media: vsp1: drm: Implement writeback support

Extend the vsp1_du_atomic_flush() API with writeback support by adding
format, pitch and memory addresses of the writeback framebuffer.
Writeback completion is reported through the existing frame completion
callback with a new VSP1_DU_STATUS_WRITEBACK status flag.

Signed-off-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Kieran Bingham <[e-mail]>
Reviewed-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/vsp1/vsp1_dl.c

···
  *
  * The VSP1_DL_FRAME_END_INTERNAL flag indicates that the display list that just
  * became active had been queued with the internal notification flag.
+ *
+ * The VSP1_DL_FRAME_END_WRITEBACK flag indicates that the previously active
+ * display list had been queued with the writeback flag.
  */
 unsigned int vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm)
 {
···
 	 */
 	if (status & VI6_STATUS_FLD_STD(dlm->index))
 		goto done;
+
+	/*
+	 * If the active display list has the writeback flag set, the frame
+	 * completion marks the end of the writeback capture. Return the
+	 * VSP1_DL_FRAME_END_WRITEBACK flag and reset the display list's
+	 * writeback flag.
+	 */
+	if (dlm->active && (dlm->active->flags & VSP1_DL_FRAME_END_WRITEBACK)) {
+		flags |= VSP1_DL_FRAME_END_WRITEBACK;
+		dlm->active->flags &= ~VSP1_DL_FRAME_END_WRITEBACK;
+	}
 
 	/*
 	 * The device starts processing the queued display list right after the

drivers/media/platform/vsp1/vsp1_dl.h

···
 
 /* Keep these flags in sync with VSP1_DU_STATUS_* in include/media/vsp1.h. */
 #define VSP1_DL_FRAME_END_COMPLETED		BIT(0)
-#define VSP1_DL_FRAME_END_INTERNAL		BIT(1)
+#define VSP1_DL_FRAME_END_WRITEBACK		BIT(1)
+#define VSP1_DL_FRAME_END_INTERNAL		BIT(2)
 
 /**
  * struct vsp1_dl_ext_cmd - Extended Display command

drivers/media/platform/vsp1/vsp1_drm.c

···
 
 	if (drm_pipe->du_complete) {
 		struct vsp1_entity *uif = drm_pipe->uif;
-		unsigned int status = completion & VSP1_DU_STATUS_COMPLETE;
+		unsigned int status = completion
+				    & (VSP1_DU_STATUS_COMPLETE |
+				       VSP1_DU_STATUS_WRITEBACK);
 		u32 crc;
 
 		crc = uif ? vsp1_uif_get_crc(to_uif(&uif->subdev)) : 0;
···
 
 	if (drm_pipe->force_brx_release)
 		dl_flags |= VSP1_DL_FRAME_END_INTERNAL;
+	if (pipe->output->writeback)
+		dl_flags |= VSP1_DL_FRAME_END_WRITEBACK;
 
 	dl = vsp1_dl_list_get(pipe->output->dlm);
 	dlb = vsp1_dl_list_get_body0(dl);
···
 	struct vsp1_device *vsp1 = dev_get_drvdata(dev);
 	struct vsp1_drm_pipeline *drm_pipe = &vsp1->drm->pipe[pipe_index];
 	struct vsp1_pipeline *pipe = &drm_pipe->pipe;
+	int ret;
 
 	drm_pipe->crc = cfg->crc;
 
 	mutex_lock(&vsp1->drm->lock);
+
+	if (cfg->writeback.pixelformat) {
+		const struct vsp1_du_writeback_config *wb_cfg = &cfg->writeback;
+
+		ret = vsp1_du_pipeline_set_rwpf_format(vsp1, pipe->output,
+						       wb_cfg->pixelformat,
+						       wb_cfg->pitch);
+		if (WARN_ON(ret < 0))
+			goto done;
+
+		pipe->output->mem.addr[0] = wb_cfg->mem[0];
+		pipe->output->mem.addr[1] = wb_cfg->mem[1];
+		pipe->output->mem.addr[2] = wb_cfg->mem[2];
+		pipe->output->writeback = true;
+	}
+
 	vsp1_du_pipeline_setup_inputs(vsp1, pipe);
 	vsp1_du_pipeline_configure(pipe);
+
+done:
 	mutex_unlock(&vsp1->drm->lock);
 }
 EXPORT_SYMBOL_GPL(vsp1_du_atomic_flush);

include/media/vsp1.h

···
 int vsp1_du_init(struct device *dev);
 
 #define VSP1_DU_STATUS_COMPLETE		BIT(0)
+#define VSP1_DU_STATUS_WRITEBACK	BIT(1)
 
 /**
  * struct vsp1_du_lif_config - VSP LIF configuration
···
 };
 
 /**
+ * struct vsp1_du_writeback_config - VSP writeback configuration parameters
+ * @pixelformat: plane pixel format (V4L2 4CC)
+ * @pitch: line pitch in bytes for the first plane
+ * @mem: DMA memory address for each plane of the frame buffer
+ */
+struct vsp1_du_writeback_config {
+	u32 pixelformat;
+	unsigned int pitch;
+	dma_addr_t mem[3];
+};
+
+/**
  * struct vsp1_du_atomic_pipe_config - VSP atomic pipe configuration parameters
  * @crc: CRC computation configuration
+ * @writeback: writeback configuration
  */
 struct vsp1_du_atomic_pipe_config {
 	struct vsp1_du_crc_config crc;
+	struct vsp1_du_writeback_config writeback;
 };
 
 void vsp1_du_atomic_begin(struct device *dev, unsigned int pipe_index);