usb: dwc2: host: Add a delay before releasing periodic bandwidth (17dd5b64) · Commits · 戴 / test

drivers/usb/dwc2/hcd.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -215,6 +215,7 @@ enum dwc2_transaction_type {
		/**
		* struct dwc2_qh - Software queue head structure
		*
		* @hsotg: The HCD state structure for the DWC OTG controller
		* @ep_type: Endpoint type. One of the following values:
		* - USB_ENDPOINT_XFER_CONTROL
		* - USB_ENDPOINT_XFER_BULK
		@@ -252,13 +253,16 @@ enum dwc2_transaction_type {
		* @n_bytes: Xfer Bytes array. Each element corresponds to a transfer
		* descriptor and indicates original XferSize value for the
		* descriptor
		* @unreserve_timer: Timer for releasing periodic reservation.
		* @tt_buffer_dirty True if clear_tt_buffer_complete is pending
		* @unreserve_pending: True if we planned to unreserve but haven't yet.
		*
		* A Queue Head (QH) holds the static characteristics of an endpoint and
		* maintains a list of transfers (QTDs) for that endpoint. A QH structure may
		* be entered in either the non-periodic or periodic schedule.
		*/
		struct dwc2_qh {
		struct dwc2_hsotg *hsotg;
		u8 ep_type;
		u8 ep_is_in;
		u16 maxp;
		@@ -281,7 +285,9 @@ struct dwc2_qh {
		dma_addr_t desc_list_dma;
		u32 desc_list_sz;
		u32 *n_bytes;
		struct timer_list unreserve_timer;
		unsigned tt_buffer_dirty:1;
		unsigned unreserve_pending:1;
		};

		/**

drivers/usb/dwc2/hcd_queue.c

+181 −56

Original line number	Diff line number	Diff line
		@@ -53,6 +53,94 @@
		#include "core.h"
		#include "hcd.h"

		/* Wait this long before releasing periodic reservation */
		#define DWC2_UNRESERVE_DELAY (msecs_to_jiffies(5))

		/**
		* dwc2_do_unreserve() - Actually release the periodic reservation
		*
		* This function actually releases the periodic bandwidth that was reserved
		* by the given qh.
		*
		* @hsotg: The HCD state structure for the DWC OTG controller
		* @qh: QH for the periodic transfer.
		*/
		static void dwc2_do_unreserve(struct dwc2_hsotg hsotg, struct dwc2_qh qh)
		{
		assert_spin_locked(&hsotg->lock);

		WARN_ON(!qh->unreserve_pending);

		/* No more unreserve pending--we're doing it */
		qh->unreserve_pending = false;

		if (WARN_ON(!list_empty(&qh->qh_list_entry)))
		list_del_init(&qh->qh_list_entry);

		/* Update claimed usecs per (micro)frame */
		hsotg->periodic_usecs -= qh->usecs;

		if (hsotg->core_params->uframe_sched > 0) {
		int i;

		for (i = 0; i < 8; i++) {
		hsotg->frame_usecs[i] += qh->frame_usecs[i];
		qh->frame_usecs[i] = 0;
		}
		} else {
		/* Release periodic channel reservation */
		hsotg->periodic_channels--;
		}
		}

		/**
		* dwc2_unreserve_timer_fn() - Timer function to release periodic reservation
		*
		* According to the kernel doc for usb_submit_urb() (specifically the part about
		* "Reserved Bandwidth Transfers"), we need to keep a reservation active as
		* long as a device driver keeps submitting. Since we're using HCD_BH to give
		* back the URB we need to give the driver a little bit of time before we
		* release the reservation. This worker is called after the appropriate
		* delay.
		*
		* @work: Pointer to a qh unreserve_work.
		*/
		static void dwc2_unreserve_timer_fn(unsigned long data)
		{
		struct dwc2_qh qh = (struct dwc2_qh )data;
		struct dwc2_hsotg *hsotg = qh->hsotg;
		unsigned long flags;

		/*
		* Wait for the lock, or for us to be scheduled again. We
		* could be scheduled again if:
		* - We started executing but didn't get the lock yet.
		* - A new reservation came in, but cancel didn't take effect
		* because we already started executing.
		* - The timer has been kicked again.
		* In that case cancel and wait for the next call.
		*/
		while (!spin_trylock_irqsave(&hsotg->lock, flags)) {
		if (timer_pending(&qh->unreserve_timer))
		return;
		}

		/*
		* Might be no more unreserve pending if:
		* - We started executing but didn't get the lock yet.
		* - A new reservation came in, but cancel didn't take effect
		* because we already started executing.
		*
		* We can't put this in the loop above because unreserve_pending needs
		* to be accessed under lock, so we can only check it once we got the
		* lock.
		*/
		if (qh->unreserve_pending)
		dwc2_do_unreserve(hsotg, qh);

		spin_unlock_irqrestore(&hsotg->lock, flags);
		}

		/**
		* dwc2_qh_init() - Initializes a QH structure
		*
		@@ -71,6 +159,9 @@ static void dwc2_qh_init(struct dwc2_hsotg hsotg, struct dwc2_qh qh,
		dev_vdbg(hsotg->dev, "%s()\n", __func__);

