ohci-hub.c

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/*
 * OHCI HCD (Host Controller Driver) for USB.
 *
 * (C) Copyright 1999 Roman Weissgaerber <[email protected]>
 * (C) Copyright 2000-2004 David Brownell <[email protected]>
 *
 * This file is licenced under GPL
 */

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

/*
 * OHCI Root Hub ... the nonsharable stuff
 */

#define dbg_port(hc,label,num,value) \
    ohci_dbg (hc, \
        "%s roothub.portstatus [%d] " \
        "= 0x%08x%s%s%s%s%s%s%s%s%s%s%s%s\n", \
        label, num, temp, \
        (temp & RH_PS_PRSC) ? " PRSC" : "", \
        (temp & RH_PS_OCIC) ? " OCIC" : "", \
        (temp & RH_PS_PSSC) ? " PSSC" : "", \
        (temp & RH_PS_PESC) ? " PESC" : "", \
        (temp & RH_PS_CSC) ? " CSC" : "", \
        \
        (temp & RH_PS_LSDA) ? " LSDA" : "", \
        (temp & RH_PS_PPS) ? " PPS" : "", \
        (temp & RH_PS_PRS) ? " PRS" : "", \
        (temp & RH_PS_POCI) ? " POCI" : "", \
        (temp & RH_PS_PSS) ? " PSS" : "", \
        \
        (temp & RH_PS_PES) ? " PES" : "", \
        (temp & RH_PS_CCS) ? " CCS" : "" \
        );

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

#define OHCI_SCHED_ENABLES \
    (OHCI_CTRL_CLE|OHCI_CTRL_BLE|OHCI_CTRL_PLE|OHCI_CTRL_IE)

static void dl_done_list (struct ohci_hcd *);
static void finish_unlinks (struct ohci_hcd *, u16);

#ifdef  CONFIG_PM
static int ohci_rh_suspend (struct ohci_hcd *ohci, int autostop)
__releases(ohci->lock)
__acquires(ohci->lock)
{
    int         status = 0;

    ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
    switch (ohci->hc_control & OHCI_CTRL_HCFS) {
    case OHCI_USB_RESUME:
        ohci_dbg (ohci, "resume/suspend?\n");
        ohci->hc_control &= ~OHCI_CTRL_HCFS;
        ohci->hc_control |= OHCI_USB_RESET;
        ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
        (void) ohci_readl (ohci, &ohci->regs->control);
        /* FALL THROUGH */
    case OHCI_USB_RESET:
        status = -EBUSY;
        ohci_dbg (ohci, "needs reinit!\n");
        goto done;
    case OHCI_USB_SUSPEND:
        if (!ohci->autostop) {
            ohci_dbg (ohci, "already suspended\n");
            goto done;
        }
    }
    ohci_dbg (ohci, "%s root hub\n",
            autostop ? "auto-stop" : "suspend");

    /* First stop any processing */
    if (!autostop && (ohci->hc_control & OHCI_SCHED_ENABLES)) {
        ohci->hc_control &= ~OHCI_SCHED_ENABLES;
        ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
        ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
        ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrstatus);

        /* sched disables take effect on the next frame,
         * then the last WDH could take 6+ msec
         */
        ohci_dbg (ohci, "stopping schedules ...\n");
        ohci->autostop = 0;
        spin_unlock_irq (&ohci->lock);
        msleep (8);
        spin_lock_irq (&ohci->lock);
    }
    dl_done_list (ohci);
    finish_unlinks (ohci, ohci_frame_no(ohci));

    /* maybe resume can wake root hub */
    if (ohci_to_hcd(ohci)->self.root_hub->do_remote_wakeup || autostop) {
        ohci->hc_control |= OHCI_CTRL_RWE;
    } else {
        ohci_writel(ohci, OHCI_INTR_RHSC | OHCI_INTR_RD,
                &ohci->regs->intrdisable);
        ohci->hc_control &= ~OHCI_CTRL_RWE;
    }

