xref: /openbmc/linux/drivers/usb/host/ohci-hub.c (revision 93dc544c)
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 /* hcd->hub_irq_enable() */
40 static void ohci_rhsc_enable (struct usb_hcd *hcd)
41 {
42 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
43 
44 	spin_lock_irq(&ohci->lock);
45 	if (!ohci->autostop)
46 		del_timer(&hcd->rh_timer);	/* Prevent next poll */
47 	ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
48 	spin_unlock_irq(&ohci->lock);
49 }
50 
51 #define OHCI_SCHED_ENABLES \
52 	(OHCI_CTRL_CLE|OHCI_CTRL_BLE|OHCI_CTRL_PLE|OHCI_CTRL_IE)
53 
54 static void dl_done_list (struct ohci_hcd *);
55 static void finish_unlinks (struct ohci_hcd *, u16);
56 
57 #ifdef	CONFIG_PM
58 static int ohci_rh_suspend (struct ohci_hcd *ohci, int autostop)
59 __releases(ohci->lock)
60 __acquires(ohci->lock)
61 {
62 	int			status = 0;
63 
64 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
65 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
66 	case OHCI_USB_RESUME:
67 		ohci_dbg (ohci, "resume/suspend?\n");
68 		ohci->hc_control &= ~OHCI_CTRL_HCFS;
69 		ohci->hc_control |= OHCI_USB_RESET;
70 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
71 		(void) ohci_readl (ohci, &ohci->regs->control);
72 		/* FALL THROUGH */
73 	case OHCI_USB_RESET:
74 		status = -EBUSY;
75 		ohci_dbg (ohci, "needs reinit!\n");
76 		goto done;
77 	case OHCI_USB_SUSPEND:
78 		if (!ohci->autostop) {
79 			ohci_dbg (ohci, "already suspended\n");
80 			goto done;
81 		}
82 	}
83 	ohci_dbg (ohci, "%s root hub\n",
84 			autostop ? "auto-stop" : "suspend");
85 
86 	/* First stop any processing */
87 	if (!autostop && (ohci->hc_control & OHCI_SCHED_ENABLES)) {
88 		ohci->hc_control &= ~OHCI_SCHED_ENABLES;
89 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
90 		ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
91 		ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrstatus);
92 
93 		/* sched disables take effect on the next frame,
94 		 * then the last WDH could take 6+ msec
95 		 */
96 		ohci_dbg (ohci, "stopping schedules ...\n");
97 		ohci->autostop = 0;
98 		spin_unlock_irq (&ohci->lock);
99 		msleep (8);
100 		spin_lock_irq (&ohci->lock);
101 	}
102 	dl_done_list (ohci);
103 	finish_unlinks (ohci, ohci_frame_no(ohci));
104 
105 	/* maybe resume can wake root hub */
106 	if (ohci_to_hcd(ohci)->self.root_hub->do_remote_wakeup || autostop) {
107 		ohci->hc_control |= OHCI_CTRL_RWE;
108 	} else {
109 		ohci_writel(ohci, OHCI_INTR_RHSC | OHCI_INTR_RD,
110 				&ohci->regs->intrdisable);
111 		ohci->hc_control &= ~OHCI_CTRL_RWE;
112 	}
113 
114 	/* Suspend hub ... this is the "global (to this bus) suspend" mode,
115 	 * which doesn't imply ports will first be individually suspended.
