oxu210hp-hcd.c

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/*
 * Copyright (c) 2008 Rodolfo Giometti <[email protected]>
 * Copyright (c) 2008 Eurotech S.p.A. <[email protected]>
 *
 * This code is *strongly* based on EHCI-HCD code by David Brownell since
 * the chip is a quasi-EHCI compatible.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <linux/moduleparam.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <asm/unaligned.h>

#include <linux/irq.h>
#include <linux/platform_device.h>

#include "oxu210hp.h"

#define DRIVER_VERSION "0.0.50"

/*
 * Main defines
 */

#define oxu_dbg(oxu, fmt, args...) \
        dev_dbg(oxu_to_hcd(oxu)->self.controller , fmt , ## args)
#define oxu_err(oxu, fmt, args...) \
        dev_err(oxu_to_hcd(oxu)->self.controller , fmt , ## args)
#define oxu_info(oxu, fmt, args...) \
        dev_info(oxu_to_hcd(oxu)->self.controller , fmt , ## args)

static inline struct usb_hcd *oxu_to_hcd(struct oxu_hcd *oxu)
{
    return container_of((void *) oxu, struct usb_hcd, hcd_priv);
}

static inline struct oxu_hcd *hcd_to_oxu(struct usb_hcd *hcd)
{
    return (struct oxu_hcd *) (hcd->hcd_priv);
}

/*
 * Debug stuff
 */

#undef OXU_URB_TRACE
#undef OXU_VERBOSE_DEBUG

#ifdef OXU_VERBOSE_DEBUG
#define oxu_vdbg            oxu_dbg
#else
#define oxu_vdbg(oxu, fmt, args...) /* Nop */
#endif

#ifdef DEBUG

static int __attribute__((__unused__))
dbg_status_buf(char *buf, unsigned len, const char *label, u32 status)
{
    return scnprintf(buf, len, "%s%sstatus %04x%s%s%s%s%s%s%s%s%s%s",
        label, label[0] ? " " : "", status,
        (status & STS_ASS) ? " Async" : "",
        (status & STS_PSS) ? " Periodic" : "",
        (status & STS_RECL) ? " Recl" : "",
        (status & STS_HALT) ? " Halt" : "",
        (status & STS_IAA) ? " IAA" : "",
        (status & STS_FATAL) ? " FATAL" : "",
        (status & STS_FLR) ? " FLR" : "",
        (status & STS_PCD) ? " PCD" : "",
        (status & STS_ERR) ? " ERR" : "",
        (status & STS_INT) ? " INT" : ""
        );
}

static int __attribute__((__unused__))
dbg_intr_buf(char *buf, unsigned len, const char *label, u32 enable)
{
    return scnprintf(buf, len, "%s%sintrenable %02x%s%s%s%s%s%s",
        label, label[0] ? " " : "", enable,
        (enable & STS_IAA) ? " IAA" : "",
        (enable & STS_FATAL) ? " FATAL" : "",
        (enable & STS_FLR) ? " FLR" : "",
        (enable & STS_PCD) ? " PCD" : "",
        (enable & STS_ERR) ? " ERR" : "",
        (enable & STS_INT) ? " INT" : ""
        );
}

static const char *const fls_strings[] =
    { "1024", "512", "256", "??" };

static int dbg_command_buf(char *buf, unsigned len,
                const char *label, u32 command)
{
    return scnprintf(buf, len,
        "%s%scommand %06x %s=%d ithresh=%d%s%s%s%s period=%s%s %s",
        label, label[0] ? " " : "", command,
        (command & CMD_PARK) ? "park" : "(park)",
        CMD_PARK_CNT(command),
        (command >> 16) & 0x3f,
        (command & CMD_LRESET) ? " LReset" : "",
        (command & CMD_IAAD) ? " IAAD" : "",
        (command & CMD_ASE) ? " Async" : "",
        (command & CMD_PSE) ? " Periodic" : "",
        fls_strings[(command >> 2) & 0x3],
        (command & CMD_RESET) ? " Reset" : "",
        (command & CMD_RUN) ? "RUN" : "HALT"
        );
}

static int dbg_port_buf(char *buf, unsigned len, const char *label,
                int port, u32 status)
{
    char    *sig;

    /* signaling state */
    switch (status & (3 << 10)) {
    case 0 << 10:
        sig = "se0";
        break;
    case 1 << 10:
        sig = "k";  /* low speed */
        break;
    case 2 << 10:
        sig = "j";
        break;
    default:
        sig = "?";
        break;
    }

    return scnprintf(buf, len,
        "%s%sport %d status %06x%s%s sig=%s%s%s%s%s%s%s%s%s%s",
        label, label[0] ? " " : "", port, status,
        (status & PORT_POWER) ? " POWER" : "",
        (status & PORT_OWNER) ? " OWNER" : "",
        sig,
        (status & PORT_RESET) ? " RESET" : "",
        (status & PORT_SUSPEND) ? " SUSPEND" : "",
        (status & PORT_RESUME) ? " RESUME" : "",
        (status & PORT_OCC) ? " OCC" : "",
        (status & PORT_OC) ? " OC" : "",
        (status & PORT_PEC) ? " PEC" : "",
        (status & PORT_PE) ? " PE" : "",
        (status & PORT_CSC) ? " CSC" : "",
        (status & PORT_CONNECT) ? " CONNECT" : ""
        );
}

#else

static inline int __attribute__((__unused__))
dbg_status_buf(char *buf, unsigned len, const char *label, u32 status)
{ return 0; }

static inline int __attribute__((__unused__))
dbg_command_buf(char *buf, unsigned len, const char *label, u32 command)
{ return 0; }

static inline int __attribute__((__unused__))
dbg_intr_buf(char *buf, unsigned len, const char *label, u32 enable)
{ return 0; }

static inline int __attribute__((__unused__))
dbg_port_buf(char *buf, unsigned len, const char *label, int port, u32 status)
{ return 0; }

#endif /* DEBUG */

/* functions have the "wrong" filename when they're output... */
#define dbg_status(oxu, label, status) { \
    char _buf[80]; \
    dbg_status_buf(_buf, sizeof _buf, label, status); \
    oxu_dbg(oxu, "%s\n", _buf); \
}

#define dbg_cmd(oxu, label, command) { \
    char _buf[80]; \
    dbg_command_buf(_buf, sizeof _buf, label, command); \
    oxu_dbg(oxu, "%s\n", _buf); \
}

#define dbg_port(oxu, label, port, status) { \
    char _buf[80]; \
    dbg_port_buf(_buf, sizeof _buf, label, port, status); \
    oxu_dbg(oxu, "%s\n", _buf); \
}

/*
 * Module parameters
 */

/* Initial IRQ latency: faster than hw default */
static int log2_irq_thresh;         /* 0 to 6 */
module_param(log2_irq_thresh, int, S_IRUGO);
MODULE_PARM_DESC(log2_irq_thresh, "log2 IRQ latency, 1-64 microframes");

/* Initial park setting: slower than hw default */
static unsigned park;
module_param(park, uint, S_IRUGO);
MODULE_PARM_DESC(park, "park setting; 1-3 back-to-back async packets");

/* For flakey hardware, ignore overcurrent indicators */
static bool ignore_oc;
module_param(ignore_oc, bool, S_IRUGO);
MODULE_PARM_DESC(ignore_oc, "ignore bogus hardware overcurrent indications");


static void ehci_work(struct oxu_hcd *oxu);
static int oxu_hub_control(struct usb_hcd *hcd,
                u16 typeReq, u16 wValue, u16 wIndex,
                char *buf, u16 wLength);

/*
 * Local functions
 */

/* Low level read/write registers functions */
static inline u32 oxu_readl(void *base, u32 reg)
{
    return readl(base + reg);
}

static inline void oxu_writel(void *base, u32 reg, u32 val)
{
    writel(val, base + reg);
}

static inline void timer_action_done(struct oxu_hcd *oxu,
                    enum ehci_timer_action action)
{
    clear_bit(action, &oxu->actions);
}

static inline void timer_action(struct oxu_hcd *oxu,
                    enum ehci_timer_action action)
{
    if (!test_and_set_bit(action, &oxu->actions)) {
        unsigned long t;

        switch (action) {
        case TIMER_IAA_WATCHDOG:
            t = EHCI_IAA_JIFFIES;
            break;
        case TIMER_IO_WATCHDOG:
            t = EHCI_IO_JIFFIES;
            break;
        case TIMER_ASYNC_OFF:
            t = EHCI_ASYNC_JIFFIES;
            break;
        case TIMER_ASYNC_SHRINK:
        default:
            t = EHCI_SHRINK_JIFFIES;
            break;
        }
        t += jiffies;
        /* all timings except IAA watchdog can be overridden.
         * async queue SHRINK often precedes IAA.  while it's ready
         * to go OFF neither can matter, and afterwards the IO
         * watchdog stops unless there's still periodic traffic.
         */
        if (action != TIMER_IAA_WATCHDOG
                && t > oxu->watchdog.expires
                && timer_pending(&oxu->watchdog))
            return;
        mod_timer(&oxu->watchdog, t);
    }
}

/*
 * handshake - spin reading hc until handshake completes or fails
 * @ptr: address of hc register to be read
 * @mask: bits to look at in result of read
 * @done: value of those bits when handshake succeeds
 * @usec: timeout in microseconds
 *
 * Returns negative errno, or zero on success
 *
 * Success happens when the "mask" bits have the specified value (hardware
 * handshake done).  There are two failure modes:  "usec" have passed (major
 * hardware flakeout), or the register reads as all-ones (hardware removed).
 *
 * That last failure should_only happen in cases like physical cardbus eject
 * before driver shutdown. But it also seems to be caused by bugs in cardbus
 * bridge shutdown:  shutting down the bridge before the devices using it.
 */
static int handshake(struct oxu_hcd *oxu, void __iomem *ptr,
                    u32 mask, u32 done, int usec)
{
    u32 result;

    do {
        result = readl(ptr);
        if (result == ~(u32)0)      /* card removed */
            return -ENODEV;
        result &= mask;
        if (result == done)
            return 0;
        udelay(1);
        usec--;
    } while (usec > 0);
    return -ETIMEDOUT;
}

/* Force HC to halt state from unknown (EHCI spec section 2.3) */
static int ehci_halt(struct oxu_hcd *oxu)
{
    u32 temp = readl(&oxu->regs->status);

    /* disable any irqs left enabled by previous code */
    writel(0, &oxu->regs->intr_enable);

    if ((temp & STS_HALT) != 0)
        return 0;

    temp = readl(&oxu->regs->command);
    temp &= ~CMD_RUN;
    writel(temp, &oxu->regs->command);
    return handshake(oxu, &oxu->regs->status,
              STS_HALT, STS_HALT, 16 * 125);
}

/* Put TDI/ARC silicon into EHCI mode */
static void tdi_reset(struct oxu_hcd *oxu)
{
    u32 __iomem *reg_ptr;
    u32 tmp;

    reg_ptr = (u32 __iomem *)(((u8 __iomem *)oxu->regs) + 0x68);
    tmp = readl(reg_ptr);
    tmp |= 0x3;
    writel(tmp, reg_ptr);
}

/* Reset a non-running (STS_HALT == 1) controller */
static int ehci_reset(struct oxu_hcd *oxu)
{
    int retval;
    u32 command = readl(&oxu->regs->command);

    command |= CMD_RESET;
    dbg_cmd(oxu, "reset", command);
    writel(command, &oxu->regs->command);
    oxu_to_hcd(oxu)->state = HC_STATE_HALT;
    oxu->next_statechange = jiffies;
    retval = handshake(oxu, &oxu->regs->command,
                CMD_RESET, 0, 250 * 1000);

    if (retval)
        return retval;

    tdi_reset(oxu);

    return retval;
}

/* Idle the controller (from running) */
static void ehci_quiesce(struct oxu_hcd *oxu)
{
    u32 temp;

#ifdef DEBUG
    if (!HC_IS_RUNNING(oxu_to_hcd(oxu)->state))
        BUG();
#endif

    /* wait for any schedule enables/disables to take effect */
    temp = readl(&oxu->regs->command) << 10;
    temp &= STS_ASS | STS_PSS;
    if (handshake(oxu, &oxu->regs->status, STS_ASS | STS_PSS,
                temp, 16 * 125) != 0) {
        oxu_to_hcd(oxu)->state = HC_STATE_HALT;
        return;
    }

    /* then disable anything that's still active */
    temp = readl(&oxu->regs->command);
    temp &= ~(CMD_ASE | CMD_IAAD | CMD_PSE);
    writel(temp, &oxu->regs->command);

    /* hardware can take 16 microframes to turn off ... */
    if (handshake(oxu, &oxu->regs->status, STS_ASS | STS_PSS,
                0, 16 * 125) != 0) {
        oxu_to_hcd(oxu)->state = HC_STATE_HALT;
        return;
    }
}

static int check_reset_complete(struct oxu_hcd *oxu, int index,
                u32 __iomem *status_reg, int port_status)
{
    if (!(port_status & PORT_CONNECT)) {
        oxu->reset_done[index] = 0;
        return port_status;
    }

    /* if reset finished and it's still not enabled -- handoff */
    if (!(port_status & PORT_PE)) {
        oxu_dbg(oxu, "Failed to enable port %d on root hub TT\n",
                index+1);
        return port_status;
    } else
        oxu_dbg(oxu, "port %d high speed\n", index + 1);

    return port_status;
}

static void ehci_hub_descriptor(struct oxu_hcd *oxu,
                struct usb_hub_descriptor *desc)
{
    int ports = HCS_N_PORTS(oxu->hcs_params);
    u16 temp;

    desc->bDescriptorType = 0x29;
    desc->bPwrOn2PwrGood = 10;  /* oxu 1.0, 2.3.9 says 20ms max */
    desc->bHubContrCurrent = 0;

    desc->bNbrPorts = ports;
    temp = 1 + (ports / 8);
    desc->bDescLength = 7 + 2 * temp;

    /* ports removable, and usb 1.0 legacy PortPwrCtrlMask */
    memset(&desc->u.hs.DeviceRemovable[0], 0, temp);
    memset(&desc->u.hs.DeviceRemovable[temp], 0xff, temp);

    temp = 0x0008;          /* per-port overcurrent reporting */
    if (HCS_PPC(oxu->hcs_params))
        temp |= 0x0001;     /* per-port power control */
    else
        temp |= 0x0002;     /* no power switching */
    desc->wHubCharacteristics = (__force __u16)cpu_to_le16(temp);
}


/* Allocate an OXU210HP on-chip memory data buffer
 *
 * An on-chip memory data buffer is required for each OXU210HP USB transfer.
 * Each transfer descriptor has one or more on-chip memory data buffers.
 *
 * Data buffers are allocated from a fix sized pool of data blocks.
 * To minimise fragmentation and give reasonable memory utlisation,
 * data buffers are allocated with sizes the power of 2 multiples of
 * the block size, starting on an address a multiple of the allocated size.
 *
 * FIXME: callers of this function require a buffer to be allocated for
 * len=0. This is a waste of on-chip memory and should be fix. Then this
 * function should be changed to not allocate a buffer for len=0.
 */
static int oxu_buf_alloc(struct oxu_hcd *oxu, struct ehci_qtd *qtd, int len)
{
    int n_blocks;   /* minium blocks needed to hold len */
    int a_blocks;   /* blocks allocated */
    int i, j;

    /* Don't allocte bigger than supported */
    if (len > BUFFER_SIZE * BUFFER_NUM) {
        oxu_err(oxu, "buffer too big (%d)\n", len);
        return -ENOMEM;
    }

    spin_lock(&oxu->mem_lock);

    /* Number of blocks needed to hold len */
    n_blocks = (len + BUFFER_SIZE - 1) / BUFFER_SIZE;

    /* Round the number of blocks up to the power of 2 */
    for (a_blocks = 1; a_blocks < n_blocks; a_blocks <<= 1)
        ;

    /* Find a suitable available data buffer */
    for (i = 0; i < BUFFER_NUM;
            i += max(a_blocks, (int)oxu->db_used[i])) {

