2 * OHCI HCD (Host Controller Driver) for USB.
4 * (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
5 * (C) Copyright 2000-2004 David Brownell <dbrownell@users.sourceforge.net>
7 * This file is licenced under GPL
10 /*-------------------------------------------------------------------------*/
13 * OHCI Root Hub ... the nonsharable stuff
16 #define dbg_port(hc,label,num,value) \
18 "%s roothub.portstatus [%d] " \
19 "= 0x%08x%s%s%s%s%s%s%s%s%s%s%s%s\n", \
21 (temp & RH_PS_PRSC) ? " PRSC" : "", \
22 (temp & RH_PS_OCIC) ? " OCIC" : "", \
23 (temp & RH_PS_PSSC) ? " PSSC" : "", \
24 (temp & RH_PS_PESC) ? " PESC" : "", \
25 (temp & RH_PS_CSC) ? " CSC" : "", \
27 (temp & RH_PS_LSDA) ? " LSDA" : "", \
28 (temp & RH_PS_PPS) ? " PPS" : "", \
29 (temp & RH_PS_PRS) ? " PRS" : "", \
30 (temp & RH_PS_POCI) ? " POCI" : "", \
31 (temp & RH_PS_PSS) ? " PSS" : "", \
33 (temp & RH_PS_PES) ? " PES" : "", \
34 (temp & RH_PS_CCS) ? " CCS" : "" \
37 /*-------------------------------------------------------------------------*/
39 #define OHCI_SCHED_ENABLES \
40 (OHCI_CTRL_CLE|OHCI_CTRL_BLE|OHCI_CTRL_PLE|OHCI_CTRL_IE)
42 static void dl_done_list (struct ohci_hcd *);
43 static void finish_unlinks (struct ohci_hcd *, u16);
46 static int ohci_rh_suspend (struct ohci_hcd *ohci, int autostop)
47 __releases(ohci->lock)
48 __acquires(ohci->lock)
52 ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
53 switch (ohci->hc_control & OHCI_CTRL_HCFS) {
55 ohci_dbg (ohci, "resume/suspend?\n");
56 ohci->hc_control &= ~OHCI_CTRL_HCFS;
57 ohci->hc_control |= OHCI_USB_RESET;
58 ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
59 (void) ohci_readl (ohci, &ohci->regs->control);
63 ohci_dbg (ohci, "needs reinit!\n");
65 case OHCI_USB_SUSPEND:
66 if (!ohci->autostop) {
67 ohci_dbg (ohci, "already suspended\n");
71 ohci_dbg (ohci, "%s root hub\n",
72 autostop ? "auto-stop" : "suspend");
74 /* First stop any processing */
75 if (!autostop && (ohci->hc_control & OHCI_SCHED_ENABLES)) {
76 ohci->hc_control &= ~OHCI_SCHED_ENABLES;
77 ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
78 ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
79 ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrstatus);
81 /* sched disables take effect on the next frame,
82 * then the last WDH could take 6+ msec
84 ohci_dbg (ohci, "stopping schedules ...\n");
86 spin_unlock_irq (&ohci->lock);
88 spin_lock_irq (&ohci->lock);
91 finish_unlinks (ohci, ohci_frame_no(ohci));
93 /* maybe resume can wake root hub */
94 if (ohci_to_hcd(ohci)->self.root_hub->do_remote_wakeup || autostop) {
95 ohci->hc_control |= OHCI_CTRL_RWE;
97 ohci_writel(ohci, OHCI_INTR_RHSC | OHCI_INTR_RD,
98 &ohci->regs->intrdisable);
99 ohci->hc_control &= ~OHCI_CTRL_RWE;
102 /* Suspend hub ... this is the "global (to this bus) suspend" mode,
103 * which doesn't imply ports will first be individually suspended.