116 	 */
117 	ohci->hc_control &= ~OHCI_CTRL_HCFS;
118 	ohci->hc_control |= OHCI_USB_SUSPEND;
119 	ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
120 	(void) ohci_readl (ohci, &ohci->regs->control);
121 
122 	/* no resumes until devices finish suspending */
123 	if (!autostop) {
124 		ohci->next_statechange = jiffies + msecs_to_jiffies (5);
125 		ohci->autostop = 0;
126 	}
127 
128 done:
129 	return status;
130 }
131 
132 static inline struct ed *find_head (struct ed *ed)
133 {
134 	/* for bulk and control lists */
135 	while (ed->ed_prev)
136 		ed = ed->ed_prev;
137 	return ed;
138 }
139 
140 /* caller has locked the root hub */
141 static int ohci_rh_resume (struct ohci_hcd *ohci)
142 __releases(ohci->lock)
143 __acquires(ohci->lock)
144 {
145 	struct usb_hcd		*hcd = ohci_to_hcd (ohci);
146 	u32			temp, enables;
147 	int			status = -EINPROGRESS;
148 	int			autostopped = ohci->autostop;
149 
150 	ohci->autostop = 0;
151 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
152 
153 	if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
154 		/* this can happen after resuming a swsusp snapshot */
155 		if (hcd->state == HC_STATE_RESUMING) {
156 			ohci_dbg (ohci, "BIOS/SMM active, control %03x\n",
157 					ohci->hc_control);
158 			status = -EBUSY;
159 		/* this happens when pmcore resumes HC then root */
160 		} else {
161 			ohci_dbg (ohci, "duplicate resume\n");
162 			status = 0;
163 		}
164 	} else switch (ohci->hc_control & OHCI_CTRL_HCFS) {
165 	case OHCI_USB_SUSPEND:
166 		ohci->hc_control &= ~(OHCI_CTRL_HCFS|OHCI_SCHED_ENABLES);
167 		ohci->hc_control |= OHCI_USB_RESUME;
168 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
169 		(void) ohci_readl (ohci, &ohci->regs->control);
170 		ohci_dbg (ohci, "%s root hub\n",
171 				autostopped ? "auto-start" : "resume");
172 		break;
173 	case OHCI_USB_RESUME:
174 		/* HCFS changes sometime after INTR_RD */
175 		ohci_dbg(ohci, "%swakeup root hub\n",
176 				autostopped ? "auto-" : "");
177 		break;
178 	case OHCI_USB_OPER:
179 		/* this can happen after resuming a swsusp snapshot */
180 		ohci_dbg (ohci, "snapshot resume? reinit\n");
181 		status = -EBUSY;
182 		break;
183 	default:		/* RESET, we lost power */
184 		ohci_dbg (ohci, "lost power\n");
185 		status = -EBUSY;
186 	}
187 	if (status == -EBUSY) {
188 		if (!autostopped) {
189 			spin_unlock_irq (&ohci->lock);
190 			(void) ohci_init (ohci);
191 			status = ohci_restart (ohci);
192 
193 			usb_root_hub_lost_power(hcd->self.root_hub);
194 
195 			spin_lock_irq (&ohci->lock);
196 		}
197 		return status;
198 	}
199 	if (status != -EINPROGRESS)
200 		return status;
201 	if (autostopped)
202 		goto skip_resume;
203 	spin_unlock_irq (&ohci->lock);
204 
205 	/* Some controllers (lucent erratum) need extra-long delays */
206 	msleep (20 /* usb 11.5.1.10 */ + 12 /* 32 msec counter */ + 1);
207 
208 	temp = ohci_readl (ohci, &ohci->regs->control);
209 	temp &= OHCI_CTRL_HCFS;
210 	if (temp != OHCI_USB_RESUME) {
211 		ohci_err (ohci, "controller won't resume\n");
212 		spin_lock_irq(&ohci->lock);
213 		return -EBUSY;
214 	}
215 
216 	/* disable old schedule state, reinit from scratch */
217 	ohci_writel (ohci, 0, &ohci->regs->ed_controlhead);
218 	ohci_writel (ohci, 0, &ohci->regs->ed_controlcurrent);
