xref: /openbmc/linux/drivers/usb/host/ohci-hub.c (revision b830f94f)
1 // SPDX-License-Identifier: GPL-1.0+
2 /*
3  * OHCI HCD (Host Controller Driver) for USB.
4  *
5  * (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
6  * (C) Copyright 2000-2004 David Brownell <dbrownell@users.sourceforge.net>
7  *
8  * This file is licenced under GPL
9  */
10 
11 /*-------------------------------------------------------------------------*/
12 
13 /*
14  * OHCI Root Hub ... the nonsharable stuff
15  */
16 
17 #define dbg_port(hc,label,num,value) \
18 	ohci_dbg (hc, \
19 		"%s roothub.portstatus [%d] " \
20 		"= 0x%08x%s%s%s%s%s%s%s%s%s%s%s%s\n", \
21 		label, num, value, \
22 		(value & RH_PS_PRSC) ? " PRSC" : "", \
23 		(value & RH_PS_OCIC) ? " OCIC" : "", \
24 		(value & RH_PS_PSSC) ? " PSSC" : "", \
25 		(value & RH_PS_PESC) ? " PESC" : "", \
26 		(value & RH_PS_CSC) ? " CSC" : "", \
27 		\
28 		(value & RH_PS_LSDA) ? " LSDA" : "", \
29 		(value & RH_PS_PPS) ? " PPS" : "", \
30 		(value & RH_PS_PRS) ? " PRS" : "", \
31 		(value & RH_PS_POCI) ? " POCI" : "", \
32 		(value & RH_PS_PSS) ? " PSS" : "", \
33 		\
34 		(value & RH_PS_PES) ? " PES" : "", \
35 		(value & RH_PS_CCS) ? " CCS" : "" \
36 		);
37 
38 /*-------------------------------------------------------------------------*/
39 
40 #define OHCI_SCHED_ENABLES \
41 	(OHCI_CTRL_CLE|OHCI_CTRL_BLE|OHCI_CTRL_PLE|OHCI_CTRL_IE)
42 
43 static void update_done_list(struct ohci_hcd *);
44 static void ohci_work(struct ohci_hcd *);
45 
46 #ifdef	CONFIG_PM
47 static int ohci_rh_suspend (struct ohci_hcd *ohci, int autostop)
48 __releases(ohci->lock)
49 __acquires(ohci->lock)
50 {
51 	int			status = 0;
52 
53 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
54 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
55 	case OHCI_USB_RESUME:
56 		ohci_dbg (ohci, "resume/suspend?\n");
57 		ohci->hc_control &= ~OHCI_CTRL_HCFS;
58 		ohci->hc_control |= OHCI_USB_RESET;
59 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
60 		(void) ohci_readl (ohci, &ohci->regs->control);
61 		/* FALL THROUGH */
62 	case OHCI_USB_RESET:
63 		status = -EBUSY;
64 		ohci_dbg (ohci, "needs reinit!\n");
65 		goto done;
66 	case OHCI_USB_SUSPEND:
67 		if (!ohci->autostop) {
68 			ohci_dbg (ohci, "already suspended\n");
69 			goto done;
70 		}
71 	}
72 	ohci_dbg (ohci, "%s root hub\n",
73 			autostop ? "auto-stop" : "suspend");
74 
75 	/* First stop any processing */
76 	if (!autostop && (ohci->hc_control & OHCI_SCHED_ENABLES)) {
77 		ohci->hc_control &= ~OHCI_SCHED_ENABLES;
78 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
79 		ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
80 		ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrstatus);
81 
82 		/* sched disables take effect on the next frame,
83 		 * then the last WDH could take 6+ msec
84 		 */
85 		ohci_dbg (ohci, "stopping schedules ...\n");
86 		ohci->autostop = 0;
87 		spin_unlock_irq (&ohci->lock);
88 		msleep (8);
89 		spin_lock_irq (&ohci->lock);
90 	}
91 	update_done_list(ohci);
92 	ohci_work(ohci);
93 
94 	/*
95 	 * Some controllers don't handle "global" suspend properly if
96 	 * there are unsuspended ports.  For these controllers, put all
97 	 * the enabled ports into suspend before suspending the root hub.