    /* Suspend hub ... this is the "global (to this bus) suspend" mode,
     * which doesn't imply ports will first be individually suspended.
     */
    ohci->hc_control &= ~OHCI_CTRL_HCFS;
    ohci->hc_control |= OHCI_USB_SUSPEND;
    ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
    (void) ohci_readl (ohci, &ohci->regs->control);

    /* no resumes until devices finish suspending */
    if (!autostop) {
        ohci->next_statechange = jiffies + msecs_to_jiffies (5);
        ohci->autostop = 0;
        ohci->rh_state = OHCI_RH_SUSPENDED;
    }

done:
    return status;
}

static inline struct ed *find_head (struct ed *ed)
{
    /* for bulk and control lists */
    while (ed->ed_prev)
        ed = ed->ed_prev;
    return ed;
}

/* caller has locked the root hub */
static int ohci_rh_resume (struct ohci_hcd *ohci)
__releases(ohci->lock)
__acquires(ohci->lock)
{
    struct usb_hcd      *hcd = ohci_to_hcd (ohci);
    u32         temp, enables;
    int         status = -EINPROGRESS;
    int         autostopped = ohci->autostop;

    ohci->autostop = 0;
    ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);

    if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
        /* this can happen after resuming a swsusp snapshot */
        if (ohci->rh_state != OHCI_RH_RUNNING) {
            ohci_dbg (ohci, "BIOS/SMM active, control %03x\n",
                    ohci->hc_control);
            status = -EBUSY;
        /* this happens when pmcore resumes HC then root */
        } else {
            ohci_dbg (ohci, "duplicate resume\n");
            status = 0;
        }
    } else switch (ohci->hc_control & OHCI_CTRL_HCFS) {
    case OHCI_USB_SUSPEND:
        ohci->hc_control &= ~(OHCI_CTRL_HCFS|OHCI_SCHED_ENABLES);
        ohci->hc_control |= OHCI_USB_RESUME;
        ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
        (void) ohci_readl (ohci, &ohci->regs->control);
        ohci_dbg (ohci, "%s root hub\n",
                autostopped ? "auto-start" : "resume");
        break;
    case OHCI_USB_RESUME:
        /* HCFS changes sometime after INTR_RD */
        ohci_dbg(ohci, "%swakeup root hub\n",
                autostopped ? "auto-" : "");
        break;
    case OHCI_USB_OPER:
        /* this can happen after resuming a swsusp snapshot */
        ohci_dbg (ohci, "snapshot resume? reinit\n");
        status = -EBUSY;
        break;
    default:        /* RESET, we lost power */
        ohci_dbg (ohci, "lost power\n");
        status = -EBUSY;
    }
    if (status == -EBUSY) {
        if (!autostopped) {
            spin_unlock_irq (&ohci->lock);
            (void) ohci_init (ohci);
            status = ohci_restart (ohci);

            usb_root_hub_lost_power(hcd->self.root_hub);

            spin_lock_irq (&ohci->lock);
        }
        return status;
    }
    if (status != -EINPROGRESS)
        return status;
    if (autostopped)
        goto skip_resume;
    spin_unlock_irq (&ohci->lock);

    /* Some controllers (lucent erratum) need extra-long delays */
    msleep (20 /* usb 11.5.1.10 */ + 12 /* 32 msec counter */ + 1);

    temp = ohci_readl (ohci, &ohci->regs->control);
    temp &= OHCI_CTRL_HCFS;
    if (temp != OHCI_USB_RESUME) {
        ohci_err (ohci, "controller won't resume\n");
        spin_lock_irq(&ohci->lock);
        return -EBUSY;
    }

    /* disable old schedule state, reinit from scratch */
    ohci_writel (ohci, 0, &ohci->regs->ed_controlhead);
    ohci_writel (ohci, 0, &ohci->regs->ed_controlcurrent);
    ohci_writel (ohci, 0, &ohci->regs->ed_bulkhead);
    ohci_writel (ohci, 0, &ohci->regs->ed_bulkcurrent);
    ohci_writel (ohci, 0, &ohci->regs->ed_periodcurrent);
    ohci_writel (ohci, (u32) ohci->hcca_dma, &ohci->regs->hcca);