219 	ohci_writel (ohci, 0, &ohci->regs->ed_bulkhead);
220 	ohci_writel (ohci, 0, &ohci->regs->ed_bulkcurrent);
221 	ohci_writel (ohci, 0, &ohci->regs->ed_periodcurrent);
222 	ohci_writel (ohci, (u32) ohci->hcca_dma, &ohci->regs->hcca);
223 
224 	/* Sometimes PCI D3 suspend trashes frame timings ... */
225 	periodic_reinit (ohci);
226 
227 	/* the following code is executed with ohci->lock held and
228 	 * irqs disabled if and only if autostopped is true
229 	 */
230 
231 skip_resume:
232 	/* interrupts might have been disabled */
233 	ohci_writel (ohci, OHCI_INTR_INIT, &ohci->regs->intrenable);
234 	if (ohci->ed_rm_list)
235 		ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrenable);
236 
237 	/* Then re-enable operations */
238 	ohci_writel (ohci, OHCI_USB_OPER, &ohci->regs->control);
239 	(void) ohci_readl (ohci, &ohci->regs->control);
240 	if (!autostopped)
241 		msleep (3);
242 
243 	temp = ohci->hc_control;
244 	temp &= OHCI_CTRL_RWC;
245 	temp |= OHCI_CONTROL_INIT | OHCI_USB_OPER;
246 	ohci->hc_control = temp;
247 	ohci_writel (ohci, temp, &ohci->regs->control);
248 	(void) ohci_readl (ohci, &ohci->regs->control);
249 
250 	/* TRSMRCY */
251 	if (!autostopped) {
252 		msleep (10);
253 		spin_lock_irq (&ohci->lock);
254 	}
255 	/* now ohci->lock is always held and irqs are always disabled */
256 
257 	/* keep it alive for more than ~5x suspend + resume costs */
258 	ohci->next_statechange = jiffies + STATECHANGE_DELAY;
259 
260 	/* maybe turn schedules back on */
261 	enables = 0;
262 	temp = 0;
263 	if (!ohci->ed_rm_list) {
264 		if (ohci->ed_controltail) {
265 			ohci_writel (ohci,
266 					find_head (ohci->ed_controltail)->dma,
267 					&ohci->regs->ed_controlhead);
268 			enables |= OHCI_CTRL_CLE;
269 			temp |= OHCI_CLF;
270 		}
271 		if (ohci->ed_bulktail) {
272 			ohci_writel (ohci, find_head (ohci->ed_bulktail)->dma,
273 				&ohci->regs->ed_bulkhead);
274 			enables |= OHCI_CTRL_BLE;
275 			temp |= OHCI_BLF;
276 		}
277 	}
278 	if (hcd->self.bandwidth_isoc_reqs || hcd->self.bandwidth_int_reqs)
279 		enables |= OHCI_CTRL_PLE|OHCI_CTRL_IE;
280 	if (enables) {
281 		ohci_dbg (ohci, "restarting schedules ... %08x\n", enables);
282 		ohci->hc_control |= enables;
283 		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
284 		if (temp)
285 			ohci_writel (ohci, temp, &ohci->regs->cmdstatus);
286 		(void) ohci_readl (ohci, &ohci->regs->control);
287 	}
288 
289 	return 0;
290 }
291 
292 static int ohci_bus_suspend (struct usb_hcd *hcd)
293 {
294 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
295 	int			rc;
296 
297 	spin_lock_irq (&ohci->lock);
298 
299 	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
300 		rc = -ESHUTDOWN;
301 	else
302 		rc = ohci_rh_suspend (ohci, 0);
303 	spin_unlock_irq (&ohci->lock);
304 	return rc;
305 }
306 
307 static int ohci_bus_resume (struct usb_hcd *hcd)
308 {
309 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
310 	int			rc;
311 
312 	if (time_before (jiffies, ohci->next_statechange))
313 		msleep(5);
314 
315 	spin_lock_irq (&ohci->lock);
316 
317 	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
318 		rc = -ESHUTDOWN;
319 	else
320 		rc = ohci_rh_resume (ohci);
321 	spin_unlock_irq (&ohci->lock);
322 
323 	/* poll until we know a device is connected or we autostop */
