xref: /openbmc/linux/drivers/usb/host/ohci-hub.c (revision 384740dc)
1 /*
2  * OHCI HCD (Host Controller Driver) for USB.
3  *
4  * (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
5  * (C) Copyright 2000-2004 David Brownell <dbrownell@users.sourceforge.net>
6  *
7  * This file is licenced under GPL
8  */
9 
10 /*-------------------------------------------------------------------------*/
11 
12 /*
13  * OHCI Root Hub ... the nonsharable stuff
14  */
15 
16 #define dbg_port(hc,label,num,value) \
17 	ohci_dbg (hc, \
18 		"%s roothub.portstatus [%d] " \
19 		"= 0x%08x%s%s%s%s%s%s%s%s%s%s%s%s\n", \
20 		label, num, temp, \
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" : "", \
26 		\
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" : "", \
32 		\
33 		(temp & RH_PS_PES) ? " PES" : "", \
34 		(temp & RH_PS_CCS) ? " CCS" : "" \
35 		);
36 
37 /*-------------------------------------------------------------------------*/
38 
39 #define OHCI_SCHED_ENABLES \
40 	(OHCI_CTRL_CLE|OHCI_CTRL_BLE|OHCI_CTRL_PLE|OHCI_CTRL_IE)
41 
42 static void dl_done_list (struct ohci_hcd *);
43 static void finish_unlinks (struct ohci_hcd *, u16);
44 
45 #ifdef	CONFIG_PM
46 static int ohci_rh_suspend (struct ohci_hcd *ohci, int autostop)
47 __releases(ohci->lock)
48 __acquires(ohci->lock)
49 {
50 	int			status = 0;
51 
52 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
53 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
54 	case OHCI_USB_RESUME:
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);
60 		/* FALL THROUGH */
61 	case OHCI_USB_RESET:
62 		status = -EBUSY;
63 		ohci_dbg (ohci, "needs reinit!\n");
64 		goto done;
65 	case OHCI_USB_SUSPEND:
66 		if (!ohci->autostop) {
67 			ohci_dbg (ohci, "already suspended\n");
68 			goto done;
69 		}
70 	}
71 	ohci_dbg (ohci, "%s root hub\n",
72 			autostop ? "auto-stop" : "suspend");
73 
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);
80 
81 		/* sched disables take effect on the next frame,
82 		 * then the last WDH could take 6+ msec
83 		 */
84 		ohci_dbg (ohci, "stopping schedules ...\n");
85 		ohci->autostop = 0;
86 		spin_unlock_irq (&ohci->lock);
87 		msleep (8);
88 		spin_lock_irq (&ohci->lock);
89 	}
90 	dl_done_list (ohci);
91 	finish_unlinks (ohci, ohci_frame_no(ohci));
92 
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;
96 	} else {
97 		ohci_writel(ohci, OHCI_INTR_RHSC | OHCI_INTR_RD,
98 				&ohci->regs->intrdisable);
99 		ohci->hc_control &= ~OHCI_CTRL_RWE;
100 	}
101 
102 	/* Suspend hub ... this is the "global (to this bus) suspend" mode,
103 	 * which doesn't imply ports will first be individually suspended.
