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>
This commit is contained in:
Alan Stern
Greg Kroah-Hartman
parent
2e2eb83ffd
commit
07d29b63ef
6 changed files with 75 additions and 38 deletions
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@ -786,9 +786,7 @@ static ssize_t fill_registers_buffer(struct debug_buffer *buf)
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}
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if (ehci->reclaim) {
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temp = scnprintf (next, size, "reclaim qh %p%s\n",
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ehci->reclaim,
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ehci->reclaim_ready ? " ready" : "");
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temp = scnprintf(next, size, "reclaim qh %p\n", ehci->reclaim);
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size -= temp;
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next += temp;
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}
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@ -110,7 +110,7 @@ static const char hcd_name [] = "ehci_hcd";
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#define EHCI_TUNE_MULT_TT 1
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#define EHCI_TUNE_FLS 2 /* (small) 256 frame schedule */
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#define EHCI_IAA_JIFFIES (HZ/100) /* arbitrary; ~10 msec */
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#define EHCI_IAA_MSECS 10 /* arbitrary */
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#define EHCI_IO_JIFFIES (HZ/10) /* io watchdog > irq_thresh */
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#define EHCI_ASYNC_JIFFIES (HZ/20) /* async idle timeout */
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#define EHCI_SHRINK_JIFFIES (HZ/200) /* async qh unlink delay */
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@ -267,6 +267,7 @@ static void ehci_quiesce (struct ehci_hcd *ehci)
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/*-------------------------------------------------------------------------*/
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static void end_unlink_async(struct ehci_hcd *ehci);
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static void ehci_work(struct ehci_hcd *ehci);
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#include "ehci-hub.c"
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@ -276,25 +277,41 @@ static void ehci_work(struct ehci_hcd *ehci);
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/*-------------------------------------------------------------------------*/
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static void ehci_watchdog (unsigned long param)
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static void ehci_iaa_watchdog(unsigned long param)
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{
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struct ehci_hcd *ehci = (struct ehci_hcd *) param;
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unsigned long flags;
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u32 status, cmd;
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spin_lock_irqsave (&ehci->lock, flags);
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WARN_ON(!ehci->reclaim);
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/* lost IAA irqs wedge things badly; seen with a vt8235 */
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status = ehci_readl(ehci, &ehci->regs->status);
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cmd = ehci_readl(ehci, &ehci->regs->command);
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ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd);
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/* lost IAA irqs wedge things badly; seen first with a vt8235 */
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if (ehci->reclaim) {
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u32 status = ehci_readl(ehci, &ehci->regs->status);
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if (status & STS_IAA) {
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ehci_vdbg (ehci, "lost IAA\n");
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COUNT (ehci->stats.lost_iaa);
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ehci_writel(ehci, STS_IAA, &ehci->regs->status);
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ehci->reclaim_ready = 1;
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}
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ehci_writel(ehci, cmd & ~CMD_IAAD, &ehci->regs->command);
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end_unlink_async(ehci);
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}
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/* stop async processing after it's idled a bit */
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spin_unlock_irqrestore(&ehci->lock, flags);
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}
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static void ehci_watchdog(unsigned long param)
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{
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struct ehci_hcd *ehci = (struct ehci_hcd *) param;
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unsigned long flags;
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spin_lock_irqsave(&ehci->lock, flags);
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/* stop async processing after it's idled a bit */
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if (test_bit (TIMER_ASYNC_OFF, &ehci->actions))
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start_unlink_async (ehci, ehci->async);
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@ -364,8 +381,6 @@ static void ehci_port_power (struct ehci_hcd *ehci, int is_on)
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static void ehci_work (struct ehci_hcd *ehci)
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{
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timer_action_done (ehci, TIMER_IO_WATCHDOG);
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if (ehci->reclaim_ready)
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end_unlink_async (ehci);
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/* another CPU may drop ehci->lock during a schedule scan while
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* it reports urb completions. this flag guards against bogus
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@ -400,6 +415,7 @@ static void ehci_stop (struct usb_hcd *hcd)
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/* no more interrupts ... */
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del_timer_sync (&ehci->watchdog);
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del_timer_sync(&ehci->iaa_watchdog);
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spin_lock_irq(&ehci->lock);
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if (HC_IS_RUNNING (hcd->state))
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@ -448,6 +464,10 @@ static int ehci_init(struct usb_hcd *hcd)
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ehci->watchdog.function = ehci_watchdog;
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ehci->watchdog.data = (unsigned long) ehci;
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init_timer(&ehci->iaa_watchdog);
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ehci->iaa_watchdog.function = ehci_iaa_watchdog;
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ehci->iaa_watchdog.data = (unsigned long) ehci;
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/*
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* hw default: 1K periodic list heads, one per frame.
