diff options
Diffstat (limited to 'drivers/usb/host/ehci-timer.c')
| -rw-r--r-- | drivers/usb/host/ehci-timer.c | 426 |
1 files changed, 426 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c new file mode 100644 index 000000000..a79c8ac0a --- /dev/null +++ b/drivers/usb/host/ehci-timer.c @@ -0,0 +1,426 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2012 by Alan Stern + */ + +/* This file is part of ehci-hcd.c */ + +/*-------------------------------------------------------------------------*/ + +/* Set a bit in the USBCMD register */ +static void ehci_set_command_bit(struct ehci_hcd *ehci, u32 bit) +{ + ehci->command |= bit; + ehci_writel(ehci, ehci->command, &ehci->regs->command); + + /* unblock posted write */ + ehci_readl(ehci, &ehci->regs->command); +} + +/* Clear a bit in the USBCMD register */ +static void ehci_clear_command_bit(struct ehci_hcd *ehci, u32 bit) +{ + ehci->command &= ~bit; + ehci_writel(ehci, ehci->command, &ehci->regs->command); + + /* unblock posted write */ + ehci_readl(ehci, &ehci->regs->command); +} + +/*-------------------------------------------------------------------------*/ + +/* + * EHCI timer support... Now using hrtimers. + * + * Lots of different events are triggered from ehci->hrtimer. Whenever + * the timer routine runs, it checks each possible event; events that are + * currently enabled and whose expiration time has passed get handled. + * The set of enabled events is stored as a collection of bitflags in + * ehci->enabled_hrtimer_events, and they are numbered in order of + * increasing delay values (ranging between 1 ms and 100 ms). + * + * Rather than implementing a sorted list or tree of all pending events, + * we keep track only of the lowest-numbered pending event, in + * ehci->next_hrtimer_event. Whenever ehci->hrtimer gets restarted, its + * expiration time is set to the timeout value for this event. + * + * As a result, events might not get handled right away; the actual delay + * could be anywhere up to twice the requested delay. This doesn't + * matter, because none of the events are especially time-critical. The + * ones that matter most all have a delay of 1 ms, so they will be + * handled after 2 ms at most, which is okay. In addition to this, we + * allow for an expiration range of 1 ms. + */ + +/* + * Delay lengths for the hrtimer event types. + * Keep this list sorted by delay length, in the same order as + * the event types indexed by enum ehci_hrtimer_event in ehci.h. + */ +static unsigned event_delays_ns[] = { + 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_ASS */ + 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_PSS */ + 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_DEAD */ + 1125 * NSEC_PER_USEC, /* EHCI_HRTIMER_UNLINK_INTR */ + 2 * NSEC_PER_MSEC, /* EHCI_HRTIMER_FREE_ITDS */ + 2 * NSEC_PER_MSEC, /* EHCI_HRTIMER_ACTIVE_UNLINK */ + 5 * NSEC_PER_MSEC, /* EHCI_HRTIMER_START_UNLINK_INTR */ + 6 * NSEC_PER_MSEC, /* EHCI_HRTIMER_ASYNC_UNLINKS */ + 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IAA_WATCHDOG */ + 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */ + 15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */ + 100 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IO_WATCHDOG */ +}; + +/* Enable a pending hrtimer event */ +static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event, + bool resched) +{ + ktime_t *timeout = &ehci->hr_timeouts[event]; + + if (resched) + *timeout = ktime_add(ktime_get(), event_delays_ns[event]); + ehci->enabled_hrtimer_events |= (1 << event); + + /* Track only the lowest-numbered pending event */ + if (event < ehci->next_hrtimer_event) { + ehci->next_hrtimer_event = event; + hrtimer_start_range_ns(&ehci->hrtimer, *timeout, + NSEC_PER_MSEC, HRTIMER_MODE_ABS); + } +} + + +/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */ +static void ehci_poll_ASS(struct ehci_hcd *ehci) +{ + unsigned actual, want; + + /* Don't enable anything if the controller isn't running (e.g., died) */ + if (ehci->rh_state != EHCI_RH_RUNNING) + return; + + want = (ehci->command & CMD_ASE) ? STS_ASS : 0; + actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS; + + if (want != actual) { + + /* Poll again later, but give up after about 2-4 ms */ + if (ehci->ASS_poll_count++ < 2) { + ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true); + return; + } + ehci_dbg(ehci, "Waited