[PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation

[Michael Walle]

mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
always have the CRTC with id 0, the ext id 1 and the third id 2. This
is only true if the paths are all available. But paths are optional (see
also comment in mtk_drm_kms_init()), e.g. the main path might not be
enabled or available at all. Then the CRTC IDs will shift one up, e.g.
ext will be 0 and the third path will be 1.

To fix that, dynamically calculate the IDs by the presence of the paths.

While at it, make the return code a signed one and return -ENOENT if no
path is found and handle the error in the callers.

Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting possible_crtc way")
Suggested-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
Signed-off-by: Michael Walle <mwalle at kernel.org>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
---
v4:
 - return -ENOENT if mtk_drm_find_possible_crtc_by_comp() doesn't find
   any path
v3:
 - use data instead of priv_n->data
 - fixed typos
 - collected Rb and Tb tags
v2:
 - iterate over all_drm_private[] to get any vdosys
 - new check if a path is available
---
 drivers/gpu/drm/mediatek/mtk_dpi.c          |  5 +-
 drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 75 ++++++++++++++++-----
 drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |  3 +-
 drivers/gpu/drm/mediatek/mtk_dsi.c          |  5 +-
 4 files changed, 68 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
index 2f931e4e2b60..f9250f7ee706 100644
--- a/drivers/gpu/drm/mediatek/mtk_dpi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
@@ -796,7 +796,10 @@ static int mtk_dpi_bind(struct device *dev, struct device *master, void *data)
 		return ret;
 	}
 
-	dpi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
+	ret = mtk_drm_find_possible_crtc_by_comp(drm_dev, dpi->dev);
+	if (ret < 0)
+		goto err_cleanup;
+	dpi->encoder.possible_crtcs = ret;
 
 	ret = drm_bridge_attach(&dpi->encoder, &dpi->bridge, NULL,
 				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
index 771f4e173353..83ae75ecd858 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
@@ -507,6 +507,27 @@ static bool mtk_drm_find_comp_in_ddp(struct device *dev,
 	return false;
 }
 
+static bool mtk_ddp_path_available(const unsigned int *path,
+				   unsigned int path_len,
+				   struct device_node **comp_node)
+{
+	unsigned int i;
+
+	if (!path)
+		return false;
+
+	for (i = 0U; i < path_len; i++) {
+		/* OVL_ADAPTOR doesn't have a device node */
+		if (path[i] == DDP_COMPONENT_DRM_OVL_ADAPTOR)
+			continue;
+
+		if (!comp_node[path[i]])
+			return false;
+	}
+
+	return true;
+}
+
 int mtk_ddp_comp_get_id(struct device_node *node,
 			enum mtk_ddp_comp_type comp_type)
 {
@@ -522,25 +543,47 @@ int mtk_ddp_comp_get_id(struct device_node *node,
 	return -EINVAL;
 }
 
-unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm,
-						struct device *dev)
+int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct device *dev)
 {
 	struct mtk_drm_private *private = drm->dev_private;
-	unsigned int ret = 0;
-
-	if (mtk_drm_find_comp_in_ddp(dev, private->data->main_path, private->data->main_len,
-				     private->ddp_comp))
-		ret = BIT(0);
-	else if (mtk_drm_find_comp_in_ddp(dev, private->data->ext_path,
-					  private->data->ext_len, private->ddp_comp))
-		ret = BIT(1);
-	else if (mtk_drm_find_comp_in_ddp(dev, private->data->third_path,
-					  private->data->third_len, private->ddp_comp))
-		ret = BIT(2);
-	else
-		DRM_INFO("Failed to find comp in ddp table\n");
+	const struct mtk_mmsys_driver_data *data;
+	struct mtk_drm_private *priv_n;
+	int i = 0, j;
+
+	for (j = 0; j < private->data->mmsys_dev_num; j++) {
+		priv_n = private->all_drm_private[j];
+		data = priv_n->data;
+
+		if (mtk_ddp_path_available(data->main_path, data->main_len,
+					   priv_n->comp_node)) {
+			if (mtk_drm_find_comp_in_ddp(dev, data->main_path,
+						     data->main_len,
+						     priv_n->ddp_comp))
+				return BIT(i);
+			i++;
+		}
+
+		if (mtk_ddp_path_available(data->ext_path, data->ext_len,
+					   priv_n->comp_node)) {
+			if (mtk_drm_find_comp_in_ddp(dev, data->ext_path,
+						     data->ext_len,
+						     priv_n->ddp_comp))
+				return BIT(i);
+			i++;
+		}
+
+		if (mtk_ddp_path_available(data->third_path, data->third_len,
+					   priv_n->comp_node)) {
+			if (mtk_drm_find_comp_in_ddp(dev, data->third_path,
+						     data->third_len,
+						     priv_n->ddp_comp))
+				return BIT(i);
+			i++;
+		}
+	}
 
-	return ret;
+	DRM_INFO("Failed to find comp in ddp table\n");
+	return -ENOENT;
 }
 
 int mtk_ddp_comp_init(struct device_node *node, struct mtk_ddp_comp *comp,
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
index febcaeef16a1..6a95df72de0a 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
@@ -277,8 +277,7 @@ static inline bool mtk_ddp_comp_disconnect(struct mtk_ddp_comp *comp, struct dev
 
 int mtk_ddp_comp_get_id(struct device_node *node,
 			enum mtk_ddp_comp_type comp_type);
-unsigned int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm,
-						struct device *dev);
+int mtk_drm_find_possible_crtc_by_comp(struct drm_device *drm, struct device *dev);
 int mtk_ddp_comp_init(struct device_node *comp_node, struct mtk_ddp_comp *comp,
 		      unsigned int comp_id);
 enum mtk_ddp_comp_type mtk_ddp_comp_get_type(unsigned int comp_id);
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index d8bfc2cce54d..d67e5c61a9b9 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -843,7 +843,10 @@ static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
 		return ret;
 	}
 
-	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+	ret = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+	if (ret < 0)
+		goto err_cleanup_encoder;
+	dsi->encoder.possible_crtcs = ret;
 
 	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
 				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
-- 
2.39.2