98 	 */
99 	if (ohci->flags & OHCI_QUIRK_GLOBAL_SUSPEND) {
100 		__hc32 __iomem	*portstat = ohci->regs->roothub.portstatus;
101 		int		i;
102 		unsigned	temp;
103 
104 		for (i = 0; i < ohci->num_ports; (++i, ++portstat)) {
105 			temp = ohci_readl(ohci, portstat);
106 			if ((temp & (RH_PS_PES | RH_PS_PSS)) ==
107 					RH_PS_PES)
108 				ohci_writel(ohci, RH_PS_PSS, portstat);
109 		}
110 	}
111 
112 	/* maybe resume can wake root hub */
113 	if (ohci_to_hcd(ohci)->self.root_hub->do_remote_wakeup || autostop) {
114 		ohci->hc_control |= OHCI_CTRL_RWE;
115 	} else {
116 		ohci_writel(ohci, OHCI_INTR_RHSC | OHCI_INTR_RD,
117 				&ohci->regs->intrdisable);
118 		ohci->hc_control &= ~OHCI_CTRL_RWE;
119 	}
120 
121 	/* Suspend hub ... this is the "global (to this bus) suspend" mode,
122 	 * which doesn't imply ports will first be individually suspended.
123 	 */
124 	ohci->hc_control &= ~OHCI_CTRL_HCFS;
125 	ohci->hc_control |= OHCI_USB_SUSPEND;
126 	ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
127 	(void) ohci_readl (ohci, &ohci->regs->control);
128 
129 	/* no resumes until devices finish suspending */
130 	if (!autostop) {
131 		ohci->next_statechange = jiffies + msecs_to_jiffies (5);
132 		ohci->autostop = 0;
133 		ohci->rh_state = OHCI_RH_SUSPENDED;
134 	}
135 
136 done:
137 	return status;
138 }
139 
140 static inline struct ed *find_head (struct ed *ed)
141 {
142 	/* for bulk and control lists */
143 	while (ed->ed_prev)
144 		ed = ed->ed_prev;
145 	return ed;
146 }
147 
148 /* caller has locked the root hub */
149 static int ohci_rh_resume (struct ohci_hcd *ohci)
150 __releases(ohci->lock)
151 __acquires(ohci->lock)
152 {
153 	struct usb_hcd		*hcd = ohci_to_hcd (ohci);
154 	u32			temp, enables;
155 	int			status = -EINPROGRESS;
156 	int			autostopped = ohci->autostop;
157 
158 	ohci->autostop = 0;
159 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
160 
161 	if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
162 		/* this can happen after resuming a swsusp snapshot */
163 		if (ohci->rh_state != OHCI_RH_RUNNING) {
164 			ohci_dbg (ohci, "BIOS/SMM active, control %03x\n",
165 					ohci->hc_control);
166 			status = -EBUSY;
167 		/* this happens when pmcore resumes HC then root */
168 		} else {
169 			ohci_dbg (ohci, "duplicate resume\n");
170 			status = 0;
171 		}
172 	} else switch (ohci->hc_control & OHCI_CTRL_HCFS) {
173 	case OHCI_USB_SUSPEND:
174 		ohci->hc_control &= ~(OHCI_CTRL_HCFS|OHCI_SCHED_ENABLES);
175 		ohci->hc_control |= OHCI_USB_RESUME;
176 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
177 		(void) ohci_readl (ohci, &ohci->regs->control);
178 		ohci_dbg (ohci, "%s root hub\n",
179 				autostopped ? "auto-start" : "resume");
180 		break;
181 	case OHCI_USB_RESUME:
182 		/* HCFS changes sometime after INTR_RD */
183 		ohci_dbg(ohci, "%swakeup root hub\n",
184 				autostopped ? "auto-" : "");
185 		break;
