diff options
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 62 |
1 files changed, 46 insertions, 16 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index b8ad55aff842..46ee7f4c0912 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -281,23 +281,44 @@ static void ehci_iaa_watchdog(unsigned long param) { struct ehci_hcd *ehci = (struct ehci_hcd *) param; unsigned long flags; - u32 status, cmd; spin_lock_irqsave (&ehci->lock, flags); - WARN_ON(!ehci->reclaim); - status = ehci_readl(ehci, &ehci->regs->status); - cmd = ehci_readl(ehci, &ehci->regs->command); - ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd); - - /* lost IAA irqs wedge things badly; seen first with a vt8235 */ - if (ehci->reclaim) { - if (status & STS_IAA) { - ehci_vdbg (ehci, "lost IAA\n"); + /* 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->reclaim + && !timer_pending(&ehci->iaa_watchdog) + && HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) { + 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 (cmd & CMD_IAAD) + ehci_writel(ehci, cmd & ~CMD_IAAD, + &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_writel(ehci, cmd & ~CMD_IAAD, &ehci->regs->command); + + ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n", + status, cmd); end_unlink_async(ehci); } @@ -631,7 +652,7 @@ static int ehci_run (struct usb_hcd *hcd) static irqreturn_t ehci_irq (struct usb_hcd *hcd) { struct ehci_hcd *ehci = hcd_to_ehci (hcd); - u32 status, pcd_status = 0; + u32 status, pcd_status = 0, cmd; int bh; spin_lock (&ehci->lock); @@ -652,7 +673,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) /* clear (just) interrupts */ ehci_writel(ehci, status, &ehci->regs->status); - ehci_readl(ehci, &ehci->regs->command); /* unblock posted write */ + cmd = ehci_readl(ehci, &ehci->regs->command); bh = 0; #ifdef EHCI_VERBOSE_DEBUG @@ -673,8 +694,17 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) /* complete the unlinking of some qh [4.15.2.3] */ if (status & STS_IAA) { - COUNT (ehci->stats.reclaim); - end_unlink_async(ehci); + /* guard against (alleged) silicon errata */ + if (cmd & CMD_IAAD) { + ehci_writel(ehci, cmd & ~CMD_IAAD, + &ehci->regs->command); + ehci_dbg(ehci, "IAA with IAAD still set?\n"); + } + if (ehci->reclaim) { + COUNT(ehci->stats.reclaim); + end_unlink_async(ehci); + } else + ehci_dbg(ehci, "IAA with nothing to reclaim?\n"); } /* remote wakeup [4.3.1] */ @@ -781,7 +811,7 @@ static int ehci_urb_enqueue ( static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh) { /* failfast */ - if (!HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) + if (!HC_IS_RUNNING(ehci_to_hcd(ehci)->state) && ehci->reclaim) end_unlink_async(ehci); /* if it's not linked then there's nothing to do */ |