[mirror_ubuntu-artful-kernel.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 */
	2 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_ACTIVE_UNLINK */
	5 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_START_UNLINK_INTR */
	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 */
	100 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_IO_WATCHDOG */
};

/* 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 2-4 ms */
		if (ehci->ASS_poll_count++ < 2) {
			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
			return;
		}
		ehci_dbg(ehci, "Waited too long for the async schedule status (%x/%x), giving up\n",
				want, actual);
	}
	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 2-4 ms */
		if (ehci->PSS_poll_count++ < 2) {
			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true);
			return;
		}
		ehci_dbg(ehci, "Waited too long for the periodic schedule status (%x/%x), giving up\n",
				want, actual);
	}
	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)
			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 */
}

/* start to unlink interrupt QHs  */
static void ehci_handle_start_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.
	 */
	while (!list_empty(&ehci->intr_unlink_wait)) {
		struct ehci_qh	*qh;

		qh = list_first_entry(&ehci->intr_unlink_wait,
				struct ehci_qh, unlink_node);
		if (!stopped && (qh->unlink_cycle ==
				ehci->intr_unlink_wait_cycle))
			break;
		list_del_init(&qh->unlink_node);
		qh->unlink_reason |= QH_UNLINK_QUEUE_EMPTY;
		start_unlink_intr(ehci, qh);
	}

	/* Handle remaining entries later */
	if (!list_empty(&ehci->intr_unlink_wait)) {
		ehci_enable_event(ehci, EHCI_HRTIMER_START_UNLINK_INTR, true);
		++ehci->intr_unlink_wait_cycle;
	}
}

/* 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 (!list_empty(&ehci->intr_unlink)) {
		struct ehci_qh	*qh;

		qh = list_first_entry(&ehci->intr_unlink, struct ehci_qh,
				unlink_node);
		if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle)
			break;
		list_del_init(&qh->unlink_node);
		end_unlink_intr(ehci, qh);
	}

	/* Handle remaining entries later */
	if (!list_empty(&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)
{
	u32 cmd, status;

	/*
	 * 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->iaa_in_progress || ehci->rh_state != EHCI_RH_RUNNING)
		return;

	/* 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_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd);
	end_iaa_cycle(ehci);
}


/* Enable the I/O watchdog, if appropriate */
static void turn_on_io_watchdog(struct ehci_hcd *ehci)
{
	/* Not needed if the controller isn't running or it's already enabled */
	if (ehci->rh_state != EHCI_RH_RUNNING ||
			(ehci->enabled_hrtimer_events &
				BIT(EHCI_HRTIMER_IO_WATCHDOG)))
		return;

	/*
	 * Isochronous transfers always need the watchdog.
	 * For other sorts we use it only if the flag is set.
	 */
	if (ehci->isoc_count > 0 || (ehci->need_io_watchdog &&
			ehci->async_count + ehci->intr_count > 0))
		ehci_enable_event(ehci, EHCI_HRTIMER_IO_WATCHDOG, true);
}


/*
 * 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 */
	end_unlink_async,		/* EHCI_HRTIMER_ACTIVE_UNLINK */
	ehci_handle_start_intr_unlinks,	/* EHCI_HRTIMER_START_UNLINK_INTR */
	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 */
	ehci_work,			/* EHCI_HRTIMER_IO_WATCHDOG */
};