186 	case OHCI_USB_OPER:
187 		/* this can happen after resuming a swsusp snapshot */
188 		ohci_dbg (ohci, "snapshot resume? reinit\n");
189 		status = -EBUSY;
190 		break;
191 	default:		/* RESET, we lost power */
192 		ohci_dbg (ohci, "lost power\n");
193 		status = -EBUSY;
194 	}
195 	if (status == -EBUSY) {
196 		if (!autostopped) {
197 			spin_unlock_irq (&ohci->lock);
198 			status = ohci_restart (ohci);
199 
200 			usb_root_hub_lost_power(hcd->self.root_hub);
201 
202 			spin_lock_irq (&ohci->lock);
203 		}
204 		return status;
205 	}
206 	if (status != -EINPROGRESS)
207 		return status;
208 	if (autostopped)
209 		goto skip_resume;
210 	spin_unlock_irq (&ohci->lock);
211 
212 	/* Some controllers (lucent erratum) need extra-long delays */
213 	msleep (20 /* usb 11.5.1.10 */ + 12 /* 32 msec counter */ + 1);
214 
215 	temp = ohci_readl (ohci, &ohci->regs->control);
216 	temp &= OHCI_CTRL_HCFS;
217 	if (temp != OHCI_USB_RESUME) {
218 		ohci_err (ohci, "controller won't resume\n");
219 		spin_lock_irq(&ohci->lock);
220 		return -EBUSY;
221 	}
222 
223 	/* disable old schedule state, reinit from scratch */
224 	ohci_writel (ohci, 0, &ohci->regs->ed_controlhead);
225 	ohci_writel (ohci, 0, &ohci->regs->ed_controlcurrent);
226 	ohci_writel (ohci, 0, &ohci->regs->ed_bulkhead);
227 	ohci_writel (ohci, 0, &ohci->regs->ed_bulkcurrent);
228 	ohci_writel (ohci, 0, &ohci->regs->ed_periodcurrent);
229 	ohci_writel (ohci, (u32) ohci->hcca_dma, &ohci->regs->hcca);
230 
231 	/* Sometimes PCI D3 suspend trashes frame timings ... */
232 	periodic_reinit (ohci);
233 
234 	/*
235 	 * The following code is executed with ohci->lock held and
236 	 * irqs disabled if and only if autostopped is true.  This
237 	 * will cause sparse to warn about a "context imbalance".
238 	 */
239 skip_resume:
240 	/* interrupts might have been disabled */
241 	ohci_writel (ohci, OHCI_INTR_INIT, &ohci->regs->intrenable);
242 	if (ohci->ed_rm_list)
243 		ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrenable);
244 
245 	/* Then re-enable operations */
246 	ohci_writel (ohci, OHCI_USB_OPER, &ohci->regs->control);
247 	(void) ohci_readl (ohci, &ohci->regs->control);
248 	if (!autostopped)
249 		msleep (3);
250 
251 	temp = ohci->hc_control;
252 	temp &= OHCI_CTRL_RWC;
253 	temp |= OHCI_CONTROL_INIT | OHCI_USB_OPER;
254 	ohci->hc_control = temp;
255 	ohci_writel (ohci, temp, &ohci->regs->control);
256 	(void) ohci_readl (ohci, &ohci->regs->control);
257 
258 	/* TRSMRCY */
259 	if (!autostopped) {
260 		msleep (10);
261 		spin_lock_irq (&ohci->lock);
262 	}
263 	/* now ohci->lock is always held and irqs are always disabled */
264 
265 	/* keep it alive for more than ~5x suspend + resume costs */
266 	ohci->next_statechange = jiffies + STATECHANGE_DELAY;
267 
268 	/* maybe turn schedules back on */
269 	enables = 0;
270 	temp = 0;
271 	if (!ohci->ed_rm_list) {
272 		if (ohci->ed_controltail) {