324 	if (rc == 0)
325 		usb_hcd_poll_rh_status(hcd);
326 	return rc;
327 }
328 
329 /* Carry out the final steps of resuming the controller device */
330 static void ohci_finish_controller_resume(struct usb_hcd *hcd)
331 {
332 	struct ohci_hcd		*ohci = hcd_to_ohci(hcd);
333 	int			port;
334 	bool			need_reinit = false;
335 
336 	/* See if the controller is already running or has been reset */
337 	ohci->hc_control = ohci_readl(ohci, &ohci->regs->control);
338 	if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
339 		need_reinit = true;
340 	} else {
341 		switch (ohci->hc_control & OHCI_CTRL_HCFS) {
342 		case OHCI_USB_OPER:
343 		case OHCI_USB_RESET:
344 			need_reinit = true;
345 		}
346 	}
347 
348 	/* If needed, reinitialize and suspend the root hub */
349 	if (need_reinit) {
350 		spin_lock_irq(&ohci->lock);
351 		hcd->state = HC_STATE_RESUMING;
352 		ohci_rh_resume(ohci);
353 		hcd->state = HC_STATE_QUIESCING;
354 		ohci_rh_suspend(ohci, 0);
355 		hcd->state = HC_STATE_SUSPENDED;
356 		spin_unlock_irq(&ohci->lock);
357 	}
358 
359 	/* Normally just turn on port power and enable interrupts */
360 	else {
361 		ohci_dbg(ohci, "powerup ports\n");
362 		for (port = 0; port < ohci->num_ports; port++)
363 			ohci_writel(ohci, RH_PS_PPS,
364 					&ohci->regs->roothub.portstatus[port]);
365 
366 		ohci_writel(ohci, OHCI_INTR_MIE, &ohci->regs->intrenable);
367 		ohci_readl(ohci, &ohci->regs->intrenable);
368 		msleep(20);
369 	}
370 }
371 
372 /* Carry out polling-, autostop-, and autoresume-related state changes */
373 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
374 		int any_connected)
375 {
376 	int	poll_rh = 1;
377 
378 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
379 
380 	case OHCI_USB_OPER:
381 		/* keep on polling until we know a device is connected
382 		 * and RHSC is enabled */
383 		if (!ohci->autostop) {
384 			if (any_connected ||
385 					!device_may_wakeup(&ohci_to_hcd(ohci)
386 						->self.root_hub->dev)) {
387 				if (ohci_readl(ohci, &ohci->regs->intrenable) &
388 						OHCI_INTR_RHSC)
389 					poll_rh = 0;
390 			} else {
391 				ohci->autostop = 1;
392 				ohci->next_statechange = jiffies + HZ;
393 			}
394 
395 		/* if no devices have been attached for one second, autostop */
396 		} else {
397 			if (changed || any_connected) {
398 				ohci->autostop = 0;
399 				ohci->next_statechange = jiffies +
400 						STATECHANGE_DELAY;
401 			} else if (time_after_eq(jiffies,
402 						ohci->next_statechange)
403 					&& !ohci->ed_rm_list
404 					&& !(ohci->hc_control &
405 						OHCI_SCHED_ENABLES)) {
406 				ohci_rh_suspend(ohci, 1);
407 			}
408 		}
409 		break;
410 
411 	/* if there is a port change, autostart or ask to be resumed */
412 	case OHCI_USB_SUSPEND:
413 	case OHCI_USB_RESUME:
414 		if (changed) {
415 			if (ohci->autostop)
416 				ohci_rh_resume(ohci);
417 			else
418 				usb_hcd_resume_root_hub(ohci_to_hcd(ohci));
419 		} else {
420 			/* everything is idle, no need for polling */
421 			poll_rh = 0;
422 		}
423 		break;
424 	}
425 	return poll_rh;
426 }
427 
428 #else	/* CONFIG_PM */
429 
430 static inline int ohci_rh_resume(struct ohci_hcd *ohci)
431 {
432 	return 0;
433 }
434 
435 /* Carry out polling-related state changes.
436  * autostop isn't used when CONFIG_PM is turned off.