104 	 */
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);
109 
110 	/* no resumes until devices finish suspending */
111 	if (!autostop) {
112 		ohci->next_statechange = jiffies + msecs_to_jiffies (5);
113 		ohci->autostop = 0;
114 	}
115 
116 done:
117 	return status;
118 }
119 
120 static inline struct ed *find_head (struct ed *ed)
121 {
122 	/* for bulk and control lists */
123 	while (ed->ed_prev)
124 		ed = ed->ed_prev;
125 	return ed;
126 }
127 
128 /* caller has locked the root hub */
129 static int ohci_rh_resume (struct ohci_hcd *ohci)
130 __releases(ohci->lock)
131 __acquires(ohci->lock)
132 {
133 	struct usb_hcd		*hcd = ohci_to_hcd (ohci);
134 	u32			temp, enables;
135 	int			status = -EINPROGRESS;
136 	int			autostopped = ohci->autostop;
137 
138 	ohci->autostop = 0;
139 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
140 
141 	if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
142 		/* this can happen after resuming a swsusp snapshot */
143 		if (hcd->state == HC_STATE_RESUMING) {
144 			ohci_dbg (ohci, "BIOS/SMM active, control %03x\n",
145 					ohci->hc_control);
146 			status = -EBUSY;
147 		/* this happens when pmcore resumes HC then root */
148 		} else {
149 			ohci_dbg (ohci, "duplicate resume\n");
150 			status = 0;
151 		}
152 	} else switch (ohci->hc_control & OHCI_CTRL_HCFS) {
153 	case OHCI_USB_SUSPEND:
154 		ohci->hc_control &= ~(OHCI_CTRL_HCFS|OHCI_SCHED_ENABLES);
155 		ohci->hc_control |= OHCI_USB_RESUME;
156 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
157 		(void) ohci_readl (ohci, &ohci->regs->control);
158 		ohci_dbg (ohci, "%s root hub\n",
159 				autostopped ? "auto-start" : "resume");
160 		break;
161 	case OHCI_USB_RESUME:
162 		/* HCFS changes sometime after INTR_RD */
163 		ohci_dbg(ohci, "%swakeup root hub\n",
164 				autostopped ? "auto-" : "");
165 		break;
166 	case OHCI_USB_OPER:
167 		/* this can happen after resuming a swsusp snapshot */
168 		ohci_dbg (ohci, "snapshot resume? reinit\n");
169 		status = -EBUSY;
170 		break;
171 	default:		/* RESET, we lost power */
172 		ohci_dbg (ohci, "lost power\n");
173 		status = -EBUSY;
174 	}
175 	if (status == -EBUSY) {
176 		if (!autostopped) {
177 			spin_unlock_irq (&ohci->lock);
178 			(void) ohci_init (ohci);
179 			status = ohci_restart (ohci);
180 
181 			usb_root_hub_lost_power(hcd->self.root_hub);
182 
183 			spin_lock_irq (&ohci->lock);
184 		}
185 		return status;
186 	}
187 	if (status != -EINPROGRESS)
188 		return status;
189 	if (autostopped)
190 		goto skip_resume;
191 	spin_unlock_irq (&ohci->lock);
192 
193 	/* Some controllers (lucent erratum) need extra-long delays */
194 	msleep (20 /* usb 11.5.1.10 */ + 12 /* 32 msec counter */ + 1);
195 
196 	temp = ohci_readl (ohci, &ohci->regs->control);
197 	temp &= OHCI_CTRL_HCFS;
198 	if (temp != OHCI_USB_RESUME) {
199 		ohci_err (ohci, "controller won't resume\n");
200 		spin_lock_irq(&ohci->lock);
201 		return -EBUSY;
202 	}
203 
204 	/* disable old schedule state, reinit from scratch */
205 	ohci_writel (ohci, 0, &ohci->regs->ed_controlhead);
206 	ohci_writel (ohci, 0, &ohci->regs->ed_controlcurrent);
207 	ohci_writel (ohci, 0, &ohci->regs->ed_bulkhead);
208 	ohci_writel (ohci, 0, &ohci->regs->ed_bulkcurrent);
209 	ohci_writel (ohci, 0, &ohci->regs->ed_periodcurrent);
210 	ohci_writel (ohci, (u32) ohci->hcca_dma, &ohci->regs->hcca);
211 
212 	/* Sometimes PCI D3 suspend trashes frame timings ... */
213 	periodic_reinit (ohci);
214 
215 	/* the following code is executed with ohci->lock held and
216 	 * irqs disabled if and only if autostopped is true
217 	 */
218 
219 skip_resume:
220 	/* interrupts might have been disabled */
221 	ohci_writel (ohci, OHCI_INTR_INIT, &ohci->regs->intrenable);
222 	if (ohci->ed_rm_list)
223 		ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrenable);
224 
225 	/* Then re-enable operations */
226 	ohci_writel (ohci, OHCI_USB_OPER, &ohci->regs->control);
227 	(void) ohci_readl (ohci, &ohci->regs->control);
228 	if (!autostopped)
229 		msleep (3);
230 
231 	temp = ohci->hc_control;
232 	temp &= OHCI_CTRL_RWC;
233 	temp |= OHCI_CONTROL_INIT | OHCI_USB_OPER;
234 	ohci->hc_control = temp;
