media: vim2m: use workqueue

v4l2_ctrl uses mutexes, so we can't setup a ctrl_handler in
interrupt context. Switch to a workqueue instead and drop the timer.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/vim2m.c

@@ -3,7 +3,8 @@
  *
  * This is a virtual device driver for testing mem-to-mem videobuf framework.
  * It simulates a device that uses memory buffers for both source and
- * destination, processes the data and issues an "irq" (simulated by a timer).
+ * destination, processes the data and issues an "irq" (simulated by a delayed
+ * workqueue).
  * The device is capable of multi-instance, multi-buffer-per-transaction
  * operation (via the mem2mem framework).
  *
@@ -19,7 +20,6 @@
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/fs.h>
-#include <linux/timer.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 
@@ -148,7 +148,7 @@ struct vim2m_dev {
 	struct mutex		dev_mutex;
 	spinlock_t		irqlock;
 
-	struct timer_list	timer;
+	struct delayed_work	work_run;
 
 	struct v4l2_m2m_dev	*m2m_dev;
 };
@@ -336,12 +336,6 @@ static int device_process(struct vim2m_ctx *ctx,
 	return 0;
 }
 
-static void schedule_irq(struct vim2m_dev *dev, int msec_timeout)
-{
-	dprintk(dev, "Scheduling a simulated irq\n");
-	mod_timer(&dev->timer, jiffies + msecs_to_jiffies(msec_timeout));
-}
-
 /*
  * mem2mem callbacks
  */
@@ -387,13 +381,14 @@ static void device_run(void *priv)
 
 	device_process(ctx, src_buf, dst_buf);
 
-	/* Run a timer, which simulates a hardware irq  */
-	schedule_irq(dev, ctx->transtime);
+	/* Run delayed work, which simulates a hardware irq  */
+	schedule_delayed_work(&dev->work_run, msecs_to_jiffies(ctx->transtime));
 }
 
-static void device_isr(struct timer_list *t)
+static void device_work(struct work_struct *w)
 {
-	struct vim2m_dev *vim2m_dev = from_timer(vim2m_dev, t, timer);
+	struct vim2m_dev *vim2m_dev =
+		container_of(w, struct vim2m_dev, work_run.work);
 	struct vim2m_ctx *curr_ctx;
 	struct vb2_v4l2_buffer *src_vb, *dst_vb;
 	unsigned long flags;
@@ -805,6 +800,7 @@ static void vim2m_stop_streaming(struct vb2_queue *q)
 	struct vb2_v4l2_buffer *vbuf;
 	unsigned long flags;
 
+	flush_scheduled_work();
 	for (;;) {
 		if (V4L2_TYPE_IS_OUTPUT(q->type))
 			vbuf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
@@ -1015,6 +1011,7 @@ static int vim2m_probe(struct platform_device *pdev)
 	vfd = &dev->vfd;
 	vfd->lock = &dev->dev_mutex;
 	vfd->v4l2_dev = &dev->v4l2_dev;
+	INIT_DELAYED_WORK(&dev->work_run, device_work);
 
 	ret = video_register_device(vfd, VFL_TYPE_GRABBER, 0);
 	if (ret) {
@@ -1026,7 +1023,6 @@ static int vim2m_probe(struct platform_device *pdev)
 	v4l2_info(&dev->v4l2_dev,
 			"Device registered as /dev/video%d\n", vfd->num);
 
-	timer_setup(&dev->timer, device_isr, 0);
 	platform_set_drvdata(pdev, dev);
 
 	dev->m2m_dev = v4l2_m2m_init(&m2m_ops);
@@ -1083,7 +1079,6 @@ static int vim2m_remove(struct platform_device *pdev)
 	media_device_cleanup(&dev->mdev);
 #endif
 	v4l2_m2m_release(dev->m2m_dev);
-	del_timer_sync(&dev->timer);
 	video_unregister_device(&dev->vfd);
 	v4l2_device_unregister(&dev->v4l2_dev);