    /* Sometimes PCI D3 suspend trashes frame timings ... */
    periodic_reinit (ohci);

    /* the following code is executed with ohci->lock held and
     * irqs disabled if and only if autostopped is true
     */

skip_resume:
    /* interrupts might have been disabled */
    ohci_writel (ohci, OHCI_INTR_INIT, &ohci->regs->intrenable);
    if (ohci->ed_rm_list)
        ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrenable);

    /* Then re-enable operations */
    ohci_writel (ohci, OHCI_USB_OPER, &ohci->regs->control);
    (void) ohci_readl (ohci, &ohci->regs->control);
    if (!autostopped)
        msleep (3);

    temp = ohci->hc_control;
    temp &= OHCI_CTRL_RWC;
    temp |= OHCI_CONTROL_INIT | OHCI_USB_OPER;
    ohci->hc_control = temp;
    ohci_writel (ohci, temp, &ohci->regs->control);
    (void) ohci_readl (ohci, &ohci->regs->control);

    /* TRSMRCY */
    if (!autostopped) {
        msleep (10);
        spin_lock_irq (&ohci->lock);
    }
    /* now ohci->lock is always held and irqs are always disabled */

    /* keep it alive for more than ~5x suspend + resume costs */
    ohci->next_statechange = jiffies + STATECHANGE_DELAY;

    /* maybe turn schedules back on */
    enables = 0;
    temp = 0;
    if (!ohci->ed_rm_list) {
        if (ohci->ed_controltail) {
            ohci_writel (ohci,
                    find_head (ohci->ed_controltail)->dma,
                    &ohci->regs->ed_controlhead);
            enables |= OHCI_CTRL_CLE;
            temp |= OHCI_CLF;
        }
        if (ohci->ed_bulktail) {
            ohci_writel (ohci, find_head (ohci->ed_bulktail)->dma,
                &ohci->regs->ed_bulkhead);
            enables |= OHCI_CTRL_BLE;
            temp |= OHCI_BLF;
        }
    }
    if (hcd->self.bandwidth_isoc_reqs || hcd->self.bandwidth_int_reqs)
        enables |= OHCI_CTRL_PLE|OHCI_CTRL_IE;
    if (enables) {
        ohci_dbg (ohci, "restarting schedules ... %08x\n", enables);
        ohci->hc_control |= enables;
        ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
        if (temp)
            ohci_writel (ohci, temp, &ohci->regs->cmdstatus);
        (void) ohci_readl (ohci, &ohci->regs->control);
    }

    ohci->rh_state = OHCI_RH_RUNNING;
    return 0;
}

static int ohci_bus_suspend (struct usb_hcd *hcd)
{
    struct ohci_hcd     *ohci = hcd_to_ohci (hcd);
    int         rc;

    spin_lock_irq (&ohci->lock);

    if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
        rc = -ESHUTDOWN;
    else
        rc = ohci_rh_suspend (ohci, 0);
    spin_unlock_irq (&ohci->lock);
    return rc;
}

static int ohci_bus_resume (struct usb_hcd *hcd)
{
    struct ohci_hcd     *ohci = hcd_to_ohci (hcd);
    int         rc;

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

    spin_lock_irq (&ohci->lock);

    if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
        rc = -ESHUTDOWN;
    else
        rc = ohci_rh_resume (ohci);
    spin_unlock_irq (&ohci->lock);

    /* poll until we know a device is connected or we autostop */
    if (rc == 0)
        usb_hcd_poll_rh_status(hcd);
    return rc;
}

/* Carry out the final steps of resuming the controller device */
static void __maybe_unused ohci_finish_controller_resume(struct usb_hcd *hcd)
{
    struct ohci_hcd     *ohci = hcd_to_ohci(hcd);
    int         port;
    bool            need_reinit = false;