273 			ohci_writel (ohci,
274 					find_head (ohci->ed_controltail)->dma,
275 					&ohci->regs->ed_controlhead);
276 			enables |= OHCI_CTRL_CLE;
277 			temp |= OHCI_CLF;
278 		}
279 		if (ohci->ed_bulktail) {
280 			ohci_writel (ohci, find_head (ohci->ed_bulktail)->dma,
281 				&ohci->regs->ed_bulkhead);
282 			enables |= OHCI_CTRL_BLE;
283 			temp |= OHCI_BLF;
284 		}
285 	}
286 	if (hcd->self.bandwidth_isoc_reqs || hcd->self.bandwidth_int_reqs)
287 		enables |= OHCI_CTRL_PLE|OHCI_CTRL_IE;
288 	if (enables) {
289 		ohci_dbg (ohci, "restarting schedules ... %08x\n", enables);
290 		ohci->hc_control |= enables;
291 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
292 		if (temp)
293 			ohci_writel (ohci, temp, &ohci->regs->cmdstatus);
294 		(void) ohci_readl (ohci, &ohci->regs->control);
295 	}
296 
297 	ohci->rh_state = OHCI_RH_RUNNING;
298 	return 0;
299 }
300 
301 static int ohci_bus_suspend (struct usb_hcd *hcd)
302 {
303 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
304 	int			rc;
305 
306 	spin_lock_irq (&ohci->lock);
307 
308 	if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
309 		rc = -ESHUTDOWN;
310 	else
311 		rc = ohci_rh_suspend (ohci, 0);
312 	spin_unlock_irq (&ohci->lock);
313 
314 	if (rc == 0) {
315 		del_timer_sync(&ohci->io_watchdog);
316 		ohci->prev_frame_no = IO_WATCHDOG_OFF;
317 	}
318 	return rc;
319 }
320 
321 static int ohci_bus_resume (struct usb_hcd *hcd)
322 {
323 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
324 	int			rc;
325 
326 	if (time_before (jiffies, ohci->next_statechange))
327 		msleep(5);
328 
329 	spin_lock_irq (&ohci->lock);
330 
331 	if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
332 		rc = -ESHUTDOWN;
333 	else
334 		rc = ohci_rh_resume (ohci);
335 	spin_unlock_irq (&ohci->lock);
336 
337 	/* poll until we know a device is connected or we autostop */
338 	if (rc == 0)
339 		usb_hcd_poll_rh_status(hcd);
340 	return rc;
341 }
342 
343 /* Carry out polling-, autostop-, and autoresume-related state changes */
344 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
345 		int any_connected, int rhsc_status)
346 {
347 	int	poll_rh = 1;
348 	int	rhsc_enable;
349 
350 	/* Some broken controllers never turn off RHSC in the interrupt
351 	 * status register.  For their sake we won't re-enable RHSC
352 	 * interrupts if the interrupt bit is already active.
353 	 */
354 	rhsc_enable = ohci_readl(ohci, &ohci->regs->intrenable) &
355 			OHCI_INTR_RHSC;
356 
357 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
358 	case OHCI_USB_OPER:
359 		/* If no status changes are pending, enable RHSC interrupts. */
360 		if (!rhsc_enable && !rhsc_status && !changed) {
361 			rhsc_enable = OHCI_INTR_RHSC;
362 			ohci_writel(ohci, rhsc_enable, &ohci->regs->intrenable);
363 		}
364 
365 		/* Keep on polling until we know a device is connected
366 		 * and RHSC is enabled, or until we autostop.