105 ohci->hc_control &= ~OHCI_CTRL_HCFS;
106 ohci->hc_control |= OHCI_USB_SUSPEND;
107 ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
108 (void) ohci_readl (ohci, &ohci->regs->control);
110 /* no resumes until devices finish suspending */
112 ohci->next_statechange = jiffies + msecs_to_jiffies (5);
114 ohci->rh_state = OHCI_RH_SUSPENDED;
121 static inline struct ed *find_head (struct ed *ed)
123 /* for bulk and control lists */
129 /* caller has locked the root hub */
130 static int ohci_rh_resume (struct ohci_hcd *ohci)
131 __releases(ohci->lock)
132 __acquires(ohci->lock)
134 struct usb_hcd *hcd = ohci_to_hcd (ohci);
136 int status = -EINPROGRESS;
137 int autostopped = ohci->autostop;
140 ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
142 if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
143 /* this can happen after resuming a swsusp snapshot */
144 if (ohci->rh_state != OHCI_RH_RUNNING) {
145 ohci_dbg (ohci, "BIOS/SMM active, control %03x\n",
148 /* this happens when pmcore resumes HC then root */
150 ohci_dbg (ohci, "duplicate resume\n");
153 } else switch (ohci->hc_control & OHCI_CTRL_HCFS) {
154 case OHCI_USB_SUSPEND:
155 ohci->hc_control &= ~(OHCI_CTRL_HCFS|OHCI_SCHED_ENABLES);
156 ohci->hc_control |= OHCI_USB_RESUME;
157 ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
158 (void) ohci_readl (ohci, &ohci->regs->control);
159 ohci_dbg (ohci, "%s root hub\n",
160 autostopped ? "auto-start" : "resume");
162 case OHCI_USB_RESUME:
163 /* HCFS changes sometime after INTR_RD */
164 ohci_dbg(ohci, "%swakeup root hub\n",
165 autostopped ? "auto-" : "");
168 /* this can happen after resuming a swsusp snapshot */
169 ohci_dbg (ohci, "snapshot resume? reinit\n");
172 default: /* RESET, we lost power */
173 ohci_dbg (ohci, "lost power\n");
176 if (status == -EBUSY) {
178 spin_unlock_irq (&ohci->lock);
179 (void) ohci_init (ohci);
180 status = ohci_restart (ohci);
182 usb_root_hub_lost_power(hcd->self.root_hub);
184 spin_lock_irq (&ohci->lock);
188 if (status != -EINPROGRESS)
192 spin_unlock_irq (&ohci->lock);
194 /* Some controllers (lucent erratum) need extra-long delays */
195 msleep (20 /* usb 11.5.1.10 */ + 12 /* 32 msec counter */ + 1);
197 temp = ohci_readl (ohci, &ohci->regs->control);
198 temp &= OHCI_CTRL_HCFS;
199 if (temp != OHCI_USB_RESUME) {
200 ohci_err (ohci, "controller won't resume\n");
201 spin_lock_irq(&ohci->lock);
205 /* disable old schedule state, reinit from scratch */
206 ohci_writel (ohci, 0, &ohci->regs->ed_controlhead);
207 ohci_writel (ohci, 0, &ohci->regs->ed_controlcurrent);
208 ohci_writel (ohci, 0, &ohci->regs->ed_bulkhead);
209 ohci_writel (ohci, 0, &ohci->regs->ed_bulkcurrent);
210 ohci_writel (ohci, 0, &ohci->regs->ed_periodcurrent);
211 ohci_writel (ohci, (u32) ohci->hcca_dma, &ohci->regs->hcca);
213 /* Sometimes PCI D3 suspend trashes frame timings ... */
214 periodic_reinit (ohci);
216 /* the following code is executed with ohci->lock held and
217 * irqs disabled if and only if autostopped is true
221 /* interrupts might have been disabled */
222 ohci_writel (ohci, OHCI_INTR_INIT, &ohci->regs->intrenable);
223 if (ohci->ed_rm_list)
224 ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrenable);
226 /* Then re-enable operations */
227 ohci_writel (ohci, OHCI_USB_OPER, &ohci->regs->control);