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 >= ehci->hr_timeouts[e])
			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 */
87d61912	75	2 * NSEC_PER_MSEC, /* EHCI_HRTIMER_ACTIVE_UNLINK */
9118f9eb	76	5 * NSEC_PER_MSEC, /* EHCI_HRTIMER_START_UNLINK_INTR */
32830f20	77	6 * NSEC_PER_MSEC, /* EHCI_HRTIMER_ASYNC_UNLINKS */
9d938747	78	10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IAA_WATCHDOG */
3ca9aeba	79	10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */
31446610	80	15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */
18aafe64	81	100 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IO_WATCHDOG */
d58b4bcc AS	82	};
	83
	84	/* Enable a pending hrtimer event */
	85	static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event,
	86	bool resched)
	87	{
	88	ktime_t *timeout = &ehci->hr_timeouts[event];
	89
	90	if (resched)
	91	*timeout = ktime_add(ktime_get(),
	92	ktime_set(0, event_delays_ns[event]));
	93	ehci->enabled_hrtimer_events \|= (1 << event);
	94
	95	/* Track only the lowest-numbered pending event */
	96	if (event < ehci->next_hrtimer_event) {
	97	ehci->next_hrtimer_event = event;
	98	hrtimer_start_range_ns(&ehci->hrtimer, *timeout,
	99	NSEC_PER_MSEC, HRTIMER_MODE_ABS);
	100	}
	101	}
	102
	103
31446610 AS	104	/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */
	105	static void ehci_poll_ASS(struct ehci_hcd *ehci)
	106	{
	107	unsigned actual, want;
	108
	109	/* Don't enable anything if the controller isn't running (e.g., died) */
	110	if (ehci->rh_state != EHCI_RH_RUNNING)
	111	return;
	112
	113	want = (ehci->command & CMD_ASE) ? STS_ASS : 0;
	114	actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS;
	115
	116	if (want != actual) {
	117
6d5df897 AS	118	/* Poll again later, but give up after about 2-4 ms */
6d5df897 AS	119	if (ehci->ASS_poll_count++ < 2) {
221f8dfc AS	120	ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
	121	return;
	122	}
	123	ehci_dbg(ehci, "Waited too long for the async schedule status (%x/%x), giving up\n",
	124	want, actual);
31446610 AS	125	}
	126	ehci->ASS_poll_count = 0;
	127
	128	/* The status is up-to-date; restart or stop the schedule as needed */
	129	if (want == 0) { /* Stopped */
	130	if (ehci->async_count > 0)
	131	ehci_set_command_bit(ehci, CMD_ASE);
	132
	133	} else { /* Running */
	134	if (ehci->async_count == 0) {
	135
	136	/* Turn off the schedule after a while */
	137	ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC,
	138	true);
	139	}
	140	}
	141	}
	142
	143	/* Turn off the async schedule after a brief delay */
	144	static void ehci_disable_ASE(struct ehci_hcd *ehci)
	145	{
	146	ehci_clear_command_bit(ehci, CMD_ASE);
	147	}
	148
	149
3ca9aeba AS	150	/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */
	151	static void ehci_poll_PSS(struct ehci_hcd *ehci)
	152	{
	153	unsigned actual, want;
	154
	155	/* Don't do anything if the controller isn't running (e.g., died) */
	156	if (ehci->rh_state != EHCI_RH_RUNNING)
	157	return;
	158
	159	want = (ehci->command & CMD_PSE) ? STS_PSS : 0;
	160	actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS;
	161
	162	if (want != actual) {
	163
6d5df897 AS	164	/* Poll again later, but give up after about 2-4 ms */
6d5df897 AS	165	if (ehci->PSS_poll_count++ < 2) {
221f8dfc AS	166	ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true);
	167	return;
	168	}
	169	ehci_dbg(ehci, "Waited too long for the periodic schedule status (%x/%x), giving up\n",
	170	want, actual);
3ca9aeba AS	171	}
	172	ehci->PSS_poll_count = 0;
	173
	174	/* The status is up-to-date; restart or stop the schedule as needed */
	175	if (want == 0) { /* Stopped */
569b394f	176	if (ehci->periodic_count > 0)
3ca9aeba	177	ehci_set_command_bit(ehci, CMD_PSE);
3ca9aeba AS	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
9118f9eb ML	220	/* start to unlink interrupt QHs */
	221	static void ehci_handle_start_intr_unlinks(struct ehci_hcd *ehci)
	222	{
