[PATCH RFC 06/15] drm/vkms: Introduce plane configuration

From: Louis Chauvet
Date: Wed Aug 14 2024 - 10:39:26 EST


The current vkms driver only allows the usage of one primary, eight
overlays and one cursor plane. This new configuration structure aims to
make the configuration more flexible.

Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
---
drivers/gpu/drm/vkms/vkms_config.c | 90 ++++++++++++++++++++++++++++++++++++--
drivers/gpu/drm/vkms/vkms_config.h | 44 +++++++++++++++++--
drivers/gpu/drm/vkms/vkms_drv.c | 33 +++++---------
drivers/gpu/drm/vkms/vkms_plane.c | 4 +-
drivers/gpu/drm/vkms/vkms_plane.h | 3 +-
5 files changed, 141 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 27b49a2ad9c8..b1c6160d350f 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -13,32 +13,111 @@ struct vkms_config *vkms_config_create(void)
if (!config)
return ERR_PTR(-ENOMEM);

+ INIT_LIST_HEAD(&config->planes);
+
return config;
}

struct vkms_config *vkms_config_alloc_default(bool enable_writeback, bool enable_overlay,
bool enable_cursor)
{
+ struct vkms_config_plane *plane;
struct vkms_config *vkms_config = vkms_config_create();

if (IS_ERR(vkms_config))
return vkms_config;

vkms_config->writeback = enable_writeback;
- vkms_config->overlay = enable_overlay;
- vkms_config->cursor = enable_cursor;
+
+ plane = vkms_config_create_plane(vkms_config);
+ if (!plane)
+ goto err_alloc;
+
+ plane->type = DRM_PLANE_TYPE_PRIMARY;
+
+ if (enable_overlay) {
+ for (int i = 0; i < NUM_OVERLAY_PLANES; i++) {
+ plane = vkms_config_create_plane(vkms_config);
+ if (!plane)
+ goto err_alloc;
+ plane->type = DRM_PLANE_TYPE_OVERLAY;
+ }
+ }
+ if (enable_cursor) {
+ plane = vkms_config_create_plane(vkms_config);
+ if (!plane)
+ goto err_alloc;
+ plane->type = DRM_PLANE_TYPE_CURSOR;
+ }

return vkms_config;
+err_alloc:
+ vkms_config_destroy(vkms_config);
+ return ERR_PTR(-ENOMEM);
}

+struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *vkms_config)
+{
+ if (!vkms_config)
+ return NULL;
+
+ struct vkms_config_plane *vkms_config_overlay = kzalloc(sizeof(*vkms_config_overlay),
+ GFP_KERNEL);
+
+ if (!vkms_config_overlay)
+ return NULL;
+
+ vkms_config_overlay->type = DRM_PLANE_TYPE_OVERLAY;
+
+ list_add(&vkms_config_overlay->link, &vkms_config->planes);
+
+ return vkms_config_overlay;
+}
+
+void vkms_config_delete_plane(struct vkms_config_plane *vkms_config_overlay)
+{
+ if (!vkms_config_overlay)
+ return;
+ list_del(&vkms_config_overlay->link);
+ kfree(vkms_config_overlay);
+}

void vkms_config_destroy(struct vkms_config *config)
{
+ struct vkms_config_plane *vkms_config_plane, *tmp_plane;
+
+ list_for_each_entry_safe(vkms_config_plane, tmp_plane, &config->planes, link) {
+ vkms_config_delete_plane(vkms_config_plane);
+ }
+
kfree(config);
}

bool vkms_config_is_valid(struct vkms_config *config)
{
+ struct vkms_config_plane *config_plane;
+
+ bool has_cursor = false;
+ bool has_primary = false;
+
+ list_for_each_entry(config_plane, &config->planes, link) {
+ if (config_plane->type == DRM_PLANE_TYPE_PRIMARY) {
+ // Multiple primary planes for only one CRTC
+ if (has_primary)
+ return false;
+ has_primary = true;
+ }
+ if (config_plane->type == DRM_PLANE_TYPE_CURSOR) {
+ // Multiple cursor planes for only one CRTC
+ if (has_cursor)
+ return false;
+ has_cursor = true;
+ }
+ }
+
+ if (!has_primary)
+ return false;
+
return true;
}

