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author | Alan Stern <stern@rowland.harvard.edu> | 2012-07-11 11:22:44 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-07-16 16:56:46 -0700 |
commit | 9d9387475af261949f61a5ec465e1f762d7be08a (patch) | |
tree | 7aa6688962bde78fba655b791612e60cc1b50adf /drivers/usb/host | |
parent | 8c5bf7be56f1a8aecc1f802f132d53f556a9bc45 (diff) | |
download | blackbird-op-linux-9d9387475af261949f61a5ec465e1f762d7be08a.tar.gz blackbird-op-linux-9d9387475af261949f61a5ec465e1f762d7be08a.zip |
USB: EHCI: use hrtimer for the IAA watchdog
This patch (as1581) replaces the iaa_watchdog kernel timer used by
ehci-hcd with an hrtimer event, in keeping with the general conversion
to high-res timers.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host')
-rw-r--r-- | drivers/usb/host/ehci-hcd.c | 66 | ||||
-rw-r--r-- | drivers/usb/host/ehci-hub.c | 1 | ||||
-rw-r--r-- | drivers/usb/host/ehci-q.c | 4 | ||||
-rw-r--r-- | drivers/usb/host/ehci-timer.c | 45 | ||||
-rw-r--r-- | drivers/usb/host/ehci.h | 16 |
5 files changed, 61 insertions, 71 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index fb1966cf5649..f74ba277c22d 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -93,7 +93,6 @@ static const char hcd_name [] = "ehci_hcd"; */ #define EHCI_TUNE_FLS 1 /* (medium) 512-frame schedule */ -#define EHCI_IAA_MSECS 10 /* arbitrary */ #define EHCI_IO_JIFFIES (HZ/10) /* io watchdog > irq_thresh */ #define EHCI_SHRINK_JIFFIES (DIV_ROUND_UP(HZ, 200) + 1) /* 5-ms async qh unlink delay */ @@ -322,51 +321,6 @@ static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh); /*-------------------------------------------------------------------------*/ -static void ehci_iaa_watchdog(unsigned long param) -{ - struct ehci_hcd *ehci = (struct ehci_hcd *) param; - unsigned long flags; - - spin_lock_irqsave (&ehci->lock, flags); - - /* Lost IAA irqs wedge things badly; seen first with a vt8235. - * So we need this watchdog, but must protect it against both - * (a) SMP races against real IAA firing and retriggering, and - * (b) clean HC shutdown, when IAA watchdog was pending. - */ - if (ehci->async_unlink - && !timer_pending(&ehci->iaa_watchdog) - && ehci->rh_state == EHCI_RH_RUNNING) { - u32 cmd, status; - - /* If we get here, IAA is *REALLY* late. It's barely - * conceivable that the system is so busy that CMD_IAAD - * is still legitimately set, so let's be sure it's - * clear before we read STS_IAA. (The HC should clear - * CMD_IAAD when it sets STS_IAA.) - */ - cmd = ehci_readl(ehci, &ehci->regs->command); - - /* If IAA is set here it either legitimately triggered - * before we cleared IAAD above (but _way_ late, so we'll - * still count it as lost) ... or a silicon erratum: - * - VIA seems to set IAA without triggering the IRQ; - * - IAAD potentially cleared without setting IAA. - */ - status = ehci_readl(ehci, &ehci->regs->status); - if ((status & STS_IAA) || !(cmd & CMD_IAAD)) { - COUNT (ehci->stats.lost_iaa); - ehci_writel(ehci, STS_IAA, &ehci->regs->status); - } - - ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n", - status, cmd); - end_unlink_async(ehci); - } - - spin_unlock_irqrestore(&ehci->lock, flags); -} - static void ehci_watchdog(unsigned long param) { struct ehci_hcd *ehci = (struct ehci_hcd *) param; @@ -418,7 +372,6 @@ static void ehci_shutdown(struct usb_hcd *hcd) struct ehci_hcd *ehci = hcd_to_ehci(hcd); del_timer_sync(&ehci->watchdog); - del_timer_sync(&ehci->iaa_watchdog); spin_lock_irq(&ehci->lock); ehci->rh_state = EHCI_RH_STOPPING; @@ -491,7 +444,6 @@ 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); ehci->enabled_hrtimer_events = 0; @@ -547,10 +499,6 @@ 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; - hrtimer_init(&ehci->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); ehci->hrtimer.function = ehci_hrtimer_func; ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT; @@ -830,6 +778,20 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) /* complete the unlinking of some qh [4.15.2.3] */ if (status & STS_IAA) { + + /* Turn off the IAA watchdog */ + ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_IAA_WATCHDOG); + + /* + * Mild optimization: Allow another IAAD to reset the + * hrtimer, if one occurs before the next expiration. + * In theory we could always cancel the hrtimer, but + * tests show that about half the time it will be reset + * for some other event anyway. + */ + if (ehci->next_hrtimer_event == EHCI_HRTIMER_IAA_WATCHDOG) + ++ehci->next_hrtimer_event; + /* guard against (alleged) silicon errata */ if (cmd & CMD_IAAD) ehci_dbg(ehci, "IAA with IAAD still set?