235 	ohci_writel (ohci, temp, &ohci->regs->control);
236 	(void) ohci_readl (ohci, &ohci->regs->control);
237 
238 	/* TRSMRCY */
239 	if (!autostopped) {
240 		msleep (10);
241 		spin_lock_irq (&ohci->lock);
242 	}
243 	/* now ohci->lock is always held and irqs are always disabled */
244 
245 	/* keep it alive for more than ~5x suspend + resume costs */
246 	ohci->next_statechange = jiffies + STATECHANGE_DELAY;
247 
248 	/* maybe turn schedules back on */
249 	enables = 0;
250 	temp = 0;
251 	if (!ohci->ed_rm_list) {
252 		if (ohci->ed_controltail) {
253 			ohci_writel (ohci,
254 					find_head (ohci->ed_controltail)->dma,
255 					&ohci->regs->ed_controlhead);
256 			enables |= OHCI_CTRL_CLE;
257 			temp |= OHCI_CLF;
258 		}
259 		if (ohci->ed_bulktail) {
260 			ohci_writel (ohci, find_head (ohci->ed_bulktail)->dma,
261 				&ohci->regs->ed_bulkhead);
262 			enables |= OHCI_CTRL_BLE;
263 			temp |= OHCI_BLF;
264 		}
265 	}
266 	if (hcd->self.bandwidth_isoc_reqs || hcd->self.bandwidth_int_reqs)
267 		enables |= OHCI_CTRL_PLE|OHCI_CTRL_IE;
268 	if (enables) {
269 		ohci_dbg (ohci, "restarting schedules ... %08x\n", enables);
270 		ohci->hc_control |= enables;
271 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
272 		if (temp)
273 			ohci_writel (ohci, temp, &ohci->regs->cmdstatus);
274 		(void) ohci_readl (ohci, &ohci->regs->control);
275 	}
276 
277 	return 0;
278 }
279 
280 static int ohci_bus_suspend (struct usb_hcd *hcd)
281 {
282 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
283 	int			rc;
284 
285 	spin_lock_irq (&ohci->lock);
286 
287 	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
288 		rc = -ESHUTDOWN;
289 	else
290 		rc = ohci_rh_suspend (ohci, 0);
291 	spin_unlock_irq (&ohci->lock);
292 	return rc;
293 }
294 
295 static int ohci_bus_resume (struct usb_hcd *hcd)
296 {
297 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
298 	int			rc;
299 
300 	if (time_before (jiffies, ohci->next_statechange))
301 		msleep(5);
302 
303 	spin_lock_irq (&ohci->lock);
304 
305 	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
306 		rc = -ESHUTDOWN;
307 	else
308 		rc = ohci_rh_resume (ohci);
309 	spin_unlock_irq (&ohci->lock);
310 
311 	/* poll until we know a device is connected or we autostop */
312 	if (rc == 0)
313 		usb_hcd_poll_rh_status(hcd);
314 	return rc;
315 }
316 
317 /* Carry out the final steps of resuming the controller device */
318 static void ohci_finish_controller_resume(struct usb_hcd *hcd)
319 {
320 	struct ohci_hcd		*ohci = hcd_to_ohci(hcd);
321 	int			port;
322 	bool			need_reinit = false;
323 
324 	/* See if the controller is already running or has been reset */
325 	ohci->hc_control = ohci_readl(ohci, &ohci->regs->control);
326 	if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
327 		need_reinit = true;
328 	} else {
329 		switch (ohci->hc_control & OHCI_CTRL_HCFS) {
330 		case OHCI_USB_OPER:
331 		case OHCI_USB_RESET:
332 			need_reinit = true;
333 		}
334 	}
335 
336 	/* If needed, reinitialize and suspend the root hub */
337 	if (need_reinit) {
338 		spin_lock_irq(&ohci->lock);
339 		hcd->state = HC_STATE_RESUMING;
340 		ohci_rh_resume(ohci);
341 		hcd->state = HC_STATE_QUIESCING;
342 		ohci_rh_suspend(ohci, 0);
343 		hcd->state = HC_STATE_SUSPENDED;
344 		spin_unlock_irq(&ohci->lock);
345 	}
346 
347 	/* Normally just turn on port power and enable interrupts */
348 	else {
349 		ohci_dbg(ohci, "powerup ports\n");
350 		for (port = 0; port < ohci->num_ports; port++)
351 			ohci_writel(ohci, RH_PS_PPS,
352 					&ohci->regs->roothub.portstatus[port]);
353 
354 		ohci_writel(ohci, OHCI_INTR_MIE, &ohci->regs->intrenable);
355 		ohci_readl(ohci, &ohci->regs->intrenable);
356 		msleep(20);
357 	}
358 }
359 
360 /* Carry out polling-, autostop-, and autoresume-related state changes */
361 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
362 		int any_connected)
363 {
364 	int	poll_rh = 1;
365 	int	rhsc;
366 
367 	rhsc = ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC;
368 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
369 
370 	case OHCI_USB_OPER:
371 		/* If no status changes are pending, enable status-change
372 		 * interrupts.