367 		 */
368 		if (!ohci->autostop) {
369 			if (any_connected ||
370 					!device_may_wakeup(&ohci_to_hcd(ohci)
371 						->self.root_hub->dev)) {
372 				if (rhsc_enable)
373 					poll_rh = 0;
374 			} else {
375 				ohci->autostop = 1;
376 				ohci->next_statechange = jiffies + HZ;
377 			}
378 
379 		/* if no devices have been attached for one second, autostop */
380 		} else {
381 			if (changed || any_connected) {
382 				ohci->autostop = 0;
383 				ohci->next_statechange = jiffies +
384 						STATECHANGE_DELAY;
385 			} else if (time_after_eq(jiffies,
386 						ohci->next_statechange)
387 					&& !ohci->ed_rm_list
388 					&& !(ohci->hc_control &
389 						OHCI_SCHED_ENABLES)) {
390 				ohci_rh_suspend(ohci, 1);
391 				if (rhsc_enable)
392 					poll_rh = 0;
393 			}
394 		}
395 		break;
396 
397 	case OHCI_USB_SUSPEND:
398 	case OHCI_USB_RESUME:
399 		/* if there is a port change, autostart or ask to be resumed */
400 		if (changed) {
401 			if (ohci->autostop)
402 				ohci_rh_resume(ohci);
403 			else
404 				usb_hcd_resume_root_hub(ohci_to_hcd(ohci));
405 
406 		/* If remote wakeup is disabled, stop polling */
407 		} else if (!ohci->autostop &&
408 				!ohci_to_hcd(ohci)->self.root_hub->
409 					do_remote_wakeup) {
410 			poll_rh = 0;
411 
412 		} else {
413 			/* If no status changes are pending,
414 			 * enable RHSC interrupts
415 			 */
416 			if (!rhsc_enable && !rhsc_status) {
417 				rhsc_enable = OHCI_INTR_RHSC;
418 				ohci_writel(ohci, rhsc_enable,
419 						&ohci->regs->intrenable);
420 			}
421 			/* Keep polling until RHSC is enabled */
422 			if (rhsc_enable)
423 				poll_rh = 0;
424 		}
425 		break;
426 	}
427 	return poll_rh;
428 }
429 
430 #else	/* CONFIG_PM */
431 
432 static inline int ohci_rh_resume(struct ohci_hcd *ohci)
433 {
434 	return 0;
435 }
436 
437 /* Carry out polling-related state changes.
438  * autostop isn't used when CONFIG_PM is turned off.
439  */
440 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
441 		int any_connected, int rhsc_status)
442 {
443 	/* If RHSC is enabled, don't poll */
444 	if (ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC)
445 		return 0;
446 
447 	/* If status changes are pending, continue polling.
448 	 * Conversely, if no status changes are pending but the RHSC
449 	 * status bit was set, then RHSC may be broken so continue polling.
450 	 */
451 	if (changed || rhsc_status)
452 		return 1;
453 
454 	/* It's safe to re-enable RHSC interrupts */
455 	ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
456 	return 0;
457 }
458 
459 #endif	/* CONFIG_PM */
460 
461 /*-------------------------------------------------------------------------*/
462 
463 /* build "status change" packet (one or two bytes) from HC registers */
464 
465 int ohci_hub_status_data(struct usb_hcd *hcd, char *buf)
466 {
467 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
468 	int		i, changed = 0, length = 1;
469 	int		any_connected = 0;
470 	int		rhsc_status;
471 	unsigned long	flags;
472 
473 	spin_lock_irqsave (&ohci->lock, flags);
474 	if (!HCD_HW_ACCESSIBLE(hcd))
475 		goto done;
476 
477 	/* undocumented erratum seen on at least rev D */
478 	if ((ohci->flags & OHCI_QUIRK_AMD756)
479 			&& (roothub_a (ohci) & RH_A_NDP) > MAX_ROOT_PORTS) {
480 		ohci_warn (ohci, "bogus NDP, rereads as NDP=%d\n",
481 			  ohci_readl (ohci, &ohci->regs->roothub.a) & RH_A_NDP);
482 		/* retry later; "should not happen" */
483 		goto done;
484 	}
485 
486 	/* init status */
487 	if (roothub_status (ohci) & (RH_HS_LPSC | RH_HS_OCIC))
488 		buf [0] = changed = 1;
489 	else
490 		buf [0] = 0;