        /* Check all the required blocks are available */
        for (j = 0; j < a_blocks; j++)
            if (oxu->db_used[i + j])
                break;

        if (j != a_blocks)
            continue;

        /* Allocate blocks found! */
        qtd->buffer = (void *) &oxu->mem->db_pool[i];
        qtd->buffer_dma = virt_to_phys(qtd->buffer);

        qtd->qtd_buffer_len = BUFFER_SIZE * a_blocks;
        oxu->db_used[i] = a_blocks;

        spin_unlock(&oxu->mem_lock);

        return 0;
    }

    /* Failed */

    spin_unlock(&oxu->mem_lock);

    return -ENOMEM;
}

static void oxu_buf_free(struct oxu_hcd *oxu, struct ehci_qtd *qtd)
{
    int index;

    spin_lock(&oxu->mem_lock);

    index = (qtd->buffer - (void *) &oxu->mem->db_pool[0])
                             / BUFFER_SIZE;
    oxu->db_used[index] = 0;
    qtd->qtd_buffer_len = 0;
    qtd->buffer_dma = 0;
    qtd->buffer = NULL;

    spin_unlock(&oxu->mem_lock);
}

static inline void ehci_qtd_init(struct ehci_qtd *qtd, dma_addr_t dma)
{
    memset(qtd, 0, sizeof *qtd);
    qtd->qtd_dma = dma;
    qtd->hw_token = cpu_to_le32(QTD_STS_HALT);
    qtd->hw_next = EHCI_LIST_END;
    qtd->hw_alt_next = EHCI_LIST_END;
    INIT_LIST_HEAD(&qtd->qtd_list);
}

static inline void oxu_qtd_free(struct oxu_hcd *oxu, struct ehci_qtd *qtd)
{
    int index;

    if (qtd->buffer)
        oxu_buf_free(oxu, qtd);

    spin_lock(&oxu->mem_lock);

    index = qtd - &oxu->mem->qtd_pool[0];
    oxu->qtd_used[index] = 0;

    spin_unlock(&oxu->mem_lock);
}

static struct ehci_qtd *ehci_qtd_alloc(struct oxu_hcd *oxu)
{
    int i;
    struct ehci_qtd *qtd = NULL;

    spin_lock(&oxu->mem_lock);

    for (i = 0; i < QTD_NUM; i++)
        if (!oxu->qtd_used[i])
            break;

    if (i < QTD_NUM) {
        qtd = (struct ehci_qtd *) &oxu->mem->qtd_pool[i];
        memset(qtd, 0, sizeof *qtd);

        qtd->hw_token = cpu_to_le32(QTD_STS_HALT);
        qtd->hw_next = EHCI_LIST_END;
        qtd->hw_alt_next = EHCI_LIST_END;
        INIT_LIST_HEAD(&qtd->qtd_list);

        qtd->qtd_dma = virt_to_phys(qtd);

        oxu->qtd_used[i] = 1;
    }

    spin_unlock(&oxu->mem_lock);

    return qtd;
}

static void oxu_qh_free(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    int index;

    spin_lock(&oxu->mem_lock);

    index = qh - &oxu->mem->qh_pool[0];
    oxu->qh_used[index] = 0;

    spin_unlock(&oxu->mem_lock);
}

static void qh_destroy(struct kref *kref)
{
    struct ehci_qh *qh = container_of(kref, struct ehci_qh, kref);
    struct oxu_hcd *oxu = qh->oxu;

    /* clean qtds first, and know this is not linked */
    if (!list_empty(&qh->qtd_list) || qh->qh_next.ptr) {
        oxu_dbg(oxu, "unused qh not empty!\n");
        BUG();
    }
    if (qh->dummy)
        oxu_qtd_free(oxu, qh->dummy);
    oxu_qh_free(oxu, qh);
}

static struct ehci_qh *oxu_qh_alloc(struct oxu_hcd *oxu)
{
    int i;
    struct ehci_qh *qh = NULL;

    spin_lock(&oxu->mem_lock);

    for (i = 0; i < QHEAD_NUM; i++)
        if (!oxu->qh_used[i])
            break;

    if (i < QHEAD_NUM) {
        qh = (struct ehci_qh *) &oxu->mem->qh_pool[i];
        memset(qh, 0, sizeof *qh);

        kref_init(&qh->kref);
        qh->oxu = oxu;
        qh->qh_dma = virt_to_phys(qh);
        INIT_LIST_HEAD(&qh->qtd_list);

        /* dummy td enables safe urb queuing */
        qh->dummy = ehci_qtd_alloc(oxu);
        if (qh->dummy == NULL) {
            oxu_dbg(oxu, "no dummy td\n");
            oxu->qh_used[i] = 0;
            qh = NULL;
            goto unlock;
        }

        oxu->qh_used[i] = 1;
    }
unlock:
    spin_unlock(&oxu->mem_lock);

    return qh;
}

/* to share a qh (cpu threads, or hc) */
static inline struct ehci_qh *qh_get(struct ehci_qh *qh)
{
    kref_get(&qh->kref);
    return qh;
}

static inline void qh_put(struct ehci_qh *qh)
{
    kref_put(&qh->kref, qh_destroy);
}

static void oxu_murb_free(struct oxu_hcd *oxu, struct oxu_murb *murb)
{
    int index;

    spin_lock(&oxu->mem_lock);

    index = murb - &oxu->murb_pool[0];
    oxu->murb_used[index] = 0;

    spin_unlock(&oxu->mem_lock);
}

static struct oxu_murb *oxu_murb_alloc(struct oxu_hcd *oxu)

{
    int i;
    struct oxu_murb *murb = NULL;

    spin_lock(&oxu->mem_lock);

    for (i = 0; i < MURB_NUM; i++)
        if (!oxu->murb_used[i])
            break;

    if (i < MURB_NUM) {
        murb = &(oxu->murb_pool)[i];

        oxu->murb_used[i] = 1;
    }

    spin_unlock(&oxu->mem_lock);

    return murb;
}

/* The queue heads and transfer descriptors are managed from pools tied
 * to each of the "per device" structures.
 * This is the initialisation and cleanup code.
 */
static void ehci_mem_cleanup(struct oxu_hcd *oxu)
{
    kfree(oxu->murb_pool);
    oxu->murb_pool = NULL;

    if (oxu->async)
        qh_put(oxu->async);
    oxu->async = NULL;

    del_timer(&oxu->urb_timer);

    oxu->periodic = NULL;

    /* shadow periodic table */
    kfree(oxu->pshadow);
    oxu->pshadow = NULL;
}

/* Remember to add cleanup code (above) if you add anything here.
 */
static int ehci_mem_init(struct oxu_hcd *oxu, gfp_t flags)
{
    int i;

    for (i = 0; i < oxu->periodic_size; i++)
        oxu->mem->frame_list[i] = EHCI_LIST_END;
    for (i = 0; i < QHEAD_NUM; i++)
        oxu->qh_used[i] = 0;
    for (i = 0; i < QTD_NUM; i++)
        oxu->qtd_used[i] = 0;

    oxu->murb_pool = kcalloc(MURB_NUM, sizeof(struct oxu_murb), flags);
    if (!oxu->murb_pool)
        goto fail;

    for (i = 0; i < MURB_NUM; i++)
        oxu->murb_used[i] = 0;

    oxu->async = oxu_qh_alloc(oxu);
    if (!oxu->async)
        goto fail;

    oxu->periodic = (__le32 *) &oxu->mem->frame_list;
    oxu->periodic_dma = virt_to_phys(oxu->periodic);

    for (i = 0; i < oxu->periodic_size; i++)
        oxu->periodic[i] = EHCI_LIST_END;

    /* software shadow of hardware table */
    oxu->pshadow = kcalloc(oxu->periodic_size, sizeof(void *), flags);
    if (oxu->pshadow != NULL)
        return 0;

fail:
    oxu_dbg(oxu, "couldn't init memory\n");
    ehci_mem_cleanup(oxu);
    return -ENOMEM;
}

/* Fill a qtd, returning how much of the buffer we were able to queue up.
 */
static int qtd_fill(struct ehci_qtd *qtd, dma_addr_t buf, size_t len,
                int token, int maxpacket)
{
    int i, count;
    u64 addr = buf;

    /* one buffer entry per 4K ... first might be short or unaligned */
    qtd->hw_buf[0] = cpu_to_le32((u32)addr);
    qtd->hw_buf_hi[0] = cpu_to_le32((u32)(addr >> 32));
    count = 0x1000 - (buf & 0x0fff);    /* rest of that page */
    if (likely(len < count))        /* ... iff needed */
        count = len;
    else {
        buf +=  0x1000;
        buf &= ~0x0fff;

        /* per-qtd limit: from 16K to 20K (best alignment) */
        for (i = 1; count < len && i < 5; i++) {
            addr = buf;
            qtd->hw_buf[i] = cpu_to_le32((u32)addr);
            qtd->hw_buf_hi[i] = cpu_to_le32((u32)(addr >> 32));
            buf += 0x1000;
            if ((count + 0x1000) < len)
                count += 0x1000;
            else
                count = len;
        }

        /* short packets may only terminate transfers */
        if (count != len)
            count -= (count % maxpacket);
    }
    qtd->hw_token = cpu_to_le32((count << 16) | token);
    qtd->length = count;

    return count;
}

static inline void qh_update(struct oxu_hcd *oxu,
                struct ehci_qh *qh, struct ehci_qtd *qtd)
{
    /* writes to an active overlay are unsafe */
    BUG_ON(qh->qh_state != QH_STATE_IDLE);

    qh->hw_qtd_next = QTD_NEXT(qtd->qtd_dma);
    qh->hw_alt_next = EHCI_LIST_END;

    /* Except for control endpoints, we make hardware maintain data
     * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
     * and set the pseudo-toggle in udev. Only usb_clear_halt() will
     * ever clear it.
     */
    if (!(qh->hw_info1 & cpu_to_le32(1 << 14))) {
        unsigned    is_out, epnum;

        is_out = !(qtd->hw_token & cpu_to_le32(1 << 8));
        epnum = (le32_to_cpup(&qh->hw_info1) >> 8) & 0x0f;
        if (unlikely(!usb_gettoggle(qh->dev, epnum, is_out))) {
            qh->hw_token &= ~cpu_to_le32(QTD_TOGGLE);
            usb_settoggle(qh->dev, epnum, is_out, 1);
        }
    }

    /* HC must see latest qtd and qh data before we clear ACTIVE+HALT */
    wmb();
    qh->hw_token &= cpu_to_le32(QTD_TOGGLE | QTD_STS_PING);
}

/* If it weren't for a common silicon quirk (writing the dummy into the qh
 * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
 * recovery (including urb dequeue) would need software changes to a QH...
 */
static void qh_refresh(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    struct ehci_qtd *qtd;

    if (list_empty(&qh->qtd_list))
        qtd = qh->dummy;
    else {
        qtd = list_entry(qh->qtd_list.next,
                struct ehci_qtd, qtd_list);
        /* first qtd may already be partially processed */
        if (cpu_to_le32(qtd->qtd_dma) == qh->hw_current)
            qtd = NULL;
    }

    if (qtd)
        qh_update(oxu, qh, qtd);
}

static void qtd_copy_status(struct oxu_hcd *oxu, struct urb *urb,
                size_t length, u32 token)
{
    /* count IN/OUT bytes, not SETUP (even short packets) */
    if (likely(QTD_PID(token) != 2))
        urb->actual_length += length - QTD_LENGTH(token);

    /* don't modify error codes */
    if (unlikely(urb->status != -EINPROGRESS))
        return;

    /* force cleanup after short read; not always an error */
    if (unlikely(IS_SHORT_READ(token)))
        urb->status = -EREMOTEIO;

    /* serious "can't proceed" faults reported by the hardware */
    if (token & QTD_STS_HALT) {
        if (token & QTD_STS_BABBLE) {
            /* FIXME "must" disable babbling device's port too */
            urb->status = -EOVERFLOW;
        } else if (token & QTD_STS_MMF) {
            /* fs/ls interrupt xfer missed the complete-split */
            urb->status = -EPROTO;
        } else if (token & QTD_STS_DBE) {
            urb->status = (QTD_PID(token) == 1) /* IN ? */
                ? -ENOSR  /* hc couldn't read data */
                : -ECOMM; /* hc couldn't write data */
        } else if (token & QTD_STS_XACT) {
            /* timeout, bad crc, wrong PID, etc; retried */
            if (QTD_CERR(token))
                urb->status = -EPIPE;
            else {
                oxu_dbg(oxu, "devpath %s ep%d%s 3strikes\n",
                    urb->dev->devpath,
                    usb_pipeendpoint(urb->pipe),
                    usb_pipein(urb->pipe) ? "in" : "out");
                urb->status = -EPROTO;
            }
        /* CERR nonzero + no errors + halt --> stall */
        } else if (QTD_CERR(token))
            urb->status = -EPIPE;
        else    /* unknown */
            urb->status = -EPROTO;

        oxu_vdbg(oxu, "dev%d ep%d%s qtd token %08x --> status %d\n",
            usb_pipedevice(urb->pipe),
            usb_pipeendpoint(urb->pipe),
            usb_pipein(urb->pipe) ? "in" : "out",
            token, urb->status);
    }
}

static void ehci_urb_done(struct oxu_hcd *oxu, struct urb *urb)
__releases(oxu->lock)
__acquires(oxu->lock)
{
    if (likely(urb->hcpriv != NULL)) {
        struct ehci_qh  *qh = (struct ehci_qh *) urb->hcpriv;

        /* S-mask in a QH means it's an interrupt urb */
        if ((qh->hw_info2 & cpu_to_le32(QH_SMASK)) != 0) {

            /* ... update hc-wide periodic stats (for usbfs) */
            oxu_to_hcd(oxu)->self.bandwidth_int_reqs--;
        }
        qh_put(qh);
    }

    urb->hcpriv = NULL;
    switch (urb->status) {
    case -EINPROGRESS:      /* success */
        urb->status = 0;
    default:            /* fault */
        break;
    case -EREMOTEIO:        /* fault or normal */
        if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
            urb->status = 0;
        break;
    case -ECONNRESET:       /* canceled */
    case -ENOENT:
        break;
    }

#ifdef OXU_URB_TRACE
    oxu_dbg(oxu, "%s %s urb %p ep%d%s status %d len %d/%d\n",
        __func__, urb->dev->devpath, urb,
        usb_pipeendpoint(urb->pipe),
        usb_pipein(urb->pipe) ? "in" : "out",
        urb->status,
        urb->actual_length, urb->transfer_buffer_length);
#endif

    /* complete() can reenter this HCD */
    spin_unlock(&oxu->lock);
    usb_hcd_giveback_urb(oxu_to_hcd(oxu), urb, urb->status);
    spin_lock(&oxu->lock);
}

static void start_unlink_async(struct oxu_hcd *oxu, struct ehci_qh *qh);
static void unlink_async(struct oxu_hcd *oxu, struct ehci_qh *qh);

static void intr_deschedule(struct oxu_hcd *oxu, struct ehci_qh *qh);
static int qh_schedule(struct oxu_hcd *oxu, struct ehci_qh *qh);

#define HALT_BIT cpu_to_le32(QTD_STS_HALT)

/* Process and free completed qtds for a qh, returning URBs to drivers.
 * Chases up to qh->hw_current.  Returns number of completions called,
 * indicating how much "real" work we did.
 */
static unsigned qh_completions(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    struct ehci_qtd *last = NULL, *end = qh->dummy;
    struct list_head *entry, *tmp;
    int stopped;
    unsigned count = 0;
    int do_status = 0;
    u8 state;
    struct oxu_murb *murb = NULL;

    if (unlikely(list_empty(&qh->qtd_list)))
        return count;

    /* completions (or tasks on other cpus) must never clobber HALT
     * till we've gone through and cleaned everything up, even when
     * they add urbs to this qh's queue or mark them for unlinking.
     *
     * NOTE:  unlinking expects to be done in queue order.
     */
    state = qh->qh_state;
    qh->qh_state = QH_STATE_COMPLETING;
    stopped = (state == QH_STATE_IDLE);

