb, "SessReq while on B state");
                return IRQ_HANDLED;
        }

        musb_dbg(musb, "SESSION_REQUEST (%s)",
                usb_otg_state_string(musb->xceiv->otg->state));

        /* IRQ arrives from ID pin sense or (later, if VBUS power
         * is removed) SRP.  responses are time critical:
         *  - turn on VBUS (with silicon-specific mechanism)
         *  - go through A_WAIT_VRISE
         *  - ... to A_WAIT_BCON.
         * a_wait_vrise_tmout triggers VBUS_ERROR transitions
         */
        musb_writeb(mbase, MUSB_DEVCTL, MUSB_DEVCTL_SESSION);
        musb->ep0_stage = MUSB_EP0_START;
        musb->xceiv->otg->state = OTG_STATE_A_IDLE;
        MUSB_HST_MODE(musb);
        musb_platform_set_vbus(musb, 1);

        return IRQ_NONE;
}

static void musb_handle_intr_vbuserr(struct musb *musb, u8 devctl)
{
        int     ignore = 0;

        /* During connection as an A-Device, we may see a short
         * current spikes causing voltage drop, because of cable
         * and peripheral capacitance combined with vbus draw.
         * (So: less common with truly self-powered devices, where
         * vbus doesn't act like a power supply.)
         *
         * Such spikes are short; usually less than ~500 usec, max
         * of ~2 msec.  That is, they're not sustained overcurrent
         * errors, though they're reported using VBUSERROR irqs.
         *
         * Workarounds:  (a) hardware: use self powered devices.
         * (b) software:  ignore non-repeated VBUS errors.
         *
         * REVISIT:  do delays from lots of DEBUG_KERNEL checks
         * make trouble here, keeping VBUS < 4.4V ?
         */
        switch (musb->xceiv->otg->state) {
        case OTG_STATE_A_HOST:
                /* recovery is dicey once we've gotten past the
                 * initial stages of enumeration, but if VBUS
                 * stayed ok at the other end of the link, and
                 * another reset is due (at least for high speed,
                 * to redo the chirp etc), it might work OK...
                 */
        case OTG_STATE_A_WAIT_BCON:
        case OTG_STATE_A_WAIT_VRISE:
                if (musb->vbuserr_retry) {
                        void __iomem *mbase = musb->mregs;

                        musb->vbuserr_retry--;
                        ignore = 1;
                        devctl |= MUSB_DEVCTL_SESSION;
                        musb_writeb(mbase, MUSB_DEVCTL, devctl);
                } else {
                        musb->port1_status |=
                                  USB_PORT_STAT_OVERCURRENT
                                | (USB_PORT_STAT_C_OVERCURRENT << 16);
                }
                break;
        default:
                break;
        }

        dev_printk(ignore ? KERN_DEBUG : KERN_ERR, musb->controller,
                        "VBUS_ERROR in %s (%02x, %s), retry #%d, port1 %08x\n",
                        usb_otg_state_string(musb->xceiv->otg->state),
                        devctl,
                        ({ char *s;
                        switch (devctl & MUSB_DEVCTL_VBUS) {
                        case 0 << MUSB_DEVCTL_VBUS_SHIFT:
                                s = "<SessEnd"; break;
                        case 1 << MUSB_DEVCTL_VBUS_SHIFT:
                                s = "<AValid"; break;
                        case 2 << MUSB_DEVCTL_VBUS_SHIFT:
                                s = "<VBusValid"; break;
                        /* case 3 << MUSB_DEVCTL_VBUS_SHIFT: */
                        default:
                                s = "VALID"; break;
                        } s; }),
                        VBUSERR_RETRY_COUNT - musb->vbuserr_retry,
                        musb->port1_status);

        /* go through A_WAIT_VFALL then start a new session */
        if (!ignore)
                musb_platform_set_vbus(musb, 0);
}

static void musb_handle_intr_suspend(struct musb *musb, u8 devctl)
{
        musb_dbg(musb, "SUSPEND (%s) devctl %02x",
                usb_otg_state_string(musb->xceiv->otg->state), devctl);

        switch (musb->xceiv->otg->state) {
        case OTG_STATE_A_PERIPHERAL:
                /* We also come here if the cable is removed, since
                 * this silicon doesn't report ID-no-longer-grounded.
                 *
                 * We depend on T(a_wait_bcon) to shut us down, and
                 * hope users don't do anything dicey during this
                 * undesired detour through A_WAIT_BCON.
                 */
                musb_hnp_stop(musb);
                musb_host_resume_root_hub(musb);
                musb_root_disconnect(musb);
                musb_platform_try_idle(musb, jiffies
                                + msecs_to_jiffies(musb->a_wait_bcon
                                        ? : OTG_TIME_A_WAIT_BCON));

                break;
        case OTG_STATE_B_IDLE:
                if (!musb->is_active)
                        break;
                /* fall through */
        case OTG_STATE_B_PERIPHERAL:
                musb_g_suspend(musb);
                musb->is_active = musb->g.b_hnp_enable;
                if (musb->is_active) {
                        musb->xceiv->otg->state = OTG_STATE_B_WAIT_ACON;
                        musb_dbg(musb, "HNP: Setting timer for b_ase0_brst");
                        mod_timer(&musb->otg_timer, jiffies
                                + msecs_to_jiffies(
                                                OTG_TIME_B_ASE0_BRST));
                }
                break;
        case OTG_STATE_A_WAIT_BCON:
                if (musb->a_wait_bcon != 0)
                        musb_platform_try_idle(musb, jiffies
                                + msecs_to_jiffies(musb->a_wait_bcon));
                break;
        case OTG_STATE_A_HOST:
                musb->xceiv->otg->state = OTG_STATE_A_SUSPEND;
                musb->is_active = musb->hcd->self.b_hnp_enable;
                break;
        case OTG_STATE_B_HOST:
                /* Transition to B_PERIPHERAL, see 6.8.2.6 p 44 */
                musb_dbg(musb, "REVISIT: SUSPEND as B_HOST");
                break;
        default:
                /* "should not happen" */
                musb->is_active = 0;
                break;
        }
}

static void musb_handle_intr_connect(struct musb *musb, u8 devctl, u8 int_usb)
{
        struct usb_hcd *hcd = musb->hcd;

        musb->is_active = 1;
        musb->ep0_stage = MUSB_EP0_START;

        musb->intrtxe = musb->epmask;
        musb_writew(musb->mregs, MUSB_INTRTXE, musb->intrtxe);
        musb->intrrxe = musb->epmask & 0xfffe;
        musb_writew(musb->mregs, MUSB_INTRRXE, musb->intrrxe);
        musb_writeb(musb->mregs, MUSB_INTRUSBE, 0xf7);
        musb->port1_status &= ~(USB_PORT_STAT_LOW_SPEED
                                |USB_PORT_STAT_HIGH_SPEED
                                |USB_PORT_STAT_ENABLE
                                );
        musb->port1_status |= USB_PORT_STAT_CONNECTION
                                |(USB_PORT_STAT_C_CONNECTION << 16);

        /* high vs full speed is just a guess until after reset */
        if (devctl & MUSB_DEVCTL_LSDEV)
                musb->port1_status |= USB_PORT_STAT_LOW_SPEED;

        /* indicate new connection to OTG machine */
        switch (musb->xceiv->otg->state) {
        case OTG_STATE_B_PERIPHERAL:
                if (int_usb & MUSB_INTR_SUSPEND) {
                        musb_dbg(musb, "HNP: SUSPEND+CONNECT, now b_host");
                        int_usb &= ~MUSB_INTR_SUSPEND;
                        goto b_host;
                } else
                        musb_dbg(musb, "CONNECT as b_peripheral???");
                break;
        case OTG_STATE_B_WAIT_ACON:
                musb_dbg(musb, "HNP: CONNECT, now b_host");
b_host:
                musb->xceiv->otg->state = OTG_STATE_B_HOST;
                if (musb->hcd)
                        musb->hcd->self.is_b_host = 1;
                del_timer(&musb->otg_timer);
                break;
        default:
                if ((devctl & MUSB_DEVCTL_VBUS)
                                == (3 << MUSB_DEVCTL_VBUS_SHIFT)) {
                        musb->xceiv->otg->state = OTG_STATE_A_HOST;
                        if (hcd)
                                hcd->self.is_b_host = 0;
                }
                break;
        }

        musb_host_poke_root_hub(musb);

        musb_dbg(musb, "CONNECT (%s) devctl %02x",
                        usb_otg_state_string(musb->xceiv->otg->state), devctl);
}

static void musb_handle_intr_disconnect(struct musb *musb, u8 devctl)
{
        musb_dbg(musb, "DISCONNECT (%s) as %s, devctl %02x",
                        usb_otg_state_string(musb->xceiv->otg->state),
                        MUSB_MODE(musb), devctl);

        switch (musb->xceiv->otg->state) {
        case OTG_STATE_A_HOST:
        case OTG_STATE_A_SUSPEND:
                musb_host_resume_root_hub(musb);
                musb_root_disconnect(musb);
                if (musb->a_wait_bcon != 0)
                        musb_platform_try_idle(musb, jiffies
                                + msecs_to_jiffies(musb->a_wait_bcon));
                break;
        case OTG_STATE_B_HOST:
                /* REVISIT this behaves for "real disconnect"
                 * cases; make sure the other transitions from
                 * from B_HOST act right too.  The B_HOST code
                 * in hnp_stop() is currently not used...
                 */
                musb_root_disconnect(musb);
                if (musb->hcd)
                        musb->hcd->self.is_b_host = 0;
                musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
                MUSB_DEV_MODE(musb);
                musb_g_disconnect(musb);
                break;
        case OTG_STATE_A_PERIPHERAL:
                musb_hnp_stop(musb);
                musb_root_disconnect(musb);
                /* FALLTHROUGH */
        case OTG_STATE_B_WAIT_ACON:
                /* FALLTHROUGH */
        case OTG_STATE_B_PERIPHERAL:
        case OTG_STATE_B_IDLE:
                musb_g_disconnect(musb);
                break;
        default:
                WARNING("unhandled DISCONNECT transition (%s)\n",
                        usb_otg_state_string(musb->xceiv->otg->state));
                break;
        }
}

