media: imx: add mem2mem device

Add a single imx-media mem2mem video device that uses the IPU IC PP
(image converter post processing) task for scaling and colorspace
conversion.
On i.MX6Q/DL SoCs with two IPUs currently only the first IPU is used.

The hardware only supports writing to destination buffers up to
1024x1024 pixels in a single pass, so the mem2mem video device is
limited to this resolution. After fixing the tiling code it should
be possible to extend this to arbitrary sizes by rendering multiple
tiles per frame.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/staging/media/imx/Kconfig

@@ -6,6 +6,7 @@ config VIDEO_IMX_MEDIA
 	depends on HAS_DMA
 	select VIDEOBUF2_DMA_CONTIG
 	select V4L2_FWNODE
+	select V4L2_MEM2MEM_DEV
 	---help---
 	  Say yes here to enable support for video4linux media controller
 	  driver for the i.MX5/6 SOC.

drivers/staging/media/imx/Makefile

@@ -6,6 +6,7 @@ imx-media-ic-objs := imx-ic-common.o imx-ic-prp.o imx-ic-prpencvf.o
 obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media.o
 obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-common.o
 obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-capture.o
+obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-mem2mem.o
 obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-vdic.o
 obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-ic.o
 

drivers/staging/media/imx/imx-media-dev.c

@@ -359,6 +359,17 @@ static int imx_media_probe_complete(struct v4l2_async_notifier *notifier)
 		goto unlock;
 
 	ret = v4l2_device_register_subdev_nodes(&imxmd->v4l2_dev);
+	if (ret)
+		goto unlock;
+
+	/* TODO: check whether we have IC subdevices first */
+	imxmd->m2m_vdev = imx_media_mem2mem_device_init(imxmd);
+	if (IS_ERR(imxmd->m2m_vdev)) {
+		ret = PTR_ERR(imxmd->m2m_vdev);
+		goto unlock;
+	}
+
+	ret = imx_media_mem2mem_device_register(imxmd->m2m_vdev);
 unlock:
 	mutex_unlock(&imxmd->mutex);
 	if (ret)

drivers/staging/media/imx/imx-media.h

@@ -149,6 +149,9 @@ struct imx_media_dev {
 	/* for async subdev registration */
 	struct list_head asd_list;
 	struct v4l2_async_notifier subdev_notifier;
+
+	/* IC scaler/CSC mem2mem video device */
+	struct imx_media_video_dev *m2m_vdev;
 };
 
 enum codespace_sel {
@@ -262,6 +265,13 @@ void imx_media_capture_device_set_format(struct imx_media_video_dev *vdev,
 					 struct v4l2_pix_format *pix);
 void imx_media_capture_device_error(struct imx_media_video_dev *vdev);
 
+/* imx-media-mem2mem.c */
+struct imx_media_video_dev *
+imx_media_mem2mem_device_init(struct imx_media_dev *dev);
+void imx_media_mem2mem_device_remove(struct imx_media_video_dev *vdev);
+int imx_media_mem2mem_device_register(struct imx_media_video_dev *vdev);
+void imx_media_mem2mem_device_unregister(struct imx_media_video_dev *vdev);
+
 /* subdev group ids */
 #define IMX_MEDIA_GRP_ID_CSI2      BIT(8)
 #define IMX_MEDIA_GRP_ID_CSI_BIT   9