[deliverable/linux.git] / drivers / usb / host / ehci-timer.c

/*
 * Copyright (C) 2012 by Alan Stern
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

/* This file is part of ehci-hcd.c */

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

/* Set a bit in the USBCMD register */
static void ehci_set_command_bit(struct ehci_hcd *ehci, u32 bit)
{
	ehci->command |= bit;
	ehci_writel(ehci, ehci->command, &ehci->regs->command);

	/* unblock posted write */
	ehci_readl(ehci, &ehci->regs->command);
}

/* Clear a bit in the USBCMD register */
static void ehci_clear_command_bit(struct ehci_hcd *ehci, u32 bit)
{
	ehci->command &= ~bit;
	ehci_writel(ehci, ehci->command, &ehci->regs->command);

	/* unblock posted write */
	ehci_readl(ehci, &ehci->regs->command);
}

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

/*
 * EHCI timer support...  Now using hrtimers.
 *
 * Lots of different events are triggered from ehci->hrtimer.  Whenever
 * the timer routine runs, it checks each possible event; events that are
 * currently enabled and whose expiration time has passed get handled.
 * The set of enabled events is stored as a collection of bitflags in
 * ehci->enabled_hrtimer_events, and they are numbered in order of
 * increasing delay values (ranging between 1 ms and 100 ms).
 *
 * Rather than implementing a sorted list or tree of all pending events,
 * we keep track only of the lowest-numbered pending event, in
 * ehci->next_hrtimer_event.  Whenever ehci->hrtimer gets restarted, its
 * expiration time is set to the timeout value for this event.
 *
 * As a result, events might not get handled right away; the actual delay
 * could be anywhere up to twice the requested delay.  This doesn't
 * matter, because none of the events are especially time-critical.  The
 * ones that matter most all have a delay of 1 ms, so they will be
 * handled after 2 ms at most, which is okay.  In addition to this, we
 * allow for an expiration range of 1 ms.
 */

/*
 * Delay lengths for the hrtimer event types.
 * Keep this list sorted by delay length, in the same order as
 * the event types indexed by enum ehci_hrtimer_event in ehci.h.
 */
static unsigned event_delays_ns[] = {
	1 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_POLL_ASS */
	1 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_POLL_PSS */
	1 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_POLL_DEAD */
	1125 * NSEC_PER_USEC,	/* EHCI_HRTIMER_UNLINK_INTR */
	2 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_FREE_ITDS */
	6 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_ASYNC_UNLINKS */
	10 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_IAA_WATCHDOG */
	10 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_DISABLE_PERIODIC */
	15 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_DISABLE_ASYNC */
};

/* Enable a pending hrtimer event */
static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event,
		bool resched)
{
	ktime_t		*timeout = &ehci->hr_timeouts[event];

	if (resched)
		*timeout = ktime_add(ktime_get(),
				ktime_set(0, event_delays_ns[event]));
	ehci->enabled_hrtimer_events |= (1 << event);

	/* Track only the lowest-numbered pending event */
	if (event < ehci->next_hrtimer_event) {
		ehci->next_hrtimer_event = event;
		hrtimer_start_range_ns(&ehci->hrtimer, *timeout,
				NSEC_PER_MSEC, HRTIMER_MODE_ABS);
	}
}


/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */
static void ehci_poll_ASS(struct ehci_hcd *ehci)
{
	unsigned	actual, want;

	/* Don't enable anything if the controller isn't running (e.g., died) */
	if (ehci->rh_state != EHCI_RH_RUNNING)
		return;

	want = (ehci->command & CMD_ASE) ? STS_ASS : 0;
	actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS;

	if (want != actual) {

		/* Poll again later, but give up after about 20 ms */
		if (ehci->ASS_poll_count++ < 20) {
			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
			return;
		}
		ehci_warn(ehci, "Waited too long for the async schedule status, giving up\n");
	}
	ehci->ASS_poll_count = 0;

	/* The status is up-to-date; restart or stop the schedule as needed */
	if (want == 0) {	/* Stopped */
		if (ehci->async_count > 0)
			ehci_set_command_bit(ehci, CMD_ASE);

