USB: EHCI update VIA workaround
This revamps handling of the hardware "async advance" IRQ, and its watchdog
timer. Basically it dis-entangles that important timeout from the others,
simplifying the associated state and code to make it more robust.
This reportedly improves behavior of EHCI on some systems with VIA chips,
and AFAIK won't affect non-VIA hardware. VIA systems need this code to
recover from silcon bugs whereby the "async advance" IRQ isn't issued.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/ehci-dbg.c b/drivers/usb/host/ehci-dbg.c
index 34b7a31..23b95b2 100644
--- a/drivers/usb/host/ehci-dbg.c
+++ b/drivers/usb/host/ehci-dbg.c
@@ -754,9 +754,7 @@
}
if (ehci->reclaim) {
- temp = scnprintf (next, size, "reclaim qh %p%s\n",
- ehci->reclaim,
- ehci->reclaim_ready ? " ready" : "");
+ temp = scnprintf (next, size, "reclaim qh %p\n", ehci->reclaim);
size -= temp;
next += temp;
}
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 4e1a8c3..5ac9185 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -111,7 +111,7 @@
#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 */
@@ -254,6 +254,7 @@
/*-------------------------------------------------------------------------*/
+static void end_unlink_async (struct ehci_hcd *ehci, struct pt_regs *regs);
static void ehci_work(struct ehci_hcd *ehci, struct pt_regs *regs);
#include "ehci-hub.c"
@@ -263,6 +264,29 @@
/*-------------------------------------------------------------------------*/
+static void ehci_iaa_watchdog (unsigned long param)
+{
+ struct ehci_hcd *ehci = (struct ehci_hcd *) param;
+ unsigned long flags;
+ u32 status;
+
+ spin_lock_irqsave (&ehci->lock, flags);
+ WARN_ON(!ehci->reclaim);
+
+ /* lost IAA irqs wedge things badly; seen first with a vt8235 */
+ if (ehci->reclaim) {
+ status = readl (&ehci->regs->status);
+ if (status & STS_IAA) {
+ ehci_vdbg (ehci, "lost IAA\n");
+ COUNT (ehci->stats.lost_iaa);
+ writel (STS_IAA, &ehci->regs->status);
+ end_unlink_async (ehci, NULL);
+ }
+ }
+
+ spin_unlock_irqrestore (&ehci->lock, flags);
+}
+
static void ehci_watchdog (unsigned long param)
{
struct ehci_hcd *ehci = (struct ehci_hcd *) param;
@@ -270,21 +294,9 @@
spin_lock_irqsave (&ehci->lock, flags);
- /* lost IAA irqs wedge things badly; seen with a vt8235 */
- if (ehci->reclaim) {
- u32 status = readl (&ehci->regs->status);
-
- if (status & STS_IAA) {
- ehci_vdbg (ehci, "lost IAA\n");
- COUNT (ehci->stats.lost_iaa);
- writel (STS_IAA, &ehci->regs->status);
- ehci->reclaim_ready = 1;
- }
- }
-
- /* stop async processing after it's idled a bit */
+ /* stop async processing after it's idled a bit */
if (test_bit (TIMER_ASYNC_OFF, &ehci->actions))
- start_unlink_async (ehci, ehci->async);
+ start_unlink_async (ehci, ehci->async);
/* ehci could run by timer, without IRQs ... */
ehci_work (ehci, NULL);
@@ -333,8 +345,6 @@
static void ehci_work (struct ehci_hcd *ehci, struct pt_regs *regs)
{
timer_action_done (ehci, TIMER_IO_WATCHDOG);
- if (ehci->reclaim_ready)
- end_unlink_async (ehci, regs);
/* another CPU may drop ehci->lock during a schedule scan while
* it reports urb completions. this flag guards against bogus
@@ -369,6 +379,7 @@
/* 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))
@@ -415,6 +426,10 @@
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.