	223	bool stopped = (ehci->rh_state < EHCI_RH_RUNNING);
	224
	225	/*
	226	* Process all the QHs on the intr_unlink list that were added
	227	* before the current unlink cycle began. The list is in
	228	* temporal order, so stop when we reach the first entry in the
	229	* current cycle. But if the root hub isn't running then
	230	* process all the QHs on the list.
	231	*/
	232	while (!list_empty(&ehci->intr_unlink_wait)) {
	233	struct ehci_qh *qh;
	234
	235	qh = list_first_entry(&ehci->intr_unlink_wait,
	236	struct ehci_qh, unlink_node);
	237	if (!stopped && (qh->unlink_cycle ==
	238	ehci->intr_unlink_wait_cycle))
	239	break;
	240	list_del_init(&qh->unlink_node);
fcc5184e	241	qh->unlink_reason \|= QH_UNLINK_QUEUE_EMPTY;
9118f9eb ML	242	start_unlink_intr(ehci, qh);
	243	}
	244
	245	/* Handle remaining entries later */
	246	if (!list_empty(&ehci->intr_unlink_wait)) {
	247	ehci_enable_event(ehci, EHCI_HRTIMER_START_UNLINK_INTR, true);
	248	++ehci->intr_unlink_wait_cycle;
	249	}
	250	}
bf6387bc	251
df202255 AS	252	/* Handle unlinked interrupt QHs once they are gone from the hardware */
	253	static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci)
	254	{
	255	bool stopped = (ehci->rh_state < EHCI_RH_RUNNING);
	256
	257	/*
	258	* Process all the QHs on the intr_unlink list that were added
	259	* before the current unlink cycle began. The list is in
	260	* temporal order, so stop when we reach the first entry in the
	261	* current cycle. But if the root hub isn't running then
	262	* process all the QHs on the list.
	263	*/
	264	ehci->intr_unlinking = true;
6e018751 AS	265	while (!list_empty(&ehci->intr_unlink)) {
6e018751 AS	266	struct ehci_qh *qh;
df202255	267
6e018751 AS	268	qh = list_first_entry(&ehci->intr_unlink, struct ehci_qh,
6e018751 AS	269	unlink_node);
df202255 AS	270	if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle)
df202255 AS	271	break;
9118f9eb	272	list_del_init(&qh->unlink_node);
df202255 AS	273	end_unlink_intr(ehci, qh);
	274	}
	275
	276	/* Handle remaining entries later */
6e018751	277	if (!list_empty(&ehci->intr_unlink)) {
df202255 AS	278	ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true);
	279	++ehci->intr_unlink_cycle;
	280	}
	281	ehci->intr_unlinking = false;
	282	}
	283
	284
55934eb3 AS	285	/* Start another free-iTDs/siTDs cycle */
	286	static void start_free_itds(struct ehci_hcd *ehci)
	287	{
	288	if (!(ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_FREE_ITDS))) {
	289	ehci->last_itd_to_free = list_entry(
	290	ehci->cached_itd_list.prev,
	291	struct ehci_itd, itd_list);
	292	ehci->last_sitd_to_free = list_entry(
	293	ehci->cached_sitd_list.prev,
	294	struct ehci_sitd, sitd_list);
	295	ehci_enable_event(ehci, EHCI_HRTIMER_FREE_ITDS, true);
	296	}
	297	}
	298
	299	/* Wait for controller to stop using old iTDs and siTDs */
	300	static void end_free_itds(struct ehci_hcd *ehci)
	301	{
	302	struct ehci_itd itd, n;
	303	struct ehci_sitd sitd, sn;
	304
	305	if (ehci->rh_state < EHCI_RH_RUNNING) {
	306	ehci->last_itd_to_free = NULL;
	307	ehci->last_sitd_to_free = NULL;
	308	}
	309
	310	list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
	311	list_del(&itd->itd_list);
	312	dma_pool_free(ehci->itd_pool, itd, itd->itd_dma);
	313	if (itd == ehci->last_itd_to_free)
	314	break;
	315	}
	316	list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) {
	317	list_del(&sitd->sitd_list);
	318	dma_pool_free(ehci->sitd_pool, sitd, sitd->sitd_dma);
	319	if (sitd == ehci->last_sitd_to_free)
	320	break;
	321	}
	322
	323	if (!list_empty(&ehci->cached_itd_list) \|\|
	324	!list_empty(&ehci->cached_sitd_list))
	325	start_free_itds(ehci);
	326	}
	327
	328
9d938747 AS	329	/* Handle lost (or very late) IAA interrupts */
	330	static void ehci_iaa_watchdog(struct ehci_hcd *ehci)
	331	{
60fd4aa7	332	u32 cmd, status;
9d938747	333
417c765a AS	334	/*
	335	* Lost IAA irqs wedge things badly; seen first with a vt8235.