	} else {		/* Running */
		if (ehci->async_count == 0) {

			/* Turn off the schedule after a while */
			ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC,
					true);
		}
	}
}

/* Turn off the async schedule after a brief delay */
static void ehci_disable_ASE(struct ehci_hcd *ehci)
{
	ehci_clear_command_bit(ehci, CMD_ASE);
}


/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */
static void ehci_poll_PSS(struct ehci_hcd *ehci)
{
	unsigned	actual, want;

	/* Don't do anything if the controller isn't running (e.g., died) */
	if (ehci->rh_state != EHCI_RH_RUNNING)
		return;

	want = (ehci->command & CMD_PSE) ? STS_PSS : 0;
	actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS;

	if (want != actual) {

		/* Poll again later, but give up after about 20 ms */
		if (ehci->PSS_poll_count++ < 20) {
			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true);
			return;
		}
		ehci_warn(ehci, "Waited too long for the periodic schedule status, giving up\n");
	}
	ehci->PSS_poll_count = 0;

	/* The status is up-to-date; restart or stop the schedule as needed */
	if (want == 0) {	/* Stopped */
		if (ehci->periodic_count > 0) {

			/* make sure ehci_work scans these */
			ehci->next_uframe = ehci_read_frame_index(ehci)
					& ((ehci->periodic_size << 3) - 1);
			ehci_set_command_bit(ehci, CMD_PSE);
		}

	} else {		/* Running */
		if (ehci->periodic_count == 0) {

			/* Turn off the schedule after a while */
			ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_PERIODIC,
					true);
		}
	}
}

/* Turn off the periodic schedule after a brief delay */
static void ehci_disable_PSE(struct ehci_hcd *ehci)
{
	ehci_clear_command_bit(ehci, CMD_PSE);
}


/* Poll the STS_HALT status bit; see when a dead controller stops */
static void ehci_handle_controller_death(struct ehci_hcd *ehci)
{
	if (!(ehci_readl(ehci, &ehci->regs->status) & STS_HALT)) {

		/* Give up after a few milliseconds */
		if (ehci->died_poll_count++ < 5) {
			/* Try again later */
			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_DEAD, true);
			return;
		}
		ehci_warn(ehci, "Waited too long for the controller to stop, giving up\n");
	}

	/* Clean up the mess */
	ehci->rh_state = EHCI_RH_HALTED;
	ehci_writel(ehci, 0, &ehci->regs->configured_flag);
	ehci_writel(ehci, 0, &ehci->regs->intr_enable);
	ehci_work(ehci);
	end_unlink_async(ehci);

	/* Not in process context, so don't try to reset the controller */
}


/* Handle unlinked interrupt QHs once they are gone from the hardware */
static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci)
{
	bool		stopped = (ehci->rh_state < EHCI_RH_RUNNING);

	/*
	 * Process all the QHs on the intr_unlink list that were added
	 * before the current unlink cycle began.  The list is in
	 * temporal order, so stop when we reach the first entry in the
	 * current cycle.  But if the root hub isn't running then
	 * process all the QHs on the list.
	 */
	ehci->intr_unlinking = true;
	while (ehci->intr_unlink) {
		struct ehci_qh	*qh = ehci->intr_unlink;

		if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle)
			break;
		ehci->intr_unlink = qh->unlink_next;
		qh->unlink_next = NULL;
		end_unlink_intr(ehci, qh);
	}

	/* Handle remaining entries later */
	if (ehci->intr_unlink) {
		ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true);
		++ehci->intr_unlink_cycle;
	}
	ehci->intr_unlinking = false;
}


/* Start another free-iTDs/siTDs cycle */
static void start_free_itds(struct ehci_hcd *ehci)
{
	if (!(ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_FREE_ITDS))) {
		ehci->last_itd_to_free = list_entry(
				ehci->cached_itd_list.prev,
				struct ehci_itd, itd_list);
		ehci->last_sitd_to_free = list_entry(
				ehci->cached_sitd_list.prev,
				struct ehci_sitd, sitd_list);
		ehci_enable_event(ehci, EHCI_HRTIMER_FREE_ITDS, true);
	}
}