491 	if (ohci->num_ports > 7) {
492 		buf [1] = 0;
493 		length++;
494 	}
495 
496 	/* Clear the RHSC status flag before reading the port statuses */
497 	ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrstatus);
498 	rhsc_status = ohci_readl(ohci, &ohci->regs->intrstatus) &
499 			OHCI_INTR_RHSC;
500 
501 	/* look at each port */
502 	for (i = 0; i < ohci->num_ports; i++) {
503 		u32	status = roothub_portstatus (ohci, i);
504 
505 		/* can't autostop if ports are connected */
506 		any_connected |= (status & RH_PS_CCS);
507 
508 		if (status & (RH_PS_CSC | RH_PS_PESC | RH_PS_PSSC
509 				| RH_PS_OCIC | RH_PS_PRSC)) {
510 			changed = 1;
511 			if (i < 7)
512 			    buf [0] |= 1 << (i + 1);
513 			else
514 			    buf [1] |= 1 << (i - 7);
515 		}
516 	}
517 
518 	if (ohci_root_hub_state_changes(ohci, changed,
519 			any_connected, rhsc_status))
520 		set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
521 	else
522 		clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
523 
524 
525 done:
526 	spin_unlock_irqrestore (&ohci->lock, flags);
527 
528 	return changed ? length : 0;
529 }
530 EXPORT_SYMBOL_GPL(ohci_hub_status_data);
531 
532 /*-------------------------------------------------------------------------*/
533 
534 static void
535 ohci_hub_descriptor (
536 	struct ohci_hcd			*ohci,
537 	struct usb_hub_descriptor	*desc
538 ) {
539 	u32		rh = roothub_a (ohci);
540 	u16		temp;
541 
542 	desc->bDescriptorType = USB_DT_HUB;
543 	desc->bPwrOn2PwrGood = (rh & RH_A_POTPGT) >> 24;
544 	desc->bHubContrCurrent = 0;
545 
546 	desc->bNbrPorts = ohci->num_ports;
547 	temp = 1 + (ohci->num_ports / 8);
548 	desc->bDescLength = 7 + 2 * temp;
549 
550 	temp = HUB_CHAR_COMMON_LPSM | HUB_CHAR_COMMON_OCPM;
551 	if (rh & RH_A_NPS)		/* no power switching? */
552 		temp |= HUB_CHAR_NO_LPSM;
553 	if (rh & RH_A_PSM)		/* per-port power switching? */
554 		temp |= HUB_CHAR_INDV_PORT_LPSM;
555 	if (rh & RH_A_NOCP)		/* no overcurrent reporting? */
556 		temp |= HUB_CHAR_NO_OCPM;
557 	else if (rh & RH_A_OCPM)	/* per-port overcurrent reporting? */
558 		temp |= HUB_CHAR_INDV_PORT_OCPM;
559 	desc->wHubCharacteristics = cpu_to_le16(temp);
560 
561 	/* ports removable, and usb 1.0 legacy PortPwrCtrlMask */
562 	rh = roothub_b (ohci);
563 	memset(desc->u.hs.DeviceRemovable, 0xff,
564 			sizeof(desc->u.hs.DeviceRemovable));
565 	desc->u.hs.DeviceRemovable[0] = rh & RH_B_DR;
566 	if (ohci->num_ports > 7) {
567 		desc->u.hs.DeviceRemovable[1] = (rh & RH_B_DR) >> 8;
568 		desc->u.hs.DeviceRemovable[2] = 0xff;
569 	} else
570 		desc->u.hs.DeviceRemovable[1] = 0xff;
571 }
572 
573 /*-------------------------------------------------------------------------*/
574 
575 #ifdef	CONFIG_USB_OTG
576 
577 static int ohci_start_port_reset (struct usb_hcd *hcd, unsigned port)
578 {
579 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
580 	u32			status;
581 
582 	if (!port)
583 		return -EINVAL;
584 	port--;
585 
586 	/* start port reset before HNP protocol times out */
587 	status = ohci_readl(ohci, &ohci->regs->roothub.portstatus [port]);
588 	if (!(status & RH_PS_CCS))
589 		return -ENODEV;
590 
591 	/* hub_wq will finish the reset later */
592 	ohci_writel(ohci, RH_PS_PRS, &ohci->regs->roothub.portstatus [port]);
593 	return 0;
594 }
595 
596 #else
597 
598 #define	ohci_start_port_reset		NULL
599 
600 #endif
601 
602 /*-------------------------------------------------------------------------*/
603 
604 
605 /* See usb 7.1.7.5:  root hubs must issue at least 50 msec reset signaling,
606  * not necessarily continuous ... to guard against resume signaling.