437  */
438 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
439 		int any_connected)
440 {
441 	int	poll_rh = 1;
442 
443 	/* keep on polling until RHSC is enabled */
444 	if (ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC)
445 		poll_rh = 0;
446 	return poll_rh;
447 }
448 
449 #endif	/* CONFIG_PM */
450 
451 /*-------------------------------------------------------------------------*/
452 
453 /* build "status change" packet (one or two bytes) from HC registers */
454 
455 static int
456 ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
457 {
458 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
459 	int		i, changed = 0, length = 1;
460 	int		any_connected = 0;
461 	unsigned long	flags;
462 
463 	spin_lock_irqsave (&ohci->lock, flags);
464 	if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))
465 		goto done;
466 
467 	/* undocumented erratum seen on at least rev D */
468 	if ((ohci->flags & OHCI_QUIRK_AMD756)
469 			&& (roothub_a (ohci) & RH_A_NDP) > MAX_ROOT_PORTS) {
470 		ohci_warn (ohci, "bogus NDP, rereads as NDP=%d\n",
471 			  ohci_readl (ohci, &ohci->regs->roothub.a) & RH_A_NDP);
472 		/* retry later; "should not happen" */
473 		goto done;
474 	}
475 
476 	/* init status */
477 	if (roothub_status (ohci) & (RH_HS_LPSC | RH_HS_OCIC))
478 		buf [0] = changed = 1;
479 	else
480 		buf [0] = 0;
481 	if (ohci->num_ports > 7) {
482 		buf [1] = 0;
483 		length++;
484 	}
485 
486 	/* look at each port */
487 	for (i = 0; i < ohci->num_ports; i++) {
488 		u32	status = roothub_portstatus (ohci, i);
489 
490 		/* can't autostop if ports are connected */
491 		any_connected |= (status & RH_PS_CCS);
492 
493 		if (status & (RH_PS_CSC | RH_PS_PESC | RH_PS_PSSC
494 				| RH_PS_OCIC | RH_PS_PRSC)) {
495 			changed = 1;
496 			if (i < 7)
497 			    buf [0] |= 1 << (i + 1);
498 			else
499 			    buf [1] |= 1 << (i - 7);
500 		}
501 	}
502 
503 	hcd->poll_rh = ohci_root_hub_state_changes(ohci, changed,
504 			any_connected);
505 
506 done:
507 	spin_unlock_irqrestore (&ohci->lock, flags);
508 
509 	return changed ? length : 0;
510 }
511 
512 /*-------------------------------------------------------------------------*/
513 
514 static void
515 ohci_hub_descriptor (
516 	struct ohci_hcd			*ohci,
517 	struct usb_hub_descriptor	*desc
518 ) {
519 	u32		rh = roothub_a (ohci);
520 	u16		temp;
521 
522 	desc->bDescriptorType = 0x29;
523 	desc->bPwrOn2PwrGood = (rh & RH_A_POTPGT) >> 24;
524 	desc->bHubContrCurrent = 0;
525 
526 	desc->bNbrPorts = ohci->num_ports;
527 	temp = 1 + (ohci->num_ports / 8);
528 	desc->bDescLength = 7 + 2 * temp;
529 
530 	temp = 0;
531 	if (rh & RH_A_NPS)		/* no power switching? */
532 	    temp |= 0x0002;
533 	if (rh & RH_A_PSM)		/* per-port power switching? */
534 	    temp |= 0x0001;
535 	if (rh & RH_A_NOCP)		/* no overcurrent reporting? */
536 	    temp |= 0x0010;
537 	else if (rh & RH_A_OCPM)	/* per-port overcurrent reporting? */
538 	    temp |= 0x0008;
539 	desc->wHubCharacteristics = (__force __u16)cpu_to_hc16(ohci, temp);
540 
541 	/* two bitmaps:  ports removable, and usb 1.0 legacy PortPwrCtrlMask */
542 	rh = roothub_b (ohci);
543 	memset(desc->bitmap, 0xff, sizeof(desc->bitmap));
544 	desc->bitmap [0] = rh & RH_B_DR;
545 	if (ohci->num_ports > 7) {
546 		desc->bitmap [1] = (rh & RH_B_DR) >> 8;
547 		desc->bitmap [2] = 0xff;
548 	} else
549 		desc->bitmap [1] = 0xff;
550 }
551 
552 /*-------------------------------------------------------------------------*/
553 
554 #ifdef	CONFIG_USB_OTG
555 
556 static int ohci_start_port_reset (struct usb_hcd *hcd, unsigned port)
557 {
558 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
559 	u32			status;
560 
561 	if (!port)
562 		return -EINVAL;
563 	port--;
564 
565 	/* start port reset before HNP protocol times out */
566 	status = ohci_readl(ohci, &ohci->regs->roothub.portstatus [port]);
567 	if (!(status & RH_PS_CCS))
568 		return -ENODEV;
569 
570 	/* khubd will finish the reset later */
571 	ohci_writel(ohci, RH_PS_PRS, &ohci->regs->roothub.portstatus [port]);
572 	return 0;
573 }
574 
575 static void start_hnp(struct ohci_hcd *ohci);
576 
577 #else
578 
579 #define	ohci_start_port_reset		NULL
580 
581 #endif
582 
583 /*-------------------------------------------------------------------------*/
584 
585 
586 /* See usb 7.1.7.5:  root hubs must issue at least 50 msec reset signaling,
587  * not necessarily continuous ... to guard against resume signaling.