373 		 */
374 		if (!rhsc && !changed) {
375 			rhsc = OHCI_INTR_RHSC;
376 			ohci_writel(ohci, rhsc, &ohci->regs->intrenable);
377 		}
378 
379 		/* Keep on polling until we know a device is connected
380 		 * and RHSC is enabled, or until we autostop.
381 		 */
382 		if (!ohci->autostop) {
383 			if (any_connected ||
384 					!device_may_wakeup(&ohci_to_hcd(ohci)
385 						->self.root_hub->dev)) {
386 				if (rhsc)
387 					poll_rh = 0;
388 			} else {
389 				ohci->autostop = 1;
390 				ohci->next_statechange = jiffies + HZ;
391 			}
392 
393 		/* if no devices have been attached for one second, autostop */
394 		} else {
395 			if (changed || any_connected) {
396 				ohci->autostop = 0;
397 				ohci->next_statechange = jiffies +
398 						STATECHANGE_DELAY;
399 			} else if (rhsc && time_after_eq(jiffies,
400 						ohci->next_statechange)
401 					&& !ohci->ed_rm_list
402 					&& !(ohci->hc_control &
403 						OHCI_SCHED_ENABLES)) {
404 				ohci_rh_suspend(ohci, 1);
405 				poll_rh = 0;
406 			}
407 		}
408 		break;
409 
410 	/* if there is a port change, autostart or ask to be resumed */
411 	case OHCI_USB_SUSPEND:
412 	case OHCI_USB_RESUME:
413 		if (changed) {
414 			if (ohci->autostop)
415 				ohci_rh_resume(ohci);
416 			else
417 				usb_hcd_resume_root_hub(ohci_to_hcd(ohci));
418 		} else {
419 			if (!rhsc && (ohci->autostop ||
420 					ohci_to_hcd(ohci)->self.root_hub->
421 						do_remote_wakeup))
422 				ohci_writel(ohci, OHCI_INTR_RHSC,
423 						&ohci->regs->intrenable);
424 
425 			/* everything is idle, no need for polling */
426 			poll_rh = 0;
427 		}
428 		break;
429 	}
430 	return poll_rh;
431 }
432 
433 #else	/* CONFIG_PM */
434 
435 static inline int ohci_rh_resume(struct ohci_hcd *ohci)
436 {
437 	return 0;
438 }
439 
440 /* Carry out polling-related state changes.
441  * autostop isn't used when CONFIG_PM is turned off.