/*
 * mentor saves a bit: bus reset and babble share the same irq.
 * only host sees babble; only peripheral sees bus reset.
 */
static void musb_handle_intr_reset(struct musb *musb)
{
        if (is_host_active(musb)) {
                /*
                 * When BABBLE happens what we can depends on which
                 * platform MUSB is running, because some platforms
                 * implemented proprietary means for 'recovering' from
                 * Babble conditions. One such platform is AM335x. In
                 * most cases, however, the only thing we can do is
                 * drop the session.
                 */
                dev_err(musb->controller, "Babble\n");
                musb_recover_from_babble(musb);
        } else {
                musb_dbg(musb, "BUS RESET as %s",
                        usb_otg_state_string(musb->xceiv->otg->state));
                switch (musb->xceiv->otg->state) {
                case OTG_STATE_A_SUSPEND:
                        musb_g_reset(musb);
                        /* FALLTHROUGH */
                case OTG_STATE_A_WAIT_BCON:     /* OPT TD.4.7-900ms */
                        /* never use invalid T(a_wait_bcon) */
                        musb_dbg(musb, "HNP: in %s, %d msec timeout",
                                usb_otg_state_string(musb->xceiv->otg->state),
                                TA_WAIT_BCON(musb));
                        mod_timer(&musb->otg_timer, jiffies
                                + msecs_to_jiffies(TA_WAIT_BCON(musb)));
                        break;
                case OTG_STATE_A_PERIPHERAL:
                        del_timer(&musb->otg_timer);
                        musb_g_reset(musb);
                        break;
                case OTG_STATE_B_WAIT_ACON:
                        musb_dbg(musb, "HNP: RESET (%s), to b_peripheral",
                                usb_otg_state_string(musb->xceiv->otg->state));
                        musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
                        musb_g_reset(musb);
                        break;
                case OTG_STATE_B_IDLE:
                        musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
                        /* FALLTHROUGH */
                case OTG_STATE_B_PERIPHERAL:
                        musb_g_reset(musb);
                        break;
                default:
                        musb_dbg(musb, "Unhandled BUS RESET as %s",
                                usb_otg_state_string(musb->xceiv->otg->state));
                }
        }
}

/*
 * Interrupt Service Routine to record USB "global" interrupts.
 * Since these do not happen often and signify things of
 * paramount importance, it seems OK to check them individually;
 * the order of the tests is specified in the manual
 *
 * @param musb instance pointer
 * @param int_usb register contents
 * @param devctl
 * @param power
 */

static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
                                u8 devctl)
{
        irqreturn_t handled = IRQ_NONE;

        musb_dbg(musb, "<== DevCtl=%02x, int_usb=0x%x", devctl, int_usb);

        /* in host mode, the peripheral may issue remote wakeup.
         * in peripheral mode, the host may resume the link.
         * spurious RESUME irqs happen too, paired with SUSPEND.
         */
        if (int_usb & MUSB_INTR_RESUME) {
                musb_handle_intr_resume(musb, devctl);
                handled = IRQ_HANDLED;
        }

        /* see manual for the order of the tests */
        if (int_usb & MUSB_INTR_SESSREQ) {
                if (musb_handle_intr_sessreq(musb, devctl))
                        return IRQ_HANDLED;
                handled = IRQ_HANDLED;
        }

        if (int_usb & MUSB_INTR_VBUSERROR) {
                musb_handle_intr_vbuserr(musb, devctl);
                handled = IRQ_HANDLED;
        }

        if (int_usb & MUSB_INTR_SUSPEND) {
                musb_handle_intr_suspend(musb, devctl);
                handled = IRQ_HANDLED;
        }

        if (int_usb & MUSB_INTR_CONNECT) {
                musb_handle_intr_connect(musb, devctl, int_usb);
                handled = IRQ_HANDLED;
        }

        if (int_usb & MUSB_INTR_DISCONNECT) {
                musb_handle_intr_disconnect(musb, devctl);
                handled = IRQ_HANDLED;
        }

        if (int_usb & MUSB_INTR_RESET) {
                musb_handle_intr_reset(musb);
                handled = IRQ_HANDLED;
        }

#if 0
/* REVISIT ... this would be for multiplexing periodic endpoints, or
 * supporting transfer phasing to prevent exceeding ISO bandwidth
 * limits of a given frame or microframe.
 *
 * It's not needed for peripheral side, which dedicates endpoints;
 * though it _might_ use SOF irqs for other purposes.
 *
 * And it's not currently needed for host side, which also dedicates
 * endpoints, relies on TX/RX interval registers, and isn't claimed
 * to support ISO transfers yet.
 */
        if (int_usb & MUSB_INTR_SOF) {
                void __iomem *mbase = musb->mregs;
                struct musb_hw_ep       *ep;
                u8 epnum;
                u16 frame;

                dev_dbg(musb->controller, "START_OF_FRAME\n");
                handled = IRQ_HANDLED;

                /* start any periodic Tx transfers waiting for current frame */
                frame = musb_readw(mbase, MUSB_FRAME);
                ep = musb->endpoints;
                for (epnum = 1; (epnum < musb->nr_endpoints)
                                        && (musb->epmask >= (1 << epnum));
                                epnum++, ep++) {
                        /*
                         * FIXME handle framecounter wraps (12 bits)
                         * eliminate duplicated StartUrb logic
                         */
                        if (ep->dwWaitFrame >= frame) {
                                ep->dwWaitFrame = 0;
                                pr_debug("SOF --> periodic TX%s on %d\n",
                                        ep->tx_channel ? " DMA" : "",
                                        epnum);
                                if (!ep->tx_channel)
                                        musb_h_tx_start(musb, epnum);

                                else
                                        cppi_hostdma_start(musb, epnum);
                        }
                }               /* end of for loop */
        }
#endif

        schedule_delayed_work(&musb->irq_work, 0);

        return handled;
}

/*-------------------------------------------------------------------------*/

static void musb_disable_interrupts(struct musb *musb)
{
        void __iomem    *mbase = musb->mregs;
        u16     temp;

        /* disable interrupts */
        musb_writeb(mbase, MUSB_INTRUSBE, 0);
        musb->intrtxe = 0;
        musb_writew(mbase, MUSB_INTRTXE, 0);
        musb->intrrxe = 0;
        musb_writew(mbase, MUSB_INTRRXE, 0);

        /*  flush pending interrupts */
        temp = musb_readb(mbase, MUSB_INTRUSB);
        temp = musb_readw(mbase, MUSB_INTRTX);
        temp = musb_readw(mbase, MUSB_INTRRX);
}

static void musb_enable_interrupts(struct musb *musb)
{
        void __iomem    *regs = musb->mregs;

        /*  Set INT enable registers, enable interrupts */
        musb->intrtxe = musb->epmask;
        musb_writew(regs, MUSB_INTRTXE, musb->intrtxe);
        musb->intrrxe = musb->epmask & 0xfffe;
        musb_writew(regs, MUSB_INTRRXE, musb->intrrxe);
        musb_writeb(regs, MUSB_INTRUSBE, 0xf7);

}

/*
 * Program the HDRC to start (enable interrupts, dma, etc.).
 */
void musb_start(struct musb *musb)
{
        void __iomem    *regs = musb->mregs;
        u8              devctl = musb_readb(regs, MUSB_DEVCTL);
        u8              power;

        musb_dbg(musb, "<== devctl %02x", devctl);

        musb_enable_interrupts(musb);
        musb_writeb(regs, MUSB_TESTMODE, 0);

        power = MUSB_POWER_ISOUPDATE;
        /*
         * treating UNKNOWN as unspecified maximum speed, in which case
         * we will default to high-speed.
         */
        if (musb->config->maximum_speed == USB_SPEED_HIGH ||
                        musb->config->maximum_speed == USB_SPEED_UNKNOWN)
                power |= MUSB_POWER_HSENAB;
        musb_writeb(regs, MUSB_POWER, power);

        musb->is_active = 0;
        devctl = musb_readb(regs, MUSB_DEVCTL);
        devctl &= ~MUSB_DEVCTL_SESSION;

        /* session started after:
         * (a) ID-grounded irq, host mode;
         * (b) vbus present/connect IRQ, peripheral mode;
         * (c) peripheral initiates, using SRP
         */
        if (musb->port_mode != MUSB_HOST &&
                        musb->xceiv->otg->state != OTG_STATE_A_WAIT_BCON &&
                        (devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS) {
                musb->is_active = 1;
        } else {
                devctl |= MUSB_DEVCTL_SESSION;
        }

        musb_platform_enable(musb);
        musb_writeb(regs, MUSB_DEVCTL, devctl);
}

/*
 * Make the HDRC stop (disable interrupts, etc.);
 * reversible by musb_start
 * called on gadget driver unregister
 * with controller locked, irqs blocked
 * acts as a NOP unless some role activated the hardware
 */
void musb_stop(struct musb *musb)
{
        /* stop IRQs, timers, ... */
        musb_platform_disable(musb);
        musb_disable_interrupts(musb);
        musb_writeb(musb->mregs, MUSB_DEVCTL, 0);