/* Wait for controller to stop using old iTDs and siTDs */
static void end_free_itds(struct ehci_hcd *ehci)
{
	struct ehci_itd		*itd, *n;
	struct ehci_sitd	*sitd, *sn;

	if (ehci->rh_state < EHCI_RH_RUNNING) {
		ehci->last_itd_to_free = NULL;
		ehci->last_sitd_to_free = NULL;
	}

	list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
		list_del(&itd->itd_list);
		dma_pool_free(ehci->itd_pool, itd, itd->itd_dma);
		if (itd == ehci->last_itd_to_free)
			break;
	}
	list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) {
		list_del(&sitd->sitd_list);
		dma_pool_free(ehci->sitd_pool, sitd, sitd->sitd_dma);
		if (sitd == ehci->last_sitd_to_free)
			break;
	}

	if (!list_empty(&ehci->cached_itd_list) ||
			!list_empty(&ehci->cached_sitd_list))
		start_free_itds(ehci);
}


/* Handle lost (or very late) IAA interrupts */
static void ehci_iaa_watchdog(struct ehci_hcd *ehci)
{
	if (ehci->rh_state != EHCI_RH_RUNNING)
		return;

	/*
	 * Lost IAA irqs wedge things badly; seen first with a vt8235.
	 * So we need this watchdog, but must protect it against both
	 * (a) SMP races against real IAA firing and retriggering, and
	 * (b) clean HC shutdown, when IAA watchdog was pending.
	 */
	if (ehci->async_iaa) {
		u32 cmd, status;

		/* If we get here, IAA is *REALLY* late.  It's barely
		 * conceivable that the system is so busy that CMD_IAAD
		 * is still legitimately set, so let's be sure it's
		 * clear before we read STS_IAA.  (The HC should clear
		 * CMD_IAAD when it sets STS_IAA.)
		 */
		cmd = ehci_readl(ehci, &ehci->regs->command);

		/*
		 * If IAA is set here it either legitimately triggered
		 * after the watchdog timer expired (_way_ late, so we'll
		 * still count it as lost) ... or a silicon erratum:
		 * - VIA seems to set IAA without triggering the IRQ;
		 * - IAAD potentially cleared without setting IAA.
		 */
		status = ehci_readl(ehci, &ehci->regs->status);
		if ((status & STS_IAA) || !(cmd & CMD_IAAD)) {
			COUNT(ehci->stats.lost_iaa);
			ehci_writel(ehci, STS_IAA, &ehci->regs->status);
		}

		ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n",
				status, cmd);
		end_unlink_async(ehci);
	}
}


/*
 * Handler functions for the hrtimer event types.
 * Keep this array in the same order as the event types indexed by
 * enum ehci_hrtimer_event in ehci.h.
 */
static void (*event_handlers[])(struct ehci_hcd *) = {
	ehci_poll_ASS,			/* EHCI_HRTIMER_POLL_ASS */
	ehci_poll_PSS,			/* EHCI_HRTIMER_POLL_PSS */
	ehci_handle_controller_death,	/* EHCI_HRTIMER_POLL_DEAD */
	ehci_handle_intr_unlinks,	/* EHCI_HRTIMER_UNLINK_INTR */
	end_free_itds,			/* EHCI_HRTIMER_FREE_ITDS */
	unlink_empty_async,		/* EHCI_HRTIMER_ASYNC_UNLINKS */
	ehci_iaa_watchdog,		/* EHCI_HRTIMER_IAA_WATCHDOG */
	ehci_disable_PSE,		/* EHCI_HRTIMER_DISABLE_PERIODIC */
	ehci_disable_ASE,		/* EHCI_HRTIMER_DISABLE_ASYNC */
};

static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t)
{
	struct ehci_hcd	*ehci = container_of(t, struct ehci_hcd, hrtimer);
	ktime_t		now;
	unsigned long	events;
	unsigned long	flags;
	unsigned	e;

	spin_lock_irqsave(&ehci->lock, flags);

	events = ehci->enabled_hrtimer_events;
	ehci->enabled_hrtimer_events = 0;
	ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;

