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USB: EHCI: add separate IAA watchdog timer

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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>
This commit is contained in:
Alan Stern 2007-12-11 16:05:30 -05:00 committed by Greg Kroah-Hartman
parent 2e2eb83ffd
commit 07d29b63ef
6 changed files with 75 additions and 38 deletions
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4
drivers/usb/host/ehci-dbg.c
View File

@ -786,9 +786,7 @@ static ssize_t fill_registers_buffer(struct debug_buffer *buf)
}
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;
}

77
drivers/usb/host/ehci-hcd.c
View File

@ -110,7 +110,7 @@ static const char hcd_name [] = "ehci_hcd";
#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 ehci_quiesce (struct ehci_hcd *ehci)
/*-------------------------------------------------------------------------*/
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_work(struct ehci_hcd *ehci);
/*-------------------------------------------------------------------------*/
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_port_power (struct ehci_hcd *ehci, int is_on)
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 @@ static void ehci_stop (struct usb_hcd *hcd)
/* 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 @@ static int ehci_init(struct usb_hcd *hcd)
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 @@ static int ehci_init(struct usb_hcd *hcd)
ehci->i_thresh = 2 + HCC_ISOC_THRES(hcc_params);
ehci->reclaim = NULL;
ehci->reclaim_ready = 0;
ehci->next_uframe = -1;
/*
@ -655,8 +674,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
/* 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 int ehci_urb_enqueue (
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 @@ static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
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 @@ static int ehci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
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 @@ ehci_endpoint_disable (struct usb_hcd *hcd, struct usb_host_endpoint *ep)
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);

2
drivers/usb/host/ehci-hub.c
View File

@ -134,7 +134,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
}
ehci->command = ehci_readl(ehci, &ehci->regs->command);
if (ehci->reclaim)
ehci->reclaim_ready = 1;
end_unlink_async(ehci);
ehci_work(ehci);
/* Unlike other USB host controller types, EHCI doesn't have

2
drivers/usb/host/ehci-pci.c
View File

@ -305,7 +305,7 @@ static int ehci_pci_resume(struct usb_hcd *hcd)
/* emptying the schedule aborts any urbs */
spin_lock_irq(&ehci->lock);
if (ehci->reclaim)
ehci->reclaim_ready = 1;
end_unlink_async(ehci);
ehci_work(ehci);
spin_unlock_irq(&ehci->lock);

6
drivers/usb/host/ehci-q.c
View File

@ -973,7 +973,7 @@ static void end_unlink_async (struct ehci_hcd *ehci)
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_hc32(qh->qh_dma);
qh->qh_state = QH_STATE_IDLE;
@ -983,7 +983,6 @@ static void end_unlink_async (struct ehci_hcd *ehci)
/* 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);
@ -1059,11 +1058,10 @@ static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
return;
}
ehci->reclaim_ready = 0;
cmd |= CMD_IAAD;
ehci_writel(ehci, cmd, &ehci->regs->command);
(void)ehci_readl(ehci, &ehci->regs->command);
timer_action (ehci, TIMER_IAA_WATCHDOG);
iaa_watchdog_start(ehci);
}
/*-------------------------------------------------------------------------*/

22
drivers/usb/host/ehci.h
View File

@ -74,7 +74,6 @@ struct ehci_hcd { /* one per controller */
/* async schedule support */
struct ehci_qh *async;
struct ehci_qh *reclaim;
unsigned reclaim_ready : 1;
unsigned scanning : 1;
/* periodic schedule support */
@ -105,6 +104,7 @@ struct ehci_hcd { /* one per controller */
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;
@ -148,9 +148,21 @@ static inline struct usb_hcd *ehci_to_hcd (struct ehci_hcd *ehci)
}
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,
};
@ -168,9 +180,6 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
unsigned long t;
switch (action) {
case TIMER_IAA_WATCHDOG:
t = EHCI_IAA_JIFFIES;
break;
case TIMER_IO_WATCHDOG:
t = EHCI_IO_JIFFIES;
break;
@ -187,8 +196,7 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
// 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);