media: v4l2-mem2mem: add v4l2_m2m_suspend, v4l2_m2m_resume

Add two functions that can be used to stop new jobs from being queued /
continue running queued job. This can be used while a driver using m2m
helper is going to suspend / wake up from resume, and can ensure that
there's no job running in suspend process.
Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
Signed-off-by: Jerry-ch Chen <jerry-ch.chen@mediatek.corp-partner.google.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/v4l2-core/v4l2-mem2mem.c

@@ -43,6 +43,10 @@ module_param(debug, bool, 0644);
 #define TRANS_ABORT		(1 << 2)
 
 
+/* The job queue is not running new jobs */
+#define QUEUE_PAUSED		(1 << 0)
+
+
 /* Offset base for buffers on the destination queue - used to distinguish
  * between source and destination buffers when mmapping - they receive the same
  * offsets but for different queues */
@@ -84,6 +88,7 @@ static const char * const m2m_entity_name[] = {
  * @job_queue:		instances queued to run
  * @job_spinlock:	protects job_queue
  * @job_work:		worker to run queued jobs.
+ * @job_queue_flags:	flags of the queue status, %QUEUE_PAUSED.
  * @m2m_ops:		driver callbacks
  */
 struct v4l2_m2m_dev {
@@ -101,6 +106,7 @@ struct v4l2_m2m_dev {
 	struct list_head	job_queue;
 	spinlock_t		job_spinlock;
 	struct work_struct	job_work;
+	unsigned long		job_queue_flags;
 
 	const struct v4l2_m2m_ops *m2m_ops;
 };
@@ -263,6 +269,12 @@ static void v4l2_m2m_try_run(struct v4l2_m2m_dev *m2m_dev)
 		return;
 	}
 
+	if (m2m_dev->job_queue_flags & QUEUE_PAUSED) {
+		spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
+		dprintk("Running new jobs is paused\n");
+		return;
+	}
+
 	m2m_dev->curr_ctx = list_first_entry(&m2m_dev->job_queue,
 				   struct v4l2_m2m_ctx, queue);
 	m2m_dev->curr_ctx->job_flags |= TRANS_RUNNING;
@@ -504,6 +516,7 @@ void v4l2_m2m_buf_done_and_job_finish(struct v4l2_m2m_dev *m2m_dev,
 
 	if (WARN_ON(!src_buf || !dst_buf))
 		goto unlock;
+	v4l2_m2m_buf_done(src_buf, state);
 	dst_buf->is_held = src_buf->flags & V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF;
 	if (!dst_buf->is_held) {
 		v4l2_m2m_dst_buf_remove(m2m_ctx);
@@ -528,6 +541,34 @@ void v4l2_m2m_buf_done_and_job_finish(struct v4l2_m2m_dev *m2m_dev,
 }
 EXPORT_SYMBOL(v4l2_m2m_buf_done_and_job_finish);
 
+void v4l2_m2m_suspend(struct v4l2_m2m_dev *m2m_dev)
+{
+	unsigned long flags;
+	struct v4l2_m2m_ctx *curr_ctx;
+
+	spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
+	m2m_dev->job_queue_flags |= QUEUE_PAUSED;
+	curr_ctx = m2m_dev->curr_ctx;
+	spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
+
+	if (curr_ctx)
+		wait_event(curr_ctx->finished,
+			   !(curr_ctx->job_flags & TRANS_RUNNING));
+}
+EXPORT_SYMBOL(v4l2_m2m_suspend);
+
+void v4l2_m2m_resume(struct v4l2_m2m_dev *m2m_dev)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
+	m2m_dev->job_queue_flags &= ~QUEUE_PAUSED;
+	spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
+
+	v4l2_m2m_try_run(m2m_dev);
+}
+EXPORT_SYMBOL(v4l2_m2m_resume);
+
 int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 		     struct v4l2_requestbuffers *reqbufs)
 {

include/media/v4l2-mem2mem.h

@@ -304,6 +304,28 @@ v4l2_m2m_is_last_draining_src_buf(struct v4l2_m2m_ctx *m2m_ctx,
 void v4l2_m2m_last_buffer_done(struct v4l2_m2m_ctx *m2m_ctx,
 			       struct vb2_v4l2_buffer *vbuf);
 
+/**
+ * v4l2_m2m_suspend() - stop new jobs from being run and wait for current job
+ * to finish
+ *
+ * @m2m_dev: opaque pointer to the internal data to handle M2M context
+ *
+ * Called by a driver in the suspend hook. Stop new jobs from being run, and
+ * wait for current running job to finish.
+ */
+void v4l2_m2m_suspend(struct v4l2_m2m_dev *m2m_dev);
+
+/**
+ * v4l2_m2m_resume() - resume job running and try to run a queued job
+ *
+ * @m2m_dev: opaque pointer to the internal data to handle M2M context
+ *
+ * Called by a driver in the resume hook. This reverts the operation of
+ * v4l2_m2m_suspend() and allows job to be run. Also try to run a queued job if
+ * there is any.
+ */
+void v4l2_m2m_resume(struct v4l2_m2m_dev *m2m_dev);
+
 /**
  * v4l2_m2m_reqbufs() - multi-queue-aware REQBUFS multiplexer
  *