| /* |
| * Copyright (C) 2012 by Alan Stern |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the |
| * Free Software Foundation; either version 2 of the License, or (at your |
| * option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * for more details. |
| */ |
| |
| /* 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 */ |
| 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(), |
| ktime_set(0, 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 20 ms */ |
| if (ehci->ASS_poll_count++ < 20) { |
| ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true); |
| return; |
| } |
| ehci_warn(ehci, "Waited too long for the async schedule status, giving up\n"); |
| } |
| 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 20 ms */ |
| if (ehci->PSS_poll_count++ < 20) { |
| ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true); |
| return; |
| } |
| ehci_warn(ehci, "Waited too long for the periodic schedule status, giving up\n"); |
| } |
| 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 */ |
| } |
| |
| |
| /* 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 (ehci->intr_unlink) { |
| struct ehci_qh *qh = ehci->intr_unlink; |
| |
| if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle) |
| break; |
| ehci->intr_unlink = qh->unlink_next; |
| qh->unlink_next = NULL; |
| end_unlink_intr(ehci, qh); |
| } |
| |
| /* Handle remaining entries later */ |
| if (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) |
| { |
| 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_iaa) { |
| 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); |
| } |
| } |
| |
| |
| /* 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 */ |
| 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 (now.tv64 >= ehci->hr_timeouts[e].tv64) |
| event_handlers[e](ehci); |
| else |
| ehci_enable_event(ehci, e, false); |
| } |
| |
| spin_unlock_irqrestore(&ehci->lock, flags); |
| return HRTIMER_NORESTART; |
| } |