        /* FIXME
         *  - mark host and/or peripheral drivers unusable/inactive
         *  - disable DMA (and enable it in HdrcStart)
         *  - make sure we can musb_start() after musb_stop(); with
         *    OTG mode, gadget driver module rmmod/modprobe cycles that
         *  - ...
         */
        musb_platform_try_idle(musb, 0);
}

/*-------------------------------------------------------------------------*/

/*
 * The silicon either has hard-wired endpoint configurations, or else
 * "dynamic fifo" sizing.  The driver has support for both, though at this
 * writing only the dynamic sizing is very well tested.   Since we switched
 * away from compile-time hardware parameters, we can no longer rely on
 * dead code elimination to leave only the relevant one in the object file.
 *
 * We don't currently use dynamic fifo setup capability to do anything
 * more than selecting one of a bunch of predefined configurations.
 */
static ushort fifo_mode;

/* "modprobe ... fifo_mode=1" etc */
module_param(fifo_mode, ushort, 0);
MODULE_PARM_DESC(fifo_mode, "initial endpoint configuration");

/*
 * tables defining fifo_mode values.  define more if you like.
 * for host side, make sure both halves of ep1 are set up.
 */

/* mode 0 - fits in 2KB */
static struct musb_fifo_cfg mode_0_cfg[] = {
{ .hw_ep_num = 1, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num = 1, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num = 2, .style = FIFO_RXTX, .maxpacket = 512, },
{ .hw_ep_num = 3, .style = FIFO_RXTX, .maxpacket = 256, },
{ .hw_ep_num = 4, .style = FIFO_RXTX, .maxpacket = 256, },
};

/* mode 1 - fits in 4KB */
static struct musb_fifo_cfg mode_1_cfg[] = {
{ .hw_ep_num = 1, .style = FIFO_TX,   .maxpacket = 512, .mode = BUF_DOUBLE, },
{ .hw_ep_num = 1, .style = FIFO_RX,   .maxpacket = 512, .mode = BUF_DOUBLE, },
{ .hw_ep_num = 2, .style = FIFO_RXTX, .maxpacket = 512, .mode = BUF_DOUBLE, },
{ .hw_ep_num = 3, .style = FIFO_RXTX, .maxpacket = 256, },
{ .hw_ep_num = 4, .style = FIFO_RXTX, .maxpacket = 256, },
};

/* mode 2 - fits in 4KB */
static struct musb_fifo_cfg mode_2_cfg[] = {
{ .hw_ep_num = 1, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num = 1, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num = 2, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num = 2, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num = 3, .style = FIFO_RXTX, .maxpacket = 960, },
{ .hw_ep_num = 4, .style = FIFO_RXTX, .maxpacket = 1024, },
};

/* mode 3 - fits in 4KB */
static struct musb_fifo_cfg mode_3_cfg[] = {
{ .hw_ep_num = 1, .style = FIFO_TX,   .maxpacket = 512, .mode = BUF_DOUBLE, },
{ .hw_ep_num = 1, .style = FIFO_RX,   .maxpacket = 512, .mode = BUF_DOUBLE, },
{ .hw_ep_num = 2, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num = 2, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num = 3, .style = FIFO_RXTX, .maxpacket = 256, },
{ .hw_ep_num = 4, .style = FIFO_RXTX, .maxpacket = 256, },
};

/* mode 4 - fits in 16KB */
static struct musb_fifo_cfg mode_4_cfg[] = {
{ .hw_ep_num =  1, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  1, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  2, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  2, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  3, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  3, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  4, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  4, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  5, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  5, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  6, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  6, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  7, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  7, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  8, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  8, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  9, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  9, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num = 10, .style = FIFO_TX,   .maxpacket = 256, },
{ .hw_ep_num = 10, .style = FIFO_RX,   .maxpacket = 64, },
{ .hw_ep_num = 11, .style = FIFO_TX,   .maxpacket = 256, },
{ .hw_ep_num = 11, .style = FIFO_RX,   .maxpacket = 64, },
{ .hw_ep_num = 12, .style = FIFO_TX,   .maxpacket = 256, },
{ .hw_ep_num = 12, .style = FIFO_RX,   .maxpacket = 64, },
{ .hw_ep_num = 13, .style = FIFO_RXTX, .maxpacket = 4096, },
{ .hw_ep_num = 14, .style = FIFO_RXTX, .maxpacket = 1024, },
{ .hw_ep_num = 15, .style = FIFO_RXTX, .maxpacket = 1024, },
};

/* mode 5 - fits in 8KB */
static struct musb_fifo_cfg mode_5_cfg[] = {
{ .hw_ep_num =  1, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  1, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  2, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  2, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  3, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  3, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  4, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  4, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  5, .style = FIFO_TX,   .maxpacket = 512, },
{ .hw_ep_num =  5, .style = FIFO_RX,   .maxpacket = 512, },
{ .hw_ep_num =  6, .style = FIFO_TX,   .maxpacket = 32, },
{ .hw_ep_num =  6, .style = FIFO_RX,   .maxpacket = 32, },
{ .hw_ep_num =  7, .style = FIFO_TX,   .maxpacket = 32, },
{ .hw_ep_num =  7, .style = FIFO_RX,   .maxpacket = 32, },
{ .hw_ep_num =  8, .style = FIFO_TX,   .maxpacket = 32, },
{ .hw_ep_num =  8, .style = FIFO_RX,   .maxpacket = 32, },
{ .hw_ep_num =  9, .style = FIFO_TX,   .maxpacket = 32, },
{ .hw_ep_num =  9, .style = FIFO_RX,   .maxpacket = 32, },
{ .hw_ep_num = 10, .style = FIFO_TX,   .maxpacket = 32, },
{ .hw_ep_num = 10, .style = FIFO_RX,   .maxpacket = 32, },
{ .hw_ep_num = 11, .style = FIFO_TX,   .maxpacket = 32, },
{ .hw_ep_num = 11, .style = FIFO_RX,   .maxpacket = 32, },
{ .hw_ep_num = 12, .style = FIFO_TX,   .maxpacket = 32, },
{ .hw_ep_num = 12, .style = FIFO_RX,   .maxpacket = 32, },
{ .hw_ep_num = 13, .style = FIFO_RXTX, .maxpacket = 512, },
{ .hw_ep_num = 14, .style = FIFO_RXTX, .maxpacket = 1024, },
{ .hw_ep_num = 15, .style = FIFO_RXTX, .maxpacket = 1024, },
};

/*
 * configure a fifo; for non-shared endpoints, this may be called
 * once for a tx fifo and once for an rx fifo.
 *
 * returns negative errno or offset for next fifo.
 */
static int
fifo_setup(struct musb *musb, struct musb_hw_ep  *hw_ep,
                const struct musb_fifo_cfg *cfg, u16 offset)
{
        void __iomem    *mbase = musb->mregs;
        int     size = 0;
        u16     maxpacket = cfg->maxpacket;
        u16     c_off = offset >> 3;
        u8      c_size;

        /* expect hw_ep has already been zero-initialized */

        size = ffs(max(maxpacket, (u16) 8)) - 1;
        maxpacket = 1 << size;

        c_size = size - 3;
        if (cfg->mode == BUF_DOUBLE) {
                if ((offset + (maxpacket << 1)) >
                                (1 << (musb->config->ram_bits + 2)))
                        return -EMSGSIZE;
                c_size |= MUSB_FIFOSZ_DPB;
        } else {
                if ((offset + maxpacket) > (1 << (musb->config->ram_bits + 2)))
                        return -EMSGSIZE;
        }

        /* configure the FIFO */
        musb_writeb(mbase, MUSB_INDEX, hw_ep->epnum);

        /* EP0 reserved endpoint for control, bidirectional;
         * EP1 reserved for bulk, two unidirectional halves.
         */
        if (hw_ep->epnum == 1)
                musb->bulk_ep = hw_ep;
        /* REVISIT error check:  be sure ep0 can both rx and tx ... */
        switch (cfg->style) {
        case FIFO_TX:
                musb_writeb(mbase, MUSB_TXFIFOSZ, c_size);
                musb_writew(mbase, MUSB_TXFIFOADD, c_off);
                hw_ep->tx_double_buffered = !!(c_size & MUSB_FIFOSZ_DPB);
                hw_ep->max_packet_sz_tx = maxpacket;
                break;
        case FIFO_RX:
                musb_writeb(mbase, MUSB_RXFIFOSZ, c_size);
                musb_writew(mbase, MUSB_RXFIFOADD, c_off);
                hw_ep->rx_double_buffered = !!(c_size & MUSB_FIFOSZ_DPB);
                hw_ep->max_packet_sz_rx = maxpacket;
                break;
        case FIFO_RXTX:
                musb_writeb(mbase, MUSB_TXFIFOSZ, c_size);
                musb_writew(mbase, MUSB_TXFIFOADD, c_off);
                hw_ep->rx_double_buffered = !!(c_size & MUSB_FIFOSZ_DPB);
                hw_ep->max_packet_sz_rx = maxpacket;

                musb_writeb(mbase, MUSB_RXFIFOSZ, c_size);
                musb_writew(mbase, MUSB_RXFIFOADD, c_off);
                hw_ep->tx_double_buffered = hw_ep->rx_double_buffered;
                hw_ep->max_packet_sz_tx = maxpacket;

                hw_ep->is_shared_fifo = true;
                break;
        }

        /* NOTE rx and tx endpoint irqs aren't managed separately,
         * which happens to be ok
         */
        musb->epmask |= (1 << hw_ep->epnum);

        return offset + (maxpacket << ((c_size & MUSB_FIFOSZ_DPB) ? 1 : 0));
}

static struct musb_fifo_cfg ep0_cfg = {
        .style = FIFO_RXTX, .maxpacket = 64,
};

static int ep_config_from_table(struct musb *musb)
{
        const struct musb_fifo_cfg      *cfg;
        unsigned                i, n;
        int                     offset;
        struct musb_hw_ep       *hw_ep = musb->endpoints;

        if (musb->config->fifo_cfg) {
                cfg = musb->config->fifo_cfg;
                n = musb->config->fifo_cfg_size;
                goto done;
        }

        switch (fifo_mode) {
        default:
                fifo_mode = 0;
                /* FALLTHROUGH */
        case 0:
                cfg = mode_0_cfg;
                n = ARRAY_SIZE(mode_0_cfg);
                break;
        case 1:
                cfg = mode_1_cfg;
                n = ARRAY_SIZE(mode_1_cfg);
                break;
        case 2:
                cfg = mode_2_cfg;
                n = ARRAY_SIZE(mode_2_cfg);
                break;
        case 3:
                cfg = mode_3_cfg;
                n = ARRAY_SIZE(mode_3_cfg);
                break;
        case 4:
                cfg = mode_4_cfg;
                n = ARRAY_SIZE(mode_4_cfg);
                break;
        case 5:
                cfg = mode_5_cfg;
                n = ARRAY_SIZE(mode_5_cfg);
                break;
        }

        pr_debug("%s: setup fifo_mode %d\n", musb_driver_name, fifo_mode);


done:
        offset = fifo_setup(musb, hw_ep, &ep0_cfg, 0);
        /* assert(offset > 0) */