228 (void) ohci_readl (ohci, &ohci->regs->control);
232 temp = ohci->hc_control;
233 temp &= OHCI_CTRL_RWC;
234 temp |= OHCI_CONTROL_INIT | OHCI_USB_OPER;
235 ohci->hc_control = temp;
236 ohci_writel (ohci, temp, &ohci->regs->control);
237 (void) ohci_readl (ohci, &ohci->regs->control);
242 spin_lock_irq (&ohci->lock);
244 /* now ohci->lock is always held and irqs are always disabled */
246 /* keep it alive for more than ~5x suspend + resume costs */
247 ohci->next_statechange = jiffies + STATECHANGE_DELAY;
249 /* maybe turn schedules back on */
252 if (!ohci->ed_rm_list) {
253 if (ohci->ed_controltail) {
255 find_head (ohci->ed_controltail)->dma,
256 &ohci->regs->ed_controlhead);
257 enables |= OHCI_CTRL_CLE;
260 if (ohci->ed_bulktail) {
261 ohci_writel (ohci, find_head (ohci->ed_bulktail)->dma,
262 &ohci->regs->ed_bulkhead);
263 enables |= OHCI_CTRL_BLE;
267 if (hcd->self.bandwidth_isoc_reqs || hcd->self.bandwidth_int_reqs)
268 enables |= OHCI_CTRL_PLE|OHCI_CTRL_IE;
270 ohci_dbg (ohci, "restarting schedules ... %08x\n", enables);
271 ohci->hc_control |= enables;
272 ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
274 ohci_writel (ohci, temp, &ohci->regs->cmdstatus);
275 (void) ohci_readl (ohci, &ohci->regs->control);
278 ohci->rh_state = OHCI_RH_RUNNING;
282 static int ohci_bus_suspend (struct usb_hcd *hcd)
284 struct ohci_hcd *ohci = hcd_to_ohci (hcd);
287 spin_lock_irq (&ohci->lock);
289 if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
292 rc = ohci_rh_suspend (ohci, 0);
293 spin_unlock_irq (&ohci->lock);
297 static int ohci_bus_resume (struct usb_hcd *hcd)
299 struct ohci_hcd *ohci = hcd_to_ohci (hcd);
302 if (time_before (jiffies, ohci->next_statechange))
305 spin_lock_irq (&ohci->lock);
307 if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
310 rc = ohci_rh_resume (ohci);
311 spin_unlock_irq (&ohci->lock);
313 /* poll until we know a device is connected or we autostop */
315 usb_hcd_poll_rh_status(hcd);
319 /* Carry out the final steps of resuming the controller device */
320 static void ohci_finish_controller_resume(struct usb_hcd *hcd)
322 struct ohci_hcd *ohci = hcd_to_ohci(hcd);
324 bool need_reinit = false;
326 /* See if the controller is already running or has been reset */
327 ohci->hc_control = ohci_readl(ohci, &ohci->regs->control);
328 if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
331 switch (ohci->hc_control & OHCI_CTRL_HCFS) {
338 /* If needed, reinitialize and suspend the root hub */
340 spin_lock_irq(&ohci->lock);
341 ohci_rh_resume(ohci);
342 ohci_rh_suspend(ohci, 0);
343 spin_unlock_irq(&ohci->lock);
346 /* Normally just turn on port power and enable interrupts */
348 ohci_dbg(ohci, "powerup ports\n");
349 for (port = 0; port < ohci->num_ports; port++)
350 ohci_writel(ohci, RH_PS_PPS,
351 &ohci->regs->roothub.portstatus[port]);
353 ohci_writel(ohci, OHCI_INTR_MIE, &ohci->regs->intrenable);
354 ohci_readl(ohci, &ohci->regs->intrenable);
358 usb_hcd_resume_root_hub(hcd);
361 /* Carry out polling-, autostop-, and autoresume-related state changes */
362 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
363 int any_connected, int rhsc_status)
368 /* Some broken controllers never turn off RHSC in the interrupt
369 * status register. For their sake we won't re-enable RHSC
370 * interrupts if the interrupt bit is already active.
