1 files changed, 401 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c
new file mode 100644
index 00000000000..eb896a2c8f2
--- /dev/null
+++ b/drivers/usb/host/ehci-timer.c
@@ -0,0 +1,401 @@
+/*
+ * 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 */
+	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 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)
+			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);
+	}
+}
+
+
+/* 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 */
+	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.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;
+}