        /* NOTE:  for RTL versions >= 1.400 EPINFO and RAMINFO would
         * be better than static musb->config->num_eps and DYN_FIFO_SIZE...
         */

        for (i = 0; i < n; i++) {
                u8      epn = cfg->hw_ep_num;

                if (epn >= musb->config->num_eps) {
                        pr_debug("%s: invalid ep %d\n",
                                        musb_driver_name, epn);
                        return -EINVAL;
                }
                offset = fifo_setup(musb, hw_ep + epn, cfg++, offset);
                if (offset < 0) {
                        pr_debug("%s: mem overrun, ep %d\n",
                                        musb_driver_name, epn);
                        return offset;
                }
                epn++;
                musb->nr_endpoints = max(epn, musb->nr_endpoints);
        }

        pr_debug("%s: %d/%d max ep, %d/%d memory\n",
                        musb_driver_name,
                        n + 1, musb->config->num_eps * 2 - 1,
                        offset, (1 << (musb->config->ram_bits + 2)));

        if (!musb->bulk_ep) {
                pr_debug("%s: missing bulk\n", musb_driver_name);
                return -EINVAL;
        }

        return 0;
}


/*
 * ep_config_from_hw - when MUSB_C_DYNFIFO_DEF is false
 * @param musb the controller
 */
static int ep_config_from_hw(struct musb *musb)
{
        u8 epnum = 0;
        struct musb_hw_ep *hw_ep;
        void __iomem *mbase = musb->mregs;
        int ret = 0;

        musb_dbg(musb, "<== static silicon ep config");

        /* FIXME pick up ep0 maxpacket size */

        for (epnum = 1; epnum < musb->config->num_eps; epnum++) {
                musb_ep_select(mbase, epnum);
                hw_ep = musb->endpoints + epnum;

                ret = musb_read_fifosize(musb, hw_ep, epnum);
                if (ret < 0)
                        break;

                /* FIXME set up hw_ep->{rx,tx}_double_buffered */

                /* pick an RX/TX endpoint for bulk */
                if (hw_ep->max_packet_sz_tx < 512
                                || hw_ep->max_packet_sz_rx < 512)
                        continue;

                /* REVISIT:  this algorithm is lazy, we should at least
                 * try to pick a double buffered endpoint.
                 */
                if (musb->bulk_ep)
                        continue;
                musb->bulk_ep = hw_ep;
        }

        if (!musb->bulk_ep) {
                pr_debug("%s: missing bulk\n", musb_driver_name);
                return -EINVAL;
        }

        return 0;
}

enum { MUSB_CONTROLLER_MHDRC, MUSB_CONTROLLER_HDRC, };

/* Initialize MUSB (M)HDRC part of the USB hardware subsystem;
 * configure endpoints, or take their config from silicon
 */
static int musb_core_init(u16 musb_type, struct musb *musb)
{
        u8 reg;
        char *type;
        char aInfo[90];
        void __iomem    *mbase = musb->mregs;
        int             status = 0;
        int             i;

        /* log core options (read using indexed model) */
        reg = musb_read_configdata(mbase);

        strcpy(aInfo, (reg & MUSB_CONFIGDATA_UTMIDW) ? "UTMI-16" : "UTMI-8");
        if (reg & MUSB_CONFIGDATA_DYNFIFO) {
                strcat(aInfo, ", dyn FIFOs");
                musb->dyn_fifo = true;
        }
        if (reg & MUSB_CONFIGDATA_MPRXE) {
                strcat(aInfo, ", bulk combine");
                musb->bulk_combine = true;
        }
        if (reg & MUSB_CONFIGDATA_MPTXE) {
                strcat(aInfo, ", bulk split");
                musb->bulk_split = true;
        }
        if (reg & MUSB_CONFIGDATA_HBRXE) {
                strcat(aInfo, ", HB-ISO Rx");
                musb->hb_iso_rx = true;
        }
        if (reg & MUSB_CONFIGDATA_HBTXE) {
                strcat(aInfo, ", HB-ISO Tx");
                musb->hb_iso_tx = true;
        }
        if (reg & MUSB_CONFIGDATA_SOFTCONE)
                strcat(aInfo, ", SoftConn");

        pr_debug("%s: ConfigData=0x%02x (%s)\n", musb_driver_name, reg, aInfo);

        if (MUSB_CONTROLLER_MHDRC == musb_type) {
                musb->is_multipoint = 1;
                type = "M";
        } else {
                musb->is_multipoint = 0;
                type = "";
                if (IS_ENABLED(CONFIG_USB) &&
                    !IS_ENABLED(CONFIG_USB_OTG_BLACKLIST_HUB)) {
                        pr_err("%s: kernel must blacklist external hubs\n",
                               musb_driver_name);
                }
        }

        /* log release info */
        musb->hwvers = musb_readw(mbase, MUSB_HWVERS);
        pr_debug("%s: %sHDRC RTL version %d.%d%s\n",
                 musb_driver_name, type, MUSB_HWVERS_MAJOR(musb->hwvers),
                 MUSB_HWVERS_MINOR(musb->hwvers),
                 (musb->hwvers & MUSB_HWVERS_RC) ? "RC" : "");

        /* configure ep0 */
        musb_configure_ep0(musb);

        /* discover endpoint configuration */
        musb->nr_endpoints = 1;
        musb->epmask = 1;

        if (musb->dyn_fifo)
                status = ep_config_from_table(musb);
        else
                status = ep_config_from_hw(musb);

        if (status < 0)
                return status;

        /* finish init, and print endpoint config */
        for (i = 0; i < musb->nr_endpoints; i++) {
                struct musb_hw_ep       *hw_ep = musb->endpoints + i;

                hw_ep->fifo = musb->io.fifo_offset(i) + mbase;
#if IS_ENABLED(CONFIG_USB_MUSB_TUSB6010)
                if (musb->ops->quirks & MUSB_IN_TUSB) {
                        hw_ep->fifo_async = musb->async + 0x400 +
                                musb->io.fifo_offset(i);
                        hw_ep->fifo_sync = musb->sync + 0x400 +
                                musb->io.fifo_offset(i);
                        hw_ep->fifo_sync_va =
                                musb->sync_va + 0x400 + musb->io.fifo_offset(i);

                        if (i == 0)
                                hw_ep->conf = mbase - 0x400 + TUSB_EP0_CONF;
                        else
                                hw_ep->conf = mbase + 0x400 +
                                        (((i - 1) & 0xf) << 2);
                }
#endif

                hw_ep->regs = musb->io.ep_offset(i, 0) + mbase;
                hw_ep->rx_reinit = 1;
                hw_ep->tx_reinit = 1;

                if (hw_ep->max_packet_sz_tx) {
                        musb_dbg(musb, "%s: hw_ep %d%s, %smax %d",
                                musb_driver_name, i,
                                hw_ep->is_shared_fifo ? "shared" : "tx",
                                hw_ep->tx_double_buffered
                                        ? "doublebuffer, " : "",
                                hw_ep->max_packet_sz_tx);
                }
                if (hw_ep->max_packet_sz_rx && !hw_ep->is_shared_fifo) {
                        musb_dbg(musb, "%s: hw_ep %d%s, %smax %d",
                                musb_driver_name, i,
                                "rx",
                                hw_ep->rx_double_buffered
                                        ? "doublebuffer, " : "",
                                hw_ep->max_packet_sz_rx);
                }
                if (!(hw_ep->max_packet_sz_tx || hw_ep->max_packet_sz_rx))
                        musb_dbg(musb, "hw_ep %d not configured", i);
        }

        return 0;
}

/*-------------------------------------------------------------------------*/

/*
 * handle all the irqs defined by the HDRC core. for now we expect:  other
 * irq sources (phy, dma, etc) will be handled first, musb->int_* values
 * will be assigned, and the irq will already have been acked.
 *
 * called in irq context with spinlock held, irqs blocked
 */
irqreturn_t musb_interrupt(struct musb *musb)
{
        irqreturn_t     retval = IRQ_NONE;
        unsigned long   status;
        unsigned long   epnum;
        u8              devctl;

        if (!musb->int_usb && !musb->int_tx && !musb->int_rx)
                return IRQ_NONE;

        devctl = musb_readb(musb->mregs, MUSB_DEVCTL);

        trace_musb_isr(musb);