442  */
443 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
444 		int any_connected)
445 {
446 	/* If RHSC is enabled, don't poll */
447 	if (ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC)
448 		return 0;
449 
450 	/* If no status changes are pending, enable status-change interrupts */
451 	if (!changed) {
452 		ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
453 		return 0;
454 	}
455 	return 1;
456 }
457 
458 #endif	/* CONFIG_PM */
459 
460 /*-------------------------------------------------------------------------*/
461 
462 /* build "status change" packet (one or two bytes) from HC registers */
463 
464 static int
465 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 	unsigned long	flags;
471 
472 	spin_lock_irqsave (&ohci->lock, flags);
473 	if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))
474 		goto done;
475 
476 	/* undocumented erratum seen on at least rev D */
477 	if ((ohci->flags & OHCI_QUIRK_AMD756)
478 			&& (roothub_a (ohci) & RH_A_NDP) > MAX_ROOT_PORTS) {
479 		ohci_warn (ohci, "bogus NDP, rereads as NDP=%d\n",
480 			  ohci_readl (ohci, &ohci->regs->roothub.a) & RH_A_NDP);
481 		/* retry later; "should not happen" */
482 		goto done;
483 	}
484 
485 	/* init status */
486 	if (roothub_status (ohci) & (RH_HS_LPSC | RH_HS_OCIC))
487 		buf [0] = changed = 1;
488 	else
489 		buf [0] = 0;
490 	if (ohci->num_ports > 7) {
491 		buf [1] = 0;
492 		length++;
493 	}
494 
495 	/* Some broken controllers never turn off RHCS in the interrupt
496 	 * status register.  For their sake we won't re-enable RHSC
497 	 * interrupts if the flag is already set.
498 	 */
499 	if (ohci_readl(ohci, &ohci->regs->intrstatus) & OHCI_INTR_RHSC)
500 		changed = 1;
501 
502 	/* look at each port */
503 	for (i = 0; i < ohci->num_ports; i++) {
504 		u32	status = roothub_portstatus (ohci, i);
505 
506 		/* can't autostop if ports are connected */
507 		any_connected |= (status & RH_PS_CCS);
508 
509 		if (status & (RH_PS_CSC | RH_PS_PESC | RH_PS_PSSC
510 				| RH_PS_OCIC | RH_PS_PRSC)) {
511 			changed = 1;
512 			if (i < 7)
513 			    buf [0] |= 1 << (i + 1);
514 			else
515 			    buf [1] |= 1 << (i - 7);
516 		}
517 	}
518 
519 	hcd->poll_rh = ohci_root_hub_state_changes(ohci, changed,
520 			any_connected);
521 
522 done:
523 	spin_unlock_irqrestore (&ohci->lock, flags);
524 
525 	return changed ? length : 0;
526 }
527 
528 /*-------------------------------------------------------------------------*/
529 
530 static void
531 ohci_hub_descriptor (
532 	struct ohci_hcd			*ohci,
533 	struct usb_hub_descriptor	*desc
534 ) {
535 	u32		rh = roothub_a (ohci);
536 	u16		temp;
537 
538 	desc->bDescriptorType = 0x29;
539 	desc->bPwrOn2PwrGood = (rh & RH_A_POTPGT) >> 24;
540 	desc->bHubContrCurrent = 0;
541 
542 	desc->bNbrPorts = ohci->num_ports;
543 	temp = 1 + (ohci->num_ports / 8);
544 	desc->bDescLength = 7 + 2 * temp;
545 
546 	temp = 0;
547 	if (rh & RH_A_NPS)		/* no power switching? */
548 	    temp |= 0x0002;
549 	if (rh & RH_A_PSM)		/* per-port power switching? */
550 	    temp |= 0x0001;
551 	if (rh & RH_A_NOCP)		/* no overcurrent reporting? */
552 	    temp |= 0x0010;
553 	else if (rh & RH_A_OCPM)	/* per-port overcurrent reporting? */
554 	    temp |= 0x0008;
555 	desc->wHubCharacteristics = (__force __u16)cpu_to_hc16(ohci, temp);
556 
557 	/* two bitmaps:  ports removable, and usb 1.0 legacy PortPwrCtrlMask */
558 	rh = roothub_b (ohci);
559 	memset(desc->bitmap, 0xff, sizeof(desc->bitmap));
560 	desc->bitmap [0] = rh & RH_B_DR;
561 	if (ohci->num_ports > 7) {
562 		desc->bitmap [1] = (rh & RH_B_DR) >> 8;
563 		desc->bitmap [2] = 0xff;
564 	} else
565 		desc->bitmap [1] = 0xff;
566 }
567 
568 /*-------------------------------------------------------------------------*/
569 
570 #ifdef	CONFIG_USB_OTG
571 
572 static int ohci_start_port_reset (struct usb_hcd *hcd, unsigned port)
573 {
574 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
575 	u32			status;
576 
577 	if (!port)
578 		return -EINVAL;
579 	port--;
580 
581 	/* start port reset before HNP protocol times out */
582 	status = ohci_readl(ohci, &ohci->regs->roothub.portstatus [port]);
583 	if (!(status & RH_PS_CCS))
584 		return -ENODEV;
585 
586 	/* khubd will finish the reset later */
587 	ohci_writel(ohci, RH_PS_PRS, &ohci->regs->roothub.portstatus [port]);
588 	return 0;
589 }
590 
591 #else
592 
593 #define	ohci_start_port_reset		NULL
594 
595 #endif
596 
597 /*-------------------------------------------------------------------------*/
598 
599 
600 /* See usb 7.1.7.5:  root hubs must issue at least 50 msec reset signaling,
601  * not necessarily continuous ... to guard against resume signaling.