    /* remove de-activated QTDs from front of queue.
     * after faults (including short reads), cleanup this urb
     * then let the queue advance.
     * if queue is stopped, handles unlinks.
     */
    list_for_each_safe(entry, tmp, &qh->qtd_list) {
        struct ehci_qtd *qtd;
        struct urb *urb;
        u32 token = 0;

        qtd = list_entry(entry, struct ehci_qtd, qtd_list);
        urb = qtd->urb;

        /* Clean up any state from previous QTD ...*/
        if (last) {
            if (likely(last->urb != urb)) {
                if (last->urb->complete == NULL) {
                    murb = (struct oxu_murb *) last->urb;
                    last->urb = murb->main;
                    if (murb->last) {
                        ehci_urb_done(oxu, last->urb);
                        count++;
                    }
                    oxu_murb_free(oxu, murb);
                } else {
                    ehci_urb_done(oxu, last->urb);
                    count++;
                }
            }
            oxu_qtd_free(oxu, last);
            last = NULL;
        }

        /* ignore urbs submitted during completions we reported */
        if (qtd == end)
            break;

        /* hardware copies qtd out of qh overlay */
        rmb();
        token = le32_to_cpu(qtd->hw_token);

        /* always clean up qtds the hc de-activated */
        if ((token & QTD_STS_ACTIVE) == 0) {

            if ((token & QTD_STS_HALT) != 0) {
                stopped = 1;

            /* magic dummy for some short reads; qh won't advance.
             * that silicon quirk can kick in with this dummy too.
             */
            } else if (IS_SHORT_READ(token) &&
                    !(qtd->hw_alt_next & EHCI_LIST_END)) {
                stopped = 1;
                goto halt;
            }

        /* stop scanning when we reach qtds the hc is using */
        } else if (likely(!stopped &&
                HC_IS_RUNNING(oxu_to_hcd(oxu)->state))) {
            break;

        } else {
            stopped = 1;

            if (unlikely(!HC_IS_RUNNING(oxu_to_hcd(oxu)->state)))
                urb->status = -ESHUTDOWN;

            /* ignore active urbs unless some previous qtd
             * for the urb faulted (including short read) or
             * its urb was canceled.  we may patch qh or qtds.
             */
            if (likely(urb->status == -EINPROGRESS))
                continue;

            /* issue status after short control reads */
            if (unlikely(do_status != 0)
                    && QTD_PID(token) == 0 /* OUT */) {
                do_status = 0;
                continue;
            }

            /* token in overlay may be most current */
            if (state == QH_STATE_IDLE
                    && cpu_to_le32(qtd->qtd_dma)
                        == qh->hw_current)
                token = le32_to_cpu(qh->hw_token);

            /* force halt for unlinked or blocked qh, so we'll
             * patch the qh later and so that completions can't
             * activate it while we "know" it's stopped.
             */
            if ((HALT_BIT & qh->hw_token) == 0) {
halt:
                qh->hw_token |= HALT_BIT;
                wmb();
            }
        }

        /* Remove it from the queue */
        qtd_copy_status(oxu, urb->complete ?
                    urb : ((struct oxu_murb *) urb)->main,
                qtd->length, token);
        if ((usb_pipein(qtd->urb->pipe)) &&
                (NULL != qtd->transfer_buffer))
            memcpy(qtd->transfer_buffer, qtd->buffer, qtd->length);
        do_status = (urb->status == -EREMOTEIO)
                && usb_pipecontrol(urb->pipe);

        if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
            last = list_entry(qtd->qtd_list.prev,
                    struct ehci_qtd, qtd_list);
            last->hw_next = qtd->hw_next;
        }
        list_del(&qtd->qtd_list);
        last = qtd;
    }

    /* last urb's completion might still need calling */
    if (likely(last != NULL)) {
        if (last->urb->complete == NULL) {
            murb = (struct oxu_murb *) last->urb;
            last->urb = murb->main;
            if (murb->last) {
                ehci_urb_done(oxu, last->urb);
                count++;
            }
            oxu_murb_free(oxu, murb);
        } else {
            ehci_urb_done(oxu, last->urb);
            count++;
        }
        oxu_qtd_free(oxu, last);
    }

    /* restore original state; caller must unlink or relink */
    qh->qh_state = state;

    /* be sure the hardware's done with the qh before refreshing
     * it after fault cleanup, or recovering from silicon wrongly
     * overlaying the dummy qtd (which reduces DMA chatter).
     */
    if (stopped != 0 || qh->hw_qtd_next == EHCI_LIST_END) {
        switch (state) {
        case QH_STATE_IDLE:
            qh_refresh(oxu, qh);
            break;
        case QH_STATE_LINKED:
            /* should be rare for periodic transfers,
             * except maybe high bandwidth ...
             */
            if ((cpu_to_le32(QH_SMASK)
                    & qh->hw_info2) != 0) {
                intr_deschedule(oxu, qh);
                (void) qh_schedule(oxu, qh);
            } else
                unlink_async(oxu, qh);
            break;
        /* otherwise, unlink already started */
        }
    }

    return count;
}

/* High bandwidth multiplier, as encoded in highspeed endpoint descriptors */
#define hb_mult(wMaxPacketSize)     (1 + (((wMaxPacketSize) >> 11) & 0x03))
/* ... and packet size, for any kind of endpoint descriptor */
#define max_packet(wMaxPacketSize)  ((wMaxPacketSize) & 0x07ff)

/* Reverse of qh_urb_transaction: free a list of TDs.
 * used for cleanup after errors, before HC sees an URB's TDs.
 */
static void qtd_list_free(struct oxu_hcd *oxu,
                struct urb *urb, struct list_head *qtd_list)
{
    struct list_head *entry, *temp;

    list_for_each_safe(entry, temp, qtd_list) {
        struct ehci_qtd *qtd;

        qtd = list_entry(entry, struct ehci_qtd, qtd_list);
        list_del(&qtd->qtd_list);
        oxu_qtd_free(oxu, qtd);
    }
}

/* Create a list of filled qtds for this URB; won't link into qh.
 */
static struct list_head *qh_urb_transaction(struct oxu_hcd *oxu,
                        struct urb *urb,
                        struct list_head *head,
                        gfp_t flags)
{
    struct ehci_qtd *qtd, *qtd_prev;
    dma_addr_t buf;
    int len, maxpacket;
    int is_input;
    u32 token;
    void *transfer_buf = NULL;
    int ret;

    /*
     * URBs map to sequences of QTDs: one logical transaction
     */
    qtd = ehci_qtd_alloc(oxu);
    if (unlikely(!qtd))
        return NULL;
    list_add_tail(&qtd->qtd_list, head);
    qtd->urb = urb;

    token = QTD_STS_ACTIVE;
    token |= (EHCI_TUNE_CERR << 10);
    /* for split transactions, SplitXState initialized to zero */

    len = urb->transfer_buffer_length;
    is_input = usb_pipein(urb->pipe);
    if (!urb->transfer_buffer && urb->transfer_buffer_length && is_input)
        urb->transfer_buffer = phys_to_virt(urb->transfer_dma);

    if (usb_pipecontrol(urb->pipe)) {
        /* SETUP pid */
        ret = oxu_buf_alloc(oxu, qtd, sizeof(struct usb_ctrlrequest));
        if (ret)
            goto cleanup;

        qtd_fill(qtd, qtd->buffer_dma, sizeof(struct usb_ctrlrequest),
                token | (2 /* "setup" */ << 8), 8);
        memcpy(qtd->buffer, qtd->urb->setup_packet,
                sizeof(struct usb_ctrlrequest));

        /* ... and always at least one more pid */
        token ^= QTD_TOGGLE;
        qtd_prev = qtd;
        qtd = ehci_qtd_alloc(oxu);
        if (unlikely(!qtd))
            goto cleanup;
        qtd->urb = urb;
        qtd_prev->hw_next = QTD_NEXT(qtd->qtd_dma);
        list_add_tail(&qtd->qtd_list, head);

        /* for zero length DATA stages, STATUS is always IN */
        if (len == 0)
            token |= (1 /* "in" */ << 8);
    }

    /*
     * Data transfer stage: buffer setup
     */

    ret = oxu_buf_alloc(oxu, qtd, len);
    if (ret)
        goto cleanup;

    buf = qtd->buffer_dma;
    transfer_buf = urb->transfer_buffer;

    if (!is_input)
        memcpy(qtd->buffer, qtd->urb->transfer_buffer, len);

    if (is_input)
        token |= (1 /* "in" */ << 8);
    /* else it's already initted to "out" pid (0 << 8) */

    maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));

    /*
     * buffer gets wrapped in one or more qtds;
     * last one may be "short" (including zero len)
     * and may serve as a control status ack
     */
    for (;;) {
        int this_qtd_len;

        this_qtd_len = qtd_fill(qtd, buf, len, token, maxpacket);
        qtd->transfer_buffer = transfer_buf;
        len -= this_qtd_len;
        buf += this_qtd_len;
        transfer_buf += this_qtd_len;
        if (is_input)
            qtd->hw_alt_next = oxu->async->hw_alt_next;

        /* qh makes control packets use qtd toggle; maybe switch it */
        if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
            token ^= QTD_TOGGLE;

        if (likely(len <= 0))
            break;

        qtd_prev = qtd;
        qtd = ehci_qtd_alloc(oxu);
        if (unlikely(!qtd))
            goto cleanup;
        if (likely(len > 0)) {
            ret = oxu_buf_alloc(oxu, qtd, len);
            if (ret)
                goto cleanup;
        }
        qtd->urb = urb;
        qtd_prev->hw_next = QTD_NEXT(qtd->qtd_dma);
        list_add_tail(&qtd->qtd_list, head);
    }

    /* unless the bulk/interrupt caller wants a chance to clean
     * up after short reads, hc should advance qh past this urb
     */
    if (likely((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
                || usb_pipecontrol(urb->pipe)))
        qtd->hw_alt_next = EHCI_LIST_END;

    /*
     * control requests may need a terminating data "status" ack;
     * bulk ones may need a terminating short packet (zero length).
     */
    if (likely(urb->transfer_buffer_length != 0)) {
        int one_more = 0;

        if (usb_pipecontrol(urb->pipe)) {
            one_more = 1;
            token ^= 0x0100;    /* "in" <--> "out"  */
            token |= QTD_TOGGLE;    /* force DATA1 */
        } else if (usb_pipebulk(urb->pipe)
                && (urb->transfer_flags & URB_ZERO_PACKET)
                && !(urb->transfer_buffer_length % maxpacket)) {
            one_more = 1;
        }
        if (one_more) {
            qtd_prev = qtd;
            qtd = ehci_qtd_alloc(oxu);
            if (unlikely(!qtd))
                goto cleanup;
            qtd->urb = urb;
            qtd_prev->hw_next = QTD_NEXT(qtd->qtd_dma);
            list_add_tail(&qtd->qtd_list, head);

            /* never any data in such packets */
            qtd_fill(qtd, 0, 0, token, 0);
        }
    }

    /* by default, enable interrupt on urb completion */
        qtd->hw_token |= cpu_to_le32(QTD_IOC);
    return head;

cleanup:
    qtd_list_free(oxu, urb, head);
    return NULL;
}

/* Each QH holds a qtd list; a QH is used for everything except iso.
 *
 * For interrupt urbs, the scheduler must set the microframe scheduling
 * mask(s) each time the QH gets scheduled.  For highspeed, that's
 * just one microframe in the s-mask.  For split interrupt transactions
 * there are additional complications: c-mask, maybe FSTNs.
 */
static struct ehci_qh *qh_make(struct oxu_hcd *oxu,
                struct urb *urb, gfp_t flags)
{
    struct ehci_qh *qh = oxu_qh_alloc(oxu);
    u32 info1 = 0, info2 = 0;
    int is_input, type;
    int maxp = 0;

    if (!qh)
        return qh;

    /*
     * init endpoint/device data for this QH
     */
    info1 |= usb_pipeendpoint(urb->pipe) << 8;
    info1 |= usb_pipedevice(urb->pipe) << 0;

    is_input = usb_pipein(urb->pipe);
    type = usb_pipetype(urb->pipe);
    maxp = usb_maxpacket(urb->dev, urb->pipe, !is_input);

    /* Compute interrupt scheduling parameters just once, and save.
     * - allowing for high bandwidth, how many nsec/uframe are used?
     * - split transactions need a second CSPLIT uframe; same question
     * - splits also need a schedule gap (for full/low speed I/O)
     * - qh has a polling interval
     *
     * For control/bulk requests, the HC or TT handles these.
     */
    if (type == PIPE_INTERRUPT) {
        qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
                                is_input, 0,
                hb_mult(maxp) * max_packet(maxp)));
        qh->start = NO_FRAME;

        if (urb->dev->speed == USB_SPEED_HIGH) {
            qh->c_usecs = 0;
            qh->gap_uf = 0;

            qh->period = urb->interval >> 3;
            if (qh->period == 0 && urb->interval != 1) {
                /* NOTE interval 2 or 4 uframes could work.
                 * But interval 1 scheduling is simpler, and
                 * includes high bandwidth.
                 */
                oxu_dbg(oxu, "intr period %d uframes, NYET!\n",
                    urb->interval);
                goto done;
            }
        } else {
            struct usb_tt   *tt = urb->dev->tt;
            int     think_time;

            /* gap is f(FS/LS transfer times) */
            qh->gap_uf = 1 + usb_calc_bus_time(urb->dev->speed,
                    is_input, 0, maxp) / (125 * 1000);

            /* FIXME this just approximates SPLIT/CSPLIT times */
            if (is_input) {     /* SPLIT, gap, CSPLIT+DATA */
                qh->c_usecs = qh->usecs + HS_USECS(0);
                qh->usecs = HS_USECS(1);
            } else {        /* SPLIT+DATA, gap, CSPLIT */
                qh->usecs += HS_USECS(1);
                qh->c_usecs = HS_USECS(0);
            }

            think_time = tt ? tt->think_time : 0;
            qh->tt_usecs = NS_TO_US(think_time +
                    usb_calc_bus_time(urb->dev->speed,
                    is_input, 0, max_packet(maxp)));
            qh->period = urb->interval;
        }
    }

    /* support for tt scheduling, and access to toggles */
    qh->dev = urb->dev;

    /* using TT? */
    switch (urb->dev->speed) {
    case USB_SPEED_LOW:
        info1 |= (1 << 12); /* EPS "low" */
        /* FALL THROUGH */

    case USB_SPEED_FULL:
        /* EPS 0 means "full" */
        if (type != PIPE_INTERRUPT)
            info1 |= (EHCI_TUNE_RL_TT << 28);
        if (type == PIPE_CONTROL) {
            info1 |= (1 << 27); /* for TT */
            info1 |= 1 << 14;   /* toggle from qtd */
        }
        info1 |= maxp << 16;

        info2 |= (EHCI_TUNE_MULT_TT << 30);
        info2 |= urb->dev->ttport << 23;

        /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */

        break;

    case USB_SPEED_HIGH:        /* no TT involved */
        info1 |= (2 << 12); /* EPS "high" */
        if (type == PIPE_CONTROL) {
            info1 |= (EHCI_TUNE_RL_HS << 28);
            info1 |= 64 << 16;  /* usb2 fixed maxpacket */
            info1 |= 1 << 14;   /* toggle from qtd */
            info2 |= (EHCI_TUNE_MULT_HS << 30);
        } else if (type == PIPE_BULK) {
            info1 |= (EHCI_TUNE_RL_HS << 28);
            info1 |= 512 << 16; /* usb2 fixed maxpacket */
            info2 |= (EHCI_TUNE_MULT_HS << 30);
        } else {        /* PIPE_INTERRUPT */
            info1 |= max_packet(maxp) << 16;
            info2 |= hb_mult(maxp) << 30;
        }
        break;
    default:
        oxu_dbg(oxu, "bogus dev %p speed %d\n", urb->dev, urb->dev->speed);
done:
        qh_put(qh);
        return NULL;
    }

