diff options
Diffstat (limited to 'drivers/usb/host/ehci-timer.c')
| -rw-r--r-- | drivers/usb/host/ehci-timer.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c index 8feb60ff422..aab04206422 100644 --- a/drivers/usb/host/ehci-timer.c +++ b/drivers/usb/host/ehci-timer.c @@ -72,6 +72,7 @@ static unsigned event_delays_ns[] = { 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 @@ static void end_free_itds(struct ehci_hcd *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_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 @@ static void (*event_handlers[])(struct ehci_hcd *) = { 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 */ }; |