588  * The short timeout is safe for non-root hubs, and is backward-compatible
589  * with earlier Linux hosts.
590  */
591 #ifdef	CONFIG_USB_SUSPEND
592 #define	PORT_RESET_MSEC		50
593 #else
594 #define	PORT_RESET_MSEC		10
595 #endif
596 
597 /* this timer value might be vendor-specific ... */
598 #define	PORT_RESET_HW_MSEC	10
599 
600 /* wrap-aware logic morphed from <linux/jiffies.h> */
601 #define tick_before(t1,t2) ((s16)(((s16)(t1))-((s16)(t2))) < 0)
602 
603 /* called from some task, normally khubd */
604 static inline int root_port_reset (struct ohci_hcd *ohci, unsigned port)
605 {
606 	__hc32 __iomem *portstat = &ohci->regs->roothub.portstatus [port];
607 	u32	temp = 0;
608 	u16	now = ohci_readl(ohci, &ohci->regs->fmnumber);
609 	u16	reset_done = now + PORT_RESET_MSEC;
610 	int	limit_1 = DIV_ROUND_UP(PORT_RESET_MSEC, PORT_RESET_HW_MSEC);
611 
612 	/* build a "continuous enough" reset signal, with up to
613 	 * 3msec gap between pulses.  scheduler HZ==100 must work;
614 	 * this might need to be deadline-scheduled.
615 	 */
616 	do {
617 		int limit_2;
618 
619 		/* spin until any current reset finishes */
620 		limit_2 = PORT_RESET_HW_MSEC * 2;
621 		while (--limit_2 >= 0) {
622 			temp = ohci_readl (ohci, portstat);
623 			/* handle e.g. CardBus eject */
624 			if (temp == ~(u32)0)
625 				return -ESHUTDOWN;
626 			if (!(temp & RH_PS_PRS))
627 				break;
628 			udelay (500);
629 		}
630 
631 		/* timeout (a hardware error) has been observed when
632 		 * EHCI sets CF while this driver is resetting a port;
633 		 * presumably other disconnect paths might do it too.
634 		 */
635 		if (limit_2 < 0) {
636 			ohci_dbg(ohci,
637 				"port[%d] reset timeout, stat %08x\n",
638 				port, temp);
639 			break;
640 		}
641 
642 		if (!(temp & RH_PS_CCS))
643 			break;
644 		if (temp & RH_PS_PRSC)
645 			ohci_writel (ohci, RH_PS_PRSC, portstat);
646 
647 		/* start the next reset, sleep till it's probably done */
648 		ohci_writel (ohci, RH_PS_PRS, portstat);
649 		msleep(PORT_RESET_HW_MSEC);
650 		now = ohci_readl(ohci, &ohci->regs->fmnumber);
651 	} while (tick_before(now, reset_done) && --limit_1 >= 0);
652 
653 	/* caller synchronizes using PRSC ... and handles PRS
654 	 * still being set when this returns.