    /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */

    /* init as live, toggle clear, advance to dummy */
    qh->qh_state = QH_STATE_IDLE;
    qh->hw_info1 = cpu_to_le32(info1);
    qh->hw_info2 = cpu_to_le32(info2);
    usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe), !is_input, 1);
    qh_refresh(oxu, qh);
    return qh;
}

/* Move qh (and its qtds) onto async queue; maybe enable queue.
 */
static void qh_link_async(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    __le32 dma = QH_NEXT(qh->qh_dma);
    struct ehci_qh *head;

    /* (re)start the async schedule? */
    head = oxu->async;
    timer_action_done(oxu, TIMER_ASYNC_OFF);
    if (!head->qh_next.qh) {
        u32 cmd = readl(&oxu->regs->command);

        if (!(cmd & CMD_ASE)) {
            /* in case a clear of CMD_ASE didn't take yet */
            (void)handshake(oxu, &oxu->regs->status,
                    STS_ASS, 0, 150);
            cmd |= CMD_ASE | CMD_RUN;
            writel(cmd, &oxu->regs->command);
            oxu_to_hcd(oxu)->state = HC_STATE_RUNNING;
            /* posted write need not be known to HC yet ... */
        }
    }

    /* clear halt and/or toggle; and maybe recover from silicon quirk */
    if (qh->qh_state == QH_STATE_IDLE)
        qh_refresh(oxu, qh);

    /* splice right after start */
    qh->qh_next = head->qh_next;
    qh->hw_next = head->hw_next;
    wmb();

    head->qh_next.qh = qh;
    head->hw_next = dma;

    qh->qh_state = QH_STATE_LINKED;
    /* qtd completions reported later by interrupt */
}

#define QH_ADDR_MASK    cpu_to_le32(0x7f)

/*
 * For control/bulk/interrupt, return QH with these TDs appended.
 * Allocates and initializes the QH if necessary.
 * Returns null if it can't allocate a QH it needs to.
 * If the QH has TDs (urbs) already, that's great.
 */
static struct ehci_qh *qh_append_tds(struct oxu_hcd *oxu,
                struct urb *urb, struct list_head *qtd_list,
                int epnum, void **ptr)
{
    struct ehci_qh *qh = NULL;

    qh = (struct ehci_qh *) *ptr;
    if (unlikely(qh == NULL)) {
        /* can't sleep here, we have oxu->lock... */
        qh = qh_make(oxu, urb, GFP_ATOMIC);
        *ptr = qh;
    }
    if (likely(qh != NULL)) {
        struct ehci_qtd *qtd;

        if (unlikely(list_empty(qtd_list)))
            qtd = NULL;
        else
            qtd = list_entry(qtd_list->next, struct ehci_qtd,
                    qtd_list);

        /* control qh may need patching ... */
        if (unlikely(epnum == 0)) {

            /* usb_reset_device() briefly reverts to address 0 */
            if (usb_pipedevice(urb->pipe) == 0)
                qh->hw_info1 &= ~QH_ADDR_MASK;
        }

        /* just one way to queue requests: swap with the dummy qtd.
         * only hc or qh_refresh() ever modify the overlay.
         */
        if (likely(qtd != NULL)) {
            struct ehci_qtd *dummy;
            dma_addr_t dma;
            __le32 token;

            /* to avoid racing the HC, use the dummy td instead of
             * the first td of our list (becomes new dummy).  both
             * tds stay deactivated until we're done, when the
             * HC is allowed to fetch the old dummy (4.10.2).
             */
            token = qtd->hw_token;
            qtd->hw_token = HALT_BIT;
            wmb();
            dummy = qh->dummy;

            dma = dummy->qtd_dma;
            *dummy = *qtd;
            dummy->qtd_dma = dma;

            list_del(&qtd->qtd_list);
            list_add(&dummy->qtd_list, qtd_list);
            list_splice(qtd_list, qh->qtd_list.prev);

            ehci_qtd_init(qtd, qtd->qtd_dma);
            qh->dummy = qtd;

            /* hc must see the new dummy at list end */
            dma = qtd->qtd_dma;
            qtd = list_entry(qh->qtd_list.prev,
                    struct ehci_qtd, qtd_list);
            qtd->hw_next = QTD_NEXT(dma);

            /* let the hc process these next qtds */
            dummy->hw_token = (token & ~(0x80));
            wmb();
            dummy->hw_token = token;

            urb->hcpriv = qh_get(qh);
        }
    }
    return qh;
}

static int submit_async(struct oxu_hcd  *oxu, struct urb *urb,
            struct list_head *qtd_list, gfp_t mem_flags)
{
    struct ehci_qtd *qtd;
    int epnum;
    unsigned long flags;
    struct ehci_qh *qh = NULL;
    int rc = 0;

    qtd = list_entry(qtd_list->next, struct ehci_qtd, qtd_list);
    epnum = urb->ep->desc.bEndpointAddress;

#ifdef OXU_URB_TRACE
    oxu_dbg(oxu, "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
        __func__, urb->dev->devpath, urb,
        epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
        urb->transfer_buffer_length,
        qtd, urb->ep->hcpriv);
#endif

    spin_lock_irqsave(&oxu->lock, flags);
    if (unlikely(!HCD_HW_ACCESSIBLE(oxu_to_hcd(oxu)))) {
        rc = -ESHUTDOWN;
        goto done;
    }

    qh = qh_append_tds(oxu, urb, qtd_list, epnum, &urb->ep->hcpriv);
    if (unlikely(qh == NULL)) {
        rc = -ENOMEM;
        goto done;
    }

    /* Control/bulk operations through TTs don't need scheduling,
     * the HC and TT handle it when the TT has a buffer ready.
     */
    if (likely(qh->qh_state == QH_STATE_IDLE))
        qh_link_async(oxu, qh_get(qh));
done:
    spin_unlock_irqrestore(&oxu->lock, flags);
    if (unlikely(qh == NULL))
        qtd_list_free(oxu, urb, qtd_list);
    return rc;
}

/* The async qh for the qtds being reclaimed are now unlinked from the HC */

static void end_unlink_async(struct oxu_hcd *oxu)
{
    struct ehci_qh *qh = oxu->reclaim;
    struct ehci_qh *next;

    timer_action_done(oxu, TIMER_IAA_WATCHDOG);

    qh->qh_state = QH_STATE_IDLE;
    qh->qh_next.qh = NULL;
    qh_put(qh);         /* refcount from reclaim */

    /* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
    next = qh->reclaim;
    oxu->reclaim = next;
    oxu->reclaim_ready = 0;
    qh->reclaim = NULL;

    qh_completions(oxu, qh);

    if (!list_empty(&qh->qtd_list)
            && HC_IS_RUNNING(oxu_to_hcd(oxu)->state))
        qh_link_async(oxu, qh);
    else {
        qh_put(qh);     /* refcount from async list */

        /* it's not free to turn the async schedule on/off; leave it
         * active but idle for a while once it empties.
         */
        if (HC_IS_RUNNING(oxu_to_hcd(oxu)->state)
                && oxu->async->qh_next.qh == NULL)
            timer_action(oxu, TIMER_ASYNC_OFF);
    }

    if (next) {
        oxu->reclaim = NULL;
        start_unlink_async(oxu, next);
    }
}

/* makes sure the async qh will become idle */
/* caller must own oxu->lock */

static void start_unlink_async(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    int cmd = readl(&oxu->regs->command);
    struct ehci_qh *prev;

#ifdef DEBUG
    assert_spin_locked(&oxu->lock);
    if (oxu->reclaim || (qh->qh_state != QH_STATE_LINKED
                && qh->qh_state != QH_STATE_UNLINK_WAIT))
        BUG();
#endif

    /* stop async schedule right now? */
    if (unlikely(qh == oxu->async)) {
        /* can't get here without STS_ASS set */
        if (oxu_to_hcd(oxu)->state != HC_STATE_HALT
                && !oxu->reclaim) {
            /* ... and CMD_IAAD clear */
            writel(cmd & ~CMD_ASE, &oxu->regs->command);
            wmb();
            /* handshake later, if we need to */
            timer_action_done(oxu, TIMER_ASYNC_OFF);
        }
        return;
    }

    qh->qh_state = QH_STATE_UNLINK;
    oxu->reclaim = qh = qh_get(qh);

    prev = oxu->async;
    while (prev->qh_next.qh != qh)
        prev = prev->qh_next.qh;

    prev->hw_next = qh->hw_next;
    prev->qh_next = qh->qh_next;
    wmb();

    if (unlikely(oxu_to_hcd(oxu)->state == HC_STATE_HALT)) {
        /* if (unlikely(qh->reclaim != 0))
         *  this will recurse, probably not much
         */
        end_unlink_async(oxu);
        return;
    }

    oxu->reclaim_ready = 0;
    cmd |= CMD_IAAD;
    writel(cmd, &oxu->regs->command);
    (void) readl(&oxu->regs->command);
    timer_action(oxu, TIMER_IAA_WATCHDOG);
}

static void scan_async(struct oxu_hcd *oxu)
{
    struct ehci_qh *qh;
    enum ehci_timer_action action = TIMER_IO_WATCHDOG;

    if (!++(oxu->stamp))
        oxu->stamp++;
    timer_action_done(oxu, TIMER_ASYNC_SHRINK);
rescan:
    qh = oxu->async->qh_next.qh;
    if (likely(qh != NULL)) {
        do {
            /* clean any finished work for this qh */
            if (!list_empty(&qh->qtd_list)
                    && qh->stamp != oxu->stamp) {
                int temp;

                /* unlinks could happen here; completion
                 * reporting drops the lock.  rescan using
                 * the latest schedule, but don't rescan
                 * qhs we already finished (no looping).
                 */
                qh = qh_get(qh);
                qh->stamp = oxu->stamp;
                temp = qh_completions(oxu, qh);
                qh_put(qh);
                if (temp != 0)
                    goto rescan;
            }

            /* unlink idle entries, reducing HC PCI usage as well
             * as HCD schedule-scanning costs.  delay for any qh
             * we just scanned, there's a not-unusual case that it
             * doesn't stay idle for long.
             * (plus, avoids some kind of re-activation race.)
             */
            if (list_empty(&qh->qtd_list)) {
                if (qh->stamp == oxu->stamp)
                    action = TIMER_ASYNC_SHRINK;
                else if (!oxu->reclaim
                        && qh->qh_state == QH_STATE_LINKED)
                    start_unlink_async(oxu, qh);
            }

            qh = qh->qh_next.qh;
        } while (qh);
    }
    if (action == TIMER_ASYNC_SHRINK)
        timer_action(oxu, TIMER_ASYNC_SHRINK);
}

/*
 * periodic_next_shadow - return "next" pointer on shadow list
 * @periodic: host pointer to qh/itd/sitd
 * @tag: hardware tag for type of this record
 */
static union ehci_shadow *periodic_next_shadow(union ehci_shadow *periodic,
                        __le32 tag)
{
    switch (tag) {
    default:
    case Q_TYPE_QH:
        return &periodic->qh->qh_next;
    }
}

/* caller must hold oxu->lock */
static void periodic_unlink(struct oxu_hcd *oxu, unsigned frame, void *ptr)
{
    union ehci_shadow *prev_p = &oxu->pshadow[frame];
    __le32 *hw_p = &oxu->periodic[frame];
    union ehci_shadow here = *prev_p;

    /* find predecessor of "ptr"; hw and shadow lists are in sync */
    while (here.ptr && here.ptr != ptr) {
        prev_p = periodic_next_shadow(prev_p, Q_NEXT_TYPE(*hw_p));
        hw_p = here.hw_next;
        here = *prev_p;
    }
    /* an interrupt entry (at list end) could have been shared */
    if (!here.ptr)
        return;

    /* update shadow and hardware lists ... the old "next" pointers
     * from ptr may still be in use, the caller updates them.
     */
    *prev_p = *periodic_next_shadow(&here, Q_NEXT_TYPE(*hw_p));
    *hw_p = *here.hw_next;
}

/* how many of the uframe's 125 usecs are allocated? */
static unsigned short periodic_usecs(struct oxu_hcd *oxu,
                    unsigned frame, unsigned uframe)
{
    __le32 *hw_p = &oxu->periodic[frame];
    union ehci_shadow *q = &oxu->pshadow[frame];
    unsigned usecs = 0;

    while (q->ptr) {
        switch (Q_NEXT_TYPE(*hw_p)) {
        case Q_TYPE_QH:
        default:
            /* is it in the S-mask? */
            if (q->qh->hw_info2 & cpu_to_le32(1 << uframe))
                usecs += q->qh->usecs;
            /* ... or C-mask? */
            if (q->qh->hw_info2 & cpu_to_le32(1 << (8 + uframe)))
                usecs += q->qh->c_usecs;
            hw_p = &q->qh->hw_next;
            q = &q->qh->qh_next;
            break;
        }
    }
#ifdef DEBUG
    if (usecs > 100)
        oxu_err(oxu, "uframe %d sched overrun: %d usecs\n",
                        frame * 8 + uframe, usecs);
#endif
    return usecs;
}

static int enable_periodic(struct oxu_hcd *oxu)
{
    u32 cmd;
    int status;

    /* did clearing PSE did take effect yet?
     * takes effect only at frame boundaries...
     */
    status = handshake(oxu, &oxu->regs->status, STS_PSS, 0, 9 * 125);
    if (status != 0) {
        oxu_to_hcd(oxu)->state = HC_STATE_HALT;
        usb_hc_died(oxu_to_hcd(oxu));
        return status;
    }

    cmd = readl(&oxu->regs->command) | CMD_PSE;
    writel(cmd, &oxu->regs->command);
    /* posted write ... PSS happens later */
    oxu_to_hcd(oxu)->state = HC_STATE_RUNNING;

    /* make sure ehci_work scans these */
    oxu->next_uframe = readl(&oxu->regs->frame_index)
        % (oxu->periodic_size << 3);
    return 0;
}

static int disable_periodic(struct oxu_hcd *oxu)
{
    u32 cmd;
    int status;

    /* did setting PSE not take effect yet?
     * takes effect only at frame boundaries...
     */
    status = handshake(oxu, &oxu->regs->status, STS_PSS, STS_PSS, 9 * 125);
    if (status != 0) {
        oxu_to_hcd(oxu)->state = HC_STATE_HALT;
        usb_hc_died(oxu_to_hcd(oxu));
        return status;
    }

    cmd = readl(&oxu->regs->command) & ~CMD_PSE;
    writel(cmd, &oxu->regs->command);
    /* posted write ... */

    oxu->next_uframe = -1;
    return 0;
}

/* periodic schedule slots have iso tds (normal or split) first, then a
 * sparse tree for active interrupt transfers.
 *
 * this just links in a qh; caller guarantees uframe masks are set right.
 * no FSTN support (yet; oxu 0.96+)
 */
static int qh_link_periodic(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    unsigned i;
    unsigned period = qh->period;

    dev_dbg(&qh->dev->dev,
        "link qh%d-%04x/%p start %d [%d/%d us]\n",
        period, le32_to_cpup(&qh->hw_info2) & (QH_CMASK | QH_SMASK),
        qh, qh->start, qh->usecs, qh->c_usecs);

    /* high bandwidth, or otherwise every microframe */
    if (period == 0)
        period = 1;

    for (i = qh->start; i < oxu->periodic_size; i += period) {
        union ehci_shadow   *prev = &oxu->pshadow[i];
        __le32          *hw_p = &oxu->periodic[i];
        union ehci_shadow   here = *prev;
        __le32          type = 0;

        /* skip the iso nodes at list head */
        while (here.ptr) {
            type = Q_NEXT_TYPE(*hw_p);
            if (type == Q_TYPE_QH)
                break;
            prev = periodic_next_shadow(prev, type);
            hw_p = &here.qh->hw_next;
            here = *prev;
        }

