[PATCH v4 1/2] drm: Add writeback_dest_x,y,w,h properties

[Ben Davis]

Add new properties to specify x,y coordinates and
width and height for writeback.

These are reset to 0 on duplicating state to provide
robustness against accidental scaling.

Signed-off-by: Ben Davis <ben.davis@xxxxxxx>
---
 drivers/gpu/drm/drm_atomic_state_helper.c |  6 +++
 drivers/gpu/drm/drm_atomic_uapi.c         | 17 ++++++++
 drivers/gpu/drm/drm_writeback.c           | 66 +++++++++++++++++++++++++++++++
 include/drm/drm_connector.h               | 23 +++++++++++
 include/drm/drm_mode_config.h             | 20 ++++++++++
 5 files changed, 132 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
index 25a95b9..5973ca3 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -382,6 +382,12 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
 
 	/* Don't copy over a writeback job, they are used only once */
 	state->writeback_job = NULL;
+
+	/* Auto clear writeback coordinates, should only be used once */
+	state->writeback_dest_x = 0;
+	state->writeback_dest_y = 0;
+	state->writeback_dest_w = 0;
+	state->writeback_dest_h = 0;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
 
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index d520a04..7d3fb7f 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -765,6 +765,14 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector,
 			return -EINVAL;
 		}
 		state->content_protection = val;
+	} else if (property == config->prop_writeback_dest_x) {
+		state->writeback_dest_x = val;
+	} else if (property == config->prop_writeback_dest_y) {
+		state->writeback_dest_y = val;
+	} else if (property == config->prop_writeback_dest_w) {
+		state->writeback_dest_w = val;
+	} else if (property == config->prop_writeback_dest_h) {
+		state->writeback_dest_h = val;
 	} else if (property == config->writeback_fb_id_property) {
 		struct drm_framebuffer *fb = drm_framebuffer_lookup(dev, NULL, val);
 		int ret = drm_atomic_set_writeback_fb_for_connector(state, fb);
@@ -837,6 +845,15 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
 		*val = state->scaling_mode;
 	} else if (property == connector->content_protection_property) {
 		*val = state->content_protection;
+	} else if (property == config->prop_writeback_dest_x) {
+		/* Auto clear wb co-ordinates to prevent accidental scaling */
+		*val = 0;
+	} else if (property == config->prop_writeback_dest_y) {
+		*val = 0;
+	} else if (property == config->prop_writeback_dest_w) {
+		*val = 0;
+	} else if (property == config->prop_writeback_dest_h) {
+		*val = 0;
 	} else if (property == config->writeback_fb_id_property) {
 		/* Writeback framebuffer is one-shot, write and forget */
 		*val = 0;
diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
index c20e6fe..7c53abd 100644
--- a/drivers/gpu/drm/drm_writeback.c
+++ b/drivers/gpu/drm/drm_writeback.c
@@ -74,6 +74,30 @@
  *	applications making use of writeback connectors *always* retrieve an
  *	out-fence for the commit and use it appropriately.
  *	From userspace, this property will always read as zero.
+ *
+ *  "WRITEBACK_DEST_X":
+ *	The x-coordinate to write back onto the output writeback framebuffer.
+ *	0 acts as default. If non-zero the composition will be translated
+ *	horizontally in the buffer by the amount specified. This is the case
+ *	even if not scaling on writeback.
+ *
+ *  "WRITEBACK_DEST_Y":
+ *	The y-coordinate to write back onto the output writeback framebuffer.
+ *	0 acts as default. If non-zero the composition will be translated
+ *	vertically in the buffer by the amount specified. This is the case even
+ *	if not scaling on writeback.
+ *
+ *  "WRITEBACK_DEST_W":
+ *	The width of the composition to write back. 0 acts as default. If
+ *	non-zero the composition will be scaled to match the given width.
+ *	If scaling both WRITEBACK_DEST_W and WRITEBACK_DEST_H should be
+ *	set as non-zero.
+ *
+ *  "WRITEBACK_DEST_H":
+ *	The height of the composition to write back. 0 acts as default. If
+ *	non-zero the composition will be scaled to match the given height.
+ *	If scaling both WRITEBACK_DEST_W and WRITEBACK_DEST_H should be
+ *	set as non-zero.
  */
 
 #define fence_to_wb_connector(x) container_of(x->lock, \
@@ -141,6 +165,38 @@ static int create_writeback_properties(struct drm_device *dev)
 		dev->mode_config.writeback_out_fence_ptr_property = prop;
 	}
 
