[PATCH 6/9] media: rzg2l-cru: Add suspend/resume support

[Tommaso Merciai]

The CRU has no system sleep hooks, leaving the device in an undefined
state across suspend/resume.

On suspend, stop the pipeline, requeue any buffers held by the hardware
back to the software queue, and assert the resets. On resume, deassert
the resets and restart streaming.

Add a bool running field to track pipeline state. stop_streaming uses it
to skip rzg2l_cru_set_stream() when the pipeline was already stopped by
a failed resume, avoiding a double-stop. Export rzg2l_cru_set_stream()
and add rzg2l_cru_requeue_active_buffers() for use by the PM callbacks.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@xxxxxxxxxxxxxx>
---
 .../platform/renesas/rzg2l-cru/rzg2l-core.c   | 67 +++++++++++++++++++
 .../platform/renesas/rzg2l-cru/rzg2l-cru.h    |  5 ++
 .../platform/renesas/rzg2l-cru/rzg2l-video.c  | 25 ++++++-
 3 files changed, 95 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c
index 1b12d91eaec9..2840f40e4c01 100644
--- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-core.c
@@ -246,6 +246,72 @@ static int rzg2l_cru_media_init(struct rzg2l_cru_dev *cru)
 	return 0;
 }
 
+static int rzg2l_cru_pm_suspend(struct device *dev)
+{
+	struct rzg2l_cru_dev *cru = dev_get_drvdata(dev);
+	struct reset_control_bulk_data resets[] = {
+		{ .rstc = cru->aresetn },
+		{ .rstc = cru->presetn },
+	};
+	int ret;
+
+	if (!cru->running)
+		return 0;
+
+	ret = rzg2l_cru_set_stream(cru, 0);
+	if (ret)
+		return ret;
+
+	rzg2l_cru_requeue_active_buffers(cru);
+
+	ret = reset_control_bulk_assert(ARRAY_SIZE(resets), resets);
+	if (ret) {
+		if (rzg2l_cru_set_stream(cru, 1))
+			vb2_queue_error(&cru->queue);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rzg2l_cru_pm_resume(struct device *dev)
+{
+	struct rzg2l_cru_dev *cru = dev_get_drvdata(dev);
+	struct reset_control_bulk_data resets[] = {
+		{ .rstc = cru->aresetn },
+		{ .rstc = cru->presetn },
+	};
+	int ret;
+
+	if (!cru->running)
+		return 0;
+
+	ret = reset_control_bulk_deassert(ARRAY_SIZE(resets), resets);
+	if (ret)
+		goto err_running;
+
+	ret = rzg2l_cru_set_stream(cru, 1);
+	if (ret) {
+		dev_err(cru->dev, "Failed to restart streaming: %d\n", ret);
+		goto err_reset_assert;
+	}
+
+	return 0;
+
+err_reset_assert:
+	reset_control_bulk_assert(ARRAY_SIZE(resets), resets);
+err_running:
+	cru->running = false;
+	vb2_queue_error(&cru->queue);
+
+	return ret;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(rzg2l_cru_pm_ops,
+				rzg2l_cru_pm_suspend,
+				rzg2l_cru_pm_resume);
+
 static int rzg2l_cru_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -437,6 +503,7 @@ static struct platform_driver rzg2l_cru_driver = {
 	.driver = {
 		.name = "rzg2l-cru",
 		.of_match_table = rzg2l_cru_of_id_table,
+		.pm = pm_sleep_ptr(&rzg2l_cru_pm_ops),
 	},
 	.probe = rzg2l_cru_probe,
 	.remove = rzg2l_cru_remove,
diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
index 5bf334e173d2..c079cad41266 100644
--- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
@@ -161,12 +161,17 @@ struct rzg2l_cru_dev {
 	struct list_head buf_list;
 	unsigned int sequence;
 
+	bool running;
+
 	struct v4l2_pix_format format;
 };
 
 int rzg2l_cru_start_image_processing(struct rzg2l_cru_dev *cru);
 void rzg2l_cru_stop_image_processing(struct rzg2l_cru_dev *cru);
 
+int rzg2l_cru_set_stream(struct rzg2l_cru_dev *cru, int on);
+void rzg2l_cru_requeue_active_buffers(struct rzg2l_cru_dev *cru);
+
 int rzg2l_cru_dma_register(struct rzg2l_cru_dev *cru);
 void rzg2l_cru_dma_unregister(struct rzg2l_cru_dev *cru);
 
diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
index 71d9c671f739..46a0823e1300 100644
--- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
@@ -155,6 +155,23 @@ static void rzg2l_cru_return_buffers(struct rzg2l_cru_dev *cru,
 	}
 }
 
+void rzg2l_cru_requeue_active_buffers(struct rzg2l_cru_dev *cru)
+{
+	unsigned int i;
+
+	scoped_guard(spinlock_irqsave, &cru->hw_lock) {
+		for (i = 0; i < cru->num_buf; i++) {
+			if (!cru->queue_buf[i])
+				continue;
+			scoped_guard(spinlock_irqsave, &cru->qlock) {
+				list_add_tail(to_buf_list(cru->queue_buf[i]),
+					      &cru->buf_list);
+			}
+			cru->queue_buf[i] = NULL;
+		}
+	}
+}
+
 static int rzg2l_cru_queue_setup(struct vb2_queue *vq, unsigned int *nbuffers,
 				 unsigned int *nplanes, unsigned int sizes[],
 				 struct device *alloc_devs[])
@@ -528,7 +545,7 @@ int rzg2l_cru_start_image_processing(struct rzg2l_cru_dev *cru)
 	return 0;
 }
 
-static int rzg2l_cru_set_stream(struct rzg2l_cru_dev *cru, int on)
+int rzg2l_cru_set_stream(struct rzg2l_cru_dev *cru, int on)
 {
 	struct media_pipeline *pipe;
 	struct v4l2_subdev *sd;
@@ -707,6 +724,7 @@ static int rzg2l_cru_start_streaming_vq(struct vb2_queue *vq, unsigned int count
 		goto out;
 	}
 
+	cru->running = true;
 	dev_dbg(cru->dev, "Starting to capture\n");
 	return 0;
 
@@ -731,7 +749,10 @@ static void rzg2l_cru_stop_streaming_vq(struct vb2_queue *vq)
 {
 	struct rzg2l_cru_dev *cru = vb2_get_drv_priv(vq);
 
-	rzg2l_cru_set_stream(cru, 0);
+	if (cru->running) {
+		rzg2l_cru_set_stream(cru, 0);
+		cru->running = false;
+	}
 
 	/* Free scratch buffer */
 	dma_free_coherent(cru->dev, cru->format.sizeimage,
-- 
2.54.0