[PATCH v2 2/2] media: aspeed: drain IRQ work before stopping the engine

[Myeonghun Pak <mhun512@gmail.com>]

Last close cancels resolution work while its IRQ producer is still live.
A handler can queue work after cancellation and buffer cleanup. The worker
can then turn clocks back on after stop has cleared VIDEO_STOPPED.

Release the VB2 queue before shutting down the engine, since streamoff
can need capture and mode-detect interrupts. Disable and join the IRQ,
drain work, stop the engine and free its buffers before re-enabling the
IRQ. Check VIDEO_STOPPED before enabling clocks in the worker.

Fixes: d2b4387f3bdf ("media: platform: Add Aspeed Video Engine driver")
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
No hardware testing.

Changes in v2:
- Split normal last-close ordering into a separate patch.
- Balance IRQ disable/enable within stop; add no reopen state.

 drivers/media/platform/aspeed/aspeed-video.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/media/platform/aspeed/aspeed-video.c b/drivers/media/platform/aspeed/aspeed-video.c
--- a/drivers/media/platform/aspeed/aspeed-video.c
+++ b/drivers/media/platform/aspeed/aspeed-video.c
@@ -1423,6 +1423,7 @@
 static void aspeed_video_stop(struct aspeed_video *video)
 {
 	set_bit(VIDEO_STOPPED, &video->flags);
+	disable_irq(video->irq);
 	cancel_delayed_work_sync(&video->res_work);
 
 	aspeed_video_off(video);
@@ -1438,6 +1439,7 @@
 
 	video->v4l2_input_status = V4L2_IN_ST_NO_SIGNAL;
 	video->flags = 0;
+	enable_irq(video->irq);
 }
 
 static int aspeed_video_querycap(struct file *file, void *fh,
@@ -1847,11 +1849,11 @@
 	struct aspeed_video *video = container_of(dwork, struct aspeed_video,
 						  res_work);
 
-	aspeed_video_on(video);
-
 	/* Exit early in case no clients remain */
 	if (test_bit(VIDEO_STOPPED, &video->flags))
 		goto done;
+
+	aspeed_video_on(video);
 
 	aspeed_video_init_regs(video);
 
@@ -1901,15 +1903,17 @@
 
 static int aspeed_video_release(struct file *file)
 {
+	bool last;
 	int rc;
 	struct aspeed_video *video = video_drvdata(file);
 
 	mutex_lock(&video->video_lock);
 
-	if (v4l2_fh_is_singular_file(file))
+	last = v4l2_fh_is_singular_file(file);
+	rc = _vb2_fop_release(file, NULL);
+
+	if (last)
 		aspeed_video_stop(video);
-
-	rc = _vb2_fop_release(file, NULL);
 
 	mutex_unlock(&video->video_lock);