        /**
         * According to Mentor Graphics' documentation, flowchart on page 98,
         * IRQ should be handled as follows:
         *
         * . Resume IRQ
         * . Session Request IRQ
         * . VBUS Error IRQ
         * . Suspend IRQ
         * . Connect IRQ
         * . Disconnect IRQ
         * . Reset/Babble IRQ
         * . SOF IRQ (we're not using this one)
         * . Endpoint 0 IRQ
         * . TX Endpoints
         * . RX Endpoints
         *
         * We will be following that flowchart in order to avoid any problems
         * that might arise with internal Finite State Machine.
         */

        if (musb->int_usb)
                retval |= musb_stage0_irq(musb, musb->int_usb, devctl);

        if (musb->int_tx & 1) {
                if (is_host_active(musb))
                        retval |= musb_h_ep0_irq(musb);
                else
                        retval |= musb_g_ep0_irq(musb);

                /* we have just handled endpoint 0 IRQ, clear it */
                musb->int_tx &= ~BIT(0);
        }

        status = musb->int_tx;

        for_each_set_bit(epnum, &status, 16) {
                retval = IRQ_HANDLED;
                if (is_host_active(musb))
                        musb_host_tx(musb, epnum);
                else
                        musb_g_tx(musb, epnum);
        }

        status = musb->int_rx;

        for_each_set_bit(epnum, &status, 16) {
                retval = IRQ_HANDLED;
                if (is_host_active(musb))
                        musb_host_rx(musb, epnum);
                else
                        musb_g_rx(musb, epnum);
        }

        return retval;
}
EXPORT_SYMBOL_GPL(musb_interrupt);

#ifndef CONFIG_MUSB_PIO_ONLY
static bool use_dma = 1;

/* "modprobe ... use_dma=0" etc */
module_param(use_dma, bool, 0644);
MODULE_PARM_DESC(use_dma, "enable/disable use of DMA");

void musb_dma_completion(struct musb *musb, u8 epnum, u8 transmit)
{
        /* called with controller lock already held */

        if (!epnum) {
                if (!is_cppi_enabled(musb)) {
                        /* endpoint 0 */
                        if (is_host_active(musb))
                                musb_h_ep0_irq(musb);
                        else
                                musb_g_ep0_irq(musb);
                }
        } else {
                /* endpoints 1..15 */
                if (transmit) {
                        if (is_host_active(musb))
                                musb_host_tx(musb, epnum);
                        else
                                musb_g_tx(musb, epnum);
                } else {
                        /* receive */
                        if (is_host_active(musb))
                                musb_host_rx(musb, epnum);
                        else
                                musb_g_rx(musb, epnum);
                }
        }
}
EXPORT_SYMBOL_GPL(musb_dma_completion);

#else
#define use_dma                 0
#endif

static int (*musb_phy_callback)(enum musb_vbus_id_status status);

/*
 * musb_mailbox - optional phy notifier function
 * @status phy state change
 *
 * Optionally gets called from the USB PHY. Note that the USB PHY must be
 * disabled at the point the phy_callback is registered or unregistered.
 */
int musb_mailbox(enum musb_vbus_id_status status)
{
        if (musb_phy_callback)
                return musb_phy_callback(status);

        return -ENODEV;
};
EXPORT_SYMBOL_GPL(musb_mailbox);

/*-------------------------------------------------------------------------*/

static ssize_t
mode_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct musb *musb = dev_to_musb(dev);
        unsigned long flags;
        int ret = -EINVAL;

        spin_lock_irqsave(&musb->lock, flags);
        ret = sprintf(buf, "%s\n", usb_otg_state_string(musb->xceiv->otg->state));
        spin_unlock_irqrestore(&musb->lock, flags);

        return ret;
}

static ssize_t
mode_store(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t n)
{
        struct musb     *musb = dev_to_musb(dev);
        unsigned long   flags;
        int             status;

        spin_lock_irqsave(&musb->lock, flags);
        if (sysfs_streq(buf, "host"))
                status = musb_platform_set_mode(musb, MUSB_HOST);
        else if (sysfs_streq(buf, "peripheral"))
                status = musb_platform_set_mode(musb, MUSB_PERIPHERAL);
        else if (sysfs_streq(buf, "otg"))
                status = musb_platform_set_mode(musb, MUSB_OTG);
        else
                status = -EINVAL;
        spin_unlock_irqrestore(&musb->lock, flags);

        return (status == 0) ? n : status;
}
static DEVICE_ATTR_RW(mode);

static ssize_t
vbus_store(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t n)
{
        struct musb     *musb = dev_to_musb(dev);
        unsigned long   flags;
        unsigned long   val;

        if (sscanf(buf, "%lu", &val) < 1) {
                dev_err(dev, "Invalid VBUS timeout ms value\n");
                return -EINVAL;
        }

        spin_lock_irqsave(&musb->lock, flags);
        /* force T(a_wait_bcon) to be zero/unlimited *OR* valid */
        musb->a_wait_bcon = val ? max_t(int, val, OTG_TIME_A_WAIT_BCON) : 0 ;
        if (musb->xceiv->otg->state == OTG_STATE_A_WAIT_BCON)
                musb->is_active = 0;
        musb_platform_try_idle(musb, jiffies + msecs_to_jiffies(val));
        spin_unlock_irqrestore(&musb->lock, flags);

        return n;
}

static ssize_t
vbus_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct musb     *musb = dev_to_musb(dev);
        unsigned long   flags;
        unsigned long   val;
        int             vbus;
        u8              devctl;

        pm_runtime_get_sync(dev);
        spin_lock_irqsave(&musb->lock, flags);
        val = musb->a_wait_bcon;
        vbus = musb_platform_get_vbus_status(musb);
        if (vbus < 0) {
                /* Use default MUSB method by means of DEVCTL register */
                devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
                if ((devctl & MUSB_DEVCTL_VBUS)
                                == (3 << MUSB_DEVCTL_VBUS_SHIFT))
                        vbus = 1;
                else
                        vbus = 0;
        }
        spin_unlock_irqrestore(&musb->lock, flags);
        pm_runtime_put_sync(dev);

        return sprintf(buf, "Vbus %s, timeout %lu msec\n",
                        vbus ? "on" : "off", val);
}
static DEVICE_ATTR_RW(vbus);

/* Gadget drivers can't know that a host is connected so they might want
 * to start SRP, but users can.  This allows userspace to trigger SRP.
 */
static ssize_t srp_store(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t n)
{
        struct musb     *musb = dev_to_musb(dev);
        unsigned short  srp;

        if (sscanf(buf, "%hu", &srp) != 1
                        || (srp != 1)) {
                dev_err(dev, "SRP: Value must be 1\n");
                return -EINVAL;
        }

        if (srp == 1)
                musb_g_wakeup(musb);

        return n;
}
static DEVICE_ATTR_WO(srp);

static struct attribute *musb_attributes[] = {
        &dev_attr_mode.attr,
        &dev_attr_vbus.attr,
        &dev_attr_srp.attr,
        NULL
};

static const struct attribute_group musb_attr_group = {
        .attrs = musb_attributes,
};

#define MUSB_QUIRK_B_INVALID_VBUS_91    (MUSB_DEVCTL_BDEVICE | \
                                         (2 << MUSB_DEVCTL_VBUS_SHIFT) | \
                                         MUSB_DEVCTL_SESSION)
#define MUSB_QUIRK_A_DISCONNECT_19      ((3 << MUSB_DEVCTL_VBUS_SHIFT) | \
                                         MUSB_DEVCTL_SESSION)

/*
 * Check the musb devctl session bit to determine if we want to
 * allow PM runtime for the device. In general, we want to keep things
 * active when the session bit is set except after host disconnect.
 *
 * Only called from musb_irq_work. If this ever needs to get called
 * elsewhere, proper locking must be implemented for musb->session.
 */
static void musb_pm_runtime_check_session(struct musb *musb)
{
        u8 devctl, s;
        int error;

        devctl = musb_readb(musb->mregs, MUSB_DEVCTL);

        /* Handle session status quirks first */
        s = MUSB_DEVCTL_FSDEV | MUSB_DEVCTL_LSDEV |
                MUSB_DEVCTL_HR;
        switch (devctl & ~s) {
        case MUSB_QUIRK_B_INVALID_VBUS_91:
                if (musb->quirk_retries && !musb->flush_irq_work) {
                        musb_dbg(musb,
                                 "Poll devctl on invalid vbus, assume no session");
                        schedule_delayed_work(&musb->irq_work,
                                              msecs_to_jiffies(1000));
                        musb->quirk_retries--;
                        return;
                }
                /* fall through */
        case MUSB_QUIRK_A_DISCONNECT_19:
                if (musb->quirk_retries && !musb->flush_irq_work) {
                        musb_dbg(musb,
                                 "Poll devctl on possible host mode disconnect");
                        schedule_delayed_work(&musb->irq_work,
                                              msecs_to_jiffies(1000));
                        musb->quirk_retries--;
                        return;
                }
                if (!musb->session)
                        break;
                musb_dbg(musb, "Allow PM on possible host mode disconnect");
                pm_runtime_mark_last_busy(musb->controller);
                pm_runtime_put_autosuspend(musb->controller);
                musb->session = false;
                return;
        default:
                break;
        }

        /* No need to do anything if session has not changed */
        s = devctl & MUSB_DEVCTL_SESSION;
        if (s == musb->session)
                return;