372 rhsc_enable = ohci_readl(ohci, &ohci->regs->intrenable) &
375 switch (ohci->hc_control & OHCI_CTRL_HCFS) {
377 /* If no status changes are pending, enable RHSC interrupts. */
378 if (!rhsc_enable && !rhsc_status && !changed) {
379 rhsc_enable = OHCI_INTR_RHSC;
380 ohci_writel(ohci, rhsc_enable, &ohci->regs->intrenable);
383 /* Keep on polling until we know a device is connected
384 * and RHSC is enabled, or until we autostop.
386 if (!ohci->autostop) {
388 !device_may_wakeup(&ohci_to_hcd(ohci)
389 ->self.root_hub->dev)) {
394 ohci->next_statechange = jiffies + HZ;
397 /* if no devices have been attached for one second, autostop */
399 if (changed || any_connected) {
401 ohci->next_statechange = jiffies +
403 } else if (time_after_eq(jiffies,
404 ohci->next_statechange)
406 && !(ohci->hc_control &
407 OHCI_SCHED_ENABLES)) {
408 ohci_rh_suspend(ohci, 1);
415 case OHCI_USB_SUSPEND:
416 case OHCI_USB_RESUME:
417 /* if there is a port change, autostart or ask to be resumed */
420 ohci_rh_resume(ohci);
422 usb_hcd_resume_root_hub(ohci_to_hcd(ohci));
424 /* If remote wakeup is disabled, stop polling */
425 } else if (!ohci->autostop &&
426 !ohci_to_hcd(ohci)->self.root_hub->
431 /* If no status changes are pending,
432 * enable RHSC interrupts
434 if (!rhsc_enable && !rhsc_status) {
435 rhsc_enable = OHCI_INTR_RHSC;
436 ohci_writel(ohci, rhsc_enable,
437 &ohci->regs->intrenable);
439 /* Keep polling until RHSC is enabled */
448 #else /* CONFIG_PM */
450 static inline int ohci_rh_resume(struct ohci_hcd *ohci)
455 /* Carry out polling-related state changes.
456 * autostop isn't used when CONFIG_PM is turned off.
458 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
459 int any_connected, int rhsc_status)
461 /* If RHSC is enabled, don't poll */
462 if (ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC)
465 /* If status changes are pending, continue polling.
466 * Conversely, if no status changes are pending but the RHSC
467 * status bit was set, then RHSC may be broken so continue polling.
469 if (changed || rhsc_status)
472 /* It's safe to re-enable RHSC interrupts */
473 ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
477 #endif /* CONFIG_PM */
479 /*-------------------------------------------------------------------------*/
481 /* build "status change" packet (one or two bytes) from HC registers */
484 ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
486 struct ohci_hcd *ohci = hcd_to_ohci (hcd);
487 int i, changed = 0, length = 1;
488 int any_connected = 0;
492 spin_lock_irqsave (&ohci->lock, flags);
493 if (!HCD_HW_ACCESSIBLE(hcd))
496 /* undocumented erratum seen on at least rev D */
497 if ((ohci->flags & OHCI_QUIRK_AMD756)
498 && (roothub_a (ohci) & RH_A_NDP) > MAX_ROOT_PORTS) {
499 ohci_warn (ohci, "bogus NDP, rereads as NDP=%d\n",
500 ohci_readl (ohci, &ohci->regs->roothub.a) & RH_A_NDP);
501 /* retry later; "should not happen" */
506 if (roothub_status (ohci) & (RH_HS_LPSC | RH_HS_OCIC))
507 buf [0] = changed = 1;
510 if (ohci->num_ports > 7) {
515 /* Clear the RHSC status flag before reading the port statuses */
516 ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrstatus);
517 rhsc_status = ohci_readl(ohci, &ohci->regs->intrstatus) &
520 /* look at each port */
521 for (i = 0; i < ohci->num_ports; i++) {
522 u32 status = roothub_portstatus (ohci, i);