        /* sorting each branch by period (slow-->fast)
         * enables sharing interior tree nodes
         */
        while (here.ptr && qh != here.qh) {
            if (qh->period > here.qh->period)
                break;
            prev = &here.qh->qh_next;
            hw_p = &here.qh->hw_next;
            here = *prev;
        }
        /* link in this qh, unless some earlier pass did that */
        if (qh != here.qh) {
            qh->qh_next = here;
            if (here.qh)
                qh->hw_next = *hw_p;
            wmb();
            prev->qh = qh;
            *hw_p = QH_NEXT(qh->qh_dma);
        }
    }
    qh->qh_state = QH_STATE_LINKED;
    qh_get(qh);

    /* update per-qh bandwidth for usbfs */
    oxu_to_hcd(oxu)->self.bandwidth_allocated += qh->period
        ? ((qh->usecs + qh->c_usecs) / qh->period)
        : (qh->usecs * 8);

    /* maybe enable periodic schedule processing */
    if (!oxu->periodic_sched++)
        return enable_periodic(oxu);

    return 0;
}

static void qh_unlink_periodic(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    unsigned i;
    unsigned period;

    /* FIXME:
     *   IF this isn't high speed
     *   and this qh is active in the current uframe
     *   (and overlay token SplitXstate is false?)
     * THEN
     *   qh->hw_info1 |= cpu_to_le32(1 << 7 "ignore");
     */

    /* high bandwidth, or otherwise part of every microframe */
    period = qh->period;
    if (period == 0)
        period = 1;

    for (i = qh->start; i < oxu->periodic_size; i += period)
        periodic_unlink(oxu, i, qh);

    /* update per-qh bandwidth for usbfs */
    oxu_to_hcd(oxu)->self.bandwidth_allocated -= qh->period
        ? ((qh->usecs + qh->c_usecs) / qh->period)
        : (qh->usecs * 8);

    dev_dbg(&qh->dev->dev,
        "unlink qh%d-%04x/%p start %d [%d/%d us]\n",
        qh->period,
        le32_to_cpup(&qh->hw_info2) & (QH_CMASK | QH_SMASK),
        qh, qh->start, qh->usecs, qh->c_usecs);

    /* qh->qh_next still "live" to HC */
    qh->qh_state = QH_STATE_UNLINK;
    qh->qh_next.ptr = NULL;
    qh_put(qh);

    /* maybe turn off periodic schedule */
    oxu->periodic_sched--;
    if (!oxu->periodic_sched)
        (void) disable_periodic(oxu);
}

static void intr_deschedule(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    unsigned wait;

    qh_unlink_periodic(oxu, qh);

    /* simple/paranoid:  always delay, expecting the HC needs to read
     * qh->hw_next or finish a writeback after SPLIT/CSPLIT ... and
     * expect khubd to clean up after any CSPLITs we won't issue.
     * active high speed queues may need bigger delays...
     */
    if (list_empty(&qh->qtd_list)
        || (cpu_to_le32(QH_CMASK) & qh->hw_info2) != 0)
        wait = 2;
    else
        wait = 55;  /* worst case: 3 * 1024 */

    udelay(wait);
    qh->qh_state = QH_STATE_IDLE;
    qh->hw_next = EHCI_LIST_END;
    wmb();
}

static int check_period(struct oxu_hcd *oxu,
            unsigned frame, unsigned uframe,
            unsigned period, unsigned usecs)
{
    int claimed;

    /* complete split running into next frame?
     * given FSTN support, we could sometimes check...
     */
    if (uframe >= 8)
        return 0;

    /*
     * 80% periodic == 100 usec/uframe available
     * convert "usecs we need" to "max already claimed"
     */
    usecs = 100 - usecs;

    /* we "know" 2 and 4 uframe intervals were rejected; so
     * for period 0, check _every_ microframe in the schedule.
     */
    if (unlikely(period == 0)) {
        do {
            for (uframe = 0; uframe < 7; uframe++) {
                claimed = periodic_usecs(oxu, frame, uframe);
                if (claimed > usecs)
                    return 0;
            }
        } while ((frame += 1) < oxu->periodic_size);

    /* just check the specified uframe, at that period */
    } else {
        do {
            claimed = periodic_usecs(oxu, frame, uframe);
            if (claimed > usecs)
                return 0;
        } while ((frame += period) < oxu->periodic_size);
    }

    return 1;
}

static int check_intr_schedule(struct oxu_hcd   *oxu,
                unsigned frame, unsigned uframe,
                const struct ehci_qh *qh, __le32 *c_maskp)
{
    int retval = -ENOSPC;

    if (qh->c_usecs && uframe >= 6)     /* FSTN territory? */
        goto done;

    if (!check_period(oxu, frame, uframe, qh->period, qh->usecs))
        goto done;
    if (!qh->c_usecs) {
        retval = 0;
        *c_maskp = 0;
        goto done;
    }

done:
    return retval;
}

/* "first fit" scheduling policy used the first time through,
 * or when the previous schedule slot can't be re-used.
 */
static int qh_schedule(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    int     status;
    unsigned    uframe;
    __le32      c_mask;
    unsigned    frame;      /* 0..(qh->period - 1), or NO_FRAME */

    qh_refresh(oxu, qh);
    qh->hw_next = EHCI_LIST_END;
    frame = qh->start;

    /* reuse the previous schedule slots, if we can */
    if (frame < qh->period) {
        uframe = ffs(le32_to_cpup(&qh->hw_info2) & QH_SMASK);
        status = check_intr_schedule(oxu, frame, --uframe,
                qh, &c_mask);
    } else {
        uframe = 0;
        c_mask = 0;
        status = -ENOSPC;
    }

    /* else scan the schedule to find a group of slots such that all
     * uframes have enough periodic bandwidth available.
     */
    if (status) {
        /* "normal" case, uframing flexible except with splits */
        if (qh->period) {
            frame = qh->period - 1;
            do {
                for (uframe = 0; uframe < 8; uframe++) {
                    status = check_intr_schedule(oxu,
                            frame, uframe, qh,
                            &c_mask);
                    if (status == 0)
                        break;
                }
            } while (status && frame--);

        /* qh->period == 0 means every uframe */
        } else {
            frame = 0;
            status = check_intr_schedule(oxu, 0, 0, qh, &c_mask);
        }
        if (status)
            goto done;
        qh->start = frame;

        /* reset S-frame and (maybe) C-frame masks */
        qh->hw_info2 &= cpu_to_le32(~(QH_CMASK | QH_SMASK));
        qh->hw_info2 |= qh->period
            ? cpu_to_le32(1 << uframe)
            : cpu_to_le32(QH_SMASK);
        qh->hw_info2 |= c_mask;
    } else
        oxu_dbg(oxu, "reused qh %p schedule\n", qh);

    /* stuff into the periodic schedule */
    status = qh_link_periodic(oxu, qh);
done:
    return status;
}

static int intr_submit(struct oxu_hcd *oxu, struct urb *urb,
            struct list_head *qtd_list, gfp_t mem_flags)
{
    unsigned epnum;
    unsigned long flags;
    struct ehci_qh *qh;
    int status = 0;
    struct list_head    empty;

    /* get endpoint and transfer/schedule data */
    epnum = urb->ep->desc.bEndpointAddress;

    spin_lock_irqsave(&oxu->lock, flags);

    if (unlikely(!HCD_HW_ACCESSIBLE(oxu_to_hcd(oxu)))) {
        status = -ESHUTDOWN;
        goto done;
    }

    /* get qh and force any scheduling errors */
    INIT_LIST_HEAD(&empty);
    qh = qh_append_tds(oxu, urb, &empty, epnum, &urb->ep->hcpriv);
    if (qh == NULL) {
        status = -ENOMEM;
        goto done;
    }
    if (qh->qh_state == QH_STATE_IDLE) {
        status = qh_schedule(oxu, qh);
        if (status != 0)
            goto done;
    }

    /* then queue the urb's tds to the qh */
    qh = qh_append_tds(oxu, urb, qtd_list, epnum, &urb->ep->hcpriv);
    BUG_ON(qh == NULL);

    /* ... update usbfs periodic stats */
    oxu_to_hcd(oxu)->self.bandwidth_int_reqs++;

done:
    spin_unlock_irqrestore(&oxu->lock, flags);
    if (status)
        qtd_list_free(oxu, urb, qtd_list);

    return status;
}

static inline int itd_submit(struct oxu_hcd *oxu, struct urb *urb,
                        gfp_t mem_flags)
{
    oxu_dbg(oxu, "iso support is missing!\n");
    return -ENOSYS;
}

static inline int sitd_submit(struct oxu_hcd *oxu, struct urb *urb,
                        gfp_t mem_flags)
{
    oxu_dbg(oxu, "split iso support is missing!\n");
    return -ENOSYS;
}

static void scan_periodic(struct oxu_hcd *oxu)
{
    unsigned frame, clock, now_uframe, mod;
    unsigned modified;

    mod = oxu->periodic_size << 3;

    /*
     * When running, scan from last scan point up to "now"
     * else clean up by scanning everything that's left.
     * Touches as few pages as possible:  cache-friendly.
     */
    now_uframe = oxu->next_uframe;
    if (HC_IS_RUNNING(oxu_to_hcd(oxu)->state))
        clock = readl(&oxu->regs->frame_index);
    else
        clock = now_uframe + mod - 1;
    clock %= mod;

    for (;;) {
        union ehci_shadow   q, *q_p;
        __le32          type, *hw_p;
        unsigned        uframes;

        /* don't scan past the live uframe */
        frame = now_uframe >> 3;
        if (frame == (clock >> 3))
            uframes = now_uframe & 0x07;
        else {
            /* safe to scan the whole frame at once */
            now_uframe |= 0x07;
            uframes = 8;
        }

restart:
        /* scan each element in frame's queue for completions */
        q_p = &oxu->pshadow[frame];
        hw_p = &oxu->periodic[frame];
        q.ptr = q_p->ptr;
        type = Q_NEXT_TYPE(*hw_p);
        modified = 0;

        while (q.ptr != NULL) {
            union ehci_shadow temp;
            int live;

            live = HC_IS_RUNNING(oxu_to_hcd(oxu)->state);
            switch (type) {
            case Q_TYPE_QH:
                /* handle any completions */
                temp.qh = qh_get(q.qh);
                type = Q_NEXT_TYPE(q.qh->hw_next);
                q = q.qh->qh_next;
                modified = qh_completions(oxu, temp.qh);
                if (unlikely(list_empty(&temp.qh->qtd_list)))
                    intr_deschedule(oxu, temp.qh);
                qh_put(temp.qh);
                break;
            default:
                oxu_dbg(oxu, "corrupt type %d frame %d shadow %p\n",
                    type, frame, q.ptr);
                q.ptr = NULL;
            }

            /* assume completion callbacks modify the queue */
            if (unlikely(modified))
                goto restart;
        }

        /* Stop when we catch up to the HC */

        /* FIXME:  this assumes we won't get lapped when
         * latencies climb; that should be rare, but...
         * detect it, and just go all the way around.
         * FLR might help detect this case, so long as latencies
         * don't exceed periodic_size msec (default 1.024 sec).
         */

        /* FIXME: likewise assumes HC doesn't halt mid-scan */

        if (now_uframe == clock) {
            unsigned    now;

            if (!HC_IS_RUNNING(oxu_to_hcd(oxu)->state))
                break;
            oxu->next_uframe = now_uframe;
            now = readl(&oxu->regs->frame_index) % mod;
            if (now_uframe == now)
                break;

            /* rescan the rest of this frame, then ... */
            clock = now;
        } else {
            now_uframe++;
            now_uframe %= mod;
        }
    }
}

/* On some systems, leaving remote wakeup enabled prevents system shutdown.
 * The firmware seems to think that powering off is a wakeup event!
 * This routine turns off remote wakeup and everything else, on all ports.
 */
static void ehci_turn_off_all_ports(struct oxu_hcd *oxu)
{
    int port = HCS_N_PORTS(oxu->hcs_params);

    while (port--)
        writel(PORT_RWC_BITS, &oxu->regs->port_status[port]);
}

static void ehci_port_power(struct oxu_hcd *oxu, int is_on)
{
    unsigned port;

    if (!HCS_PPC(oxu->hcs_params))
        return;

    oxu_dbg(oxu, "...power%s ports...\n", is_on ? "up" : "down");
    for (port = HCS_N_PORTS(oxu->hcs_params); port > 0; )
        (void) oxu_hub_control(oxu_to_hcd(oxu),
                is_on ? SetPortFeature : ClearPortFeature,
                USB_PORT_FEAT_POWER,
                port--, NULL, 0);
    msleep(20);
}

/* Called from some interrupts, timers, and so on.
 * It calls driver completion functions, after dropping oxu->lock.
 */
static void ehci_work(struct oxu_hcd *oxu)
{
    timer_action_done(oxu, TIMER_IO_WATCHDOG);
    if (oxu->reclaim_ready)
        end_unlink_async(oxu);

    /* another CPU may drop oxu->lock during a schedule scan while
     * it reports urb completions.  this flag guards against bogus
     * attempts at re-entrant schedule scanning.
     */
    if (oxu->scanning)
        return;
    oxu->scanning = 1;
    scan_async(oxu);
    if (oxu->next_uframe != -1)
        scan_periodic(oxu);
    oxu->scanning = 0;

    /* the IO watchdog guards against hardware or driver bugs that
     * misplace IRQs, and should let us run completely without IRQs.
     * such lossage has been observed on both VT6202 and VT8235.
     */
    if (HC_IS_RUNNING(oxu_to_hcd(oxu)->state) &&
            (oxu->async->qh_next.ptr != NULL ||
             oxu->periodic_sched != 0))
        timer_action(oxu, TIMER_IO_WATCHDOG);
}

static void unlink_async(struct oxu_hcd *oxu, struct ehci_qh *qh)
{
    /* if we need to use IAA and it's busy, defer */
    if (qh->qh_state == QH_STATE_LINKED
            && oxu->reclaim
            && HC_IS_RUNNING(oxu_to_hcd(oxu)->state)) {
        struct ehci_qh      *last;

        for (last = oxu->reclaim;
                last->reclaim;
                last = last->reclaim)
            continue;
        qh->qh_state = QH_STATE_UNLINK_WAIT;
        last->reclaim = qh;

    /* bypass IAA if the hc can't care */
    } else if (!HC_IS_RUNNING(oxu_to_hcd(oxu)->state) && oxu->reclaim)
        end_unlink_async(oxu);

    /* something else might have unlinked the qh by now */
    if (qh->qh_state == QH_STATE_LINKED)
        start_unlink_async(oxu, qh);
}

/*
 * USB host controller methods
 */

static irqreturn_t oxu210_hcd_irq(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    u32 status, pcd_status = 0;
    int bh;

    spin_lock(&oxu->lock);

    status = readl(&oxu->regs->status);

    /* e.g. cardbus physical eject */
    if (status == ~(u32) 0) {
        oxu_dbg(oxu, "device removed\n");
        goto dead;
    }

    /* Shared IRQ? */
    status &= INTR_MASK;
    if (!status || unlikely(hcd->state == HC_STATE_HALT)) {
        spin_unlock(&oxu->lock);
        return IRQ_NONE;
    }

    /* clear (just) interrupts */
    writel(status, &oxu->regs->status);
    readl(&oxu->regs->command); /* unblock posted write */
    bh = 0;

#ifdef OXU_VERBOSE_DEBUG
    /* unrequested/ignored: Frame List Rollover */
    dbg_status(oxu, "irq", status);
#endif

    /* INT, ERR, and IAA interrupt rates can be throttled */

    /* normal [4.15.1.2] or error [4.15.1.1] completion */
    if (likely((status & (STS_INT|STS_ERR)) != 0))
        bh = 1;

    /* complete the unlinking of some qh [4.15.2.3] */
    if (status & STS_IAA) {
        oxu->reclaim_ready = 1;
        bh = 1;
    }

    /* remote wakeup [4.3.1] */
    if (status & STS_PCD) {
        unsigned i = HCS_N_PORTS(oxu->hcs_params);
        pcd_status = status;