602  * The short timeout is safe for non-root hubs, and is backward-compatible
603  * with earlier Linux hosts.
604  */
605 #ifdef	CONFIG_USB_SUSPEND
606 #define	PORT_RESET_MSEC		50
607 #else
608 #define	PORT_RESET_MSEC		10
609 #endif
610 
611 /* this timer value might be vendor-specific ... */
612 #define	PORT_RESET_HW_MSEC	10
613 
614 /* wrap-aware logic morphed from <linux/jiffies.h> */
615 #define tick_before(t1,t2) ((s16)(((s16)(t1))-((s16)(t2))) < 0)
616 
617 /* called from some task, normally khubd */
618 static inline int root_port_reset (struct ohci_hcd *ohci, unsigned port)
619 {
620 	__hc32 __iomem *portstat = &ohci->regs->roothub.portstatus [port];
621 	u32	temp = 0;
622 	u16	now = ohci_readl(ohci, &ohci->regs->fmnumber);
623 	u16	reset_done = now + PORT_RESET_MSEC;
624 	int	limit_1 = DIV_ROUND_UP(PORT_RESET_MSEC, PORT_RESET_HW_MSEC);
625 
626 	/* build a "continuous enough" reset signal, with up to
627 	 * 3msec gap between pulses.  scheduler HZ==100 must work;
628 	 * this might need to be deadline-scheduled.
629 	 */
630 	do {
631 		int limit_2;
632 
633 		/* spin until any current reset finishes */
634 		limit_2 = PORT_RESET_HW_MSEC * 2;
635 		while (--limit_2 >= 0) {
636 			temp = ohci_readl (ohci, portstat);
637 			/* handle e.g. CardBus eject */
638 			if (temp == ~(u32)0)
639 				return -ESHUTDOWN;
640 			if (!(temp & RH_PS_PRS))
641 				break;
642 			udelay (500);
643 		}
644 
645 		/* timeout (a hardware error) has been observed when
646 		 * EHCI sets CF while this driver is resetting a port;
647 		 * presumably other disconnect paths might do it too.
648 		 */
649 		if (limit_2 < 0) {
650 			ohci_dbg(ohci,
651 				"port[%d] reset timeout, stat %08x\n",
652 				port, temp);
653 			break;
654 		}
655 
656 		if (!(temp & RH_PS_CCS))
657 			break;
658 		if (temp & RH_PS_PRSC)
659 			ohci_writel (ohci, RH_PS_PRSC, portstat);
660 
661 		/* start the next reset, sleep till it's probably done */
662 		ohci_writel (ohci, RH_PS_PRS, portstat);
663 		msleep(PORT_RESET_HW_MSEC);
664 		now = ohci_readl(ohci, &ohci->regs->fmnumber);
665 	} while (tick_before(now, reset_done) && --limit_1 >= 0);
666 
667 	/* caller synchronizes using PRSC ... and handles PRS
668 	 * still being set when this returns.
