USB: EHCI: use hrtimer for the IAA watchdog
This patch (as1581) replaces the iaa_watchdog kernel timer used by
ehci-hcd with an hrtimer event, in keeping with the general conversion
to high-res timers.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index fb1966c..f74ba27 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -93,7 +93,6 @@
*/
#define EHCI_TUNE_FLS 1 /* (medium) 512-frame schedule */
-#define EHCI_IAA_MSECS 10 /* arbitrary */
#define EHCI_IO_JIFFIES (HZ/10) /* io watchdog > irq_thresh */
#define EHCI_SHRINK_JIFFIES (DIV_ROUND_UP(HZ, 200) + 1)
/* 5-ms async qh unlink delay */
@@ -322,51 +321,6 @@
/*-------------------------------------------------------------------------*/
-static void ehci_iaa_watchdog(unsigned long param)
-{
- struct ehci_hcd *ehci = (struct ehci_hcd *) param;
- unsigned long flags;
-
- spin_lock_irqsave (&ehci->lock, flags);
-
- /* 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_unlink
- && !timer_pending(&ehci->iaa_watchdog)
- && ehci->rh_state == EHCI_RH_RUNNING) {
- 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
- * before we cleared IAAD above (but _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);
- }
-
- spin_unlock_irqrestore(&ehci->lock, flags);
-}
-
static void ehci_watchdog(unsigned long param)
{
struct ehci_hcd *ehci = (struct ehci_hcd *) param;
@@ -418,7 +372,6 @@
struct ehci_hcd *ehci = hcd_to_ehci(hcd);
del_timer_sync(&ehci->watchdog);
- del_timer_sync(&ehci->iaa_watchdog);
spin_lock_irq(&ehci->lock);
ehci->rh_state = EHCI_RH_STOPPING;
@@ -491,7 +444,6 @@
/* no more interrupts ... */
del_timer_sync (&ehci->watchdog);
- del_timer_sync(&ehci->iaa_watchdog);
spin_lock_irq(&ehci->lock);
ehci->enabled_hrtimer_events = 0;
@@ -547,10 +499,6 @@
ehci->watchdog.function = ehci_watchdog;
ehci->watchdog.data = (unsigned long) ehci;
- init_timer(&ehci->iaa_watchdog);
- ehci->iaa_watchdog.function = ehci_iaa_watchdog;
- ehci->iaa_watchdog.data = (unsigned long) ehci;
-
hrtimer_init(&ehci->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
ehci->hrtimer.function = ehci_hrtimer_func;
ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
@@ -830,6 +778,20 @@
/* complete the unlinking of some qh [4.15.2.3] */
if (status & STS_IAA) {
+
+ /* Turn off the IAA watchdog */
+ ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_IAA_WATCHDOG);
+
+ /*
+ * Mild optimization: Allow another IAAD to reset the
+ * hrtimer, if one occurs before the next expiration.
+ * In theory we could always cancel the hrtimer, but
+ * tests show that about half the time it will be reset
+ * for some other event anyway.
+ */
+ if (ehci->next_hrtimer_event == EHCI_HRTIMER_IAA_WATCHDOG)
+ ++ehci->next_hrtimer_event;
+
/* guard against (alleged) silicon errata */
if (cmd & CMD_IAAD)
ehci_dbg(ehci, "IAA with IAAD still set?\n");
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 6ad806b..3097872 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -209,7 +209,6 @@
if (time_before (jiffies, ehci->next_statechange))
msleep(5);
del_timer_sync(&ehci->watchdog);
- del_timer_sync(&ehci->iaa_watchdog);
spin_lock_irq (&ehci->lock);
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index d68764e..7b35933 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -1173,8 +1173,6 @@
struct ehci_qh *qh = ehci->async_unlink;
struct ehci_qh *next;
- iaa_watchdog_done(ehci);
-
// qh->hw_next = cpu_to_hc32(qh->qh_dma);
qh->qh_state = QH_STATE_IDLE;
qh->qh_next.qh = NULL;
@@ -1243,7 +1241,7 @@
ehci_writel(ehci, ehci->command | CMD_IAAD, &ehci->regs->command);
(void)ehci_readl(ehci, &ehci->regs->command);
- iaa_watchdog_start(ehci);
+ ehci_enable_event(ehci, EHCI_HRTIMER_IAA_WATCHDOG, true);
}
/*-------------------------------------------------------------------------*/
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c
index 8feb60f..aab0420 100644
--- a/drivers/usb/host/ehci-timer.c
+++ b/drivers/usb/host/ehci-timer.c
@@ -72,6 +72,7 @@
1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_DEAD */
1125 * NSEC_PER_USEC, /* EHCI_HRTIMER_UNLINK_INTR */
2 * NSEC_PER_MSEC, /* EHCI_HRTIMER_FREE_ITDS */
+ 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IAA_WATCHDOG */
10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */
15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */
};
@@ -291,6 +292,49 @@
}
+/* 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_unlink) {
+ 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
@@ -302,6 +346,7 @@
ehci_handle_controller_death, /* EHCI_HRTIMER_POLL_DEAD */
ehci_handle_intr_unlinks, /* EHCI_HRTIMER_UNLINK_INTR */
end_free_itds, /* EHCI_HRTIMER_FREE_ITDS */
+ ehci_iaa_watchdog, /* EHCI_HRTIMER_IAA_WATCHDOG */
ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */
ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */
};
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 755e30b..d9414aa 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -84,6 +84,7 @@
EHCI_HRTIMER_POLL_DEAD, /* Wait for dead controller to stop */
EHCI_HRTIMER_UNLINK_INTR, /* Wait for interrupt QH unlink */
EHCI_HRTIMER_FREE_ITDS, /* Wait for unused iTDs and siTDs */
+ EHCI_HRTIMER_IAA_WATCHDOG, /* Handle lost IAA interrupts */
EHCI_HRTIMER_DISABLE_PERIODIC, /* Wait to disable periodic sched */
EHCI_HRTIMER_DISABLE_ASYNC, /* Wait to disable async sched */
EHCI_HRTIMER_NUM_EVENTS /* Must come last */
@@ -168,7 +169,6 @@
struct dma_pool *itd_pool; /* itd per iso urb */
struct dma_pool *sitd_pool; /* sitd per split iso urb */
- struct timer_list iaa_watchdog;
struct timer_list watchdog;
unsigned long actions;
unsigned periodic_stamp;
@@ -228,20 +228,6 @@
return container_of ((void *) ehci, struct usb_hcd, hcd_priv);
}
-
-static inline void
-iaa_watchdog_start(struct ehci_hcd *ehci)
-{
- WARN_ON(timer_pending(&ehci->iaa_watchdog));
- mod_timer(&ehci->iaa_watchdog,
- jiffies + msecs_to_jiffies(EHCI_IAA_MSECS));
-}
-
-static inline void iaa_watchdog_done(struct ehci_hcd *ehci)
-{
- del_timer(&ehci->iaa_watchdog);
-}
-
enum ehci_timer_action {
TIMER_IO_WATCHDOG,
TIMER_ASYNC_SHRINK,