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* periodic_size can shrink by USBCMD update if hcc_params allows.
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@ -464,7 +484,6 @@ static int ehci_init(struct usb_hcd *hcd)
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ehci->i_thresh = 2 + HCC_ISOC_THRES(hcc_params);
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ehci->reclaim = NULL;
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ehci->reclaim_ready = 0;
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ehci->next_uframe = -1;
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/*
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@ -655,8 +674,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
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/* complete the unlinking of some qh [4.15.2.3] */
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if (status & STS_IAA) {
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COUNT (ehci->stats.reclaim);
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ehci->reclaim_ready = 1;
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bh = 1;
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end_unlink_async(ehci);
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}
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/* remote wakeup [4.3.1] */
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@ -762,10 +780,16 @@ static int ehci_urb_enqueue (
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static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
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{
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/* if we need to use IAA and it's busy, defer */
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if (qh->qh_state == QH_STATE_LINKED
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&& ehci->reclaim
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&& HC_IS_RUNNING (ehci_to_hcd(ehci)->state)) {
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/* failfast */
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if (!HC_IS_RUNNING(ehci_to_hcd(ehci)->state))
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end_unlink_async(ehci);
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/* if it's not linked then there's nothing to do */
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if (qh->qh_state != QH_STATE_LINKED)
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;
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/* defer till later if busy */
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else if (ehci->reclaim) {
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struct ehci_qh *last;
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for (last = ehci->reclaim;
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@ -775,12 +799,8 @@ static void unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
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qh->qh_state = QH_STATE_UNLINK_WAIT;
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last->reclaim = qh;
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/* bypass IAA if the hc can't care */
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} else if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state) && ehci->reclaim)
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end_unlink_async (ehci);
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/* something else might have unlinked the qh by now */
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if (qh->qh_state == QH_STATE_LINKED)
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/* start IAA cycle */
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} else
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start_unlink_async (ehci, qh);
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}
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@ -807,7 +827,19 @@ static int ehci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
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qh = (struct ehci_qh *) urb->hcpriv;
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if (!qh)
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break;
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unlink_async (ehci, qh);
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switch (qh->qh_state) {
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case QH_STATE_LINKED:
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case QH_STATE_COMPLETING:
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unlink_async(ehci, qh);
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break;
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case QH_STATE_UNLINK:
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case QH_STATE_UNLINK_WAIT:
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/* already started */
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break;
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case QH_STATE_IDLE:
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WARN_ON(1);
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break;
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}
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break;
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case PIPE_INTERRUPT:
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@ -899,6 +931,7 @@ ehci_endpoint_disable (struct usb_hcd *hcd, struct usb_host_endpoint *ep)
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unlink_async (ehci, qh);
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/* FALL THROUGH */
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case QH_STATE_UNLINK: /* wait for hw to finish? */
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case QH_STATE_UNLINK_WAIT:
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idle_timeout:
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spin_unlock_irqrestore (&ehci->lock, flags);
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schedule_timeout_uninterruptible(1);
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@ -134,7 +134,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
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}
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ehci->command = ehci_readl(ehci, &ehci->regs->command);
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if (ehci->reclaim)
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ehci->reclaim_ready = 1;
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end_unlink_async(ehci);
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ehci_work(ehci);
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/* Unlike other USB host controller types, EHCI doesn't have
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@ -305,7 +305,7 @@ static int ehci_pci_resume(struct usb_hcd *hcd)
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/* emptying the schedule aborts any urbs */
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spin_lock_irq(&ehci->lock);