	/*
	 * Check each pending event.  If its time has expired, handle
	 * the event; otherwise re-enable it.
	 */
	now = ktime_get();
	for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) {
		if (now.tv64 >= ehci->hr_timeouts[e].tv64)
			event_handlers[e](ehci);
		else
			ehci_enable_event(ehci, e, false);
	}

	spin_unlock_irqrestore(&ehci->lock, flags);
	return HRTIMER_NORESTART;
}
Commit	Line	Data
d58b4bcc AS	1	/*
	2	* Copyright (C) 2012 by Alan Stern
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License as published by the
	6	* Free Software Foundation; either version 2 of the License, or (at your
	7	* option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful, but
	10	* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
	11	* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	12	* for more details.
	13	*/
	14
	15	/* This file is part of ehci-hcd.c */
	16
	17	/-------------------------------------------------------------------------/
	18
3ca9aeba AS	19	/* Set a bit in the USBCMD register */
	20	static void ehci_set_command_bit(struct ehci_hcd *ehci, u32 bit)
	21	{
	22	ehci->command \|= bit;
	23	ehci_writel(ehci, ehci->command, &ehci->regs->command);
	24
	25	/* unblock posted write */
	26	ehci_readl(ehci, &ehci->regs->command);
	27	}
	28
	29	/* Clear a bit in the USBCMD register */
	30	static void ehci_clear_command_bit(struct ehci_hcd *ehci, u32 bit)
	31	{
	32	ehci->command &= ~bit;
	33	ehci_writel(ehci, ehci->command, &ehci->regs->command);
	34
	35	/* unblock posted write */
	36	ehci_readl(ehci, &ehci->regs->command);
	37	}
	38
	39	/-------------------------------------------------------------------------/
	40
d58b4bcc AS	41	/*
	42	* EHCI timer support... Now using hrtimers.
	43	*
	44	* Lots of different events are triggered from ehci->hrtimer. Whenever
	45	* the timer routine runs, it checks each possible event; events that are
	46	* currently enabled and whose expiration time has passed get handled.
	47	* The set of enabled events is stored as a collection of bitflags in
	48	* ehci->enabled_hrtimer_events, and they are numbered in order of
	49	* increasing delay values (ranging between 1 ms and 100 ms).
	50	*
	51	* Rather than implementing a sorted list or tree of all pending events,
	52	* we keep track only of the lowest-numbered pending event, in
	53	* ehci->next_hrtimer_event. Whenever ehci->hrtimer gets restarted, its
	54	* expiration time is set to the timeout value for this event.
	55	*
	56	* As a result, events might not get handled right away; the actual delay
	57	* could be anywhere up to twice the requested delay. This doesn't
	58	* matter, because none of the events are especially time-critical. The
	59	* ones that matter most all have a delay of 1 ms, so they will be
	60	* handled after 2 ms at most, which is okay. In addition to this, we
	61	* allow for an expiration range of 1 ms.
	62	*/
	63
	64	/*
	65	* Delay lengths for the hrtimer event types.
	66	* Keep this list sorted by delay length, in the same order as
	67	* the event types indexed by enum ehci_hrtimer_event in ehci.h.
	68	*/
	69	static unsigned event_delays_ns[] = {
31446610	70	1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_ASS */
3ca9aeba	71	1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_PSS */
bf6387bc	72	1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_DEAD */
df202255	73	1125 * NSEC_PER_USEC, /* EHCI_HRTIMER_UNLINK_INTR */
55934eb3	74	2 * NSEC_PER_MSEC, /* EHCI_HRTIMER_FREE_ITDS */