669 	 */
670 
671 	return 0;
672 }
673 
674 static int ohci_hub_control (
675 	struct usb_hcd	*hcd,
676 	u16		typeReq,
677 	u16		wValue,
678 	u16		wIndex,
679 	char		*buf,
680 	u16		wLength
681 ) {
682 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
683 	int		ports = hcd_to_bus (hcd)->root_hub->maxchild;
684 	u32		temp;
685 	int		retval = 0;
686 
687 	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
688 		return -ESHUTDOWN;
689 
690 	switch (typeReq) {
691 	case ClearHubFeature:
692 		switch (wValue) {
693 		case C_HUB_OVER_CURRENT:
694 			ohci_writel (ohci, RH_HS_OCIC,
695 					&ohci->regs->roothub.status);
696 		case C_HUB_LOCAL_POWER:
697 			break;
698 		default:
699 			goto error;
700 		}
701 		break;
702 	case ClearPortFeature:
703 		if (!wIndex || wIndex > ports)
704 			goto error;
705 		wIndex--;
706 
707 		switch (wValue) {
708 		case USB_PORT_FEAT_ENABLE:
709 			temp = RH_PS_CCS;
710 			break;
711 		case USB_PORT_FEAT_C_ENABLE:
712 			temp = RH_PS_PESC;
713 			break;
714 		case USB_PORT_FEAT_SUSPEND:
715 			temp = RH_PS_POCI;
716 			break;
717 		case USB_PORT_FEAT_C_SUSPEND:
718 			temp = RH_PS_PSSC;
719 			break;
720 		case USB_PORT_FEAT_POWER:
721 			temp = RH_PS_LSDA;
722 			break;
723 		case USB_PORT_FEAT_C_CONNECTION:
724 			temp = RH_PS_CSC;
725 			break;
726 		case USB_PORT_FEAT_C_OVER_CURRENT:
727 			temp = RH_PS_OCIC;
728 			break;
729 		case USB_PORT_FEAT_C_RESET:
730 			temp = RH_PS_PRSC;
731 			break;
732 		default:
733 			goto error;
734 		}
735 		ohci_writel (ohci, temp,
736 				&ohci->regs->roothub.portstatus [wIndex]);
737 		// ohci_readl (ohci, &ohci->regs->roothub.portstatus [wIndex]);
738 		break;
739 	case GetHubDescriptor:
740 		ohci_hub_descriptor (ohci, (struct usb_hub_descriptor *) buf);
741 		break;
742 	case GetHubStatus:
743 		temp = roothub_status (ohci) & ~(RH_HS_CRWE | RH_HS_DRWE);
744 		put_unaligned_le32(temp, buf);
745 		break;
746 	case GetPortStatus:
747 		if (!wIndex || wIndex > ports)
748 			goto error;
749 		wIndex--;
750 		temp = roothub_portstatus (ohci, wIndex);
751 		put_unaligned_le32(temp, buf);
752 
753 #ifndef	OHCI_VERBOSE_DEBUG
754 	if (*(u16*)(buf+2))	/* only if wPortChange is interesting */
755 #endif
756 		dbg_port (ohci, "GetStatus", wIndex, temp);
757 		break;
758 	case SetHubFeature:
759 		switch (wValue) {
760 		case C_HUB_OVER_CURRENT:
761 			// FIXME:  this can be cleared, yes?
762 		case C_HUB_LOCAL_POWER:
763 			break;
764 		default:
765 			goto error;
766 		}
767 		break;
768 	case SetPortFeature:
769 		if (!wIndex || wIndex > ports)
770 			goto error;
771 		wIndex--;
772 		switch (wValue) {
773 		case USB_PORT_FEAT_SUSPEND:
774 #ifdef	CONFIG_USB_OTG
775 			if (hcd->self.otg_port == (wIndex + 1)
776 					&& hcd->self.b_hnp_enable)
777 				ohci->start_hnp(ohci);
778 			else
779 #endif
780 			ohci_writel (ohci, RH_PS_PSS,
781 				&ohci->regs->roothub.portstatus [wIndex]);
782 			break;
783 		case USB_PORT_FEAT_POWER:
784 			ohci_writel (ohci, RH_PS_PPS,
785 				&ohci->regs->roothub.portstatus [wIndex]);
786 			break;
787 		case USB_PORT_FEAT_RESET:
788 			retval = root_port_reset (ohci, wIndex);
789 			break;
790 		default:
791 			goto error;
792 		}
793 		break;
794 
795 	default:
796 error:
797 		/* "protocol stall" on error */
798 		retval = -EPIPE;
799 	}
800 	return retval;
801 }
802 
803