607  */
608 #define	PORT_RESET_MSEC		50
609 
610 /* this timer value might be vendor-specific ... */
611 #define	PORT_RESET_HW_MSEC	10
612 
613 /* wrap-aware logic morphed from <linux/jiffies.h> */
614 #define tick_before(t1,t2) ((s16)(((s16)(t1))-((s16)(t2))) < 0)
615 
616 /* called from some task, normally hub_wq */
617 static inline int root_port_reset (struct ohci_hcd *ohci, unsigned port)
618 {
619 	__hc32 __iomem *portstat = &ohci->regs->roothub.portstatus [port];
620 	u32	temp = 0;
621 	u16	now = ohci_readl(ohci, &ohci->regs->fmnumber);
622 	u16	reset_done = now + PORT_RESET_MSEC;
623 	int	limit_1 = DIV_ROUND_UP(PORT_RESET_MSEC, PORT_RESET_HW_MSEC);
624 
625 	/* build a "continuous enough" reset signal, with up to
626 	 * 3msec gap between pulses.  scheduler HZ==100 must work;
627 	 * this might need to be deadline-scheduled.
628 	 */
629 	do {
630 		int limit_2;
631 
632 		/* spin until any current reset finishes */
633 		limit_2 = PORT_RESET_HW_MSEC * 2;
634 		while (--limit_2 >= 0) {
635 			temp = ohci_readl (ohci, portstat);
636 			/* handle e.g. CardBus eject */
637 			if (temp == ~(u32)0)
638 				return -ESHUTDOWN;
639 			if (!(temp & RH_PS_PRS))
640 				break;
641 			udelay (500);
642 		}
643 
644 		/* timeout (a hardware error) has been observed when
645 		 * EHCI sets CF while this driver is resetting a port;
646 		 * presumably other disconnect paths might do it too.
647 		 */
648 		if (limit_2 < 0) {
649 			ohci_dbg(ohci,
650 				"port[%d] reset timeout, stat %08x\n",
651 				port, temp);
652 			break;
653 		}
654 
655 		if (!(temp & RH_PS_CCS))
656 			break;
657 		if (temp & RH_PS_PRSC)
658 			ohci_writel (ohci, RH_PS_PRSC, portstat);
659 
660 		/* start the next reset, sleep till it's probably done */
661 		ohci_writel (ohci, RH_PS_PRS, portstat);
662 		msleep(PORT_RESET_HW_MSEC);
663 		now = ohci_readl(ohci, &ohci->regs->fmnumber);
664 	} while (tick_before(now, reset_done) && --limit_1 >= 0);
665 
666 	/* caller synchronizes using PRSC ... and handles PRS
667 	 * still being set when this returns.