@@ -47,10 +126,13 @@ static int vkms_config_show(struct seq_file *m, void *data)
struct drm_debugfs_entry *entry = m->private;
struct drm_device *dev = entry->dev;
struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
+ struct vkms_config_plane *config_plane;

seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
- seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
- seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
+ list_for_each_entry(config_plane, &vkmsdev->config->planes, link) {
+ seq_puts(m, "plane:\n");
+ seq_printf(m, "\ttype: %d\n", config_plane->type);
+ }

return 0;
}
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 50c3b021a66b..77c1c3934189 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -10,15 +10,34 @@
* struct vkms_config - General configuration for VKMS driver
*
* @writeback: If true, a writeback buffer can be attached to the CRTC
- * @cursor: If true, a cursor plane is created in the VKMS device
- * @overlay: If true, NUM_OVERLAY_PLANES will be created for the VKMS device
+ * @planes: List of planes configured for this device. They are created by the function
+ * vkms_config_create_plane().
* @dev: Used to store the current vkms device. Only set when the device is instancied.
*/
struct vkms_config {
bool writeback;
- bool cursor;
- bool overlay;
struct vkms_device *dev;
+
+ struct list_head planes;
+};
+
+/**
+ * struct vkms_config_plane
+ *
+ * @link: Link to the others planes
+ * @type: Type of the plane. The creator of configuration needs to ensures that at least one
+ * plane is primary.
+ * @plane: Internal usage. This pointer should never be considered as valid. It can be used to
+ * store a temporary reference to a vkms plane during device creation. This pointer is
+ * not managed by the configuration and must be managed by other means.
+ */
+struct vkms_config_plane {
+ struct list_head link;
+
+ enum drm_plane_type type;
+
+ /* Internal usage */
+ struct vkms_plane *plane;
};

/**
@@ -42,6 +61,23 @@ void vkms_config_destroy(struct vkms_config *config);
*/
bool vkms_config_is_valid(struct vkms_config *vkms_config);

+/**
+ * vkms_config_create_plane() - Create a plane configuration
+ *
+ * This will allocate and add a new plane to @vkms_config. This plane will have by default the
+ * maximum supported values.
+ * @vkms_config: Configuration where to insert new plane
+ */
+struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *vkms_config);
+
+/**
+ * vkms_config_delete_plane() - Remove a plane configuration and frees its memory
+ *
+ * This will delete a plane configuration from the parent configuration. This will NOT
+ * cleanup and frees the vkms_plane that can be stored in @vkms_config_plane.
+ * @vkms_config_plane: Plane configuration to cleanup
+ */
+void vkms_config_delete_plane(struct vkms_config_plane *vkms_config_plane);

/**
* vkms_config_alloc_default() - Allocate the configuration for the default device
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index af237daa3c5c..403006a0bb61 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -153,38 +153,27 @@ static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {

static int vkms_output_init(struct vkms_device *vkmsdev)
{
+ struct vkms_config_plane *config_plane;
struct drm_device *dev = &vkmsdev->drm;
struct drm_connector *connector;
struct drm_encoder *encoder;
struct vkms_crtc *crtc;
struct drm_plane *plane;
- struct vkms_plane *primary, *cursor, *overlay = NULL;
+ struct vkms_plane *primary, *cursor = NULL;
int ret;
int writeback;
- unsigned int n;

- /*
- * Initialize used plane. One primary plane is required to perform the composition.
- *
- * 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);
- if (IS_ERR(primary))
- return PTR_ERR(primary);
-
- 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))
- return PTR_ERR(overlay);
+ list_for_each_entry(config_plane, &vkmsdev->config->planes, link) {
+ config_plane->plane = vkms_plane_init(vkmsdev, config_plane);
+ if (IS_ERR(config_plane->plane)) {
+ ret = PTR_ERR(config_plane->plane);
+ return ret;
}
- }

- if (vkmsdev->config->cursor) {
- cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
- if (IS_ERR(cursor))
- return PTR_ERR(cursor);
+ if (config_plane->type == DRM_PLANE_TYPE_PRIMARY)
+ primary = config_plane->plane;
+ else if (config_plane->type == DRM_PLANE_TYPE_CURSOR)
+ cursor = config_plane->plane;
}

/* [1]: Initialize the crtc component */
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index b5740c27180b..dc9bccf60071 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -223,7 +223,7 @@ 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)
+ struct vkms_config_plane *config)
{
struct drm_device *dev = &vkmsdev->drm;
struct vkms_plane *plane;
@@ -231,7 +231,7 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 0,
&vkms_plane_funcs,
vkms_formats, ARRAY_SIZE(vkms_formats),
- NULL, type, NULL);
+ NULL, config->type, NULL);
if (IS_ERR(plane))
return plane;

diff --git a/drivers/gpu/drm/vkms/vkms_plane.h b/drivers/gpu/drm/vkms/vkms_plane.h
index 95b2428331b8..82049966ee7e 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.h
+++ b/drivers/gpu/drm/vkms/vkms_plane.h
@@ -9,6 +9,7 @@
#include <linux/iosys-map.h>

#include "vkms_formats.h"
+#include "vkms_config.h"

struct vkms_plane {
struct drm_plane base;
@@ -54,7 +55,7 @@ struct vkms_frame_info {
* @type: type of plane to initialize
*/
struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
- enum drm_plane_type type);
+ struct vkms_config_plane *config);

#define drm_plane_state_to_vkms_plane_state(target) \
container_of(target, struct vkms_plane_state, base.base)

--
2.44.2