    /* See if the controller is already running or has been reset */
    ohci->hc_control = ohci_readl(ohci, &ohci->regs->control);
    if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
        need_reinit = true;
    } else {
        switch (ohci->hc_control & OHCI_CTRL_HCFS) {
        case OHCI_USB_OPER:
        case OHCI_USB_RESET:
            need_reinit = true;
        }
    }

    /* If needed, reinitialize and suspend the root hub */
    if (need_reinit) {
        spin_lock_irq(&ohci->lock);
        ohci_rh_resume(ohci);
        ohci_rh_suspend(ohci, 0);
        spin_unlock_irq(&ohci->lock);
    }

    /* Normally just turn on port power and enable interrupts */
    else {
        ohci_dbg(ohci, "powerup ports\n");
        for (port = 0; port < ohci->num_ports; port++)
            ohci_writel(ohci, RH_PS_PPS,
                    &ohci->regs->roothub.portstatus[port]);

        ohci_writel(ohci, OHCI_INTR_MIE, &ohci->regs->intrenable);
        ohci_readl(ohci, &ohci->regs->intrenable);
        msleep(20);
    }

    usb_hcd_resume_root_hub(hcd);
}

/* Carry out polling-, autostop-, and autoresume-related state changes */
static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
        int any_connected, int rhsc_status)
{
    int poll_rh = 1;
    int rhsc_enable;

    /* Some broken controllers never turn off RHSC in the interrupt
     * status register.  For their sake we won't re-enable RHSC
     * interrupts if the interrupt bit is already active.
     */
    rhsc_enable = ohci_readl(ohci, &ohci->regs->intrenable) &
            OHCI_INTR_RHSC;

    switch (ohci->hc_control & OHCI_CTRL_HCFS) {
    case OHCI_USB_OPER:
        /* If no status changes are pending, enable RHSC interrupts. */
        if (!rhsc_enable && !rhsc_status && !changed) {
            rhsc_enable = OHCI_INTR_RHSC;
            ohci_writel(ohci, rhsc_enable, &ohci->regs->intrenable);
        }

        /* Keep on polling until we know a device is connected
         * and RHSC is enabled, or until we autostop.
         */
        if (!ohci->autostop) {
            if (any_connected ||
                    !device_may_wakeup(&ohci_to_hcd(ohci)
                        ->self.root_hub->dev)) {
                if (rhsc_enable)
                    poll_rh = 0;
            } else {
                ohci->autostop = 1;
                ohci->next_statechange = jiffies + HZ;
            }

        /* if no devices have been attached for one second, autostop */
        } else {
            if (changed || any_connected) {
                ohci->autostop = 0;
                ohci->next_statechange = jiffies +
                        STATECHANGE_DELAY;
            } else if (time_after_eq(jiffies,
                        ohci->next_statechange)
                    && !ohci->ed_rm_list
                    && !(ohci->hc_control &
                        OHCI_SCHED_ENABLES)) {
                ohci_rh_suspend(ohci, 1);
                if (rhsc_enable)
                    poll_rh = 0;
            }
        }
        break;

    case OHCI_USB_SUSPEND:
    case OHCI_USB_RESUME:
        /* if there is a port change, autostart or ask to be resumed */
        if (changed) {
            if (ohci->autostop)
                ohci_rh_resume(ohci);
            else
                usb_hcd_resume_root_hub(ohci_to_hcd(ohci));

        /* If remote wakeup is disabled, stop polling */
        } else if (!ohci->autostop &&
                !ohci_to_hcd(ohci)->self.root_hub->
                    do_remote_wakeup) {
            poll_rh = 0;

        } else {
            /* If no status changes are pending,
             * enable RHSC interrupts
             */
            if (!rhsc_enable && !rhsc_status) {
                rhsc_enable = OHCI_INTR_RHSC;
                ohci_writel(ohci, rhsc_enable,
                        &ohci->regs->intrenable);
            }
            /* Keep polling until RHSC is enabled */
            if (rhsc_enable)
                poll_rh = 0;
        }
        break;
    }
    return poll_rh;
}