\n"); diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c index 6ad806bbe468..3097872b1e74 100644 --- a/drivers/usb/host/ehci-hub.c +++ b/drivers/usb/host/ehci-hub.c @@ -209,7 +209,6 @@ static int ehci_bus_suspend (struct usb_hcd *hcd) if (time_before (jiffies, ehci->next_statechange)) msleep(5); del_timer_sync(&ehci->watchdog); - del_timer_sync(&ehci->iaa_watchdog); spin_lock_irq (&ehci->lock); diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index d68764ef4476..7b35933d91a6 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -1173,8 +1173,6 @@ static void end_unlink_async (struct ehci_hcd *ehci) struct ehci_qh *qh = ehci->async_unlink; struct ehci_qh *next; - iaa_watchdog_done(ehci); - // qh->hw_next = cpu_to_hc32(qh->qh_dma); qh->qh_state = QH_STATE_IDLE; qh->qh_next.qh = NULL; @@ -1243,7 +1241,7 @@ static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh) ehci_writel(ehci, ehci->command | CMD_IAAD, &ehci->regs->command); (void)ehci_readl(ehci, &ehci->regs->command); - iaa_watchdog_start(ehci); + ehci_enable_event(ehci, EHCI_HRTIMER_IAA_WATCHDOG, true); } /*-------------------------------------------------------------------------*/ diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c index 8feb60ff4228..aab042064226 100644 --- a/drivers/usb/host/ehci-timer.c +++ b/drivers/usb/host/ehci-timer.c @@ -72,6 +72,7 @@ static unsigned event_delays_ns[] = { 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_DEAD */ 1125 * NSEC_PER_USEC, /* EHCI_HRTIMER_UNLINK_INTR */ 2 * NSEC_PER_MSEC, /* EHCI_HRTIMER_FREE_ITDS */ + 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IAA_WATCHDOG */ 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */ 15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */ }; @@ -291,6 +292,49 @@ static void end_free_itds(struct ehci_hcd *ehci) } +/* Handle lost (or very late) IAA interrupts */ +static void ehci_iaa_watchdog(struct ehci_hcd *ehci) +{ + if (ehci->rh_state != EHCI_RH_RUNNING) + return; + + /* + * Lost IAA irqs wedge things badly; seen first with a vt8235. + * So we need this watchdog, but must protect it against both + * (a) SMP races against real IAA firing and retriggering, and + * (b) clean HC shutdown, when IAA watchdog was pending. + */ + if (ehci->async_unlink) { + u32 cmd, status; + + /* If we get here, IAA is *REALLY* late. It's barely + * conceivable that the system is so busy that CMD_IAAD + * is still legitimately set, so let's be sure it's + * clear before we read STS_IAA. (The HC should clear + * CMD_IAAD when it sets STS_IAA.) + */ + cmd = ehci_readl(ehci, &ehci->regs->command); + + /* + * If IAA is set here it either legitimately triggered + * after the watchdog timer expired (_way_ late, so we'll + * still count it as lost) ... or a silicon erratum: + * - VIA seems to set IAA without triggering the IRQ; + * - IAAD potentially cleared without setting IAA. + */ + status = ehci_readl(ehci, &ehci->regs->status); + if ((status & STS_IAA) || !(cmd & CMD_IAAD)) { + COUNT(ehci->stats.lost_iaa); + ehci_writel(ehci, STS_IAA, &ehci->regs->status); + } + + ehci_vdbg(ehci, "IAA watchdog: status %x cmd %x\n", + status, cmd); + end_unlink_async(ehci); + } +} + + /* * Handler functions for the hrtimer event types. * Keep this array in the same order as the event types indexed by @@ -302,6 +346,7 @@ static void (*event_handlers[])(struct ehci_hcd *) = { ehci_handle_controller_death, /* EHCI_HRTIMER_POLL_DEAD */ ehci_handle_intr_unlinks, /* EHCI_HRTIMER_UNLINK_INTR */ end_free_itds, /* EHCI_HRTIMER_FREE_ITDS */ + ehci_iaa_watchdog, /* EHCI_HRTIMER_IAA_WATCHDOG */ ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */ ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */ }; diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h index 755e30b0000b..d9414aae610f 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -84,6 +84,7 @@ enum ehci_hrtimer_event { EHCI_HRTIMER_POLL_DEAD, /* Wait for dead controller to stop */ EHCI_HRTIMER_UNLINK_INTR, /* Wait for interrupt QH unlink */ EHCI_HRTIMER_FREE_ITDS, /* Wait for unused iTDs and siTDs */ + EHCI_HRTIMER_IAA_WATCHDOG, /* Handle lost IAA interrupts */ EHCI_HRTIMER_DISABLE_PERIODIC, /* Wait to disable periodic sched */ EHCI_HRTIMER_DISABLE_ASYNC, /* Wait to disable async sched */ EHCI_HRTIMER_NUM_EVENTS /* Must come last */ @@ -168,7 +169,6 @@ 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 periodic_stamp; @@ -228,20 +228,6 @@ static inline struct usb_hcd *ehci_to_hcd (struct ehci_hcd *ehci) return container_of ((void *) ehci, struct usb_hcd, hcd_priv); } - -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_ASYNC_SHRINK, |