668 	 */
669 
670 	return 0;
671 }
672 
673 int ohci_hub_control(
674 	struct usb_hcd	*hcd,
675 	u16		typeReq,
676 	u16		wValue,
677 	u16		wIndex,
678 	char		*buf,
679 	u16		wLength
680 ) {
681 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
682 	int		ports = ohci->num_ports;
683 	u32		temp;
684 	int		retval = 0;
685 
686 	if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
687 		return -ESHUTDOWN;
688 
689 	switch (typeReq) {
690 	case ClearHubFeature:
691 		switch (wValue) {
692 		case C_HUB_OVER_CURRENT:
693 			ohci_writel (ohci, RH_HS_OCIC,
694 					&ohci->regs->roothub.status);
695 		case C_HUB_LOCAL_POWER:
696 			break;
697 		default:
698 			goto error;
699 		}
700 		break;
701 	case ClearPortFeature:
702 		if (!wIndex || wIndex > ports)
703 			goto error;
704 		wIndex--;
705 
706 		switch (wValue) {
707 		case USB_PORT_FEAT_ENABLE:
708 			temp = RH_PS_CCS;
709 			break;
710 		case USB_PORT_FEAT_C_ENABLE:
711 			temp = RH_PS_PESC;
712 			break;
713 		case USB_PORT_FEAT_SUSPEND:
714 			temp = RH_PS_POCI;
715 			break;
716 		case USB_PORT_FEAT_C_SUSPEND:
717 			temp = RH_PS_PSSC;
718 			break;
719 		case USB_PORT_FEAT_POWER:
720 			temp = RH_PS_LSDA;
721 			break;
722 		case USB_PORT_FEAT_C_CONNECTION:
723 			temp = RH_PS_CSC;
724 			break;
725 		case USB_PORT_FEAT_C_OVER_CURRENT:
726 			temp = RH_PS_OCIC;
727 			break;
728 		case USB_PORT_FEAT_C_RESET:
729 			temp = RH_PS_PRSC;
730 			break;
731 		default:
732 			goto error;
733 		}
734 		ohci_writel (ohci, temp,
735 				&ohci->regs->roothub.portstatus [wIndex]);
736 		// ohci_readl (ohci, &ohci->regs->roothub.portstatus [wIndex]);
737 		break;
738 	case GetHubDescriptor:
739 		ohci_hub_descriptor (ohci, (struct usb_hub_descriptor *) buf);
740 		break;
741 	case GetHubStatus:
742 		temp = roothub_status (ohci) & ~(RH_HS_CRWE | RH_HS_DRWE);
743 		put_unaligned_le32(temp, buf);
744 		break;
745 	case GetPortStatus:
746 		if (!wIndex || wIndex > ports)
747 			goto error;
748 		wIndex--;
749 		temp = roothub_portstatus (ohci, wIndex);
750 		put_unaligned_le32(temp, buf);
751 
752 		if (*(u16*)(buf+2))	/* only if wPortChange is interesting */
753 			dbg_port(ohci, "GetStatus", wIndex, temp);
754 		break;
755 	case SetHubFeature:
756 		switch (wValue) {
757 		case C_HUB_OVER_CURRENT:
758 			// FIXME:  this can be cleared, yes?
759 		case C_HUB_LOCAL_POWER:
760 			break;
761 		default:
762 			goto error;
763 		}
764 		break;
765 	case SetPortFeature:
766 		if (!wIndex || wIndex > ports)
767 			goto error;
768 		wIndex--;
769 		switch (wValue) {
770 		case USB_PORT_FEAT_SUSPEND:
771 #ifdef	CONFIG_USB_OTG
772 			if (hcd->self.otg_port == (wIndex + 1)
773 					&& hcd->self.b_hnp_enable)
774 				ohci->start_hnp(ohci);
775 			else
776 #endif
777 			ohci_writel (ohci, RH_PS_PSS,
778 				&ohci->regs->roothub.portstatus [wIndex]);
779 			break;
780 		case USB_PORT_FEAT_POWER:
781 			ohci_writel (ohci, RH_PS_PPS,
782 				&ohci->regs->roothub.portstatus [wIndex]);
783 			break;
784 		case USB_PORT_FEAT_RESET:
785 			retval = root_port_reset (ohci, wIndex);
786 			break;
787 		default:
788 			goto error;
789 		}
790 		break;
791 
792 	default:
793 error:
794 		/* "protocol stall" on error */
795 		retval = -EPIPE;
796 	}
797 	return retval;
798 }
799 EXPORT_SYMBOL_GPL(ohci_hub_control);
800