	336	* So we need this watchdog, but must protect it against both
	337	* (a) SMP races against real IAA firing and retriggering, and
	338	* (b) clean HC shutdown, when IAA watchdog was pending.
	339	*/
214ac7a0	340	if (!ehci->iaa_in_progress \|\| ehci->rh_state != EHCI_RH_RUNNING)
417c765a AS	341	return;
417c765a AS	342
60fd4aa7 AS	343	/* If we get here, IAA is REALLY late. It's barely
	344	* conceivable that the system is so busy that CMD_IAAD
	345	* is still legitimately set, so let's be sure it's
	346	* clear before we read STS_IAA. (The HC should clear
	347	* CMD_IAAD when it sets STS_IAA.)
	348	*/
	349	cmd = ehci_readl(ehci, &ehci->regs->command);
9d938747	350
60fd4aa7 AS	351	/*
	352	* If IAA is set here it either legitimately triggered
	353	* after the watchdog timer expired (_way_ late, so we'll
	354	* still count it as lost) ... or a silicon erratum:
	355	* - VIA seems to set IAA without triggering the IRQ;
	356	* - IAAD potentially cleared without setting IAA.
	357	*/
	358	status = ehci_readl(ehci, &ehci->regs->status);
	359	if ((status & STS_IAA) \|\| !(cmd & CMD_IAAD)) {
	360	COUNT(ehci->stats.lost_iaa);
	361	ehci_writel(ehci, STS_IAA, &ehci->regs->status);
9d938747	362	}
60fd4aa7 AS	363
60fd4aa7 AS	364	ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd);
f96fba0d	365	end_iaa_cycle(ehci);
9d938747 AS	366	}
	367
	368
18aafe64 AS	369	/* Enable the I/O watchdog, if appropriate */
	370	static void turn_on_io_watchdog(struct ehci_hcd *ehci)
	371	{
	372	/* Not needed if the controller isn't running or it's already enabled */
	373	if (ehci->rh_state != EHCI_RH_RUNNING \|\|
	374	(ehci->enabled_hrtimer_events &
	375	BIT(EHCI_HRTIMER_IO_WATCHDOG)))
	376	return;
	377
	378	/*
	379	* Isochronous transfers always need the watchdog.
	380	* For other sorts we use it only if the flag is set.
	381	*/
	382	if (ehci->isoc_count > 0 \|\| (ehci->need_io_watchdog &&
	383	ehci->async_count + ehci->intr_count > 0))
	384	ehci_enable_event(ehci, EHCI_HRTIMER_IO_WATCHDOG, true);
	385	}
	386
	387
d58b4bcc AS	388	/*
	389	* Handler functions for the hrtimer event types.
	390	* Keep this array in the same order as the event types indexed by
	391	* enum ehci_hrtimer_event in ehci.h.
	392	*/
	393	static void (event_handlers[])(struct ehci_hcd ) = {
31446610	394	ehci_poll_ASS, /* EHCI_HRTIMER_POLL_ASS */
3ca9aeba	395	ehci_poll_PSS, /* EHCI_HRTIMER_POLL_PSS */
bf6387bc	396	ehci_handle_controller_death, /* EHCI_HRTIMER_POLL_DEAD */
df202255	397	ehci_handle_intr_unlinks, /* EHCI_HRTIMER_UNLINK_INTR */
55934eb3	398	end_free_itds, /* EHCI_HRTIMER_FREE_ITDS */
87d61912	399	end_unlink_async, /* EHCI_HRTIMER_ACTIVE_UNLINK */
9118f9eb	400	ehci_handle_start_intr_unlinks, /* EHCI_HRTIMER_START_UNLINK_INTR */
32830f20	401	unlink_empty_async, /* EHCI_HRTIMER_ASYNC_UNLINKS */
9d938747	402	ehci_iaa_watchdog, /* EHCI_HRTIMER_IAA_WATCHDOG */
3ca9aeba	403	ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */
31446610	404	ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */
18aafe64	405	ehci_work, /* EHCI_HRTIMER_IO_WATCHDOG */
d58b4bcc AS	406	};
	407
	408	static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t)
	409	{
	410	struct ehci_hcd *ehci = container_of(t, struct ehci_hcd, hrtimer);
	411	ktime_t now;
	412	unsigned long events;
	413	unsigned long flags;
	414	unsigned e;
	415
	416	spin_lock_irqsave(&ehci->lock, flags);
	417
	418	events = ehci->enabled_hrtimer_events;
	419	ehci->enabled_hrtimer_events = 0;
	420	ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
	421
	422	/*
	423	* Check each pending event. If its time has expired, handle
	424	* the event; otherwise re-enable it.
	425	*/
	426	now = ktime_get();
	427	for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) {
2456e855	428	if (now >= ehci->hr_timeouts[e])
d58b4bcc AS	429	event_handlers[e](ehci);
	430	else
	431	ehci_enable_event(ehci, e, false);
	432	}
	433
	434	spin_unlock_irqrestore(&ehci->lock, flags);
	435	return HRTIMER_NORESTART;
	436	}