too long for the async schedule status (%x/%x), giving up\n", + want, actual); + } + ehci->ASS_poll_count = 0; + + /* The status is up-to-date; restart or stop the schedule as needed */ + if (want == 0) { /* Stopped */ + if (ehci->async_count > 0) + ehci_set_command_bit(ehci, CMD_ASE); + + } else { /* Running */ + if (ehci->async_count == 0) { + + /* Turn off the schedule after a while */ + ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC, + true); + } + } +} + +/* Turn off the async schedule after a brief delay */ +static void ehci_disable_ASE(struct ehci_hcd *ehci) +{ + ehci_clear_command_bit(ehci, CMD_ASE); +} + + +/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */ +static void ehci_poll_PSS(struct ehci_hcd *ehci) +{ + unsigned actual, want; + + /* Don't do anything if the controller isn't running (e.g., died) */ + if (ehci->rh_state != EHCI_RH_RUNNING) + return; + + want = (ehci->command & CMD_PSE) ? STS_PSS : 0; + actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS; + + if (want != actual) { + + /* Poll again later, but give up after about 2-4 ms */ + if (ehci->PSS_poll_count++ < 2) { + ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true); + return; + } + ehci_dbg(ehci, "Waited too long for the periodic schedule status (%x/%x), giving up\n", + want, actual); + } + ehci->PSS_poll_count = 0; + + /* The status is up-to-date; restart or stop the schedule as needed */ + if (want == 0) { /* Stopped */ + if (ehci->periodic_count > 0) + ehci_set_command_bit(ehci, CMD_PSE); + + } else { /* Running */ + if (ehci->periodic_count == 0) { + + /* Turn off the schedule after a while */ + ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_PERIODIC, + true); + } + } +} + +/* Turn off the periodic schedule after a brief delay */ +static void ehci_disable_PSE(struct ehci_hcd *ehci) +{ + ehci_clear_command_bit(ehci, CMD_PSE); +} + + +/* Poll the STS_HALT status bit; see when a dead controller stops */ +static void ehci_handle_controller_death(struct ehci_hcd *ehci) +{ + if (!(ehci_readl(ehci, &ehci->regs->status) & STS_HALT)) { + + /* Give up after a few milliseconds */ + if (ehci->died_poll_count++ < 5) { + /* Try again later */ + ehci_enable_event(ehci, EHCI_HRTIMER_POLL_DEAD, true); + return; + } + ehci_warn(ehci, "Waited too long for the controller to stop, giving up\n"); + } + + /* Clean up the mess */ + ehci->rh_state = EHCI_RH_HALTED; + ehci_writel(ehci, 0, &ehci->regs->configured_flag); + ehci_writel(ehci, 0, &ehci->regs->intr_enable); + ehci_work(ehci); + end_unlink_async(ehci); + + /* Not in process context, so don't try to reset the controller */ +} + +/* start to unlink interrupt QHs */ +static void ehci_handle_start_intr_unlinks(struct ehci_hcd *ehci) +{ + bool stopped = (ehci->rh_state < EHCI_RH_RUNNING); + + /* + * Process all the QHs on the intr_unlink list that were added + * before the current unlink cycle began. The list is in + * temporal order, so stop when we reach the first entry in the + * current cycle. But if the root hub isn't running then + * process all the QHs on the list. + */ + while (!list_empty(&ehci->intr_unlink_wait)) { + struct ehci_qh *qh; + + qh = list_first_entry(&ehci->intr_unlink_wait, + struct ehci_qh, unlink_node); + if (!stopped && (qh->unlink_cycle == + ehci->intr_unlink_wait_cycle)) + break; + list_del_init(&qh->unlink_node); + qh->unlink_reason |= QH_UNLINK_QUEUE_EMPTY; + start_unlink_intr(ehci, qh); + } + + /* Handle remaining entries later */ + if (!list_empty(&ehci->intr_unlink_wait)) { + ehci_enable_event(ehci, EHCI_HRTIMER_START_UNLINK_INTR, true); + ++ehci->intr_unlink_wait_cycle; + } +} + +/* Handle unlinked interrupt QHs once they are gone from the hardware */ +static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci) +{ + bool stopped = (ehci->rh_state < EHCI_RH_RUNNING); + + /* + * Process all the QHs on the intr_unlink list that were added + * before the current unlink cycle began. The list is in + * temporal order, so stop when we reach the first entry in the + * current cycle. But if the root hub isn't running then + * process all the QHs on the list. + */ + ehci->intr_unlinking = true; + while (!list_empty(&ehci->intr_unlink)) { + struct ehci_qh *qh; + + qh = list_first_entry(&ehci->intr_unlink, struct ehci_qh, + unlink_node); + if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle) + break; + list_del_init(&qh->unlink_node); + end_unlink_intr(ehci, qh); + } + + /* Handle remaining entries later */ + if (!list_empty(&ehci->intr_unlink)) { + ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true); + ++ehci->intr_unlink_cycle; + } + ehci->intr_unlinking = false; +} + + +/* Start another free-iTDs/siTDs cycle */ +static void start_free_itds(struct ehci_hcd *ehci) +{ + if (!(ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_FREE_ITDS))) { + ehci->last_itd_to_free = list_entry( + ehci->cached_itd_list.prev, + struct ehci_itd, itd_list); + ehci->last_sitd_to_free = list_entry( + ehci->cached_sitd_list.prev, + struct ehci_sitd, sitd_list); + ehci_enable_event(ehci, EHCI_HRTIMER_FREE_ITDS, true); + } +} + +/* Wait for controller to stop using old iTDs and siTDs */ +static void end_free_itds(struct ehci_hcd *ehci) +{ + struct ehci_itd *itd, *n; + struct ehci_sitd *sitd, *sn; + + if (ehci->rh_state < EHCI_RH_RUNNING) { + ehci->last_itd_to_free = NULL; + ehci->last_sitd_to_free = NULL; + } + + list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) { + list_del(&itd->itd_list); + dma_pool_free(ehci->itd_pool, itd, itd->itd_dma); + if (itd == ehci->last_itd_to_free) + break; + } + list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) { + list_del(&sitd->sitd_list); + dma_pool_free(ehci->sitd_pool, sitd, sitd->sitd_dma); + if (sitd == ehci->last_sitd_to_free) + break; + } + + if (!list_empty(&ehci->cached_itd_list) || + !list_empty(&ehci->cached_sitd_list)) + start_free_itds(ehci); +} + + +/* Handle lost (or very late) IAA interrupts */ +static void ehci_iaa_watchdog(struct ehci_hcd *ehci) +{ + u32 cmd, status; + + /* + * 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->iaa_in_progress || ehci->rh_state != EHCI_RH_RUNNING) + return; + + /* 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)) { + INCR(ehci->stats.lost_iaa); + ehci_writel(ehci, STS_IAA, &ehci->regs->status); + } + + ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd); + end_iaa_cycle(ehci); +} + + +/* Enable the I/O watchdog, if appropriate */ +static void turn_on_io_watchdog(struct ehci_hcd *ehci) +{ + /* Not needed if the controller isn't running or it's already enabled */ + if (ehci->rh_state != EHCI_RH_RUNNING || + (ehci->enabled_hrtimer_events & + BIT(EHCI_HRTIMER_IO_WATCHDOG))) + return; + + /* + * Isochronous transfers always need the watchdog. + * For other sorts we use it only if the flag is set. + */ + if (ehci->isoc_count > 0 || (ehci->need_io_watchdog && + ehci->async_count + ehci->intr_count > 0)) + ehci_enable_event(ehci, EHCI_HRTIMER_IO_WATCHDOG, true); +} + + +/* + * Handler functions for the hrtimer event types. + * Keep this array in the same order as the event types indexed by + * enum ehci_hrtimer_event in ehci.h. + */ +static void (*event_handlers[])(struct ehci_hcd *) = { + ehci_poll_ASS, /* EHCI_HRTIMER_POLL_ASS */ + ehci_poll_PSS, /* EHCI_HRTIMER_POLL_PSS */ + ehci_handle_controller_death, /* EHCI_HRTIMER_POLL_DEAD */ + ehci_handle_intr_unlinks, /* EHCI_HRTIMER_UNLINK_INTR */ + end_free_itds, /* EHCI_HRTIMER_FREE_ITDS */ + end_unlink_async, /* EHCI_HRTIMER_ACTIVE_UNLINK */ + ehci_handle_start_intr_unlinks, /* EHCI_HRTIMER_START_UNLINK_INTR */ + unlink_empty_async, /* EHCI_HRTIMER_ASYNC_UNLINKS */ + ehci_iaa_watchdog, /* EHCI_HRTIMER_IAA_WATCHDOG */ + ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */ + ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */ + ehci_work, /* EHCI_HRTIMER_IO_WATCHDOG */ +}; + +static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t) +{ + struct ehci_hcd *ehci = container_of(t, struct ehci_hcd, hrtimer); + ktime_t now; + unsigned long events; + unsigned long flags; + unsigned e; + + spin_lock_irqsave(&ehci->lock, flags); + + events = ehci->enabled_hrtimer_events; + ehci->enabled_hrtimer_events = 0; + ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT; + + /* + * Check each pending event. If its time has expired, handle + * the event; otherwise re-enable it. + */ + now = ktime_get(); + for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) { + if (ktime_compare(now, ehci->hr_timeouts[e]) >= 0) + event_handlers[e](ehci); + else + ehci_enable_event(ehci, e, false); + } + + spin_unlock_irqrestore(&ehci->lock, flags); + return HRTIMER_NORESTART; +} |