        /* resume root hub? */
        if (!(readl(&oxu->regs->command) & CMD_RUN))
            usb_hcd_resume_root_hub(hcd);

        while (i--) {
            int pstatus = readl(&oxu->regs->port_status[i]);

            if (pstatus & PORT_OWNER)
                continue;
            if (!(pstatus & PORT_RESUME)
                    || oxu->reset_done[i] != 0)
                continue;

            /* start 20 msec resume signaling from this port,
             * and make khubd collect PORT_STAT_C_SUSPEND to
             * stop that signaling.
             */
            oxu->reset_done[i] = jiffies + msecs_to_jiffies(20);
            oxu_dbg(oxu, "port %d remote wakeup\n", i + 1);
            mod_timer(&hcd->rh_timer, oxu->reset_done[i]);
        }
    }

    /* PCI errors [4.15.2.4] */
    if (unlikely((status & STS_FATAL) != 0)) {
        /* bogus "fatal" IRQs appear on some chips... why?  */
        status = readl(&oxu->regs->status);
        dbg_cmd(oxu, "fatal", readl(&oxu->regs->command));
        dbg_status(oxu, "fatal", status);
        if (status & STS_HALT) {
            oxu_err(oxu, "fatal error\n");
dead:
            ehci_reset(oxu);
            writel(0, &oxu->regs->configured_flag);
            usb_hc_died(hcd);
            /* generic layer kills/unlinks all urbs, then
             * uses oxu_stop to clean up the rest
             */
            bh = 1;
        }
    }

    if (bh)
        ehci_work(oxu);
    spin_unlock(&oxu->lock);
    if (pcd_status & STS_PCD)
        usb_hcd_poll_rh_status(hcd);
    return IRQ_HANDLED;
}

static irqreturn_t oxu_irq(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    int ret = IRQ_HANDLED;

    u32 status = oxu_readl(hcd->regs, OXU_CHIPIRQSTATUS);
    u32 enable = oxu_readl(hcd->regs, OXU_CHIPIRQEN_SET);

    /* Disable all interrupt */
    oxu_writel(hcd->regs, OXU_CHIPIRQEN_CLR, enable);

    if ((oxu->is_otg && (status & OXU_USBOTGI)) ||
        (!oxu->is_otg && (status & OXU_USBSPHI)))
        oxu210_hcd_irq(hcd);
    else
        ret = IRQ_NONE;

    /* Enable all interrupt back */
    oxu_writel(hcd->regs, OXU_CHIPIRQEN_SET, enable);

    return ret;
}

static void oxu_watchdog(unsigned long param)
{
    struct oxu_hcd  *oxu = (struct oxu_hcd *) param;
    unsigned long flags;

    spin_lock_irqsave(&oxu->lock, flags);

    /* lost IAA irqs wedge things badly; seen with a vt8235 */
    if (oxu->reclaim) {
        u32 status = readl(&oxu->regs->status);
        if (status & STS_IAA) {
            oxu_vdbg(oxu, "lost IAA\n");
            writel(STS_IAA, &oxu->regs->status);
            oxu->reclaim_ready = 1;
        }
    }

    /* stop async processing after it's idled a bit */
    if (test_bit(TIMER_ASYNC_OFF, &oxu->actions))
        start_unlink_async(oxu, oxu->async);

    /* oxu could run by timer, without IRQs ... */
    ehci_work(oxu);

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

/* One-time init, only for memory state.
 */
static int oxu_hcd_init(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    u32 temp;
    int retval;
    u32 hcc_params;

    spin_lock_init(&oxu->lock);

    init_timer(&oxu->watchdog);
    oxu->watchdog.function = oxu_watchdog;
    oxu->watchdog.data = (unsigned long) oxu;

    /*
     * hw default: 1K periodic list heads, one per frame.
     * periodic_size can shrink by USBCMD update if hcc_params allows.
     */
    oxu->periodic_size = DEFAULT_I_TDPS;
    retval = ehci_mem_init(oxu, GFP_KERNEL);
    if (retval < 0)
        return retval;

    /* controllers may cache some of the periodic schedule ... */
    hcc_params = readl(&oxu->caps->hcc_params);
    if (HCC_ISOC_CACHE(hcc_params))     /* full frame cache */
        oxu->i_thresh = 8;
    else                    /* N microframes cached */
        oxu->i_thresh = 2 + HCC_ISOC_THRES(hcc_params);

    oxu->reclaim = NULL;
    oxu->reclaim_ready = 0;
    oxu->next_uframe = -1;

    /*
     * dedicate a qh for the async ring head, since we couldn't unlink
     * a 'real' qh without stopping the async schedule [4.8].  use it
     * as the 'reclamation list head' too.
     * its dummy is used in hw_alt_next of many tds, to prevent the qh
     * from automatically advancing to the next td after short reads.
     */
    oxu->async->qh_next.qh = NULL;
    oxu->async->hw_next = QH_NEXT(oxu->async->qh_dma);
    oxu->async->hw_info1 = cpu_to_le32(QH_HEAD);
    oxu->async->hw_token = cpu_to_le32(QTD_STS_HALT);
    oxu->async->hw_qtd_next = EHCI_LIST_END;
    oxu->async->qh_state = QH_STATE_LINKED;
    oxu->async->hw_alt_next = QTD_NEXT(oxu->async->dummy->qtd_dma);

    /* clear interrupt enables, set irq latency */
    if (log2_irq_thresh < 0 || log2_irq_thresh > 6)
        log2_irq_thresh = 0;
    temp = 1 << (16 + log2_irq_thresh);
    if (HCC_CANPARK(hcc_params)) {
        /* HW default park == 3, on hardware that supports it (like
         * NVidia and ALI silicon), maximizes throughput on the async
         * schedule by avoiding QH fetches between transfers.
         *
         * With fast usb storage devices and NForce2, "park" seems to
         * make problems:  throughput reduction (!), data errors...
         */
        if (park) {
            park = min(park, (unsigned) 3);
            temp |= CMD_PARK;
            temp |= park << 8;
        }
        oxu_dbg(oxu, "park %d\n", park);
    }
    if (HCC_PGM_FRAMELISTLEN(hcc_params)) {
        /* periodic schedule size can be smaller than default */
        temp &= ~(3 << 2);
        temp |= (EHCI_TUNE_FLS << 2);
    }
    oxu->command = temp;

    return 0;
}

/* Called during probe() after chip reset completes.
 */
static int oxu_reset(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    int ret;

    spin_lock_init(&oxu->mem_lock);
    INIT_LIST_HEAD(&oxu->urb_list);
    oxu->urb_len = 0;

    /* FIMXE */
    hcd->self.controller->dma_mask = NULL;

    if (oxu->is_otg) {
        oxu->caps = hcd->regs + OXU_OTG_CAP_OFFSET;
        oxu->regs = hcd->regs + OXU_OTG_CAP_OFFSET + \
            HC_LENGTH(readl(&oxu->caps->hc_capbase));

        oxu->mem = hcd->regs + OXU_SPH_MEM;
    } else {
        oxu->caps = hcd->regs + OXU_SPH_CAP_OFFSET;
        oxu->regs = hcd->regs + OXU_SPH_CAP_OFFSET + \
            HC_LENGTH(readl(&oxu->caps->hc_capbase));

        oxu->mem = hcd->regs + OXU_OTG_MEM;
    }

    oxu->hcs_params = readl(&oxu->caps->hcs_params);
    oxu->sbrn = 0x20;

    ret = oxu_hcd_init(hcd);
    if (ret)
        return ret;

    return 0;
}

static int oxu_run(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    int retval;
    u32 temp, hcc_params;

    hcd->uses_new_polling = 1;

    /* EHCI spec section 4.1 */
    retval = ehci_reset(oxu);
    if (retval != 0) {
        ehci_mem_cleanup(oxu);
        return retval;
    }
    writel(oxu->periodic_dma, &oxu->regs->frame_list);
    writel((u32) oxu->async->qh_dma, &oxu->regs->async_next);

    /* hcc_params controls whether oxu->regs->segment must (!!!)
     * be used; it constrains QH/ITD/SITD and QTD locations.
     * pci_pool consistent memory always uses segment zero.
     * streaming mappings for I/O buffers, like pci_map_single(),
     * can return segments above 4GB, if the device allows.
     *
     * NOTE:  the dma mask is visible through dma_supported(), so
     * drivers can pass this info along ... like NETIF_F_HIGHDMA,
     * Scsi_Host.highmem_io, and so forth.  It's readonly to all
     * host side drivers though.
     */
    hcc_params = readl(&oxu->caps->hcc_params);
    if (HCC_64BIT_ADDR(hcc_params))
        writel(0, &oxu->regs->segment);

    oxu->command &= ~(CMD_LRESET | CMD_IAAD | CMD_PSE |
                CMD_ASE | CMD_RESET);
    oxu->command |= CMD_RUN;
    writel(oxu->command, &oxu->regs->command);
    dbg_cmd(oxu, "init", oxu->command);

    /*
     * Start, enabling full USB 2.0 functionality ... usb 1.1 devices
     * are explicitly handed to companion controller(s), so no TT is
     * involved with the root hub.  (Except where one is integrated,
     * and there's no companion controller unless maybe for USB OTG.)
     */
    hcd->state = HC_STATE_RUNNING;
    writel(FLAG_CF, &oxu->regs->configured_flag);
    readl(&oxu->regs->command); /* unblock posted writes */

    temp = HC_VERSION(readl(&oxu->caps->hc_capbase));
    oxu_info(oxu, "USB %x.%x started, quasi-EHCI %x.%02x, driver %s%s\n",
        ((oxu->sbrn & 0xf0)>>4), (oxu->sbrn & 0x0f),
        temp >> 8, temp & 0xff, DRIVER_VERSION,
        ignore_oc ? ", overcurrent ignored" : "");

    writel(INTR_MASK, &oxu->regs->intr_enable); /* Turn On Interrupts */

    return 0;
}

static void oxu_stop(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);

    /* Turn off port power on all root hub ports. */
    ehci_port_power(oxu, 0);

    /* no more interrupts ... */
    del_timer_sync(&oxu->watchdog);

    spin_lock_irq(&oxu->lock);
    if (HC_IS_RUNNING(hcd->state))
        ehci_quiesce(oxu);

    ehci_reset(oxu);
    writel(0, &oxu->regs->intr_enable);
    spin_unlock_irq(&oxu->lock);

    /* let companion controllers work when we aren't */
    writel(0, &oxu->regs->configured_flag);

    /* root hub is shut down separately (first, when possible) */
    spin_lock_irq(&oxu->lock);
    if (oxu->async)
        ehci_work(oxu);
    spin_unlock_irq(&oxu->lock);
    ehci_mem_cleanup(oxu);

    dbg_status(oxu, "oxu_stop completed", readl(&oxu->regs->status));
}

/* Kick in for silicon on any bus (not just pci, etc).
 * This forcibly disables dma and IRQs, helping kexec and other cases
 * where the next system software may expect clean state.
 */
static void oxu_shutdown(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);

    (void) ehci_halt(oxu);
    ehci_turn_off_all_ports(oxu);

    /* make BIOS/etc use companion controller during reboot */
    writel(0, &oxu->regs->configured_flag);

    /* unblock posted writes */
    readl(&oxu->regs->configured_flag);
}

/* Non-error returns are a promise to giveback() the urb later
 * we drop ownership so next owner (or urb unlink) can get it
 *
 * urb + dev is in hcd.self.controller.urb_list
 * we're queueing TDs onto software and hardware lists
 *
 * hcd-specific init for hcpriv hasn't been done yet
 *
 * NOTE:  control, bulk, and interrupt share the same code to append TDs
 * to a (possibly active) QH, and the same QH scanning code.
 */
static int __oxu_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
                gfp_t mem_flags)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    struct list_head qtd_list;

    INIT_LIST_HEAD(&qtd_list);

    switch (usb_pipetype(urb->pipe)) {
    case PIPE_CONTROL:
    case PIPE_BULK:
    default:
        if (!qh_urb_transaction(oxu, urb, &qtd_list, mem_flags))
            return -ENOMEM;
        return submit_async(oxu, urb, &qtd_list, mem_flags);

    case PIPE_INTERRUPT:
        if (!qh_urb_transaction(oxu, urb, &qtd_list, mem_flags))
            return -ENOMEM;
        return intr_submit(oxu, urb, &qtd_list, mem_flags);

    case PIPE_ISOCHRONOUS:
        if (urb->dev->speed == USB_SPEED_HIGH)
            return itd_submit(oxu, urb, mem_flags);
        else
            return sitd_submit(oxu, urb, mem_flags);
    }
}

/* This function is responsible for breaking URBs with big data size
 * into smaller size and processing small urbs in sequence.
 */
static int oxu_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
                gfp_t mem_flags)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    int num, rem;
    int transfer_buffer_length;
    void *transfer_buffer;
    struct urb *murb;
    int i, ret;

    /* If not bulk pipe just enqueue the URB */
    if (!usb_pipebulk(urb->pipe))
        return __oxu_urb_enqueue(hcd, urb, mem_flags);

    /* Otherwise we should verify the USB transfer buffer size! */
    transfer_buffer = urb->transfer_buffer;
    transfer_buffer_length = urb->transfer_buffer_length;

    num = urb->transfer_buffer_length / 4096;
    rem = urb->transfer_buffer_length % 4096;
    if (rem != 0)
        num++;

    /* If URB is smaller than 4096 bytes just enqueue it! */
    if (num == 1)
        return __oxu_urb_enqueue(hcd, urb, mem_flags);

    /* Ok, we have more job to do! :) */

    for (i = 0; i < num - 1; i++) {
        /* Get free micro URB poll till a free urb is received */

        do {
            murb = (struct urb *) oxu_murb_alloc(oxu);
            if (!murb)
                schedule();
        } while (!murb);

        /* Coping the urb */
        memcpy(murb, urb, sizeof(struct urb));

        murb->transfer_buffer_length = 4096;
        murb->transfer_buffer = transfer_buffer + i * 4096;

        /* Null pointer for the encodes that this is a micro urb */
        murb->complete = NULL;

        ((struct oxu_murb *) murb)->main = urb;
        ((struct oxu_murb *) murb)->last = 0;

        /* This loop is to guarantee urb to be processed when there's
         * not enough resources at a particular time by retrying.
         */
        do {
            ret  = __oxu_urb_enqueue(hcd, murb, mem_flags);
            if (ret)
                schedule();
        } while (ret);
    }

    /* Last urb requires special handling  */

    /* Get free micro URB poll till a free urb is received */
    do {
        murb = (struct urb *) oxu_murb_alloc(oxu);
        if (!murb)
            schedule();
    } while (!murb);

    /* Coping the urb */
    memcpy(murb, urb, sizeof(struct urb));

    murb->transfer_buffer_length = rem > 0 ? rem : 4096;
    murb->transfer_buffer = transfer_buffer + (num - 1) * 4096;

    /* Null pointer for the encodes that this is a micro urb */
    murb->complete = NULL;

    ((struct oxu_murb *) murb)->main = urb;
    ((struct oxu_murb *) murb)->last = 1;

    do {
        ret = __oxu_urb_enqueue(hcd, murb, mem_flags);
        if (ret)
            schedule();
    } while (ret);

    return ret;
}

/* Remove from hardware lists.
 * Completions normally happen asynchronously
 */
static int oxu_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    struct ehci_qh *qh;
    unsigned long flags;

    spin_lock_irqsave(&oxu->lock, flags);
    switch (usb_pipetype(urb->pipe)) {
    case PIPE_CONTROL:
    case PIPE_BULK:
    default:
        qh = (struct ehci_qh *) urb->hcpriv;
        if (!qh)
            break;
        unlink_async(oxu, qh);
        break;

    case PIPE_INTERRUPT:
        qh = (struct ehci_qh *) urb->hcpriv;
        if (!qh)
            break;
        switch (qh->qh_state) {
        case QH_STATE_LINKED:
            intr_deschedule(oxu, qh);
            /* FALL THROUGH */
        case QH_STATE_IDLE:
            qh_completions(oxu, qh);
            break;
        default:
            oxu_dbg(oxu, "bogus qh %p state %d\n",
                    qh, qh->qh_state);
            goto done;
        }