		/* Initialize QH */
		qh->hsotg = hsotg;
		setup_timer(&qh->unreserve_timer, dwc2_unreserve_timer_fn,
		(unsigned long)qh);
		qh->ep_type = dwc2_hcd_get_pipe_type(&urb->pipe_info);
		qh->ep_is_in = dwc2_hcd_is_pipe_in(&urb->pipe_info) ? 1 : 0;

		@@ -240,6 +331,15 @@ struct dwc2_qh dwc2_hcd_qh_create(struct dwc2_hsotg hsotg,
		*/
		void dwc2_hcd_qh_free(struct dwc2_hsotg hsotg, struct dwc2_qh qh)
		{
		/* Make sure any unreserve work is finished. */
		if (del_timer_sync(&qh->unreserve_timer)) {
		unsigned long flags;

		spin_lock_irqsave(&hsotg->lock, flags);
		dwc2_do_unreserve(hsotg, qh);
		spin_unlock_irqrestore(&hsotg->lock, flags);
		}

		if (qh->desc_list)
		dwc2_hcd_qh_free_ddma(hsotg, qh);
		kfree(qh);
		@@ -477,6 +577,26 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg hsotg, struct dwc2_qh qh)
		{
		int status;

		status = dwc2_check_max_xfer_size(hsotg, qh);
		if (status) {
		dev_dbg(hsotg->dev,
		"%s: Channel max transfer size too small for periodic transfer\n",
		__func__);
		return status;
		}

		/* Cancel pending unreserve; if canceled OK, unreserve was pending */
		if (del_timer(&qh->unreserve_timer))
		WARN_ON(!qh->unreserve_pending);

		/*
		* Only need to reserve if there's not an unreserve pending, since if an
		* unreserve is pending then by definition our old reservation is still
		* valid. Unreserve might still be pending even if we didn't cancel if
		* dwc2_unreserve_timer_fn() already started. Code in the timer handles
		* that case.
		*/
		if (!qh->unreserve_pending) {
		if (hsotg->core_params->uframe_sched > 0) {
		int frame = -1;

		@@ -490,7 +610,8 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg hsotg, struct dwc2_qh qh)
		if (frame >= 0) {
		qh->sched_frame &= ~0x7;
		qh->sched_frame \|= (frame & 7);
		dwc2_sch_dbg(hsotg, "QH=%p sched_p sch=%04x, uf=%d\n",
		dwc2_sch_dbg(hsotg,
		"QH=%p sched_p sch=%04x, uf=%d\n",
		qh, qh->sched_frame, frame);
		}

		@@ -515,14 +636,16 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg hsotg, struct dwc2_qh qh)
		return status;
		}

		status = dwc2_check_max_xfer_size(hsotg, qh);
		if (status) {
		dev_dbg(hsotg->dev,
		"%s: Channel max transfer size too small for periodic transfer\n",
		__func__);
		return status;
		if (hsotg->core_params->uframe_sched <= 0)
		/* Reserve periodic channel */
		hsotg->periodic_channels++;

		/* Update claimed usecs per (micro)frame */
		hsotg->periodic_usecs += qh->usecs;
		}

		qh->unreserve_pending = 0;

		if (hsotg->core_params->dma_desc_enable > 0)
		/* Don't rely on SOF and start in ready schedule */
		list_add_tail(&qh->qh_list_entry, &hsotg->periodic_sched_ready);
		@@ -531,13 +654,6 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg hsotg, struct dwc2_qh qh)
		list_add_tail(&qh->qh_list_entry,
		&hsotg->periodic_sched_inactive);

		if (hsotg->core_params->uframe_sched <= 0)
		/* Reserve periodic channel */
		hsotg->periodic_channels++;

		/* Update claimed usecs per (micro)frame */
		hsotg->periodic_usecs += qh->usecs;

		return status;
		}

		@@ -551,22 +667,31 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg hsotg, struct dwc2_qh qh)
		static void dwc2_deschedule_periodic(struct dwc2_hsotg *hsotg,
		struct dwc2_qh *qh)
		{
		int i;
		bool did_modify;

		list_del_init(&qh->qh_list_entry);
		assert_spin_locked(&hsotg->lock);

		/* Update claimed usecs per (micro)frame */
		hsotg->periodic_usecs -= qh->usecs;
		/*
		* Schedule the unreserve to happen in a little bit. Cases here:
		* - Unreserve worker might be sitting there waiting to grab the lock.
		* In this case it will notice it's been schedule again and will
		* quit.
		* - Unreserve worker might not be scheduled.
		*
		* We should never already be scheduled since dwc2_schedule_periodic()
		* should have canceled the scheduled unreserve timer (hence the
		* warning on did_modify).
		*
		* We add + 1 to the timer to guarantee that at least 1 jiffy has
		* passed (otherwise if the jiffy counter might tick right after we
		* read it and we'll get no delay).
		*/
		did_modify = mod_timer(&qh->unreserve_timer,
		jiffies + DWC2_UNRESERVE_DELAY + 1);
		WARN_ON(did_modify);
		qh->unreserve_pending = 1;

		if (hsotg->core_params->uframe_sched > 0) {
		for (i = 0; i < 8; i++) {
		hsotg->frame_usecs[i] += qh->frame_usecs[i];
		qh->frame_usecs[i] = 0;
		}
		} else {
		/* Release periodic channel reservation */
		hsotg->periodic_channels--;
		}
		list_del_init(&qh->qh_list_entry);
		}

		/**

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