USB: EHCI: use hrtimer for unlinking empty async QHs (32830f20) · Commits · 戴 / test

drivers/usb/host/ehci-hcd.c

+1 −15

Original line number	Diff line number	Diff line
		@@ -94,8 +94,6 @@ static const char hcd_name [] = "ehci_hcd";
		#define EHCI_TUNE_FLS 1 /* (medium) 512-frame schedule */

		#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 */

		/* Initial IRQ latency: faster than hw default */
		static int log2_irq_thresh = 0; // 0 to 6
		@@ -130,15 +128,6 @@ MODULE_PARM_DESC(hird, "host initiated resume duration, +1 for each 75us");
		static void
		timer_action(struct ehci_hcd *ehci, enum ehci_timer_action action)
		{
		/* Don't override timeouts which shrink or (later) disable
		* the async ring; just the I/O watchdog. Note that if a
		* SHRINK were pending, OFF would never be requested.
		*/
		if (timer_pending(&ehci->watchdog)
		&& (BIT(TIMER_ASYNC_SHRINK)
		& ehci->actions))
		return;

		if (!test_and_set_bit(action, &ehci->actions)) {
		unsigned long t;

		@@ -148,10 +137,6 @@ timer_action(struct ehci_hcd *ehci, enum ehci_timer_action action)
		return;
		t = EHCI_IO_JIFFIES;
		break;
		/* case TIMER_ASYNC_SHRINK: */
		default:
		t = EHCI_SHRINK_JIFFIES;
		break;
		}
		mod_timer(&ehci->watchdog, t + jiffies);
		}
		@@ -307,6 +292,7 @@ static void ehci_quiesce (struct ehci_hcd *ehci)
		/-------------------------------------------------------------------------/

		static void end_unlink_async(struct ehci_hcd *ehci);
		static void unlink_empty_async(struct ehci_hcd *ehci);
		static void ehci_work(struct ehci_hcd *ehci);
		static void start_unlink_intr(struct ehci_hcd ehci, struct ehci_qh qh);
		static void end_unlink_intr(struct ehci_hcd ehci, struct ehci_qh qh);

drivers/usb/host/ehci-hub.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -300,6 +300,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
		ehci->rh_state = EHCI_RH_SUSPENDED;

		end_unlink_async(ehci);
		unlink_empty_async(ehci);
		ehci_handle_intr_unlinks(ehci);
		end_free_itds(ehci);

drivers/usb/host/ehci-q.c

+53 −25

Original line number	Diff line number	Diff line
		@@ -1205,7 +1205,7 @@ static void start_iaa_cycle(struct ehci_hcd *ehci, bool nested)
		end_unlink_async(ehci);

		/* Otherwise start a new IAA cycle */
		} else {
		} else if (likely(ehci->rh_state == EHCI_RH_RUNNING)) {
		/* Make sure the unlinks are all visible to the hardware */
		wmb();

		@@ -1253,6 +1253,39 @@ static void end_unlink_async(struct ehci_hcd *ehci)
		}
		}

		static void unlink_empty_async(struct ehci_hcd *ehci)
		{
		struct ehci_qh qh, next;
		bool stopped = (ehci->rh_state < EHCI_RH_RUNNING);
		bool check_unlinks_later = false;

		/* Unlink all the async QHs that have been empty for a timer cycle */
		next = ehci->async->qh_next.qh;
		while (next) {
		qh = next;
		next = qh->qh_next.qh;

		if (list_empty(&qh->qtd_list) &&
		qh->qh_state == QH_STATE_LINKED) {
		if (!stopped && qh->unlink_cycle ==
		ehci->async_unlink_cycle)
		check_unlinks_later = true;
		else
		single_unlink_async(ehci, qh);
		}
		}

		/* Start a new IAA cycle if any QHs are waiting for it */
		if (ehci->async_unlink)
		start_iaa_cycle(ehci, false);

