USB: EHCI: add separate IAA watchdog timer
This patch (as1028) was mostly written by David Brownell; I made only
a few changes (extra log info and a small bug fix -- which might
account for why David's version had to be reverted). It adds a new
watchdog timer to the ehci-hcd driver to be used exclusively for
detecting lost or missing IAA notifications.
Previously a shared timer had been used, which may have led to some
problems as reported by Christian Hoffmann.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 2641826..5917c6b 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -110,7 +110,7 @@
#define EHCI_TUNE_MULT_TT 1
#define EHCI_TUNE_FLS 2 /* (small) 256 frame schedule */
-#define EHCI_IAA_JIFFIES (HZ/100) /* arbitrary; ~10 msec */
+#define EHCI_IAA_MSECS 10 /* arbitrary */
#define EHCI_IO_JIFFIES (HZ/10) /* io watchdog > irq_thresh */
#define EHCI_ASYNC_JIFFIES (HZ/20) /* async idle timeout */
#define EHCI_SHRINK_JIFFIES (HZ/200) /* async qh unlink delay */
@@ -267,6 +267,7 @@
/*-------------------------------------------------------------------------*/
+static void end_unlink_async(struct ehci_hcd *ehci);
static void ehci_work(struct ehci_hcd *ehci);
#include "ehci-hub.c"
@@ -276,25 +277,41 @@
/*-------------------------------------------------------------------------*/
-static void ehci_watchdog (unsigned long param)
+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);
- /* lost IAA irqs wedge things badly; seen with a vt8235 */
+ 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) {
- u32 status = ehci_readl(ehci, &ehci->regs->status);
if (status & STS_IAA) {
ehci_vdbg (ehci, "lost IAA\n");
COUNT (ehci->stats.lost_iaa);
ehci_writel(ehci, STS_IAA, &ehci->regs->status);
- ehci->reclaim_ready = 1;
}
+ ehci_writel(ehci, cmd & ~CMD_IAAD, &ehci->regs->command);
+ end_unlink_async(ehci);
}
- /* stop async processing after it's idled a bit */
+ spin_unlock_irqrestore(&ehci->lock, flags);
+}
+
+static void ehci_watchdog(unsigned long param)
+{
+ struct ehci_hcd *ehci = (struct ehci_hcd *) param;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ehci->lock, flags);
+
+ /* stop async processing after it's idled a bit */
if (test_bit (TIMER_ASYNC_OFF, &ehci->actions))
start_unlink_async (ehci, ehci->async);
@@ -364,8 +381,6 @@
static void ehci_work (struct ehci_hcd *ehci)
{
timer_action_done (ehci, TIMER_IO_WATCHDOG);
- if (ehci->reclaim_ready)
- end_unlink_async (ehci);
/* another CPU may drop ehci->lock during a schedule scan while
* it reports urb completions. this flag guards against bogus
@@ -400,6 +415,7 @@
/* no more interrupts ... */
del_timer_sync (&ehci->watchdog);
+ del_timer_sync(&ehci->iaa_watchdog);
spin_lock_irq(&ehci->lock);
if (HC_IS_RUNNING (hcd->state))
@@ -448,6 +464,10 @@
ehci->watchdog.function = ehci_watchdog;
ehci->watchdog.data = (unsigned long) ehci;
+ init_timer(&ehci->iaa_watchdog);
+ ehci->iaa_watchdog.function = ehci_iaa_watchdog;
+ ehci->iaa_watchdog.data = (unsigned long) ehci;
+
/*
* hw default: 1K periodic list heads, one per frame.
* periodic_size can shrink by USBCMD update if hcc_params allows.
@@ -464,7 +484,6 @@
ehci->i_thresh = 2 + HCC_ISOC_THRES(hcc_params);
ehci->reclaim = NULL;
- ehci->reclaim_ready = 0;
ehci->next_uframe = -1;
/*
@@ -655,8 +674,7 @@
/* complete the unlinking of some qh [4.15.2.3] */
if (status & STS_IAA) {
COUNT (ehci->stats.reclaim);
- ehci->reclaim_ready = 1;
- bh = 1;
+ end_unlink_async(ehci);
}
/* remote wakeup [4.3.1] */
@@ -762,10 +780,16 @@
static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
- /* if we need to use IAA and it's busy, defer */
- if (qh->qh_state == QH_STATE_LINKED
- && ehci->reclaim
- && HC_IS_RUNNING (ehci_to_hcd(ehci)->state)) {
+ /* failfast */
+ if (!HC_IS_RUNNING(ehci_to_hcd(ehci)->state))
+ end_unlink_async(ehci);
+
+ /* if it's not linked then there's nothing to do */
+ if (qh->qh_state != QH_STATE_LINKED)
+ ;
+
+ /* defer till later if busy */
+ else if (ehci->reclaim) {
struct ehci_qh *last;
for (last = ehci->reclaim;
@@ -775,12 +799,8 @@
qh->qh_state = QH_STATE_UNLINK_WAIT;
last->reclaim = qh;
- /* bypass IAA if the hc can't care */
- } else if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state) && ehci->reclaim)
- end_unlink_async (ehci);
-
- /* something else might have unlinked the qh by now */
- if (qh->qh_state == QH_STATE_LINKED)
+ /* start IAA cycle */
+ } else
start_unlink_async (ehci, qh);
}
@@ -807,7 +827,19 @@
qh = (struct ehci_qh *) urb->hcpriv;
if (!qh)
break;
- unlink_async (ehci, qh);
+ switch (qh->qh_state) {
+ case QH_STATE_LINKED:
+ case QH_STATE_COMPLETING:
+ unlink_async(ehci, qh);
+ break;
+ case QH_STATE_UNLINK:
+ case QH_STATE_UNLINK_WAIT:
+ /* already started */
+ break;
+ case QH_STATE_IDLE:
+ WARN_ON(1);
+ break;
+ }
break;
case PIPE_INTERRUPT:
@@ -899,6 +931,7 @@
unlink_async (ehci, qh);
/* FALL THROUGH */
case QH_STATE_UNLINK: /* wait for hw to finish? */
+ case QH_STATE_UNLINK_WAIT:
idle_timeout:
spin_unlock_irqrestore (&ehci->lock, flags);
schedule_timeout_uninterruptible(1);