        /* reschedule QH iff another request is queued */
        if (!list_empty(&qh->qtd_list)
                && HC_IS_RUNNING(hcd->state)) {
            int status;

            status = qh_schedule(oxu, qh);
            spin_unlock_irqrestore(&oxu->lock, flags);

            if (status != 0) {
                /* shouldn't happen often, but ...
                 * FIXME kill those tds' urbs
                 */
                dev_err(hcd->self.controller,
                    "can't reschedule qh %p, err %d\n", qh,
                    status);
            }
            return status;
        }
        break;
    }
done:
    spin_unlock_irqrestore(&oxu->lock, flags);
    return 0;
}

/* Bulk qh holds the data toggle */
static void oxu_endpoint_disable(struct usb_hcd *hcd,
                    struct usb_host_endpoint *ep)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    unsigned long       flags;
    struct ehci_qh      *qh, *tmp;

    /* ASSERT:  any requests/urbs are being unlinked */
    /* ASSERT:  nobody can be submitting urbs for this any more */

rescan:
    spin_lock_irqsave(&oxu->lock, flags);
    qh = ep->hcpriv;
    if (!qh)
        goto done;

    /* endpoints can be iso streams.  for now, we don't
     * accelerate iso completions ... so spin a while.
     */
    if (qh->hw_info1 == 0) {
        oxu_vdbg(oxu, "iso delay\n");
        goto idle_timeout;
    }

    if (!HC_IS_RUNNING(hcd->state))
        qh->qh_state = QH_STATE_IDLE;
    switch (qh->qh_state) {
    case QH_STATE_LINKED:
        for (tmp = oxu->async->qh_next.qh;
                tmp && tmp != qh;
                tmp = tmp->qh_next.qh)
            continue;
        /* periodic qh self-unlinks on empty */
        if (!tmp)
            goto nogood;
        unlink_async(oxu, qh);
        /* FALL THROUGH */
    case QH_STATE_UNLINK:       /* wait for hw to finish? */
idle_timeout:
        spin_unlock_irqrestore(&oxu->lock, flags);
        schedule_timeout_uninterruptible(1);
        goto rescan;
    case QH_STATE_IDLE:     /* fully unlinked */
        if (list_empty(&qh->qtd_list)) {
            qh_put(qh);
            break;
        }
        /* else FALL THROUGH */
    default:
nogood:
        /* caller was supposed to have unlinked any requests;
         * that's not our job.  just leak this memory.
         */
        oxu_err(oxu, "qh %p (#%02x) state %d%s\n",
            qh, ep->desc.bEndpointAddress, qh->qh_state,
            list_empty(&qh->qtd_list) ? "" : "(has tds)");
        break;
    }
    ep->hcpriv = NULL;
done:
    spin_unlock_irqrestore(&oxu->lock, flags);
}

static int oxu_get_frame(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);

    return (readl(&oxu->regs->frame_index) >> 3) %
        oxu->periodic_size;
}

/* Build "status change" packet (one or two bytes) from HC registers */
static int oxu_hub_status_data(struct usb_hcd *hcd, char *buf)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    u32 temp, mask, status = 0;
    int ports, i, retval = 1;
    unsigned long flags;

    /* if !USB_SUSPEND, root hub timers won't get shut down ... */
    if (!HC_IS_RUNNING(hcd->state))
        return 0;

    /* init status to no-changes */
    buf[0] = 0;
    ports = HCS_N_PORTS(oxu->hcs_params);
    if (ports > 7) {
        buf[1] = 0;
        retval++;
    }

    /* Some boards (mostly VIA?) report bogus overcurrent indications,
     * causing massive log spam unless we completely ignore them.  It
     * may be relevant that VIA VT8235 controllers, where PORT_POWER is
     * always set, seem to clear PORT_OCC and PORT_CSC when writing to
     * PORT_POWER; that's surprising, but maybe within-spec.
     */
    if (!ignore_oc)
        mask = PORT_CSC | PORT_PEC | PORT_OCC;
    else
        mask = PORT_CSC | PORT_PEC;

    /* no hub change reports (bit 0) for now (power, ...) */

    /* port N changes (bit N)? */
    spin_lock_irqsave(&oxu->lock, flags);
    for (i = 0; i < ports; i++) {
        temp = readl(&oxu->regs->port_status[i]);

        /*
         * Return status information even for ports with OWNER set.
         * Otherwise khubd wouldn't see the disconnect event when a
         * high-speed device is switched over to the companion
         * controller by the user.
         */

        if (!(temp & PORT_CONNECT))
            oxu->reset_done[i] = 0;
        if ((temp & mask) != 0 || ((temp & PORT_RESUME) != 0 &&
                time_after_eq(jiffies, oxu->reset_done[i]))) {
            if (i < 7)
                buf[0] |= 1 << (i + 1);
            else
                buf[1] |= 1 << (i - 7);
            status = STS_PCD;
        }
    }
    /* FIXME autosuspend idle root hubs */
    spin_unlock_irqrestore(&oxu->lock, flags);
    return status ? retval : 0;
}

/* Returns the speed of a device attached to a port on the root hub. */
static inline unsigned int oxu_port_speed(struct oxu_hcd *oxu,
                        unsigned int portsc)
{
    switch ((portsc >> 26) & 3) {
    case 0:
        return 0;
    case 1:
        return USB_PORT_STAT_LOW_SPEED;
    case 2:
    default:
        return USB_PORT_STAT_HIGH_SPEED;
    }
}

#define PORT_WAKE_BITS  (PORT_WKOC_E|PORT_WKDISC_E|PORT_WKCONN_E)
static int oxu_hub_control(struct usb_hcd *hcd, u16 typeReq,
                u16 wValue, u16 wIndex, char *buf, u16 wLength)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    int ports = HCS_N_PORTS(oxu->hcs_params);
    u32 __iomem *status_reg = &oxu->regs->port_status[wIndex - 1];
    u32 temp, status;
    unsigned long   flags;
    int retval = 0;
    unsigned selector;

    /*
     * FIXME:  support SetPortFeatures USB_PORT_FEAT_INDICATOR.
     * HCS_INDICATOR may say we can change LEDs to off/amber/green.
     * (track current state ourselves) ... blink for diagnostics,
     * power, "this is the one", etc.  EHCI spec supports this.
     */

    spin_lock_irqsave(&oxu->lock, flags);
    switch (typeReq) {
    case ClearHubFeature:
        switch (wValue) {
        case C_HUB_LOCAL_POWER:
        case C_HUB_OVER_CURRENT:
            /* no hub-wide feature/status flags */
            break;
        default:
            goto error;
        }
        break;
    case ClearPortFeature:
        if (!wIndex || wIndex > ports)
            goto error;
        wIndex--;
        temp = readl(status_reg);

        /*
         * Even if OWNER is set, so the port is owned by the
         * companion controller, khubd needs to be able to clear
         * the port-change status bits (especially
         * USB_PORT_STAT_C_CONNECTION).
         */

        switch (wValue) {
        case USB_PORT_FEAT_ENABLE:
            writel(temp & ~PORT_PE, status_reg);
            break;
        case USB_PORT_FEAT_C_ENABLE:
            writel((temp & ~PORT_RWC_BITS) | PORT_PEC, status_reg);
            break;
        case USB_PORT_FEAT_SUSPEND:
            if (temp & PORT_RESET)
                goto error;
            if (temp & PORT_SUSPEND) {
                if ((temp & PORT_PE) == 0)
                    goto error;
                /* resume signaling for 20 msec */
                temp &= ~(PORT_RWC_BITS | PORT_WAKE_BITS);
                writel(temp | PORT_RESUME, status_reg);
                oxu->reset_done[wIndex] = jiffies
                        + msecs_to_jiffies(20);
            }
            break;
        case USB_PORT_FEAT_C_SUSPEND:
            /* we auto-clear this feature */
            break;
        case USB_PORT_FEAT_POWER:
            if (HCS_PPC(oxu->hcs_params))
                writel(temp & ~(PORT_RWC_BITS | PORT_POWER),
                      status_reg);
            break;
        case USB_PORT_FEAT_C_CONNECTION:
            writel((temp & ~PORT_RWC_BITS) | PORT_CSC, status_reg);
            break;
        case USB_PORT_FEAT_C_OVER_CURRENT:
            writel((temp & ~PORT_RWC_BITS) | PORT_OCC, status_reg);
            break;
        case USB_PORT_FEAT_C_RESET:
            /* GetPortStatus clears reset */
            break;
        default:
            goto error;
        }
        readl(&oxu->regs->command); /* unblock posted write */
        break;
    case GetHubDescriptor:
        ehci_hub_descriptor(oxu, (struct usb_hub_descriptor *)
            buf);
        break;
    case GetHubStatus:
        /* no hub-wide feature/status flags */
        memset(buf, 0, 4);
        break;
    case GetPortStatus:
        if (!wIndex || wIndex > ports)
            goto error;
        wIndex--;
        status = 0;
        temp = readl(status_reg);

        /* wPortChange bits */
        if (temp & PORT_CSC)
            status |= USB_PORT_STAT_C_CONNECTION << 16;
        if (temp & PORT_PEC)
            status |= USB_PORT_STAT_C_ENABLE << 16;
        if ((temp & PORT_OCC) && !ignore_oc)
            status |= USB_PORT_STAT_C_OVERCURRENT << 16;

        /* whoever resumes must GetPortStatus to complete it!! */
        if (temp & PORT_RESUME) {

            /* Remote Wakeup received? */
            if (!oxu->reset_done[wIndex]) {
                /* resume signaling for 20 msec */
                oxu->reset_done[wIndex] = jiffies
                        + msecs_to_jiffies(20);
                /* check the port again */
                mod_timer(&oxu_to_hcd(oxu)->rh_timer,
                        oxu->reset_done[wIndex]);
            }

            /* resume completed? */
            else if (time_after_eq(jiffies,
                    oxu->reset_done[wIndex])) {
                status |= USB_PORT_STAT_C_SUSPEND << 16;
                oxu->reset_done[wIndex] = 0;

                /* stop resume signaling */
                temp = readl(status_reg);
                writel(temp & ~(PORT_RWC_BITS | PORT_RESUME),
                    status_reg);
                retval = handshake(oxu, status_reg,
                       PORT_RESUME, 0, 2000 /* 2msec */);
                if (retval != 0) {
                    oxu_err(oxu,
                        "port %d resume error %d\n",
                        wIndex + 1, retval);
                    goto error;
                }
                temp &= ~(PORT_SUSPEND|PORT_RESUME|(3<<10));
            }
        }

        /* whoever resets must GetPortStatus to complete it!! */
        if ((temp & PORT_RESET)
                && time_after_eq(jiffies,
                    oxu->reset_done[wIndex])) {
            status |= USB_PORT_STAT_C_RESET << 16;
            oxu->reset_done[wIndex] = 0;

            /* force reset to complete */
            writel(temp & ~(PORT_RWC_BITS | PORT_RESET),
                    status_reg);
            /* REVISIT:  some hardware needs 550+ usec to clear
             * this bit; seems too long to spin routinely...
             */
            retval = handshake(oxu, status_reg,
                    PORT_RESET, 0, 750);
            if (retval != 0) {
                oxu_err(oxu, "port %d reset error %d\n",
                    wIndex + 1, retval);
                goto error;
            }

            /* see what we found out */
            temp = check_reset_complete(oxu, wIndex, status_reg,
                    readl(status_reg));
        }

        /* transfer dedicated ports to the companion hc */
        if ((temp & PORT_CONNECT) &&
                test_bit(wIndex, &oxu->companion_ports)) {
            temp &= ~PORT_RWC_BITS;
            temp |= PORT_OWNER;
            writel(temp, status_reg);
            oxu_dbg(oxu, "port %d --> companion\n", wIndex + 1);
            temp = readl(status_reg);
        }

        /*
         * Even if OWNER is set, there's no harm letting khubd
         * see the wPortStatus values (they should all be 0 except
         * for PORT_POWER anyway).
         */

        if (temp & PORT_CONNECT) {
            status |= USB_PORT_STAT_CONNECTION;
            /* status may be from integrated TT */
            status |= oxu_port_speed(oxu, temp);
        }
        if (temp & PORT_PE)
            status |= USB_PORT_STAT_ENABLE;
        if (temp & (PORT_SUSPEND|PORT_RESUME))
            status |= USB_PORT_STAT_SUSPEND;
        if (temp & PORT_OC)
            status |= USB_PORT_STAT_OVERCURRENT;
        if (temp & PORT_RESET)
            status |= USB_PORT_STAT_RESET;
        if (temp & PORT_POWER)
            status |= USB_PORT_STAT_POWER;

#ifndef OXU_VERBOSE_DEBUG
    if (status & ~0xffff)   /* only if wPortChange is interesting */
#endif
        dbg_port(oxu, "GetStatus", wIndex + 1, temp);
        put_unaligned(cpu_to_le32(status), (__le32 *) buf);
        break;
    case SetHubFeature:
        switch (wValue) {
        case C_HUB_LOCAL_POWER:
        case C_HUB_OVER_CURRENT:
            /* no hub-wide feature/status flags */
            break;
        default:
            goto error;
        }
        break;
    case SetPortFeature:
        selector = wIndex >> 8;
        wIndex &= 0xff;
        if (!wIndex || wIndex > ports)
            goto error;
        wIndex--;
        temp = readl(status_reg);
        if (temp & PORT_OWNER)
            break;

        temp &= ~PORT_RWC_BITS;
        switch (wValue) {
        case USB_PORT_FEAT_SUSPEND:
            if ((temp & PORT_PE) == 0
                    || (temp & PORT_RESET) != 0)
                goto error;
            if (device_may_wakeup(&hcd->self.root_hub->dev))
                temp |= PORT_WAKE_BITS;
            writel(temp | PORT_SUSPEND, status_reg);
            break;
        case USB_PORT_FEAT_POWER:
            if (HCS_PPC(oxu->hcs_params))
                writel(temp | PORT_POWER, status_reg);
            break;
        case USB_PORT_FEAT_RESET:
            if (temp & PORT_RESUME)
                goto error;
            /* line status bits may report this as low speed,
             * which can be fine if this root hub has a
             * transaction translator built in.
             */
            oxu_vdbg(oxu, "port %d reset\n", wIndex + 1);
            temp |= PORT_RESET;
            temp &= ~PORT_PE;

            /*
             * caller must wait, then call GetPortStatus
             * usb 2.0 spec says 50 ms resets on root
             */
            oxu->reset_done[wIndex] = jiffies
                    + msecs_to_jiffies(50);
            writel(temp, status_reg);
            break;

        /* For downstream facing ports (these):  one hub port is put
         * into test mode according to USB2 11.24.2.13, then the hub
         * must be reset (which for root hub now means rmmod+modprobe,
         * or else system reboot).  See EHCI 2.3.9 and 4.14 for info
         * about the EHCI-specific stuff.
         */
        case USB_PORT_FEAT_TEST:
            if (!selector || selector > 5)
                goto error;
            ehci_quiesce(oxu);
            ehci_halt(oxu);
            temp |= selector << 16;
            writel(temp, status_reg);
            break;

        default:
            goto error;
        }
        readl(&oxu->regs->command); /* unblock posted writes */
        break;

    default:
error:
        /* "stall" on error */
        retval = -EPIPE;
    }
    spin_unlock_irqrestore(&oxu->lock, flags);
    return retval;
}

#ifdef CONFIG_PM

static int oxu_bus_suspend(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    int port;
    int mask;

    oxu_dbg(oxu, "suspend root hub\n");

    if (time_before(jiffies, oxu->next_statechange))
        msleep(5);

    port = HCS_N_PORTS(oxu->hcs_params);
    spin_lock_irq(&oxu->lock);