#else   /* CONFIG_PM */

static inline int ohci_rh_resume(struct ohci_hcd *ohci)
{
    return 0;
}

/* Carry out polling-related state changes.
 * autostop isn't used when CONFIG_PM is turned off.
 */
static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
        int any_connected, int rhsc_status)
{
    /* If RHSC is enabled, don't poll */
    if (ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC)
        return 0;

    /* If status changes are pending, continue polling.
     * Conversely, if no status changes are pending but the RHSC
     * status bit was set, then RHSC may be broken so continue polling.
     */
    if (changed || rhsc_status)
        return 1;

    /* It's safe to re-enable RHSC interrupts */
    ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
    return 0;
}

#endif  /* CONFIG_PM */

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

/* build "status change" packet (one or two bytes) from HC registers */

static int
ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
{
    struct ohci_hcd *ohci = hcd_to_ohci (hcd);
    int     i, changed = 0, length = 1;
    int     any_connected = 0;
    int     rhsc_status;
    unsigned long   flags;

    spin_lock_irqsave (&ohci->lock, flags);
    if (!HCD_HW_ACCESSIBLE(hcd))
        goto done;

    /* undocumented erratum seen on at least rev D */
    if ((ohci->flags & OHCI_QUIRK_AMD756)
            && (roothub_a (ohci) & RH_A_NDP) > MAX_ROOT_PORTS) {
        ohci_warn (ohci, "bogus NDP, rereads as NDP=%d\n",
              ohci_readl (ohci, &ohci->regs->roothub.a) & RH_A_NDP);
        /* retry later; "should not happen" */
        goto done;
    }

    /* init status */
    if (roothub_status (ohci) & (RH_HS_LPSC | RH_HS_OCIC))
        buf [0] = changed = 1;
    else
        buf [0] = 0;
    if (ohci->num_ports > 7) {
        buf [1] = 0;
        length++;
    }

    /* Clear the RHSC status flag before reading the port statuses */
    ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrstatus);
    rhsc_status = ohci_readl(ohci, &ohci->regs->intrstatus) &
            OHCI_INTR_RHSC;

    /* look at each port */
    for (i = 0; i < ohci->num_ports; i++) {
        u32 status = roothub_portstatus (ohci, i);

        /* can't autostop if ports are connected */
        any_connected |= (status & RH_PS_CCS);

        if (status & (RH_PS_CSC | RH_PS_PESC | RH_PS_PSSC
                | RH_PS_OCIC | RH_PS_PRSC)) {
            changed = 1;
            if (i < 7)
                buf [0] |= 1 << (i + 1);
            else
                buf [1] |= 1 << (i - 7);
        }
    }

    if (ohci_root_hub_state_changes(ohci, changed,
            any_connected, rhsc_status))
        set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
    else
        clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);


done:
    spin_unlock_irqrestore (&ohci->lock, flags);

    return changed ? length : 0;
}

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

static void
ohci_hub_descriptor (
    struct ohci_hcd         *ohci,
    struct usb_hub_descriptor   *desc
) {
    u32     rh = roothub_a (ohci);
    u16     temp;

    desc->bDescriptorType = 0x29;
    desc->bPwrOn2PwrGood = (rh & RH_A_POTPGT) >> 24;
    desc->bHubContrCurrent = 0;

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

    temp = 0;
    if (rh & RH_A_NPS)      /* no power switching? */
        temp |= 0x0002;
    if (rh & RH_A_PSM)      /* per-port power switching? */
        temp |= 0x0001;
    if (rh & RH_A_NOCP)     /* no overcurrent reporting? */
        temp |= 0x0010;
    else if (rh & RH_A_OCPM)    /* per-port overcurrent reporting? */
        temp |= 0x0008;
    desc->wHubCharacteristics = (__force __u16)cpu_to_hc16(ohci, temp);

