What is share plane:
Plane hardware only be used when the display scanout run into plane active
scanout, that means we can reuse the plane hardware resources on plane
non-active scanout.
--------------------------------------------------
| scanout |
| ------------------ |
| | parent plane | |
| | active scanout | |
| | | ----------------- |
| ------------------ | share plane 1 | |
| ----------------- |active scanout | |
| | share plane 0 | | | |
| |active scanout | ----------------- |
| | | |
| ----------------- |
--------------------------------------------------
One plane hardware can be reuse for multi-planes, we assume the first
plane is parent plane, other planes share the resource with first one.
parent plane
|---share plane 0
|---share plane 1
...
Because resource share, There are some limit on share plane: one group
of share planes need use same zpos, can not overlap, etc.
We assume share plane is a universal plane with some limit flags.
people who use the share plane need know the limit, should call the ioctl
DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
A group of share planes would has same shard id, so userspace can
group them, judge share plane's limit.
Signed-off-by: Mark Yao <mark.yao@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_crtc.c | 110 ++++++++++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/drm_ioctl.c | 5 ++
include/drm/drmP.h | 5 ++
include/drm/drm_crtc.h | 14 ++++++
include/uapi/drm/drm.h | 7 +++
5 files changed, 141 insertions(+)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 9d3f80e..3a8257e 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1426,6 +1426,96 @@ int drm_plane_init(struct drm_device *dev, struct drm_plane *plane,
EXPORT_SYMBOL(drm_plane_init);
/**
+ * drm_share_plane_init - Initialize a share plane
+ * @dev: DRM device
+ * @plane: plane object to init
+ * @parent: this plane share some resources with parent plane.
+ * @possible_crtcs: bitmask of possible CRTCs
+ * @funcs: callbacks for the new plane
+ * @formats: array of supported formats (%DRM_FORMAT_*)
+ * @format_count: number of elements in @formats
+ * @type: type of plane (overlay, primary, cursor)
+ *
+ * With this API, the plane can share hardware resources with other planes.
+ *
+ * --------------------------------------------------
+ * | scanout |
+ * | ------------------ |
+ * | | parent plane | |
+ * | | active scanout | |
+ * | | | ----------------- |
+ * | ------------------ | share plane 1 | |
+ * | ----------------- |active scanout | |
+ * | | share plane 0 | | | |
+ * | |active scanout | ----------------- |
+ * | | | |
+ * | ----------------- |
+ * --------------------------------------------------
+ *
+ * parent plane
+ * |---share plane 0
+ * |---share plane 1
+ * ...
+ *
+ * The plane hardware is used when the display scanout run into plane active
+ * scanout, that means we can reuse the plane hardware resources on plane
+ * non-active scanout.
+ *
+ * Because resource share, There are some limit on share plane: one group
+ * of share planes need use same zpos, can't not overlap, etc.
+ *
+ * Here assume share plane is a universal plane with some limit flags.
+ * people who use the share plane need know the limit, should call the ioctl
+ * DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+
+int drm_share_plane_init(struct drm_device *dev, struct drm_plane *plane,
+ struct drm_plane *parent,
+ unsigned long possible_crtcs,
+ const struct drm_plane_funcs *funcs,
+ const uint32_t *formats, unsigned int format_count,
+ enum drm_plane_type type)
+{
+ struct drm_mode_config *config = &dev->mode_config;
+ int ret;
+ int share_id;
+
+ /*
+ * TODO: only verified on ATOMIC drm driver.
+ */
+ if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
+ return -EINVAL;
+
+ ret = drm_universal_plane_init(dev, plane, possible_crtcs, funcs,
+ formats, format_count, type, NULL);
+ if (ret)
+ return ret;
+
+ if (parent) {
+ /*
+ * Can't support more than two level plane share.