    /* stop schedules, clean any completed work */
    if (HC_IS_RUNNING(hcd->state)) {
        ehci_quiesce(oxu);
        hcd->state = HC_STATE_QUIESCING;
    }
    oxu->command = readl(&oxu->regs->command);
    if (oxu->reclaim)
        oxu->reclaim_ready = 1;
    ehci_work(oxu);

    /* Unlike other USB host controller types, EHCI doesn't have
     * any notion of "global" or bus-wide suspend.  The driver has
     * to manually suspend all the active unsuspended ports, and
     * then manually resume them in the bus_resume() routine.
     */
    oxu->bus_suspended = 0;
    while (port--) {
        u32 __iomem *reg = &oxu->regs->port_status[port];
        u32 t1 = readl(reg) & ~PORT_RWC_BITS;
        u32 t2 = t1;

        /* keep track of which ports we suspend */
        if ((t1 & PORT_PE) && !(t1 & PORT_OWNER) &&
                !(t1 & PORT_SUSPEND)) {
            t2 |= PORT_SUSPEND;
            set_bit(port, &oxu->bus_suspended);
        }

        /* enable remote wakeup on all ports */
        if (device_may_wakeup(&hcd->self.root_hub->dev))
            t2 |= PORT_WKOC_E|PORT_WKDISC_E|PORT_WKCONN_E;
        else
            t2 &= ~(PORT_WKOC_E|PORT_WKDISC_E|PORT_WKCONN_E);

        if (t1 != t2) {
            oxu_vdbg(oxu, "port %d, %08x -> %08x\n",
                port + 1, t1, t2);
            writel(t2, reg);
        }
    }

    /* turn off now-idle HC */
    del_timer_sync(&oxu->watchdog);
    ehci_halt(oxu);
    hcd->state = HC_STATE_SUSPENDED;

    /* allow remote wakeup */
    mask = INTR_MASK;
    if (!device_may_wakeup(&hcd->self.root_hub->dev))
        mask &= ~STS_PCD;
    writel(mask, &oxu->regs->intr_enable);
    readl(&oxu->regs->intr_enable);

    oxu->next_statechange = jiffies + msecs_to_jiffies(10);
    spin_unlock_irq(&oxu->lock);
    return 0;
}

/* Caller has locked the root hub, and should reset/reinit on error */
static int oxu_bus_resume(struct usb_hcd *hcd)
{
    struct oxu_hcd *oxu = hcd_to_oxu(hcd);
    u32 temp;
    int i;

    if (time_before(jiffies, oxu->next_statechange))
        msleep(5);
    spin_lock_irq(&oxu->lock);

    /* Ideally and we've got a real resume here, and no port's power
     * was lost.  (For PCI, that means Vaux was maintained.)  But we
     * could instead be restoring a swsusp snapshot -- so that BIOS was
     * the last user of the controller, not reset/pm hardware keeping
     * state we gave to it.
     */
    temp = readl(&oxu->regs->intr_enable);
    oxu_dbg(oxu, "resume root hub%s\n", temp ? "" : " after power loss");

    /* at least some APM implementations will try to deliver
     * IRQs right away, so delay them until we're ready.
     */
    writel(0, &oxu->regs->intr_enable);

    /* re-init operational registers */
    writel(0, &oxu->regs->segment);
    writel(oxu->periodic_dma, &oxu->regs->frame_list);
    writel((u32) oxu->async->qh_dma, &oxu->regs->async_next);

    /* restore CMD_RUN, framelist size, and irq threshold */
    writel(oxu->command, &oxu->regs->command);

    /* Some controller/firmware combinations need a delay during which
     * they set up the port statuses.  See Bugzilla #8190. */
    mdelay(8);

    /* manually resume the ports we suspended during bus_suspend() */
    i = HCS_N_PORTS(oxu->hcs_params);
    while (i--) {
        temp = readl(&oxu->regs->port_status[i]);
        temp &= ~(PORT_RWC_BITS
            | PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E);
        if (test_bit(i, &oxu->bus_suspended) && (temp & PORT_SUSPEND)) {
            oxu->reset_done[i] = jiffies + msecs_to_jiffies(20);
            temp |= PORT_RESUME;
        }
        writel(temp, &oxu->regs->port_status[i]);
    }
    i = HCS_N_PORTS(oxu->hcs_params);
    mdelay(20);
    while (i--) {
        temp = readl(&oxu->regs->port_status[i]);
        if (test_bit(i, &oxu->bus_suspended) && (temp & PORT_SUSPEND)) {
            temp &= ~(PORT_RWC_BITS | PORT_RESUME);
            writel(temp, &oxu->regs->port_status[i]);
            oxu_vdbg(oxu, "resumed port %d\n", i + 1);
        }
    }
    (void) readl(&oxu->regs->command);

    /* maybe re-activate the schedule(s) */
    temp = 0;
    if (oxu->async->qh_next.qh)
        temp |= CMD_ASE;
    if (oxu->periodic_sched)
        temp |= CMD_PSE;
    if (temp) {
        oxu->command |= temp;
        writel(oxu->command, &oxu->regs->command);
    }

    oxu->next_statechange = jiffies + msecs_to_jiffies(5);
    hcd->state = HC_STATE_RUNNING;

    /* Now we can safely re-enable irqs */
    writel(INTR_MASK, &oxu->regs->intr_enable);

    spin_unlock_irq(&oxu->lock);
    return 0;
}

#else

static int oxu_bus_suspend(struct usb_hcd *hcd)
{
    return 0;
}

static int oxu_bus_resume(struct usb_hcd *hcd)
{
    return 0;
}

#endif  /* CONFIG_PM */

static const struct hc_driver oxu_hc_driver = {
    .description =      "oxu210hp_hcd",
    .product_desc =     "oxu210hp HCD",
    .hcd_priv_size =    sizeof(struct oxu_hcd),

    /*
     * Generic hardware linkage
     */
    .irq =          oxu_irq,
    .flags =        HCD_MEMORY | HCD_USB2,

    /*
     * Basic lifecycle operations
     */
    .reset =        oxu_reset,
    .start =        oxu_run,
    .stop =         oxu_stop,
    .shutdown =     oxu_shutdown,

    /*
     * Managing i/o requests and associated device resources
     */
    .urb_enqueue =      oxu_urb_enqueue,
    .urb_dequeue =      oxu_urb_dequeue,
    .endpoint_disable = oxu_endpoint_disable,

    /*
     * Scheduling support
     */
    .get_frame_number = oxu_get_frame,

    /*
     * Root hub support
     */
    .hub_status_data =  oxu_hub_status_data,
    .hub_control =      oxu_hub_control,
    .bus_suspend =      oxu_bus_suspend,
    .bus_resume =       oxu_bus_resume,
};

/*
 * Module stuff
 */

static void oxu_configuration(struct platform_device *pdev, void *base)
{
    u32 tmp;

    /* Initialize top level registers.
     * First write ever
     */
    oxu_writel(base, OXU_HOSTIFCONFIG, 0x0000037D);
    oxu_writel(base, OXU_SOFTRESET, OXU_SRESET);
    oxu_writel(base, OXU_HOSTIFCONFIG, 0x0000037D);

    tmp = oxu_readl(base, OXU_PIOBURSTREADCTRL);
    oxu_writel(base, OXU_PIOBURSTREADCTRL, tmp | 0x0040);

    oxu_writel(base, OXU_ASO, OXU_SPHPOEN | OXU_OVRCCURPUPDEN |
                    OXU_COMPARATOR | OXU_ASO_OP);

    tmp = oxu_readl(base, OXU_CLKCTRL_SET);
    oxu_writel(base, OXU_CLKCTRL_SET, tmp | OXU_SYSCLKEN | OXU_USBOTGCLKEN);

    /* Clear all top interrupt enable */
    oxu_writel(base, OXU_CHIPIRQEN_CLR, 0xff);

    /* Clear all top interrupt status */
    oxu_writel(base, OXU_CHIPIRQSTATUS, 0xff);

    /* Enable all needed top interrupt except OTG SPH core */
    oxu_writel(base, OXU_CHIPIRQEN_SET, OXU_USBSPHLPWUI | OXU_USBOTGLPWUI);
}

static int oxu_verify_id(struct platform_device *pdev, void *base)
{
    u32 id;
    static const char * const bo[] = {
        "reserved",
        "128-pin LQFP",
        "84-pin TFBGA",
        "reserved",
    };

    /* Read controller signature register to find a match */
    id = oxu_readl(base, OXU_DEVICEID);
    dev_info(&pdev->dev, "device ID %x\n", id);
    if ((id & OXU_REV_MASK) != (OXU_REV_2100 << OXU_REV_SHIFT))
        return -1;

    dev_info(&pdev->dev, "found device %x %s (%04x:%04x)\n",
        id >> OXU_REV_SHIFT,
        bo[(id & OXU_BO_MASK) >> OXU_BO_SHIFT],
        (id & OXU_MAJ_REV_MASK) >> OXU_MAJ_REV_SHIFT,
        (id & OXU_MIN_REV_MASK) >> OXU_MIN_REV_SHIFT);

    return 0;
}

static const struct hc_driver oxu_hc_driver;
static struct usb_hcd *oxu_create(struct platform_device *pdev,
                unsigned long memstart, unsigned long memlen,
                void *base, int irq, int otg)
{
    struct device *dev = &pdev->dev;

    struct usb_hcd *hcd;
    struct oxu_hcd *oxu;
    int ret;

    /* Set endian mode and host mode */
    oxu_writel(base + (otg ? OXU_OTG_CORE_OFFSET : OXU_SPH_CORE_OFFSET),
                OXU_USBMODE,
                OXU_CM_HOST_ONLY | OXU_ES_LITTLE | OXU_VBPS);

    hcd = usb_create_hcd(&oxu_hc_driver, dev,
                otg ? "oxu210hp_otg" : "oxu210hp_sph");
    if (!hcd)
        return ERR_PTR(-ENOMEM);

    hcd->rsrc_start = memstart;
    hcd->rsrc_len = memlen;
    hcd->regs = base;
    hcd->irq = irq;
    hcd->state = HC_STATE_HALT;

    oxu = hcd_to_oxu(hcd);
    oxu->is_otg = otg;

    ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
    if (ret < 0)
        return ERR_PTR(ret);

    return hcd;
}

static int oxu_init(struct platform_device *pdev,
                unsigned long memstart, unsigned long memlen,
                void *base, int irq)
{
    struct oxu_info *info = platform_get_drvdata(pdev);
    struct usb_hcd *hcd;
    int ret;

    /* First time configuration at start up */
    oxu_configuration(pdev, base);

    ret = oxu_verify_id(pdev, base);
    if (ret) {
        dev_err(&pdev->dev, "no devices found!\n");
        return -ENODEV;
    }

    /* Create the OTG controller */
    hcd = oxu_create(pdev, memstart, memlen, base, irq, 1);
    if (IS_ERR(hcd)) {
        dev_err(&pdev->dev, "cannot create OTG controller!\n");
        ret = PTR_ERR(hcd);
        goto error_create_otg;
    }
    info->hcd[0] = hcd;

    /* Create the SPH host controller */
    hcd = oxu_create(pdev, memstart, memlen, base, irq, 0);
    if (IS_ERR(hcd)) {
        dev_err(&pdev->dev, "cannot create SPH controller!\n");
        ret = PTR_ERR(hcd);
        goto error_create_sph;
    }
    info->hcd[1] = hcd;

    oxu_writel(base, OXU_CHIPIRQEN_SET,
        oxu_readl(base, OXU_CHIPIRQEN_SET) | 3);

    return 0;

error_create_sph:
    usb_remove_hcd(info->hcd[0]);
    usb_put_hcd(info->hcd[0]);

error_create_otg:
    return ret;
}

static int oxu_drv_probe(struct platform_device *pdev)
{
    struct resource *res;
    void *base;
    unsigned long memstart, memlen;
    int irq, ret;
    struct oxu_info *info;

    if (usb_disabled())
        return -ENODEV;

    /*
     * Get the platform resources
     */
    res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
    if (!res) {
        dev_err(&pdev->dev,
            "no IRQ! Check %s setup!\n", dev_name(&pdev->dev));
        return -ENODEV;
    }
    irq = res->start;
    dev_dbg(&pdev->dev, "IRQ resource %d\n", irq);

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(&pdev->dev, "no registers address! Check %s setup!\n",
            dev_name(&pdev->dev));
        return -ENODEV;
    }
    memstart = res->start;
    memlen = resource_size(res);
    dev_dbg(&pdev->dev, "MEM resource %lx-%lx\n", memstart, memlen);
    if (!request_mem_region(memstart, memlen,
                oxu_hc_driver.description)) {
        dev_dbg(&pdev->dev, "memory area already in use\n");
        return -EBUSY;
    }

    ret = irq_set_irq_type(irq, IRQF_TRIGGER_FALLING);
    if (ret) {
        dev_err(&pdev->dev, "error setting irq type\n");
        ret = -EFAULT;
        goto error_set_irq_type;
    }

    base = ioremap(memstart, memlen);
    if (!base) {
        dev_dbg(&pdev->dev, "error mapping memory\n");
        ret = -EFAULT;
        goto error_ioremap;
    }

    /* Allocate a driver data struct to hold useful info for both
     * SPH & OTG devices
     */
    info = kzalloc(sizeof(struct oxu_info), GFP_KERNEL);
    if (!info) {
        dev_dbg(&pdev->dev, "error allocating memory\n");
        ret = -EFAULT;
        goto error_alloc;
    }
    platform_set_drvdata(pdev, info);

    ret = oxu_init(pdev, memstart, memlen, base, irq);
    if (ret < 0) {
        dev_dbg(&pdev->dev, "cannot init USB devices\n");
        goto error_init;
    }

    dev_info(&pdev->dev, "devices enabled and running\n");
    platform_set_drvdata(pdev, info);

    return 0;

error_init:
    kfree(info);
    platform_set_drvdata(pdev, NULL);

error_alloc:
    iounmap(base);

error_set_irq_type:
error_ioremap:
    release_mem_region(memstart, memlen);

    dev_err(&pdev->dev, "init %s fail, %d\n", dev_name(&pdev->dev), ret);
    return ret;
}

static void oxu_remove(struct platform_device *pdev, struct usb_hcd *hcd)
{
    usb_remove_hcd(hcd);
    usb_put_hcd(hcd);
}

static int oxu_drv_remove(struct platform_device *pdev)
{
    struct oxu_info *info = platform_get_drvdata(pdev);
    unsigned long memstart = info->hcd[0]->rsrc_start,
            memlen = info->hcd[0]->rsrc_len;
    void *base = info->hcd[0]->regs;

    oxu_remove(pdev, info->hcd[0]);
    oxu_remove(pdev, info->hcd[1]);

    iounmap(base);
    release_mem_region(memstart, memlen);

    kfree(info);
    platform_set_drvdata(pdev, NULL);

    return 0;
}

static void oxu_drv_shutdown(struct platform_device *pdev)
{
    oxu_drv_remove(pdev);
}

#if 0
/* FIXME: TODO */
static int oxu_drv_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct usb_hcd *hcd = dev_get_drvdata(dev);

    return 0;
}

static int oxu_drv_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct usb_hcd *hcd = dev_get_drvdata(dev);

    return 0;
}
#else
#define oxu_drv_suspend NULL
#define oxu_drv_resume  NULL
#endif

static struct platform_driver oxu_driver = {
    .probe      = oxu_drv_probe,
    .remove     = oxu_drv_remove,
    .shutdown   = oxu_drv_shutdown,
    .suspend    = oxu_drv_suspend,
    .resume     = oxu_drv_resume,
    .driver = {
        .name = "oxu210hp-hcd",
        .bus = &platform_bus_type
    }
};

module_platform_driver(oxu_driver);

MODULE_DESCRIPTION("Oxford OXU210HP HCD driver - ver. " DRIVER_VERSION);
MODULE_AUTHOR("Rodolfo Giometti <[email protected]>");
MODULE_LICENSE("GPL");