    /* ports removable, and usb 1.0 legacy PortPwrCtrlMask */
    rh = roothub_b (ohci);
    memset(desc->u.hs.DeviceRemovable, 0xff,
            sizeof(desc->u.hs.DeviceRemovable));
    desc->u.hs.DeviceRemovable[0] = rh & RH_B_DR;
    if (ohci->num_ports > 7) {
        desc->u.hs.DeviceRemovable[1] = (rh & RH_B_DR) >> 8;
        desc->u.hs.DeviceRemovable[2] = 0xff;
    } else
        desc->u.hs.DeviceRemovable[1] = 0xff;
}

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

#ifdef  CONFIG_USB_OTG

static int ohci_start_port_reset (struct usb_hcd *hcd, unsigned port)
{
    struct ohci_hcd *ohci = hcd_to_ohci (hcd);
    u32         status;

    if (!port)
        return -EINVAL;
    port--;

    /* start port reset before HNP protocol times out */
    status = ohci_readl(ohci, &ohci->regs->roothub.portstatus [port]);
    if (!(status & RH_PS_CCS))
        return -ENODEV;

    /* khubd will finish the reset later */
    ohci_writel(ohci, RH_PS_PRS, &ohci->regs->roothub.portstatus [port]);
    return 0;
}

#else

#define ohci_start_port_reset       NULL

#endif

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


/* See usb 7.1.7.5:  root hubs must issue at least 50 msec reset signaling,
 * not necessarily continuous ... to guard against resume signaling.
 * The short timeout is safe for non-root hubs, and is backward-compatible
 * with earlier Linux hosts.
 */
#ifdef  CONFIG_USB_SUSPEND
#define PORT_RESET_MSEC     50
#else
#define PORT_RESET_MSEC     10
#endif

/* this timer value might be vendor-specific ... */
#define PORT_RESET_HW_MSEC  10

/* wrap-aware logic morphed from <linux/jiffies.h> */
#define tick_before(t1,t2) ((s16)(((s16)(t1))-((s16)(t2))) < 0)

/* called from some task, normally khubd */
static inline int root_port_reset (struct ohci_hcd *ohci, unsigned port)
{
    __hc32 __iomem *portstat = &ohci->regs->roothub.portstatus [port];
    u32 temp = 0;
    u16 now = ohci_readl(ohci, &ohci->regs->fmnumber);
    u16 reset_done = now + PORT_RESET_MSEC;
    int limit_1 = DIV_ROUND_UP(PORT_RESET_MSEC, PORT_RESET_HW_MSEC);

    /* build a "continuous enough" reset signal, with up to
     * 3msec gap between pulses.  scheduler HZ==100 must work;
     * this might need to be deadline-scheduled.
     */
    do {
        int limit_2;

        /* spin until any current reset finishes */
        limit_2 = PORT_RESET_HW_MSEC * 2;
        while (--limit_2 >= 0) {
            temp = ohci_readl (ohci, portstat);
            /* handle e.g. CardBus eject */
            if (temp == ~(u32)0)
                return -ESHUTDOWN;
            if (!(temp & RH_PS_PRS))
                break;
            udelay (500);
        }

        /* timeout (a hardware error) has been observed when
         * EHCI sets CF while this driver is resetting a port;
         * presumably other disconnect paths might do it too.
         */
        if (limit_2 < 0) {
            ohci_dbg(ohci,
                "port[%d] reset timeout, stat %08x\n",
                port, temp);
            break;
        }

        if (!(temp & RH_PS_CCS))
            break;
        if (temp & RH_PS_PRSC)
            ohci_writel (ohci, RH_PS_PRSC, portstat);

        /* start the next reset, sleep till it's probably done */
        ohci_writel (ohci, RH_PS_PRS, portstat);
        msleep(PORT_RESET_HW_MSEC);
        now = ohci_readl(ohci, &ohci->regs->fmnumber);
    } while (tick_before(now, reset_done) && --limit_1 >= 0);