        /* Block PM or allow PM? */
        if (s) {
                musb_dbg(musb, "Block PM on active session: %02x", devctl);
                error = pm_runtime_get_sync(musb->controller);
                if (error < 0)
                        dev_err(musb->controller, "Could not enable: %i\n",
                                error);
                musb->quirk_retries = 3;
        } else {
                musb_dbg(musb, "Allow PM with no session: %02x", devctl);
                pm_runtime_mark_last_busy(musb->controller);
                pm_runtime_put_autosuspend(musb->controller);
        }

        musb->session = s;
}

/* Only used to provide driver mode change events */
static void musb_irq_work(struct work_struct *data)
{
        struct musb *musb = container_of(data, struct musb, irq_work.work);
        int error;

        error = pm_runtime_get_sync(musb->controller);
        if (error < 0) {
                dev_err(musb->controller, "Could not enable: %i\n", error);

                return;
        }

        musb_pm_runtime_check_session(musb);

        if (musb->xceiv->otg->state != musb->xceiv_old_state) {
                musb->xceiv_old_state = musb->xceiv->otg->state;
                sysfs_notify(&musb->controller->kobj, NULL, "mode");
        }

        pm_runtime_mark_last_busy(musb->controller);
        pm_runtime_put_autosuspend(musb->controller);
}

static void musb_recover_from_babble(struct musb *musb)
{
        int ret;
        u8 devctl;

        musb_disable_interrupts(musb);

        /*
         * wait at least 320 cycles of 60MHz clock. That's 5.3us, we will give
         * it some slack and wait for 10us.
         */
        udelay(10);

        ret  = musb_platform_recover(musb);
        if (ret) {
                musb_enable_interrupts(musb);
                return;
        }

        /* drop session bit */
        devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
        devctl &= ~MUSB_DEVCTL_SESSION;
        musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);

        /* tell usbcore about it */
        musb_root_disconnect(musb);

        /*
         * When a babble condition occurs, the musb controller
         * removes the session bit and the endpoint config is lost.
         */
        if (musb->dyn_fifo)
                ret = ep_config_from_table(musb);
        else
                ret = ep_config_from_hw(musb);

        /* restart session */
        if (ret == 0)
                musb_start(musb);
}

/* --------------------------------------------------------------------------
 * Init support
 */

static struct musb *allocate_instance(struct device *dev,
                const struct musb_hdrc_config *config, void __iomem *mbase)
{
        struct musb             *musb;
        struct musb_hw_ep       *ep;
        int                     epnum;
        int                     ret;

        musb = devm_kzalloc(dev, sizeof(*musb), GFP_KERNEL);
        if (!musb)
                return NULL;

        INIT_LIST_HEAD(&musb->control);
        INIT_LIST_HEAD(&musb->in_bulk);
        INIT_LIST_HEAD(&musb->out_bulk);
        INIT_LIST_HEAD(&musb->pending_list);

        musb->vbuserr_retry = VBUSERR_RETRY_COUNT;
        musb->a_wait_bcon = OTG_TIME_A_WAIT_BCON;
        musb->mregs = mbase;
        musb->ctrl_base = mbase;
        musb->nIrq = -ENODEV;
        musb->config = config;
        BUG_ON(musb->config->num_eps > MUSB_C_NUM_EPS);
        for (epnum = 0, ep = musb->endpoints;
                        epnum < musb->config->num_eps;
                        epnum++, ep++) {
                ep->musb = musb;
                ep->epnum = epnum;
        }

        musb->controller = dev;

        ret = musb_host_alloc(musb);
        if (ret < 0)
                goto err_free;

        dev_set_drvdata(dev, musb);

        return musb;

err_free:
        return NULL;
}

static void musb_free(struct musb *musb)
{
        /* this has multiple entry modes. it handles fault cleanup after
         * probe(), where things may be partially set up, as well as rmmod
         * cleanup after everything's been de-activated.
         */

#ifdef CONFIG_SYSFS
        sysfs_remove_group(&musb->controller->kobj, &musb_attr_group);
#endif

        if (musb->nIrq >= 0) {
                if (musb->irq_wake)
                        disable_irq_wake(musb->nIrq);
                free_irq(musb->nIrq, musb);
        }

        musb_host_free(musb);
}

struct musb_pending_work {
        int (*callback)(struct musb *musb, void *data);
        void *data;
        struct list_head node;
};

#ifdef CONFIG_PM
/*
 * Called from musb_runtime_resume(), musb_resume(), and
 * musb_queue_resume_work(). Callers must take musb->lock.
 */
static int musb_run_resume_work(struct musb *musb)
{
        struct musb_pending_work *w, *_w;
        unsigned long flags;
        int error = 0;

        spin_lock_irqsave(&musb->list_lock, flags);
        list_for_each_entry_safe(w, _w, &musb->pending_list, node) {
                if (w->callback) {
                        error = w->callback(musb, w->data);
                        if (error < 0) {
                                dev_err(musb->controller,
                                        "resume callback %p failed: %i\n",
                                        w->callback, error);
                        }
                }
                list_del(&w->node);
                devm_kfree(musb->controller, w);
        }
        spin_unlock_irqrestore(&musb->list_lock, flags);

        return error;
}
#endif

/*
 * Called to run work if device is active or else queue the work to happen
 * on resume. Caller must take musb->lock and must hold an RPM reference.
 *
 * Note that we cowardly refuse queuing work after musb PM runtime
 * resume is done calling musb_run_resume_work() and return -EINPROGRESS
 * instead.
 */
int musb_queue_resume_work(struct musb *musb,
                           int (*callback)(struct musb *musb, void *data),
                           void *data)
{
        struct musb_pending_work *w;
        unsigned long flags;
        int error;

        if (WARN_ON(!callback))
                return -EINVAL;

        if (pm_runtime_active(musb->controller))
                return callback(musb, data);

        w = devm_kzalloc(musb->controller, sizeof(*w), GFP_ATOMIC);
        if (!w)
                return -ENOMEM;

        w->callback = callback;
        w->data = data;
        spin_lock_irqsave(&musb->list_lock, flags);
        if (musb->is_runtime_suspended) {
                list_add_tail(&w->node, &musb->pending_list);
                error = 0;
        } else {
                dev_err(musb->controller, "could not add resume work %p\n",
                        callback);
                devm_kfree(musb->controller, w);
                error = -EINPROGRESS;
        }
        spin_unlock_irqrestore(&musb->list_lock, flags);

        return error;
}
EXPORT_SYMBOL_GPL(musb_queue_resume_work);

static void musb_deassert_reset(struct work_struct *work)
{
        struct musb *musb;
        unsigned long flags;

        musb = container_of(work, struct musb, deassert_reset_work.work);

        spin_lock_irqsave(&musb->lock, flags);

        if (musb->port1_status & USB_PORT_STAT_RESET)
                musb_port_reset(musb, false);

        spin_unlock_irqrestore(&musb->lock, flags);
}

/*
 * Perform generic per-controller initialization.
 *
 * @dev: the controller (already clocked, etc)
 * @nIrq: IRQ number
 * @ctrl: virtual address of controller registers,
 *      not yet corrected for platform-specific offsets
 */
static int
musb_init_controller(struct device *dev, int nIrq, void __iomem *ctrl)
{
        int                     status;
        struct musb             *musb;
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);

        /* The driver might handle more features than the board; OK.
         * Fail when the board needs a feature that's not enabled.
         */
        if (!plat) {
                dev_err(dev, "no platform_data?\n");
                status = -ENODEV;
                goto fail0;
        }

        /* allocate */
        musb = allocate_instance(dev, plat->config, ctrl);
        if (!musb) {
                status = -ENOMEM;
                goto fail0;
        }

        spin_lock_init(&musb->lock);
        spin_lock_init(&musb->list_lock);
        musb->board_set_power = plat->set_power;
        musb->min_power = plat->min_power;
        musb->ops = plat->platform_ops;
        musb->port_mode = plat->mode;

        /*
         * Initialize the default IO functions. At least omap2430 needs
         * these early. We initialize the platform specific IO functions
         * later on.
         */
        musb_readb = musb_default_readb;
        musb_writeb = musb_default_writeb;
        musb_readw = musb_default_readw;
        musb_writew = musb_default_writew;

        /* The musb_platform_init() call:
         *   - adjusts musb->mregs
         *   - sets the musb->isr
         *   - may initialize an integrated transceiver
         *   - initializes musb->xceiv, usually by otg_get_phy()
         *   - stops powering VBUS
         *
         * There are various transceiver configurations.
         * DaVinci, TUSB60x0, and others integrate them.  OMAP3 uses
         * external/discrete ones in various flavors (twl4030 family,
         * isp1504, non-OTG, etc) mostly hooking up through ULPI.
         */
        status = musb_platform_init(musb);
        if (status < 0)
                goto fail1;

        if (!musb->isr) {
                status = -ENODEV;
                goto fail2;
        }


        /* Most devices use indexed offset or flat offset */
        if (musb->ops->quirks & MUSB_INDEXED_EP) {
                musb->io.ep_offset = musb_indexed_ep_offset;
                musb->io.ep_select = musb_indexed_ep_select;
        } else {
                musb->io.ep_offset = musb_flat_ep_offset;
                musb->io.ep_select = musb_flat_ep_select;
        }

        if (musb->ops->quirks & MUSB_G_NO_SKB_RESERVE)
                musb->g.quirk_avoids_skb_reserve = 1;

        /* At least tusb6010 has its own offsets */
        if (musb->ops->ep_offset)
                musb->io.ep_offset = musb->ops->ep_offset;
        if (musb->ops->ep_select)
                musb->io.ep_select = musb->ops->ep_select;

        if (musb->ops->fifo_mode)
                fifo_mode = musb->ops->fifo_mode;
        else
                fifo_mode = 4;

        if (musb->ops->fifo_offset)
                musb->io.fifo_offset = musb->ops->fifo_offset;
        else
                musb->io.fifo_offset = musb_default_fifo_offset;

        if (musb->ops->busctl_offset)
                musb->io.busctl_offset = musb->ops->busctl_offset;
        else
                musb->io.busctl_offset = musb_default_busctl_offset;

        if (musb->ops->readb)
                musb_readb = musb->ops->readb;
        if (musb->ops->writeb)
                musb_writeb = musb->ops->writeb;
        if (musb->ops->readw)
                musb_readw = musb->ops->readw;
        if (musb->ops->writew)
                musb_writew = musb->ops->writew;