524 /* can't autostop if ports are connected */
525 any_connected |= (status & RH_PS_CCS);
527 if (status & (RH_PS_CSC | RH_PS_PESC | RH_PS_PSSC
528 | RH_PS_OCIC | RH_PS_PRSC)) {
531 buf [0] |= 1 << (i + 1);
533 buf [1] |= 1 << (i - 7);
537 if (ohci_root_hub_state_changes(ohci, changed,
538 any_connected, rhsc_status))
539 set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
541 clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
545 spin_unlock_irqrestore (&ohci->lock, flags);
547 return changed ? length : 0;
550 /*-------------------------------------------------------------------------*/
553 ohci_hub_descriptor (
554 struct ohci_hcd *ohci,
555 struct usb_hub_descriptor *desc
557 u32 rh = roothub_a (ohci);
560 desc->bDescriptorType = 0x29;
561 desc->bPwrOn2PwrGood = (rh & RH_A_POTPGT) >> 24;
562 desc->bHubContrCurrent = 0;
564 desc->bNbrPorts = ohci->num_ports;
565 temp = 1 + (ohci->num_ports / 8);
566 desc->bDescLength = 7 + 2 * temp;
569 if (rh & RH_A_NPS) /* no power switching? */
571 if (rh & RH_A_PSM) /* per-port power switching? */
573 if (rh & RH_A_NOCP) /* no overcurrent reporting? */
575 else if (rh & RH_A_OCPM) /* per-port overcurrent reporting? */
577 desc->wHubCharacteristics = (__force __u16)cpu_to_hc16(ohci, temp);
579 /* ports removable, and usb 1.0 legacy PortPwrCtrlMask */
580 rh = roothub_b (ohci);
581 memset(desc->u.hs.DeviceRemovable, 0xff,
582 sizeof(desc->u.hs.DeviceRemovable));
583 desc->u.hs.DeviceRemovable[0] = rh & RH_B_DR;
584 if (ohci->num_ports > 7) {
585 desc->u.hs.DeviceRemovable[1] = (rh & RH_B_DR) >> 8;
586 desc->u.hs.DeviceRemovable[2] = 0xff;
588 desc->u.hs.DeviceRemovable[1] = 0xff;
591 /*-------------------------------------------------------------------------*/
593 #ifdef CONFIG_USB_OTG
595 static int ohci_start_port_reset (struct usb_hcd *hcd, unsigned port)
597 struct ohci_hcd *ohci = hcd_to_ohci (hcd);
604 /* start port reset before HNP protocol times out */
605 status = ohci_readl(ohci, &ohci->regs->roothub.portstatus [port]);
606 if (!(status & RH_PS_CCS))
609 /* khubd will finish the reset later */
610 ohci_writel(ohci, RH_PS_PRS, &ohci->regs->roothub.portstatus [port]);
616 #define ohci_start_port_reset NULL
620 /*-------------------------------------------------------------------------*/
623 /* See usb 7.1.7.5: root hubs must issue at least 50 msec reset signaling,
624 * not necessarily continuous ... to guard against resume signaling.
625 * The short timeout is safe for non-root hubs, and is backward-compatible
626 * with earlier Linux hosts.
628 #ifdef CONFIG_USB_SUSPEND
629 #define PORT_RESET_MSEC 50
631 #define PORT_RESET_MSEC 10
634 /* this timer value might be vendor-specific ... */
635 #define PORT_RESET_HW_MSEC 10
637 /* wrap-aware logic morphed from <linux/jiffies.h> */
638 #define tick_before(t1,t2) ((s16)(((s16)(t1))-((s16)(t2))) < 0)
640 /* called from some task, normally khubd */
641 static inline int root_port_reset (struct ohci_hcd *ohci, unsigned port)
643 __hc32 __iomem *portstat = &ohci->regs->roothub.portstatus [port];
645 u16 now = ohci_readl(ohci, &ohci->regs->fmnumber);
646 u16 reset_done = now + PORT_RESET_MSEC;
647 int limit_1 = DIV_ROUND_UP(PORT_RESET_MSEC, PORT_RESET_HW_MSEC);
649 /* build a "continuous enough" reset signal, with up to
650 * 3msec gap between pulses. scheduler HZ==100 must work;
651 * this might need to be deadline-scheduled.