655 	 */
656 
657 	return 0;
658 }
659 
660 static int ohci_hub_control (
661 	struct usb_hcd	*hcd,
662 	u16		typeReq,
663 	u16		wValue,
664 	u16		wIndex,
665 	char		*buf,
666 	u16		wLength
667 ) {
668 	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
669 	int		ports = hcd_to_bus (hcd)->root_hub->maxchild;
670 	u32		temp;
671 	int		retval = 0;
672 
673 	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
674 		return -ESHUTDOWN;
675 
676 	switch (typeReq) {
677 	case ClearHubFeature:
678 		switch (wValue) {
679 		case C_HUB_OVER_CURRENT:
680 			ohci_writel (ohci, RH_HS_OCIC,
681 					&ohci->regs->roothub.status);
682 		case C_HUB_LOCAL_POWER:
683 			break;
684 		default:
685 			goto error;
686 		}
687 		break;
688 	case ClearPortFeature:
689 		if (!wIndex || wIndex > ports)
690 			goto error;
691 		wIndex--;
692 
693 		switch (wValue) {
694 		case USB_PORT_FEAT_ENABLE:
695 			temp = RH_PS_CCS;
696 			break;
697 		case USB_PORT_FEAT_C_ENABLE:
698 			temp = RH_PS_PESC;
699 			break;
700 		case USB_PORT_FEAT_SUSPEND:
701 			temp = RH_PS_POCI;
702 			break;
703 		case USB_PORT_FEAT_C_SUSPEND:
704 			temp = RH_PS_PSSC;
705 			break;
706 		case USB_PORT_FEAT_POWER:
707 			temp = RH_PS_LSDA;
708 			break;
709 		case USB_PORT_FEAT_C_CONNECTION:
710 			temp = RH_PS_CSC;
711 			break;
712 		case USB_PORT_FEAT_C_OVER_CURRENT:
713 			temp = RH_PS_OCIC;
714 			break;
715 		case USB_PORT_FEAT_C_RESET:
716 			temp = RH_PS_PRSC;
717 			break;
718 		default:
719 			goto error;
720 		}
721 		ohci_writel (ohci, temp,
722 				&ohci->regs->roothub.portstatus [wIndex]);
723 		// ohci_readl (ohci, &ohci->regs->roothub.portstatus [wIndex]);
724 		break;
725 	case GetHubDescriptor:
726 		ohci_hub_descriptor (ohci, (struct usb_hub_descriptor *) buf);
727 		break;
728 	case GetHubStatus:
729 		temp = roothub_status (ohci) & ~(RH_HS_CRWE | RH_HS_DRWE);
730 		put_unaligned_le32(temp, buf);
731 		break;
732 	case GetPortStatus:
733 		if (!wIndex || wIndex > ports)
734 			goto error;
735 		wIndex--;
736 		temp = roothub_portstatus (ohci, wIndex);
737 		put_unaligned_le32(temp, buf);
738 
739 #ifndef	OHCI_VERBOSE_DEBUG
740 	if (*(u16*)(buf+2))	/* only if wPortChange is interesting */
741 #endif
742 		dbg_port (ohci, "GetStatus", wIndex, temp);
743 		break;
744 	case SetHubFeature:
745 		switch (wValue) {
746 		case C_HUB_OVER_CURRENT:
747 			// FIXME:  this can be cleared, yes?
748 		case C_HUB_LOCAL_POWER:
749 			break;
750 		default:
751 			goto error;
752 		}
753 		break;
754 	case SetPortFeature:
755 		if (!wIndex || wIndex > ports)
756 			goto error;
757 		wIndex--;
758 		switch (wValue) {
759 		case USB_PORT_FEAT_SUSPEND:
760 #ifdef	CONFIG_USB_OTG
761 			if (hcd->self.otg_port == (wIndex + 1)
762 					&& hcd->self.b_hnp_enable)
763 				start_hnp(ohci);
764 			else
765 #endif
766 			ohci_writel (ohci, RH_PS_PSS,
767 				&ohci->regs->roothub.portstatus [wIndex]);
768 			break;
769 		case USB_PORT_FEAT_POWER:
770 			ohci_writel (ohci, RH_PS_PPS,
771 				&ohci->regs->roothub.portstatus [wIndex]);
772 			break;
773 		case USB_PORT_FEAT_RESET:
774 			retval = root_port_reset (ohci, wIndex);
775 			break;
776 		default:
777 			goto error;
778 		}
779 		break;
780 
781 	default:
782 error:
783 		/* "protocol stall" on error */
784 		retval = -EPIPE;
785 	}
786 	return retval;
787 }
788 
789