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Commit bf6387bc authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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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: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent df202255

drivers/usb/host/ehci-hcd.c

+10 −10
Original line number Diff line number Diff line
@@ -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)

drivers/usb/host/ehci-timer.c

+26 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/usb/host/ehci.h

+2 −0
Original line number Diff line number Diff line
@@ -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;