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 <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 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 @@
}
+/* 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 (*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 */