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");