@@ -431,7 +446,6 @@
ehci->i_thresh = 2 + HCC_ISOC_THRES(hcc_params);
ehci->reclaim = NULL;
- ehci->reclaim_ready = 0;
ehci->next_uframe = -1;
/*
@@ -605,7 +619,7 @@
/* complete the unlinking of some qh [4.15.2.3] */
if (status & STS_IAA) {
COUNT (ehci->stats.reclaim);
- ehci->reclaim_ready = 1;
+ end_unlink_async (ehci, regs);
bh = 1;
}
@@ -709,10 +723,14 @@
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)) {
+ // BUG_ON(qh->qh_state != QH_STATE_LINKED);
+
+ /* failfast */
+ if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
+ end_unlink_async (ehci, NULL);
+
+ /* defer till later if busy */
+ else if (ehci->reclaim) {
struct ehci_qh *last;
for (last = ehci->reclaim;
@@ -722,12 +740,8 @@
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, NULL);
-
- /* 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);
}
@@ -749,7 +763,19 @@
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:
@@ -841,6 +867,7 @@
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);
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index a5eeb9c..b2ee13c 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -48,7 +48,7 @@
}
ehci->command = readl (&ehci->regs->command);
if (ehci->reclaim)
- ehci->reclaim_ready = 1;
+ end_unlink_async (ehci, NULL);
ehci_work(ehci, NULL);
/* suspend any active/unsuspended ports, maybe allow wakeup */
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index e6a3bcd..08d0472 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -303,7 +303,7 @@
/* emptying the schedule aborts any urbs */
spin_lock_irq(&ehci->lock);
if (ehci->reclaim)
- ehci->reclaim_ready = 1;
+ end_unlink_async (ehci, NULL);
ehci_work(ehci, NULL);
spin_unlock_irq(&ehci->lock);
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index c0da40b..7fc25b6 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -967,7 +967,7 @@
struct ehci_qh *qh = ehci->reclaim;
struct ehci_qh *next;
- timer_action_done (ehci, TIMER_IAA_WATCHDOG);
+ iaa_watchdog_done (ehci);
// qh->hw_next = cpu_to_le32 (qh->qh_dma);
qh->qh_state = QH_STATE_IDLE;
@@ -977,7 +977,6 @@
/* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
next = qh->reclaim;
ehci->reclaim = next;
- ehci->reclaim_ready = 0;
qh->reclaim = NULL;
qh_completions (ehci, qh, regs);
@@ -1052,11 +1051,10 @@
return;
}
- ehci->reclaim_ready = 0;
cmd |= CMD_IAAD;
writel (cmd, &ehci->regs->command);
(void) readl (&ehci->regs->command);
- timer_action (ehci, TIMER_IAA_WATCHDOG);
+ iaa_watchdog_start (ehci);
}
/*-------------------------------------------------------------------------*/
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index bbc3082..6aac39f 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -58,7 +58,6 @@
/* async schedule support */
struct ehci_qh *async;
struct ehci_qh *reclaim;
- unsigned reclaim_ready : 1;
unsigned scanning : 1;
/* periodic schedule support */
@@ -81,6 +80,7 @@
struct dma_pool *itd_pool; /* itd per iso urb */
struct dma_pool *sitd_pool; /* sitd per split iso urb */
+ struct timer_list iaa_watchdog;
struct timer_list watchdog;
unsigned long actions;
unsigned stamp;
@@ -114,9 +114,21 @@
}
+static inline void
+iaa_watchdog_start (struct ehci_hcd *ehci)
+{
+ WARN_ON(timer_pending(&ehci->iaa_watchdog));
+ mod_timer (&ehci->iaa_watchdog,
+ jiffies + msecs_to_jiffies(EHCI_IAA_MSECS));
+}
+
+static inline void iaa_watchdog_done (struct ehci_hcd *ehci)
+{
+ del_timer (&ehci->iaa_watchdog);
+}
+
enum ehci_timer_action {
TIMER_IO_WATCHDOG,
- TIMER_IAA_WATCHDOG,
TIMER_ASYNC_SHRINK,
TIMER_ASYNC_OFF,
};
@@ -134,9 +146,6 @@
unsigned long t;
switch (action) {
- case TIMER_IAA_WATCHDOG:
- t = EHCI_IAA_JIFFIES;
- break;
case TIMER_IO_WATCHDOG:
t = EHCI_IO_JIFFIES;
break;
@@ -153,8 +162,7 @@
// async queue SHRINK often precedes IAA. while it's ready
// to go OFF neither can matter, and afterwards the IO
// watchdog stops unless there's still periodic traffic.
- if (action != TIMER_IAA_WATCHDOG
- && t > ehci->watchdog.expires
+ if (time_before_eq(t, ehci->watchdog.expires)
&& timer_pending (&ehci->watchdog))
return;
mod_timer (&ehci->watchdog, t);