Commit 070ce765 authored by Boris Brezillon's avatar Boris Brezillon
Browse files

drm/panfrost: Use a threaded IRQ for job interrupts 



This should avoid switching to interrupt context when the GPU is under
heavy use.

v3:
* Don't take the job_lock in panfrost_job_handle_irq()

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Acked-by: default avatarAlyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210630062751.2832545-9-boris.brezillon@collabora.com
parent 229f4578

drivers/gpu/drm/panfrost/panfrost_job.c

+38 −15
Original line number Diff line number Diff line
@@ -459,19 +459,12 @@ static const struct drm_sched_backend_ops panfrost_sched_ops = { 
	.free_job = panfrost_job_free

};



static irqreturn_t panfrost_job_irq_handler(int irq, void *data)

static void panfrost_job_handle_irq(struct panfrost_device *pfdev, u32 status)

{

	struct panfrost_device *pfdev = data;

	u32 status = job_read(pfdev, JOB_INT_STAT);

	int j;



	dev_dbg(pfdev->dev, "jobslot irq status=%x\n", status);



	if (!status)

		return IRQ_NONE;



	pm_runtime_mark_last_busy(pfdev->dev);



	for (j = 0; status; j++) {

		u32 mask = MK_JS_MASK(j);
@@ -508,7 +501,6 @@ static irqreturn_t panfrost_job_irq_handler(int irq, void *data) 
		if (status & JOB_INT_MASK_DONE(j)) {

			struct panfrost_job *job;



			spin_lock(&pfdev->js->job_lock);

			job = pfdev->jobs[j];

			/* Only NULL if job timeout occurred */

			if (job) {
@@ -520,21 +512,49 @@ static irqreturn_t panfrost_job_irq_handler(int irq, void *data) 
				dma_fence_signal_locked(job->done_fence);

				pm_runtime_put_autosuspend(pfdev->dev);

			}

			spin_unlock(&pfdev->js->job_lock);

		}



		status &= ~mask;

	}

}



static irqreturn_t panfrost_job_irq_handler_thread(int irq, void *data)

{

	struct panfrost_device *pfdev = data;

	u32 status = job_read(pfdev, JOB_INT_RAWSTAT);



	while (status) {

		pm_runtime_mark_last_busy(pfdev->dev);



		spin_lock(&pfdev->js->job_lock);

		panfrost_job_handle_irq(pfdev, status);

		spin_unlock(&pfdev->js->job_lock);

		status = job_read(pfdev, JOB_INT_RAWSTAT);

	}



	job_write(pfdev, JOB_INT_MASK,

		  GENMASK(16 + NUM_JOB_SLOTS - 1, 16) |

		  GENMASK(NUM_JOB_SLOTS - 1, 0));

	return IRQ_HANDLED;

}



static irqreturn_t panfrost_job_irq_handler(int irq, void *data)

{

	struct panfrost_device *pfdev = data;

	u32 status = job_read(pfdev, JOB_INT_STAT);



	if (!status)

		return IRQ_NONE;



	job_write(pfdev, JOB_INT_MASK, 0);

	return IRQ_WAKE_THREAD;

}



static void panfrost_reset(struct work_struct *work)

{

	struct panfrost_device *pfdev = container_of(work,

						     struct panfrost_device,

						     reset.work);

	unsigned long flags;

	unsigned int i;

	bool cookie;
@@ -564,7 +584,7 @@ static void panfrost_reset(struct work_struct *work) 
	/* All timers have been stopped, we can safely reset the pending state. */

	atomic_set(&pfdev->reset.pending, 0);



	spin_lock_irqsave(&pfdev->js->job_lock, flags);

	spin_lock(&pfdev->js->job_lock);

	for (i = 0; i < NUM_JOB_SLOTS; i++) {

		if (pfdev->jobs[i]) {

			pm_runtime_put_noidle(pfdev->dev);
@@ -572,7 +592,7 @@ static void panfrost_reset(struct work_struct *work) 
			pfdev->jobs[i] = NULL;

		}

	}

	spin_unlock_irqrestore(&pfdev->js->job_lock, flags);

	spin_unlock(&pfdev->js->job_lock);



	panfrost_device_reset(pfdev);
@@ -599,8 +619,11 @@ int panfrost_job_init(struct panfrost_device *pfdev) 
	if (irq <= 0)

		return -ENODEV;



	ret = devm_request_irq(pfdev->dev, irq, panfrost_job_irq_handler,

			       IRQF_SHARED, KBUILD_MODNAME "-job", pfdev);

	ret = devm_request_threaded_irq(pfdev->dev, irq,

					panfrost_job_irq_handler,

					panfrost_job_irq_handler_thread,

					IRQF_SHARED, KBUILD_MODNAME "-job",

					pfdev);

	if (ret) {

		dev_err(pfdev->dev, "failed to request job irq");

		return ret;