+	if (!dev->mode_config.prop_writeback_dest_x) {
+		prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+						 "WRITEBACK_DEST_X", 0, UINT_MAX);
+		if (!prop)
+			return -ENOMEM;
+		dev->mode_config.prop_writeback_dest_x = prop;
+	}
+
+	if (!dev->mode_config.prop_writeback_dest_y) {
+		prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+						 "WRITEBACK_DEST_Y", 0, UINT_MAX);
+		if (!prop)
+			return -ENOMEM;
+		dev->mode_config.prop_writeback_dest_y = prop;
+	}
+
+	if (!dev->mode_config.prop_writeback_dest_w) {
+		prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+						 "WRITEBACK_DEST_W", 0, UINT_MAX);
+		if (!prop)
+			return -ENOMEM;
+		dev->mode_config.prop_writeback_dest_w = prop;
+	}
+
+	if (!dev->mode_config.prop_writeback_dest_h) {
+		prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+						 "WRITEBACK_DEST_H", 0, UINT_MAX);
+		if (!prop)
+			return -ENOMEM;
+		dev->mode_config.prop_writeback_dest_h = prop;
+	}
+
 	return 0;
 }
 
@@ -225,6 +281,16 @@ int drm_writeback_connector_init(struct drm_device *dev,
 	drm_object_attach_property(&connector->base,
 				   config->writeback_pixel_formats_property,
 				   blob->base.id);
+
+	drm_object_attach_property(&connector->base,
+				   config->prop_writeback_dest_x, 0);
+	drm_object_attach_property(&connector->base,
+				   config->prop_writeback_dest_y, 0);
+	drm_object_attach_property(&connector->base,
+				   config->prop_writeback_dest_w, 0);
+	drm_object_attach_property(&connector->base,
+				   config->prop_writeback_dest_h, 0);
+
 	wb_connector->pixel_formats_blob_ptr = blob;
 
 	return 0;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 8fe22ab..4c7701e 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -515,6 +515,25 @@ struct drm_connector_state {
 	 */
 	struct drm_writeback_job *writeback_job;
 
+	/** @writeback_dest_x: x coord to write plane to on wb buffer
+	 *  The written back composition will be translated by this
+	 *  amount horizontally on the output buffer.
+	 */
+	/** @writeback_dest_y: y coord to write plane to on wb buffer
+	 *  The written back composition will be translated by this
+	 *  amount vertically on the output buffer.
+	 */
+	/** @writeback_dest_w: width of plane to write to wb buffer
+	 *  The written back composition will be scaled to match this
+	 *  height dimension on the output buffer. Ignored if 0.
+	 */
+	/** @writeback_dest_h: height of plane to write to wb buffer
+	 *  The written back composition will be scaled to match this
+	 *  width dimension on the output buffer. Ignored if 0.
+	 */
+	uint32_t writeback_dest_x, writeback_dest_y,
+		 writeback_dest_w, writeback_dest_h;
+
 	/**
 	 * @max_requested_bpc: Connector property to limit the maximum bit
 	 * depth of the pixels.
@@ -704,6 +723,10 @@ struct drm_connector_funcs {
 	 * cleaned up by calling the @atomic_destroy_state hook in this
 	 * structure.
 	 *
+	 * State relating to writeback including writeback_job and
+	 * writeback_dest_x,y,w,h is not intended to be reused and so will not
+	 * be duplicated and will instead be reset to NULL/0 respectively.
+	 *
 	 * This callback is mandatory for atomic drivers.
 	 *
 	 * Atomic drivers which don't subclass &struct drm_connector_state should use
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 7f60e8e..40ce4a8 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -622,6 +622,26 @@ struct drm_mode_config {
 	 */
 	struct drm_property *prop_crtc_h;
 	/**
+	 * @prop_writeback_dest_x: Writeback connector property for the crtc
+	 * output destination position in the writeback buffer.
+	 */
+	struct drm_property *prop_writeback_dest_x;
+	/**
+	 * @prop_writeback_dest_y: Writeback connector property for the crtc
+	 * output destination position in the writeback buffer.
+	 */
+	struct drm_property *prop_writeback_dest_y;
+	/**
+	 * @prop_writeback_dest_w: Writeback connector property for the crtc
+	 * output destination position in the writeback buffer.
+	 */
+	struct drm_property *prop_writeback_dest_w;
+	/**
+	 * @prop_writeback_dest_h: Writeback connector property for the crtc
+	 * output destination position in the writeback buffer.
+	 */
+	struct drm_property *prop_writeback_dest_h;
+	/**
 	 * @prop_fb_id: Default atomic plane property to specify the
 	 * &drm_framebuffer.
 	 */
-- 
2.7.4