From bf6387bcd16975ba8952b094f262a359d74e1c8a Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 11 Jul 2012 11:22:31 -0400 Subject: [PATCH] USB: EHCI: use hrtimer for controller death This patch (as1578) adds an hrtimer event to handle the death of an EHCI controller. When a controller dies, it doesn't necessarily stop running right away. The new event polls at 1-ms intervals to see when all activity has safely stopped. This replaces a busy-wait polling loop in the current code. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-hcd.c | 20 ++++++++++---------- drivers/usb/host/ehci-timer.c | 26 ++++++++++++++++++++++++++ drivers/usb/host/ehci.h | 2 ++ 3 files changed, 38 insertions(+), 10 deletions(-) diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index edcfd2c..1676c66 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -888,20 +888,20 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) /* PCI errors [4.15.2.4] */ if (unlikely ((status & STS_FATAL) != 0)) { ehci_err(ehci, "fatal error\n"); - ehci->rh_state = EHCI_RH_STOPPING; dbg_cmd(ehci, "fatal", cmd); dbg_status(ehci, "fatal", status); - ehci_halt(ehci); dead: - ehci->enabled_hrtimer_events = 0; - hrtimer_try_to_cancel(&ehci->hrtimer); - ehci_reset(ehci); - ehci_writel(ehci, 0, &ehci->regs->configured_flag); usb_hc_died(hcd); - /* generic layer kills/unlinks all urbs, then - * uses ehci_stop to clean up the rest - */ - bh = 1; + + /* Don't let the controller do anything more */ + ehci->rh_state = EHCI_RH_STOPPING; + ehci->command &= ~(CMD_RUN | CMD_ASE | CMD_PSE); + ehci_writel(ehci, ehci->command, &ehci->regs->command); + ehci_writel(ehci, 0, &ehci->regs->intr_enable); + ehci_handle_controller_death(ehci); + + /* Handle completions when the controller stops */ + bh = 0; } if (bh) diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c index bd8b591..0c5326a 100644 --- a/drivers/usb/host/ehci-timer.c +++ b/drivers/usb/host/ehci-timer.c @@ -69,6 +69,7 @@ static void ehci_clear_command_bit(struct ehci_hcd *ehci, u32 bit) 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 */ 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */ 15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */ @@ -193,6 +194,30 @@ static void ehci_disable_PSE(struct ehci_hcd *ehci) } +/* 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); + + /* 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) { @@ -233,6 +258,7 @@ static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci) 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 */ 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 f36f1f8..6874d89 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -81,6 +81,7 @@ enum ehci_rh_state { enum ehci_hrtimer_event { EHCI_HRTIMER_POLL_ASS, /* Poll for async schedule off */ EHCI_HRTIMER_POLL_PSS, /* Poll for periodic schedule off */ + EHCI_HRTIMER_POLL_DEAD, /* Wait for dead controller to stop */ EHCI_HRTIMER_UNLINK_INTR, /* Wait for interrupt QH unlink */ EHCI_HRTIMER_DISABLE_PERIODIC, /* Wait to disable periodic sched */ EHCI_HRTIMER_DISABLE_ASYNC, /* Wait to disable async sched */ @@ -97,6 +98,7 @@ struct ehci_hcd { /* one per controller */ int PSS_poll_count; int ASS_poll_count; + int died_poll_count; /* glue to PCI and HCD framework */ struct ehci_caps __iomem *caps; -- 2.7.4