The VSP serves as an interface to memory and a compositor to the DU. It therefore needs to be suspended after and resumed before the DU, to be properly stopped and restarted in a controlled fashion driven by the DU driver. This currently works by chance. Avoid relying on luck by enforcing the correct suspend/resume ordering with device links.
Based on similar work done by Laurent Pinchart for R-Car DU. Signed-off-by: Tommaso Merciai <[email protected]> --- drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c | 16 ++++++++++++++++ drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h | 2 ++ 2 files changed, 18 insertions(+) diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c index bd486377f037..eb626c3cc421 100644 --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c @@ -20,6 +20,7 @@ #include <drm/drm_vblank.h> #include <linux/bitops.h> +#include <linux/device.h> #include <linux/dma-mapping.h> #include <linux/of_platform.h> #include <linux/platform_device.h> @@ -293,6 +294,9 @@ static void rzg2l_du_vsp_cleanup(struct drm_device *dev, void *res) { struct rzg2l_du_vsp *vsp = res; + if (vsp->link) + device_link_del(vsp->link); + put_device(vsp->vsp); } @@ -317,6 +321,18 @@ int rzg2l_du_vsp_init(struct rzg2l_du_vsp *vsp, struct device_node *np, if (ret < 0) return ret; + /* + * Enforce suspend/resume ordering between the DU (consumer) and the + * VSP (supplier). The DU will be suspended before and resume after the + * VSP. + */ + vsp->link = device_link_add(rcdu->dev, vsp->vsp, DL_FLAG_STATELESS); + if (!vsp->link) { + dev_err(rcdu->dev, "Failed to create device link to VSP %s\n", + dev_name(vsp->vsp)); + return -EINVAL; + } + ret = vsp1_du_init(vsp->vsp); if (ret < 0) return ret; diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h index 322eb80dcbaf..a22aaf0843ed 100644 --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h @@ -15,6 +15,7 @@ #include <linux/scatterlist.h> struct device; +struct device_link; struct drm_framebuffer; struct rzg2l_du_device; struct rzg2l_du_format_info; @@ -29,6 +30,7 @@ struct rzg2l_du_vsp_plane { struct rzg2l_du_vsp { unsigned int index; struct device *vsp; + struct device_link *link; struct rzg2l_du_device *dev; }; -- 2.43.0