656 /* spin until any current reset finishes */
657 limit_2 = PORT_RESET_HW_MSEC * 2;
658 while (--limit_2 >= 0) {
659 temp = ohci_readl (ohci, portstat);
660 /* handle e.g. CardBus eject */
663 if (!(temp & RH_PS_PRS))
668 /* timeout (a hardware error) has been observed when
669 * EHCI sets CF while this driver is resetting a port;
670 * presumably other disconnect paths might do it too.
674 "port[%d] reset timeout, stat %08x\n",
679 if (!(temp & RH_PS_CCS))
681 if (temp & RH_PS_PRSC)
682 ohci_writel (ohci, RH_PS_PRSC, portstat);
684 /* start the next reset, sleep till it's probably done */
685 ohci_writel (ohci, RH_PS_PRS, portstat);
686 msleep(PORT_RESET_HW_MSEC);
687 now = ohci_readl(ohci, &ohci->regs->fmnumber);
688 } while (tick_before(now, reset_done) && --limit_1 >= 0);
690 /* caller synchronizes using PRSC ... and handles PRS
691 * still being set when this returns.
697 static int ohci_hub_control (
705 struct ohci_hcd *ohci = hcd_to_ohci (hcd);
706 int ports = ohci->num_ports;
710 if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
714 case ClearHubFeature:
716 case C_HUB_OVER_CURRENT:
717 ohci_writel (ohci, RH_HS_OCIC,
718 &ohci->regs->roothub.status);
719 case C_HUB_LOCAL_POWER:
725 case ClearPortFeature:
726 if (!wIndex || wIndex > ports)
731 case USB_PORT_FEAT_ENABLE:
734 case USB_PORT_FEAT_C_ENABLE:
737 case USB_PORT_FEAT_SUSPEND:
740 case USB_PORT_FEAT_C_SUSPEND:
743 case USB_PORT_FEAT_POWER:
746 case USB_PORT_FEAT_C_CONNECTION:
749 case USB_PORT_FEAT_C_OVER_CURRENT:
752 case USB_PORT_FEAT_C_RESET:
758 ohci_writel (ohci, temp,
759 &ohci->regs->roothub.portstatus [wIndex]);
760 // ohci_readl (ohci, &ohci->regs->roothub.portstatus [wIndex]);
762 case GetHubDescriptor:
763 ohci_hub_descriptor (ohci, (struct usb_hub_descriptor *) buf);
766 temp = roothub_status (ohci) & ~(RH_HS_CRWE | RH_HS_DRWE);
767 put_unaligned_le32(temp, buf);
770 if (!wIndex || wIndex > ports)
773 temp = roothub_portstatus (ohci, wIndex);
774 put_unaligned_le32(temp, buf);
776 #ifndef OHCI_VERBOSE_DEBUG
777 if (*(u16*)(buf+2)) /* only if wPortChange is interesting */
779 dbg_port (ohci, "GetStatus", wIndex, temp);
783 case C_HUB_OVER_CURRENT:
784 // FIXME: this can be cleared, yes?
785 case C_HUB_LOCAL_POWER:
792 if (!wIndex || wIndex > ports)
796 case USB_PORT_FEAT_SUSPEND:
797 #ifdef CONFIG_USB_OTG
798 if (hcd->self.otg_port == (wIndex + 1)
799 && hcd->self.b_hnp_enable)
800 ohci->start_hnp(ohci);
803 ohci_writel (ohci, RH_PS_PSS,
804 &ohci->regs->roothub.portstatus [wIndex]);
806 case USB_PORT_FEAT_POWER:
807 ohci_writel (ohci, RH_PS_PPS,
808 &ohci->regs->roothub.portstatus [wIndex]);
810 case USB_PORT_FEAT_RESET:
811 retval = root_port_reset (ohci, wIndex);
820 /* "protocol stall" on error */