    /* caller synchronizes using PRSC ... and handles PRS
     * still being set when this returns.
     */

    return 0;
}

static int ohci_hub_control (
    struct usb_hcd  *hcd,
    u16     typeReq,
    u16     wValue,
    u16     wIndex,
    char        *buf,
    u16     wLength
) {
    struct ohci_hcd *ohci = hcd_to_ohci (hcd);
    int     ports = ohci->num_ports;
    u32     temp;
    int     retval = 0;

    if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
        return -ESHUTDOWN;

    switch (typeReq) {
    case ClearHubFeature:
        switch (wValue) {
        case C_HUB_OVER_CURRENT:
            ohci_writel (ohci, RH_HS_OCIC,
                    &ohci->regs->roothub.status);
        case C_HUB_LOCAL_POWER:
            break;
        default:
            goto error;
        }
        break;
    case ClearPortFeature:
        if (!wIndex || wIndex > ports)
            goto error;
        wIndex--;

        switch (wValue) {
        case USB_PORT_FEAT_ENABLE:
            temp = RH_PS_CCS;
            break;
        case USB_PORT_FEAT_C_ENABLE:
            temp = RH_PS_PESC;
            break;
        case USB_PORT_FEAT_SUSPEND:
            temp = RH_PS_POCI;
            break;
        case USB_PORT_FEAT_C_SUSPEND:
            temp = RH_PS_PSSC;
            break;
        case USB_PORT_FEAT_POWER:
            temp = RH_PS_LSDA;
            break;
        case USB_PORT_FEAT_C_CONNECTION:
            temp = RH_PS_CSC;
            break;
        case USB_PORT_FEAT_C_OVER_CURRENT:
            temp = RH_PS_OCIC;
            break;
        case USB_PORT_FEAT_C_RESET:
            temp = RH_PS_PRSC;
            break;
        default:
            goto error;
        }
        ohci_writel (ohci, temp,
                &ohci->regs->roothub.portstatus [wIndex]);
        // ohci_readl (ohci, &ohci->regs->roothub.portstatus [wIndex]);
        break;
    case GetHubDescriptor:
        ohci_hub_descriptor (ohci, (struct usb_hub_descriptor *) buf);
        break;
    case GetHubStatus:
        temp = roothub_status (ohci) & ~(RH_HS_CRWE | RH_HS_DRWE);
        put_unaligned_le32(temp, buf);
        break;
    case GetPortStatus:
        if (!wIndex || wIndex > ports)
            goto error;
        wIndex--;
        temp = roothub_portstatus (ohci, wIndex);
        put_unaligned_le32(temp, buf);

#ifndef OHCI_VERBOSE_DEBUG
    if (*(u16*)(buf+2)) /* only if wPortChange is interesting */
#endif
        dbg_port (ohci, "GetStatus", wIndex, temp);
        break;
    case SetHubFeature:
        switch (wValue) {
        case C_HUB_OVER_CURRENT:
            // FIXME:  this can be cleared, yes?
        case C_HUB_LOCAL_POWER:
            break;
        default:
            goto error;
        }
        break;
    case SetPortFeature:
        if (!wIndex || wIndex > ports)
            goto error;
        wIndex--;
        switch (wValue) {
        case USB_PORT_FEAT_SUSPEND:
#ifdef  CONFIG_USB_OTG
            if (hcd->self.otg_port == (wIndex + 1)
                    && hcd->self.b_hnp_enable)
                ohci->start_hnp(ohci);
            else
#endif
            ohci_writel (ohci, RH_PS_PSS,
                &ohci->regs->roothub.portstatus [wIndex]);
            break;
        case USB_PORT_FEAT_POWER:
            ohci_writel (ohci, RH_PS_PPS,
                &ohci->regs->roothub.portstatus [wIndex]);
            break;
        case USB_PORT_FEAT_RESET:
            retval = root_port_reset (ohci, wIndex);
            break;
        default:
            goto error;
        }
        break;

    default:
error:
        /* "protocol stall" on error */
        retval = -EPIPE;
    }
    return retval;
}