32830f20	75	6 * NSEC_PER_MSEC, /* EHCI_HRTIMER_ASYNC_UNLINKS */
9d938747	76	10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IAA_WATCHDOG */
3ca9aeba	77	10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */
31446610	78	15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */
d58b4bcc AS	79	};
	80
	81	/* Enable a pending hrtimer event */
	82	static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event,
	83	bool resched)
	84	{
	85	ktime_t *timeout = &ehci->hr_timeouts[event];
	86
	87	if (resched)
	88	*timeout = ktime_add(ktime_get(),
	89	ktime_set(0, event_delays_ns[event]));
	90	ehci->enabled_hrtimer_events \|= (1 << event);
	91
	92	/* Track only the lowest-numbered pending event */
	93	if (event < ehci->next_hrtimer_event) {
	94	ehci->next_hrtimer_event = event;
	95	hrtimer_start_range_ns(&ehci->hrtimer, *timeout,
	96	NSEC_PER_MSEC, HRTIMER_MODE_ABS);
	97	}
	98	}
	99
	100
31446610 AS	101	/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */
	102	static void ehci_poll_ASS(struct ehci_hcd *ehci)
	103	{
	104	unsigned actual, want;
	105
	106	/* Don't enable anything if the controller isn't running (e.g., died) */
	107	if (ehci->rh_state != EHCI_RH_RUNNING)
	108	return;
	109
	110	want = (ehci->command & CMD_ASE) ? STS_ASS : 0;
	111	actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS;
	112
	113	if (want != actual) {
	114
	115	/* Poll again later, but give up after about 20 ms */
	116	if (ehci->ASS_poll_count++ < 20) {
	117	ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
	118	return;
	119	}
	120	ehci_warn(ehci, "Waited too long for the async schedule status, giving up\n");
	121	}
	122	ehci->ASS_poll_count = 0;
	123
	124	/* The status is up-to-date; restart or stop the schedule as needed */
	125	if (want == 0) { /* Stopped */
	126	if (ehci->async_count > 0)
	127	ehci_set_command_bit(ehci, CMD_ASE);
	128
	129	} else { /* Running */
	130	if (ehci->async_count == 0) {
	131
	132	/* Turn off the schedule after a while */
	133	ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC,
	134	true);
	135	}
	136	}
	137	}
	138
	139	/* Turn off the async schedule after a brief delay */
	140	static void ehci_disable_ASE(struct ehci_hcd *ehci)
	141	{
	142	ehci_clear_command_bit(ehci, CMD_ASE);
	143	}
	144
	145
3ca9aeba AS	146	/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */
	147	static void ehci_poll_PSS(struct ehci_hcd *ehci)
	148	{
	149	unsigned actual, want;
	150
	151	/* Don't do anything if the controller isn't running (e.g., died) */
	152	if (ehci->rh_state != EHCI_RH_RUNNING)
	153	return;
	154
	155	want = (ehci->command & CMD_PSE) ? STS_PSS : 0;
	156	actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS;
	157
	158	if (want != actual) {
	159
	160	/* Poll again later, but give up after about 20 ms */
	161	if (ehci->PSS_poll_count++ < 20) {
	162	ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true);
	163	return;
	164	}
	165	ehci_warn(ehci, "Waited too long for the periodic schedule status, giving up\n");
	166	}
	167	ehci->PSS_poll_count = 0;
	168
	169	/* The status is up-to-date; restart or stop the schedule as needed */
	170	if (want == 0) { /* Stopped */
3ca9aeba AS	171	if (ehci->periodic_count > 0) {
	172
	173	/* make sure ehci_work scans these */
	174	ehci->next_uframe = ehci_read_frame_index(ehci)
	175	& ((ehci->periodic_size << 3) - 1);
	176	ehci_set_command_bit(ehci, CMD_PSE);
	177	}
	178
	179	} else { /* Running */
	180	if (ehci->periodic_count == 0) {
	181
