[PATCH] media: cedrus: Add watchdog for job completion

[Jernej Skrabec]

Currently, if job is not completed for whatever reason, userspace
application can hang on ioctl and thus become unkillable.

In order to prevent that, implement watchdog, which will complete job
after 2 seconds with error state.

Concept is borrowed from hantro driver.

Signed-off-by: Jernej Skrabec <jernej.skrabec at gmail.com>
---
 drivers/staging/media/sunxi/cedrus/cedrus.c   |  2 ++
 drivers/staging/media/sunxi/cedrus/cedrus.h   |  3 +++
 .../staging/media/sunxi/cedrus/cedrus_dec.c   |  4 +++
 .../staging/media/sunxi/cedrus/cedrus_hw.c    | 25 +++++++++++++++++++
 .../staging/media/sunxi/cedrus/cedrus_hw.h    |  2 ++
 5 files changed, 36 insertions(+)

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c
index 4a4b714b0f26..68b3dcdb5df3 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus.c
@@ -439,6 +439,8 @@ static int cedrus_probe(struct platform_device *pdev)
 
 	mutex_init(&dev->dev_mutex);
 
+	INIT_DELAYED_WORK(&dev->watchdog_work, cedrus_watchdog);
+
 	ret = v4l2_device_register(&pdev->dev, &dev->v4l2_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to register V4L2 device\n");
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.h b/drivers/staging/media/sunxi/cedrus/cedrus.h
index c345f2984041..3bc094eb497f 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus.h
+++ b/drivers/staging/media/sunxi/cedrus/cedrus.h
@@ -24,6 +24,7 @@
 
 #include <linux/iopoll.h>
 #include <linux/platform_device.h>
+#include <linux/workqueue.h>
 
 #define CEDRUS_NAME			"cedrus"
 
@@ -194,6 +195,8 @@ struct cedrus_dev {
 	struct reset_control	*rstc;
 
 	unsigned int		capabilities;
+
+	struct delayed_work	watchdog_work;
 };
 
 extern struct cedrus_dec_ops cedrus_dec_ops_mpeg2;
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
index a16c1422558f..9c7200299465 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
@@ -97,4 +97,8 @@ void cedrus_device_run(void *priv)
 		v4l2_ctrl_request_complete(src_req, &ctx->hdl);
 
 	dev->dec_ops[ctx->current_codec]->trigger(ctx);
+
+	/* Start the watchdog timer. */
+	schedule_delayed_work(&dev->watchdog_work,
+			      msecs_to_jiffies(2000));
 }
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
index 2d7663726467..a6470a89851e 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
@@ -118,6 +118,13 @@ static irqreturn_t cedrus_irq(int irq, void *data)
 	enum vb2_buffer_state state;
 	enum cedrus_irq_status status;
 
+	/*
+	 * If cancel_delayed_work returns false it means watchdog already
+	 * executed and finished the job.
+	 */
+	if (!cancel_delayed_work(&dev->watchdog_work))
+		return IRQ_HANDLED;
+
 	ctx = v4l2_m2m_get_curr_priv(dev->m2m_dev);
 	if (!ctx) {
 		v4l2_err(&dev->v4l2_dev,
@@ -143,6 +150,24 @@ static irqreturn_t cedrus_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+void cedrus_watchdog(struct work_struct *work)
+{
+	struct cedrus_dev *dev;
+	struct cedrus_ctx *ctx;
+
+	dev = container_of(to_delayed_work(work),
+			   struct cedrus_dev, watchdog_work);
+
+	ctx = v4l2_m2m_get_curr_priv(dev->m2m_dev);
+	if (!ctx)
+		return;
+
+	v4l2_err(&dev->v4l2_dev, "frame processing timed out!\n");
+	reset_control_reset(dev->rstc);
+	v4l2_m2m_buf_done_and_job_finish(ctx->dev->m2m_dev, ctx->fh.m2m_ctx,
+					 VB2_BUF_STATE_ERROR);
+}
+
 int cedrus_hw_suspend(struct device *device)
 {
 	struct cedrus_dev *dev = dev_get_drvdata(device);
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
index 45f641f0bfa2..7c92f00e36da 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
@@ -28,4 +28,6 @@ int cedrus_hw_resume(struct device *device);
 int cedrus_hw_probe(struct cedrus_dev *dev);
 void cedrus_hw_remove(struct cedrus_dev *dev);
 
+void cedrus_watchdog(struct work_struct *work);
+
 #endif
-- 
2.35.1