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if (ehci->reclaim)
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ehci->reclaim_ready = 1;
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end_unlink_async(ehci);
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ehci_work(ehci);
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spin_unlock_irq(&ehci->lock);
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@ -973,7 +973,7 @@ static void end_unlink_async (struct ehci_hcd *ehci)
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struct ehci_qh *qh = ehci->reclaim;
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struct ehci_qh *next;
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timer_action_done (ehci, TIMER_IAA_WATCHDOG);
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iaa_watchdog_done(ehci);
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// qh->hw_next = cpu_to_hc32(qh->qh_dma);
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qh->qh_state = QH_STATE_IDLE;
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@ -983,7 +983,6 @@ static void end_unlink_async (struct ehci_hcd *ehci)
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/* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */
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next = qh->reclaim;
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ehci->reclaim = next;
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ehci->reclaim_ready = 0;
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qh->reclaim = NULL;
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qh_completions (ehci, qh);
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@ -1059,11 +1058,10 @@ static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
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return;
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}
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ehci->reclaim_ready = 0;
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cmd |= CMD_IAAD;
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ehci_writel(ehci, cmd, &ehci->regs->command);
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(void)ehci_readl(ehci, &ehci->regs->command);
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timer_action (ehci, TIMER_IAA_WATCHDOG);
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iaa_watchdog_start(ehci);
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}
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/*-------------------------------------------------------------------------*/
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@ -74,7 +74,6 @@ struct ehci_hcd { /* one per controller */
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/* async schedule support */
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struct ehci_qh *async;
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struct ehci_qh *reclaim;
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unsigned reclaim_ready : 1;
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unsigned scanning : 1;
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/* periodic schedule support */
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@ -105,6 +104,7 @@ struct ehci_hcd { /* one per controller */
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struct dma_pool *itd_pool; /* itd per iso urb */
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struct dma_pool *sitd_pool; /* sitd per split iso urb */
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struct timer_list iaa_watchdog;
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struct timer_list watchdog;
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unsigned long actions;
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unsigned stamp;
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@ -148,9 +148,21 @@ static inline struct usb_hcd *ehci_to_hcd (struct ehci_hcd *ehci)
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}
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static inline void
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iaa_watchdog_start(struct ehci_hcd *ehci)
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{
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WARN_ON(timer_pending(&ehci->iaa_watchdog));
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mod_timer(&ehci->iaa_watchdog,
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jiffies + msecs_to_jiffies(EHCI_IAA_MSECS));
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}
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static inline void iaa_watchdog_done(struct ehci_hcd *ehci)
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{
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del_timer(&ehci->iaa_watchdog);
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}
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enum ehci_timer_action {
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TIMER_IO_WATCHDOG,
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TIMER_IAA_WATCHDOG,
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TIMER_ASYNC_SHRINK,
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TIMER_ASYNC_OFF,
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};
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@ -168,9 +180,6 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
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unsigned long t;
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switch (action) {
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case TIMER_IAA_WATCHDOG:
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t = EHCI_IAA_JIFFIES;
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break;
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case TIMER_IO_WATCHDOG:
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t = EHCI_IO_JIFFIES;
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break;
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@ -187,8 +196,7 @@ timer_action (struct ehci_hcd *ehci, enum ehci_timer_action action)
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// async queue SHRINK often precedes IAA. while it's ready
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// to go OFF neither can matter, and afterwards the IO
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// watchdog stops unless there's still periodic traffic.
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if (action != TIMER_IAA_WATCHDOG
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&& t > ehci->watchdog.expires
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if (time_before_eq(t, ehci->watchdog.expires)
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&& timer_pending (&ehci->watchdog))
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return;
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mod_timer (&ehci->watchdog, t);
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