VKMS currently supports only one CRTC, so it make no sense to have this
index configurable. To avoid issues, replace this hardcoded index by
drm_crtc_mask when applicable.

There is no need to manually set a crtc mask on primary and cursor plane
as it is automatically set by drmm_crtc_alloc_with_planes.

In addition, this will remove the use of an uninitialized structure in
vkms_add_overlay_plane. This currently works by chance because two things:
- vkms_plane_init always set a possible_crtcs value, so the problematic
  branch is never used;
- drm_crtc_mask on an kzalloc'd drm_crtc returns BIT(0), and the VKMS CRTC
  always have this id.

Signed-off-by: Louis Chauvet <louis.chau...@bootlin.com>
---
Changes in v2:
- Applied comments from José
- Link to v1: 
https://lore.kernel.org/r/20240906-vkms-remove-index-v1-1-3cfedd8cc...@bootlin.com
---
 drivers/gpu/drm/vkms/vkms_drv.c    |  2 +-
 drivers/gpu/drm/vkms/vkms_drv.h    |  8 ++----
 drivers/gpu/drm/vkms/vkms_output.c | 54 ++++++++++++++------------------------
 drivers/gpu/drm/vkms/vkms_plane.c  |  4 +--
 4 files changed, 24 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 2d1e95cb66e5..0f6805b9fe7b 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -174,7 +174,7 @@ static int vkms_modeset_init(struct vkms_device *vkmsdev)
        dev->mode_config.preferred_depth = 0;
        dev->mode_config.helper_private = &vkms_mode_config_helpers;
 
-       return vkms_output_init(vkmsdev, 0);
+       return vkms_output_init(vkmsdev);
 }
 
 static int vkms_create(struct vkms_config *config)
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 672fe191e239..036101ee4ea1 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -212,21 +212,17 @@ int vkms_crtc_init(struct drm_device *dev, struct 
drm_crtc *crtc,
  * vkms_output_init() - Initialize all sub-components needed for a VKMS device.
  *
  * @vkmsdev: VKMS device to initialize
- * @index: CRTC which can be attached to the planes. The caller must ensure 
that
- *        @index is positive and less or equals to 31.
  */
-int vkms_output_init(struct vkms_device *vkmsdev, int index);
+int vkms_output_init(struct vkms_device *vkmsdev);
 
 /**
  * vkms_plane_init() - Initialize a plane
  *
  * @vkmsdev: VKMS device containing the plane
  * @type: type of plane to initialize
- * @index: CRTC which can be attached to the plane. The caller must ensure that
- *        @index is positive and less or equals to 31.
  */
 struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
-                                  enum drm_plane_type type, int index);
+                                  enum drm_plane_type type);
 
 /* CRC Support */
 const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
diff --git a/drivers/gpu/drm/vkms/vkms_output.c 
b/drivers/gpu/drm/vkms/vkms_output.c
index 0a5a185aa0b0..5128aa3b2eb6 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -32,29 +32,14 @@ static const struct drm_connector_helper_funcs 
vkms_conn_helper_funcs = {
        .get_modes    = vkms_conn_get_modes,
 };
 
-static int vkms_add_overlay_plane(struct vkms_device *vkmsdev, int index,
-                                 struct drm_crtc *crtc)
-{
-       struct vkms_plane *overlay;
-
-       overlay = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_OVERLAY, index);
-       if (IS_ERR(overlay))
-               return PTR_ERR(overlay);
-
-       if (!overlay->base.possible_crtcs)
-               overlay->base.possible_crtcs = drm_crtc_mask(crtc);
-
-       return 0;
-}
-
-int vkms_output_init(struct vkms_device *vkmsdev, int index)
+int vkms_output_init(struct vkms_device *vkmsdev)
 {
        struct vkms_output *output = &vkmsdev->output;
        struct drm_device *dev = &vkmsdev->drm;
        struct drm_connector *connector = &output->connector;
        struct drm_encoder *encoder = &output->encoder;
        struct drm_crtc *crtc = &output->crtc;
-       struct vkms_plane *primary, *cursor = NULL;
+       struct vkms_plane *primary, *overlay, *cursor = NULL;
        int ret;
        int writeback;
        unsigned int n;
@@ -65,34 +50,37 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
         * The overlay and cursor planes are not mandatory, but can be used to 
perform complex
         * composition.
         */
-       primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY, index);
+       primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
        if (IS_ERR(primary))
                return PTR_ERR(primary);
 
-       if (vkmsdev->config->overlay) {
-               for (n = 0; n < NUM_OVERLAY_PLANES; n++) {
-                       ret = vkms_add_overlay_plane(vkmsdev, index, crtc);
-                       if (ret)
-                               return ret;
-               }
-       }
-
        if (vkmsdev->config->cursor) {
-               cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR, index);
+               cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
                if (IS_ERR(cursor))
                        return PTR_ERR(cursor);
        }
 
-       /* [1]: Allocation of a CRTC, its index will be BIT(0) = 1 */
        ret = vkms_crtc_init(dev, crtc, &primary->base, &cursor->base);
        if (ret)
                return ret;
 
+       if (vkmsdev->config->overlay) {
+               for (n = 0; n < NUM_OVERLAY_PLANES; n++) {
+                       overlay = vkms_plane_init(vkmsdev, 
DRM_PLANE_TYPE_OVERLAY);
+                       if (IS_ERR(overlay)) {
+                               DRM_DEV_ERROR(dev->dev, "Failed to init vkms 
plane\n");
+                               ret = PTR_ERR(overlay);
+                               goto err_crtc;
+                       }
+                       overlay->base.possible_crtcs = drm_crtc_mask(crtc);
+               }
+       }
+
        ret = drm_connector_init(dev, connector, &vkms_connector_funcs,
                                 DRM_MODE_CONNECTOR_VIRTUAL);
        if (ret) {
                DRM_ERROR("Failed to init connector\n");
-               goto err_connector;
+               goto err_crtc;
        }
 
        drm_connector_helper_add(connector, &vkms_conn_helper_funcs);
@@ -103,11 +91,7 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
                DRM_ERROR("Failed to init encoder\n");
                goto err_encoder;
        }
-       /*
-        * This is a hardcoded value to select crtc for the encoder.
-        * BIT(0) here designate the first registered CRTC, the one allocated 
in [1]
-        */
-       encoder->possible_crtcs = BIT(0);
+       encoder->possible_crtcs = drm_crtc_mask(crtc);
 
        ret = drm_connector_attach_encoder(connector, encoder);
        if (ret) {
@@ -131,7 +115,7 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
 err_encoder:
        drm_connector_cleanup(connector);
 
-err_connector:
+err_crtc:
        drm_crtc_cleanup(crtc);
 
        return ret;
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c 
b/drivers/gpu/drm/vkms/vkms_plane.c
index e5c625ab8e3e..ad137c9a75f5 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -198,12 +198,12 @@ static const struct drm_plane_helper_funcs 
vkms_plane_helper_funcs = {
 };
 
 struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
-                                  enum drm_plane_type type, int index)
+                                  enum drm_plane_type type)
 {
        struct drm_device *dev = &vkmsdev->drm;
        struct vkms_plane *plane;
 
-       plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 1 << 
index,
+       plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 0,
                                           &vkms_plane_funcs,
                                           vkms_formats, 
ARRAY_SIZE(vkms_formats),
                                           NULL, type, NULL);

---
base-commit: 33c255312660653cf54f8019896b5dca28e3c580
change-id: 20240906-vkms-remove-index-3a6e04c38e02

Best regards,
-- 
Louis Chauvet <louis.chau...@bootlin.com>

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