	182	/* Turn off the schedule after a while */
	183	ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_PERIODIC,
	184	true);
	185	}
	186	}
	187	}
	188
	189	/* Turn off the periodic schedule after a brief delay */
	190	static void ehci_disable_PSE(struct ehci_hcd *ehci)
	191	{
	192	ehci_clear_command_bit(ehci, CMD_PSE);
3ca9aeba AS	193	}
	194
	195
bf6387bc AS	196	/* Poll the STS_HALT status bit; see when a dead controller stops */
	197	static void ehci_handle_controller_death(struct ehci_hcd *ehci)
	198	{
	199	if (!(ehci_readl(ehci, &ehci->regs->status) & STS_HALT)) {
	200
	201	/* Give up after a few milliseconds */
	202	if (ehci->died_poll_count++ < 5) {
	203	/* Try again later */
	204	ehci_enable_event(ehci, EHCI_HRTIMER_POLL_DEAD, true);
	205	return;
	206	}
	207	ehci_warn(ehci, "Waited too long for the controller to stop, giving up\n");
	208	}
	209
	210	/* Clean up the mess */
	211	ehci->rh_state = EHCI_RH_HALTED;
	212	ehci_writel(ehci, 0, &ehci->regs->configured_flag);
	213	ehci_writel(ehci, 0, &ehci->regs->intr_enable);
	214	ehci_work(ehci);
3c273a05	215	end_unlink_async(ehci);
bf6387bc AS	216
	217	/* Not in process context, so don't try to reset the controller */
	218	}
	219
	220
df202255 AS	221	/* Handle unlinked interrupt QHs once they are gone from the hardware */
	222	static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci)
	223	{
	224	bool stopped = (ehci->rh_state < EHCI_RH_RUNNING);
	225
	226	/*
	227	* Process all the QHs on the intr_unlink list that were added
	228	* before the current unlink cycle began. The list is in
	229	* temporal order, so stop when we reach the first entry in the
	230	* current cycle. But if the root hub isn't running then
	231	* process all the QHs on the list.
	232	*/
	233	ehci->intr_unlinking = true;
	234	while (ehci->intr_unlink) {
	235	struct ehci_qh *qh = ehci->intr_unlink;
	236
	237	if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle)
	238	break;
	239	ehci->intr_unlink = qh->unlink_next;
	240	qh->unlink_next = NULL;
	241	end_unlink_intr(ehci, qh);
	242	}
	243
	244	/* Handle remaining entries later */
	245	if (ehci->intr_unlink) {
	246	ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true);
	247	++ehci->intr_unlink_cycle;
	248	}
	249	ehci->intr_unlinking = false;
	250	}
	251
	252
55934eb3 AS	253	/* Start another free-iTDs/siTDs cycle */
	254	static void start_free_itds(struct ehci_hcd *ehci)
	255	{
	256	if (!(ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_FREE_ITDS))) {
	257	ehci->last_itd_to_free = list_entry(
	258	ehci->cached_itd_list.prev,
	259	struct ehci_itd, itd_list);
	260	ehci->last_sitd_to_free = list_entry(
	261	ehci->cached_sitd_list.prev,
	262	struct ehci_sitd, sitd_list);
	263	ehci_enable_event(ehci, EHCI_HRTIMER_FREE_ITDS, true);
	264	}
	265	}
	266
	267	/* Wait for controller to stop using old iTDs and siTDs */
	268	static void end_free_itds(struct ehci_hcd *ehci)
	269	{
	270	struct ehci_itd itd, n;
	271	struct ehci_sitd sitd, sn;
	272
	273	if (ehci->rh_state < EHCI_RH_RUNNING) {
	274	ehci->last_itd_to_free = NULL;
	275	ehci->last_sitd_to_free = NULL;
	276	}
	277
	278	list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
	279	list_del(&itd->itd_list);
	280	dma_pool_free(ehci->itd_pool, itd, itd->itd_dma);
	281	if (itd == ehci->last_itd_to_free)
	282	break;
	283	}
	284	list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) {
	285	list_del(&sitd->sitd_list);
	286	dma_pool_free(ehci->sitd_pool, sitd, sitd->sitd_dma);