#ifndef CONFIG_MUSB_PIO_ONLY
        if (!musb->ops->dma_init || !musb->ops->dma_exit) {
                dev_err(dev, "DMA controller not set\n");
                status = -ENODEV;
                goto fail2;
        }
        musb_dma_controller_create = musb->ops->dma_init;
        musb_dma_controller_destroy = musb->ops->dma_exit;
#endif

        if (musb->ops->read_fifo)
                musb->io.read_fifo = musb->ops->read_fifo;
        else
                musb->io.read_fifo = musb_default_read_fifo;

        if (musb->ops->write_fifo)
                musb->io.write_fifo = musb->ops->write_fifo;
        else
                musb->io.write_fifo = musb_default_write_fifo;

        if (!musb->xceiv->io_ops) {
                musb->xceiv->io_dev = musb->controller;
                musb->xceiv->io_priv = musb->mregs;
                musb->xceiv->io_ops = &musb_ulpi_access;
        }

        if (musb->ops->phy_callback)
                musb_phy_callback = musb->ops->phy_callback;

        /*
         * We need musb_read/write functions initialized for PM.
         * Note that at least 2430 glue needs autosuspend delay
         * somewhere above 300 ms for the hardware to idle properly
         * after disconnecting the cable in host mode. Let's use
         * 500 ms for some margin.
         */
        pm_runtime_use_autosuspend(musb->controller);
        pm_runtime_set_autosuspend_delay(musb->controller, 500);
        pm_runtime_enable(musb->controller);
        pm_runtime_get_sync(musb->controller);

        status = usb_phy_init(musb->xceiv);
        if (status < 0)
                goto err_usb_phy_init;

        if (use_dma && dev->dma_mask) {
                musb->dma_controller =
                        musb_dma_controller_create(musb, musb->mregs);
                if (IS_ERR(musb->dma_controller)) {
                        status = PTR_ERR(musb->dma_controller);
                        goto fail2_5;
                }
        }

        /* be sure interrupts are disabled before connecting ISR */
        musb_platform_disable(musb);
        musb_disable_interrupts(musb);
        musb_writeb(musb->mregs, MUSB_DEVCTL, 0);

        /* Init IRQ workqueue before request_irq */
        INIT_DELAYED_WORK(&musb->irq_work, musb_irq_work);
        INIT_DELAYED_WORK(&musb->deassert_reset_work, musb_deassert_reset);
        INIT_DELAYED_WORK(&musb->finish_resume_work, musb_host_finish_resume);

        /* setup musb parts of the core (especially endpoints) */
        status = musb_core_init(plat->config->multipoint
                        ? MUSB_CONTROLLER_MHDRC
                        : MUSB_CONTROLLER_HDRC, musb);
        if (status < 0)
                goto fail3;

        timer_setup(&musb->otg_timer, musb_otg_timer_func, 0);

        /* attach to the IRQ */
        if (request_irq(nIrq, musb->isr, IRQF_SHARED, dev_name(dev), musb)) {
                dev_err(dev, "request_irq %d failed!\n", nIrq);
                status = -ENODEV;
                goto fail3;
        }
        musb->nIrq = nIrq;
        /* FIXME this handles wakeup irqs wrong */
        if (enable_irq_wake(nIrq) == 0) {
                musb->irq_wake = 1;
                device_init_wakeup(dev, 1);
        } else {
                musb->irq_wake = 0;
        }

        /* program PHY to use external vBus if required */
        if (plat->extvbus) {
                u8 busctl = musb_readb(musb->mregs, MUSB_ULPI_BUSCONTROL);
                busctl |= MUSB_ULPI_USE_EXTVBUS;
                musb_writeb(musb->mregs, MUSB_ULPI_BUSCONTROL, busctl);
        }

        MUSB_DEV_MODE(musb);
        musb->xceiv->otg->state = OTG_STATE_B_IDLE;

        switch (musb->port_mode) {
        case MUSB_HOST:
                status = musb_host_setup(musb, plat->power);
                if (status < 0)
                        goto fail3;
                status = musb_platform_set_mode(musb, MUSB_HOST);
                break;
        case MUSB_PERIPHERAL:
                status = musb_gadget_setup(musb);
                if (status < 0)
                        goto fail3;
                status = musb_platform_set_mode(musb, MUSB_PERIPHERAL);
                break;
        case MUSB_OTG:
                status = musb_host_setup(musb, plat->power);
                if (status < 0)
                        goto fail3;
                status = musb_gadget_setup(musb);
                if (status) {
                        musb_host_cleanup(musb);
                        goto fail3;
                }
                status = musb_platform_set_mode(musb, MUSB_OTG);
                break;
        default:
                dev_err(dev, "unsupported port mode %d\n", musb->port_mode);
                break;
        }

        if (status < 0)
                goto fail3;

        musb_init_debugfs(musb);

        status = sysfs_create_group(&musb->controller->kobj, &musb_attr_group);
        if (status)
                goto fail5;

        musb->is_initialized = 1;
        pm_runtime_mark_last_busy(musb->controller);
        pm_runtime_put_autosuspend(musb->controller);

        return 0;

fail5:
        musb_exit_debugfs(musb);

        musb_gadget_cleanup(musb);
        musb_host_cleanup(musb);

fail3:
        cancel_delayed_work_sync(&musb->irq_work);
        cancel_delayed_work_sync(&musb->finish_resume_work);
        cancel_delayed_work_sync(&musb->deassert_reset_work);
        if (musb->dma_controller)
                musb_dma_controller_destroy(musb->dma_controller);

fail2_5:
        usb_phy_shutdown(musb->xceiv);

err_usb_phy_init:
        pm_runtime_dont_use_autosuspend(musb->controller);
        pm_runtime_put_sync(musb->controller);
        pm_runtime_disable(musb->controller);

fail2:
        if (musb->irq_wake)
                device_init_wakeup(dev, 0);
        musb_platform_exit(musb);

fail1:
        if (status != -EPROBE_DEFER)
                dev_err(musb->controller,
                        "%s failed with status %d\n", __func__, status);

        musb_free(musb);

fail0:

        return status;

}

/*-------------------------------------------------------------------------*/

/* all implementations (PCI bridge to FPGA, VLYNQ, etc) should just
 * bridge to a platform device; this driver then suffices.
 */
static int musb_probe(struct platform_device *pdev)
{
        struct device   *dev = &pdev->dev;
        int             irq = platform_get_irq_byname(pdev, "mc");
        struct resource *iomem;
        void __iomem    *base;

        if (irq <= 0)
                return -ENODEV;

        iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        base = devm_ioremap_resource(dev, iomem);
        if (IS_ERR(base))
                return PTR_ERR(base);

        return musb_init_controller(dev, irq, base);
}

static int musb_remove(struct platform_device *pdev)
{
        struct device   *dev = &pdev->dev;
        struct musb     *musb = dev_to_musb(dev);
        unsigned long   flags;

        /* this gets called on rmmod.
         *  - Host mode: host may still be active
         *  - Peripheral mode: peripheral is deactivated (or never-activated)
         *  - OTG mode: both roles are deactivated (or never-activated)
         */
        musb_exit_debugfs(musb);

        cancel_delayed_work_sync(&musb->irq_work);
        cancel_delayed_work_sync(&musb->finish_resume_work);
        cancel_delayed_work_sync(&musb->deassert_reset_work);
        pm_runtime_get_sync(musb->controller);
        musb_host_cleanup(musb);
        musb_gadget_cleanup(musb);

        musb_platform_disable(musb);
        spin_lock_irqsave(&musb->lock, flags);
        musb_disable_interrupts(musb);
        musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
        spin_unlock_irqrestore(&musb->lock, flags);
        musb_platform_exit(musb);

        pm_runtime_dont_use_autosuspend(musb->controller);
        pm_runtime_put_sync(musb->controller);
        pm_runtime_disable(musb->controller);
        musb_phy_callback = NULL;
        if (musb->dma_controller)
                musb_dma_controller_destroy(musb->dma_controller);
        usb_phy_shutdown(musb->xceiv);
        musb_free(musb);
        device_init_wakeup(dev, 0);
        return 0;
}

