v4l: vsp1: Don't recycle active list at display start

When the display start interrupt occurs, we know that the hardware has
finished loading the active display list. The driver then proceeds to
recycle the list, assuming it won't be needed anymore.

This assumption holds true for headerless display lists, as the VSP
doesn't reload the list for the next frame if it hasn't changed.
However, this isn't true anymore for header display lists, as they are
loaded at every frame start regardless of whether they have been
updated.

To prepare for header display lists usage in display pipelines, we need
to postpone recycling the list until it gets replaced by a new one
through a page flip. The driver already does so in the frame end
interrupt handler, so all we need is to skip list recycling in the
display start interrupt handler.

While the active list can be recycled at display start for headerless
display lists, there's no real harm in postponing that to the frame end
interrupt handler in all cases. This simplifies interrupt handling as we
don't need to process the display start interrupt anymore.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Acked-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/vsp1/vsp1_dl.c

@@ -547,22 +547,6 @@ void vsp1_dl_list_commit(struct vsp1_dl_list *dl)
  * Display List Manager
  */
 
-/* Interrupt Handling */
-void vsp1_dlm_irq_display_start(struct vsp1_dl_manager *dlm)
-{
-	spin_lock(&dlm->lock);
-
-	/*
-	 * The display start interrupt signals the end of the display list
-	 * processing by the device. The active display list, if any, won't be
-	 * accessed anymore and can be reused.
-	 */
-	__vsp1_dl_list_put(dlm->active);
-	dlm->active = NULL;
-
-	spin_unlock(&dlm->lock);
-}
-
 /**
  * vsp1_dlm_irq_frame_end - Display list handler for the frame end interrupt
  * @dlm: the display list manager

drivers/media/platform/vsp1/vsp1_dl.h

@@ -27,7 +27,6 @@ struct vsp1_dl_manager *vsp1_dlm_create(struct vsp1_device *vsp1,
 					unsigned int prealloc);
 void vsp1_dlm_destroy(struct vsp1_dl_manager *dlm);
 void vsp1_dlm_reset(struct vsp1_dl_manager *dlm);
-void vsp1_dlm_irq_display_start(struct vsp1_dl_manager *dlm);
 bool vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm);
 
 struct vsp1_dl_list *vsp1_dl_list_get(struct vsp1_dl_manager *dlm);

drivers/media/platform/vsp1/vsp1_drm.c

@@ -32,11 +32,6 @@
  * Interrupt Handling
  */
 
-void vsp1_drm_display_start(struct vsp1_device *vsp1)
-{
-	vsp1_dlm_irq_display_start(vsp1->drm->pipe.output->dlm);
-}
-
 static void vsp1_du_pipeline_frame_end(struct vsp1_pipeline *pipe)
 {
 	struct vsp1_drm *drm = to_vsp1_drm(pipe);
@@ -224,6 +219,10 @@ int vsp1_du_setup_lif(struct device *dev, const struct vsp1_du_lif_config *cfg)
 		return ret;
 	}
 
+	/* Disable the display interrupts. */
+	vsp1_write(vsp1, VI6_DISP_IRQ_STA, 0);
+	vsp1_write(vsp1, VI6_DISP_IRQ_ENB, 0);
+
 	dev_dbg(vsp1->dev, "%s: pipeline enabled\n", __func__);
 
 	return 0;
@@ -529,13 +528,10 @@ void vsp1_du_atomic_flush(struct device *dev)
 
 	/* Start or stop the pipeline if needed. */
 	if (!vsp1->drm->num_inputs && pipe->num_inputs) {
-		vsp1_write(vsp1, VI6_DISP_IRQ_STA, 0);
-		vsp1_write(vsp1, VI6_DISP_IRQ_ENB, VI6_DISP_IRQ_ENB_DSTE);
 		spin_lock_irqsave(&pipe->irqlock, flags);
 		vsp1_pipeline_run(pipe);
 		spin_unlock_irqrestore(&pipe->irqlock, flags);
 	} else if (vsp1->drm->num_inputs && !pipe->num_inputs) {
-		vsp1_write(vsp1, VI6_DISP_IRQ_ENB, 0);
 		vsp1_pipeline_stop(pipe);
 	}
 }

drivers/media/platform/vsp1/vsp1_drm.h

@@ -50,6 +50,4 @@ int vsp1_drm_init(struct vsp1_device *vsp1);
 void vsp1_drm_cleanup(struct vsp1_device *vsp1);
 int vsp1_drm_create_links(struct vsp1_device *vsp1);
 
-void vsp1_drm_display_start(struct vsp1_device *vsp1);
-
 #endif /* __VSP1_DRM_H__ */

drivers/media/platform/vsp1/vsp1_drv.c

@@ -68,14 +68,6 @@ static irqreturn_t vsp1_irq_handler(int irq, void *data)
 		}
 	}
 
-	status = vsp1_read(vsp1, VI6_DISP_IRQ_STA);
-	vsp1_write(vsp1, VI6_DISP_IRQ_STA, ~status & VI6_DISP_IRQ_STA_DST);
-
-	if (status & VI6_DISP_IRQ_STA_DST) {
-		vsp1_drm_display_start(vsp1);
-		ret = IRQ_HANDLED;
-	}
-
 	return ret;
 }