		/* QHs that haven't been empty for long enough will be handled later */
		if (check_unlinks_later) {
		ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
		++ehci->async_unlink_cycle;
		}
		}

		/* makes sure the async qh will become idle */
		/* caller must own ehci->lock */

		@@ -1277,12 +1310,8 @@ static void start_unlink_async(struct ehci_hcd ehci, struct ehci_qh qh)

		static void scan_async (struct ehci_hcd *ehci)
		{
		bool stopped;
		struct ehci_qh *qh;
		enum ehci_timer_action action = TIMER_IO_WATCHDOG;

		timer_action_done (ehci, TIMER_ASYNC_SHRINK);
		stopped = (ehci->rh_state < EHCI_RH_RUNNING);
		bool check_unlinks_later = false;

		ehci->qh_scan_next = ehci->async->qh_next.qh;
		while (ehci->qh_scan_next) {
		@@ -1301,28 +1330,27 @@ static void scan_async (struct ehci_hcd *ehci)
		* in single_unlink_async().
		*/
		temp = qh_completions(ehci, qh);
		if (qh->needs_rescan)
		if (qh->needs_rescan) {
		start_unlink_async(ehci, qh);
		qh->unlink_time = jiffies + EHCI_SHRINK_JIFFIES;
		if (temp != 0)
		} else if (list_empty(&qh->qtd_list)
		&& qh->qh_state == QH_STATE_LINKED) {
		qh->unlink_cycle = ehci->async_unlink_cycle;
		check_unlinks_later = true;
		} else if (temp != 0)
		goto rescan;
		}
		}

		/* unlink idle entries, reducing DMA usage as well
		* as HCD schedule-scanning costs. delay for any qh
		/*
		* Unlink empty entries, reducing DMA usage as well
		* as HCD schedule-scanning costs. Delay for any qh
		* we just scanned, there's a not-unusual case that it
		* doesn't stay idle for long.
		* (plus, avoids some kind of re-activation race.)
		*/
		if (list_empty(&qh->qtd_list)
		&& qh->qh_state == QH_STATE_LINKED) {
		if (!ehci->async_unlink && (stopped \|\|
		time_after_eq(jiffies, qh->unlink_time)))
		start_unlink_async(ehci, qh);
		else
		action = TIMER_ASYNC_SHRINK;
		}
		if (check_unlinks_later && ehci->rh_state == EHCI_RH_RUNNING &&
		!(ehci->enabled_hrtimer_events &
		BIT(EHCI_HRTIMER_ASYNC_UNLINKS))) {
		ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true);
		++ehci->async_unlink_cycle;
		}
		if (action == TIMER_ASYNC_SHRINK)
		timer_action (ehci, TIMER_ASYNC_SHRINK);
		}

drivers/usb/host/ehci-timer.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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 */
		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 */
		@@ -347,6 +348,7 @@ 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 */
		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 */

drivers/usb/host/ehci.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -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_ASYNC_UNLINKS, /* Unlink empty async QHs */
		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 */
		@@ -123,6 +124,7 @@ struct ehci_hcd { /* one per controller */
		struct ehci_qh *async_unlink_last;
		struct ehci_qh *async_iaa;
		struct ehci_qh *qh_scan_next;
		unsigned async_unlink_cycle;
		unsigned async_count; /* async activity count */

		/* periodic schedule support */
		@@ -232,7 +234,6 @@ static inline struct usb_hcd ehci_to_hcd (struct ehci_hcd ehci)

		enum ehci_timer_action {
		TIMER_IO_WATCHDOG,
		TIMER_ASYNC_SHRINK,
		};

		static inline void
		@@ -382,7 +383,6 @@ struct ehci_qh {
		struct ehci_qtd *dummy;
		struct ehci_qh unlink_next; / next on unlink list */

		unsigned long unlink_time;
		unsigned unlink_cycle;
		unsigned stamp;

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