#ifdef  CONFIG_PM

static void musb_save_context(struct musb *musb)
{
        int i;
        void __iomem *musb_base = musb->mregs;
        void __iomem *epio;

        musb->context.frame = musb_readw(musb_base, MUSB_FRAME);
        musb->context.testmode = musb_readb(musb_base, MUSB_TESTMODE);
        musb->context.busctl = musb_readb(musb_base, MUSB_ULPI_BUSCONTROL);
        musb->context.power = musb_readb(musb_base, MUSB_POWER);
        musb->context.intrusbe = musb_readb(musb_base, MUSB_INTRUSBE);
        musb->context.index = musb_readb(musb_base, MUSB_INDEX);
        musb->context.devctl = musb_readb(musb_base, MUSB_DEVCTL);

        for (i = 0; i < musb->config->num_eps; ++i) {
                struct musb_hw_ep       *hw_ep;

                hw_ep = &musb->endpoints[i];
                if (!hw_ep)
                        continue;

                epio = hw_ep->regs;
                if (!epio)
                        continue;

                musb_writeb(musb_base, MUSB_INDEX, i);
                musb->context.index_regs[i].txmaxp =
                        musb_readw(epio, MUSB_TXMAXP);
                musb->context.index_regs[i].txcsr =
                        musb_readw(epio, MUSB_TXCSR);
                musb->context.index_regs[i].rxmaxp =
                        musb_readw(epio, MUSB_RXMAXP);
                musb->context.index_regs[i].rxcsr =
                        musb_readw(epio, MUSB_RXCSR);

                if (musb->dyn_fifo) {
                        musb->context.index_regs[i].txfifoadd =
                                        musb_readw(musb_base, MUSB_TXFIFOADD);
                        musb->context.index_regs[i].rxfifoadd =
                                        musb_readw(musb_base, MUSB_RXFIFOADD);
                        musb->context.index_regs[i].txfifosz =
                                        musb_readb(musb_base, MUSB_TXFIFOSZ);
                        musb->context.index_regs[i].rxfifosz =
                                        musb_readb(musb_base, MUSB_RXFIFOSZ);
                }

                musb->context.index_regs[i].txtype =
                        musb_readb(epio, MUSB_TXTYPE);
                musb->context.index_regs[i].txinterval =
                        musb_readb(epio, MUSB_TXINTERVAL);
                musb->context.index_regs[i].rxtype =
                        musb_readb(epio, MUSB_RXTYPE);
                musb->context.index_regs[i].rxinterval =
                        musb_readb(epio, MUSB_RXINTERVAL);

                musb->context.index_regs[i].txfunaddr =
                        musb_read_txfunaddr(musb, i);
                musb->context.index_regs[i].txhubaddr =
                        musb_read_txhubaddr(musb, i);
                musb->context.index_regs[i].txhubport =
                        musb_read_txhubport(musb, i);

                musb->context.index_regs[i].rxfunaddr =
                        musb_read_rxfunaddr(musb, i);
                musb->context.index_regs[i].rxhubaddr =
                        musb_read_rxhubaddr(musb, i);
                musb->context.index_regs[i].rxhubport =
                        musb_read_rxhubport(musb, i);
        }
}

static void musb_restore_context(struct musb *musb)
{
        int i;
        void __iomem *musb_base = musb->mregs;
        void __iomem *epio;
        u8 power;

        musb_writew(musb_base, MUSB_FRAME, musb->context.frame);
        musb_writeb(musb_base, MUSB_TESTMODE, musb->context.testmode);
        musb_writeb(musb_base, MUSB_ULPI_BUSCONTROL, musb->context.busctl);

        /* Don't affect SUSPENDM/RESUME bits in POWER reg */
        power = musb_readb(musb_base, MUSB_POWER);
        power &= MUSB_POWER_SUSPENDM | MUSB_POWER_RESUME;
        musb->context.power &= ~(MUSB_POWER_SUSPENDM | MUSB_POWER_RESUME);
        power |= musb->context.power;
        musb_writeb(musb_base, MUSB_POWER, power);

        musb_writew(musb_base, MUSB_INTRTXE, musb->intrtxe);
        musb_writew(musb_base, MUSB_INTRRXE, musb->intrrxe);
        musb_writeb(musb_base, MUSB_INTRUSBE, musb->context.intrusbe);
        if (musb->context.devctl & MUSB_DEVCTL_SESSION)
                musb_writeb(musb_base, MUSB_DEVCTL, musb->context.devctl);

        for (i = 0; i < musb->config->num_eps; ++i) {
                struct musb_hw_ep       *hw_ep;

                hw_ep = &musb->endpoints[i];
                if (!hw_ep)
                        continue;

                epio = hw_ep->regs;
                if (!epio)
                        continue;

                musb_writeb(musb_base, MUSB_INDEX, i);
                musb_writew(epio, MUSB_TXMAXP,
                        musb->context.index_regs[i].txmaxp);
                musb_writew(epio, MUSB_TXCSR,
                        musb->context.index_regs[i].txcsr);
                musb_writew(epio, MUSB_RXMAXP,
                        musb->context.index_regs[i].rxmaxp);
                musb_writew(epio, MUSB_RXCSR,
                        musb->context.index_regs[i].rxcsr);

                if (musb->dyn_fifo) {
                        musb_writeb(musb_base, MUSB_TXFIFOSZ,
                                musb->context.index_regs[i].txfifosz);
                        musb_writeb(musb_base, MUSB_RXFIFOSZ,
                                musb->context.index_regs[i].rxfifosz);
                        musb_writew(musb_base, MUSB_TXFIFOADD,
                                musb->context.index_regs[i].txfifoadd);
                        musb_writew(musb_base, MUSB_RXFIFOADD,
                                musb->context.index_regs[i].rxfifoadd);
                }

                musb_writeb(epio, MUSB_TXTYPE,
                                musb->context.index_regs[i].txtype);
                musb_writeb(epio, MUSB_TXINTERVAL,
                                musb->context.index_regs[i].txinterval);
                musb_writeb(epio, MUSB_RXTYPE,
                                musb->context.index_regs[i].rxtype);
                musb_writeb(epio, MUSB_RXINTERVAL,

                                musb->context.index_regs[i].rxinterval);
                musb_write_txfunaddr(musb, i,
                                musb->context.index_regs[i].txfunaddr);
                musb_write_txhubaddr(musb, i,
                                musb->context.index_regs[i].txhubaddr);
                musb_write_txhubport(musb, i,
                                musb->context.index_regs[i].txhubport);

                musb_write_rxfunaddr(musb, i,
                                musb->context.index_regs[i].rxfunaddr);
                musb_write_rxhubaddr(musb, i,
                                musb->context.index_regs[i].rxhubaddr);
                musb_write_rxhubport(musb, i,
                                musb->context.index_regs[i].rxhubport);
        }
        musb_writeb(musb_base, MUSB_INDEX, musb->context.index);
}

static int musb_suspend(struct device *dev)
{
        struct musb     *musb = dev_to_musb(dev);
        unsigned long   flags;
        int ret;

        ret = pm_runtime_get_sync(dev);
        if (ret < 0) {
                pm_runtime_put_noidle(dev);
                return ret;
        }

        musb_platform_disable(musb);
        musb_disable_interrupts(musb);

        musb->flush_irq_work = true;
        while (flush_delayed_work(&musb->irq_work))
                ;
        musb->flush_irq_work = false;

        if (!(musb->ops->quirks & MUSB_PRESERVE_SESSION))
                musb_writeb(musb->mregs, MUSB_DEVCTL, 0);

        WARN_ON(!list_empty(&musb->pending_list));

        spin_lock_irqsave(&musb->lock, flags);

        if (is_peripheral_active(musb)) {
                /* FIXME force disconnect unless we know USB will wake
                 * the system up quickly enough to respond ...
                 */
        } else if (is_host_active(musb)) {
                /* we know all the children are suspended; sometimes
                 * they will even be wakeup-enabled.
                 */
        }

        musb_save_context(musb);

        spin_unlock_irqrestore(&musb->lock, flags);
        return 0;
}

static int musb_resume(struct device *dev)
{
        struct musb *musb = dev_to_musb(dev);
        unsigned long flags;
        int error;
        u8 devctl;
        u8 mask;

        /*
         * For static cmos like DaVinci, register values were preserved
         * unless for some reason the whole soc powered down or the USB
         * module got reset through the PSC (vs just being disabled).
         *
         * For the DSPS glue layer though, a full register restore has to
         * be done. As it shouldn't harm other platforms, we do it
         * unconditionally.
         */

        musb_restore_context(musb);

        devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
        mask = MUSB_DEVCTL_BDEVICE | MUSB_DEVCTL_FSDEV | MUSB_DEVCTL_LSDEV;
        if ((devctl & mask) != (musb->context.devctl & mask))
                musb->port1_status = 0;

        musb_enable_interrupts(musb);
        musb_platform_enable(musb);

        spin_lock_irqsave(&musb->lock, flags);
        error = musb_run_resume_work(musb);
        if (error)
                dev_err(musb->controller, "resume work failed with %i\n",
                        error);
        spin_unlock_irqrestore(&musb->lock, flags);

        pm_runtime_mark_last_busy(dev);
        pm_runtime_put_autosuspend(dev);

        return 0;
}

static int musb_runtime_suspend(struct device *dev)
{
        struct musb     *musb = dev_to_musb(dev);

        musb_save_context(musb);
        musb->is_runtime_suspended = 1;

        return 0;
}

static int musb_runtime_resume(struct device *dev)
{
        struct musb *musb = dev_to_musb(dev);
        unsigned long flags;
        int error;

        /*
         * When pm_runtime_get_sync called for the first time in driver
         * init,  some of the structure is still not initialized which is
         * used in restore function. But clock needs to be
         * enabled before any register access, so
         * pm_runtime_get_sync has to be called.
         * Also context restore without save does not make
         * any sense
         */
        if (!musb->is_initialized)
                return 0;

        musb_restore_context(musb);

        spin_lock_irqsave(&musb->lock, flags);
        error = musb_run_resume_work(musb);
        if (error)
                dev_err(musb->controller, "resume work failed with %i\n",
                        error);
        musb->is_runtime_suspended = 0;
        spin_unlock_irqrestore(&musb->lock, flags);

        return 0;
}

static const struct dev_pm_ops musb_dev_pm_ops = {
        .suspend        = musb_suspend,
        .resume         = musb_resume,
        .runtime_suspend = musb_runtime_suspend,
        .runtime_resume = musb_runtime_resume,
};

#define MUSB_DEV_PM_OPS (&musb_dev_pm_ops)
#else
#define MUSB_DEV_PM_OPS NULL
#endif

static struct platform_driver musb_driver = {
        .driver = {
                .name           = (char *)musb_driver_name,
                .bus            = &platform_bus_type,
                .pm             = MUSB_DEV_PM_OPS,
        },
        .probe          = musb_probe,
        .remove         = musb_remove,
};

module_platform_driver(musb_driver);