	287	if (sitd == ehci->last_sitd_to_free)
	288	break;
	289	}
	290
	291	if (!list_empty(&ehci->cached_itd_list) \|\|
	292	!list_empty(&ehci->cached_sitd_list))
	293	start_free_itds(ehci);
	294	}
	295
	296
9d938747 AS	297	/* Handle lost (or very late) IAA interrupts */
	298	static void ehci_iaa_watchdog(struct ehci_hcd *ehci)
	299	{
	300	if (ehci->rh_state != EHCI_RH_RUNNING)
	301	return;
	302
	303	/*
	304	* Lost IAA irqs wedge things badly; seen first with a vt8235.
	305	* So we need this watchdog, but must protect it against both
	306	* (a) SMP races against real IAA firing and retriggering, and
	307	* (b) clean HC shutdown, when IAA watchdog was pending.
	308	*/
3c273a05	309	if (ehci->async_iaa) {
9d938747 AS	310	u32 cmd, status;
	311
	312	/* If we get here, IAA is REALLY late. It's barely
	313	* conceivable that the system is so busy that CMD_IAAD
	314	* is still legitimately set, so let's be sure it's
	315	* clear before we read STS_IAA. (The HC should clear
	316	* CMD_IAAD when it sets STS_IAA.)
	317	*/
	318	cmd = ehci_readl(ehci, &ehci->regs->command);
	319
	320	/*
	321	* If IAA is set here it either legitimately triggered
	322	* after the watchdog timer expired (_way_ late, so we'll
	323	* still count it as lost) ... or a silicon erratum:
	324	* - VIA seems to set IAA without triggering the IRQ;
	325	* - IAAD potentially cleared without setting IAA.
	326	*/
	327	status = ehci_readl(ehci, &ehci->regs->status);
	328	if ((status & STS_IAA) \|\| !(cmd & CMD_IAAD)) {
	329	COUNT(ehci->stats.lost_iaa);
	330	ehci_writel(ehci, STS_IAA, &ehci->regs->status);
	331	}
	332
	333	ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n",
	334	status, cmd);
	335	end_unlink_async(ehci);
	336	}
	337	}
	338
	339
d58b4bcc AS	340	/*
	341	* Handler functions for the hrtimer event types.
	342	* Keep this array in the same order as the event types indexed by
	343	* enum ehci_hrtimer_event in ehci.h.
	344	*/
	345	static void (event_handlers[])(struct ehci_hcd ) = {
31446610	346	ehci_poll_ASS, /* EHCI_HRTIMER_POLL_ASS */
3ca9aeba	347	ehci_poll_PSS, /* EHCI_HRTIMER_POLL_PSS */
bf6387bc	348	ehci_handle_controller_death, /* EHCI_HRTIMER_POLL_DEAD */
df202255	349	ehci_handle_intr_unlinks, /* EHCI_HRTIMER_UNLINK_INTR */
55934eb3	350	end_free_itds, /* EHCI_HRTIMER_FREE_ITDS */
32830f20	351	unlink_empty_async, /* EHCI_HRTIMER_ASYNC_UNLINKS */
9d938747	352	ehci_iaa_watchdog, /* EHCI_HRTIMER_IAA_WATCHDOG */
3ca9aeba	353	ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */
31446610	354	ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */
d58b4bcc AS	355	};
	356
	357	static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t)
	358	{
	359	struct ehci_hcd *ehci = container_of(t, struct ehci_hcd, hrtimer);
	360	ktime_t now;
	361	unsigned long events;
	362	unsigned long flags;
	363	unsigned e;
	364
	365	spin_lock_irqsave(&ehci->lock, flags);
	366
	367	events = ehci->enabled_hrtimer_events;
	368	ehci->enabled_hrtimer_events = 0;
	369	ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
	370
	371	/*
	372	* Check each pending event. If its time has expired, handle
	373	* the event; otherwise re-enable it.
	374	*/
	375	now = ktime_get();
	376	for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) {
	377	if (now.tv64 >= ehci->hr_timeouts[e].tv64)
	378	event_handlers[e](ehci);
	379	else
	380	ehci_enable_event(ehci, e, false);
	381	}
	382
	383	spin_unlock_irqrestore(&ehci->lock, flags);
	384	return HRTIMER_NORESTART;
	385	}