+ */
+ WARN_ON(parent->parent);
+ share_id = parent->base.id;
+ plane->parent = parent;
+
+ config->num_share_plane++;
+ if (plane->type == DRM_PLANE_TYPE_OVERLAY)
+ config->num_share_overlay_plane++;
+ } else {
+ share_id = plane->base.id;
+ }
+
+ drm_object_attach_property(&plane->base,
+ config->prop_share_id, share_id);
+ return 0;
+}
+EXPORT_SYMBOL(drm_share_plane_init);
+
+/**
* drm_plane_cleanup - Clean up the core plane usage
* @plane: plane to cleanup
*
@@ -1452,6 +1542,11 @@ void drm_plane_cleanup(struct drm_plane *plane)
dev->mode_config.num_total_plane--;
if (plane->type == DRM_PLANE_TYPE_OVERLAY)
dev->mode_config.num_overlay_plane--;
+ if (plane->parent) {
+ dev->mode_config.num_share_plane--;
+ if (plane->type == DRM_PLANE_TYPE_OVERLAY)
+ dev->mode_config.num_share_overlay_plane--;
+ }
drm_modeset_unlock_all(dev);
WARN_ON(plane->state && !plane->funcs->atomic_destroy_state);
@@ -1600,6 +1695,13 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
return -ENOMEM;
dev->mode_config.plane_type_property = prop;
+ prop = drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE,
+ "SHARE_ID", 0, UINT_MAX);
+ if (!prop)
+ return -ENOMEM;
+
+ dev->mode_config.prop_share_id = prop;
+
prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
"SRC_X", 0, UINT_MAX);
if (!prop)
@@ -2431,6 +2533,12 @@ int drm_mode_getplane_res(struct drm_device *dev, void *data,
num_planes = config->num_total_plane;
else
num_planes = config->num_overlay_plane;
+ if (!file_priv->share_planes) {
+ if (file_priv->universal_planes)
+ num_planes -= config->num_share_plane;
+ else
+ num_planes -= config->num_share_overlay_plane;
+ }
/*
* This ioctl is called twice, once to determine how much space is
@@ -2449,6 +2557,8 @@ int drm_mode_getplane_res(struct drm_device *dev, void *data,
if (plane->type != DRM_PLANE_TYPE_OVERLAY &&
!file_priv->universal_planes)
continue;
+ if (plane->parent && !file_priv->share_planes)
+ continue;
if (put_user(plane->base.id, plane_ptr + copied))
return -EFAULT;
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 33af4a5..8b0120d 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -294,6 +294,11 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
return -EINVAL;
file_priv->universal_planes = req->value;
break;
+ case DRM_CLIENT_CAP_SHARE_PLANES:
+ if (req->value > 1)
+ return -EINVAL;
+ file_priv->share_planes = req->value;
+ break;
case DRM_CLIENT_CAP_ATOMIC:
if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
return -EINVAL;
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index c2fe2cf..285d177 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -314,6 +314,11 @@ struct drm_file {
/* true if client understands atomic properties */
unsigned atomic:1;
/*
+ * true if client understands share planes and
+ * hardware support share planes.
+ */
+ unsigned share_planes:1;
+ /*
* This client is the creator of @master.
* Protected by struct drm_device::master_mutex.
*/
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 9e6ab4a..a3fe9b0 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1660,6 +1660,7 @@ enum drm_plane_type {
/**
* struct drm_plane - central DRM plane control structure
* @dev: DRM device this plane belongs to
+ * @parent: this plane share some resources with parent plane.
* @head: for list management
* @name: human readable name, can be overwritten by the driver
* @base: base mode object
@@ -1679,6 +1680,7 @@ enum drm_plane_type {
*/
struct drm_plane {
struct drm_device *dev;
+ struct drm_plane *parent;
struct list_head head;
char *name;
@@ -2408,6 +2410,8 @@ struct drm_mode_config {
*/
int num_overlay_plane;
int num_total_plane;
+ int num_share_plane;
+ int num_share_overlay_plane;
struct list_head plane_list;
int num_crtc;
@@ -2428,6 +2432,9 @@ struct drm_mode_config {
struct mutex blob_lock;
+ /* pointers to share properties */
+ struct drm_property *prop_share_id;
+
/* pointers to standard properties */
struct list_head property_blob_list;
struct drm_property *edid_property;
@@ -2636,6 +2643,13 @@ extern int drm_plane_init(struct drm_device *dev,
const struct drm_plane_funcs *funcs,
const uint32_t *formats, unsigned int format_count,
bool is_primary);
+extern int drm_share_plane_init(struct drm_device *dev, struct drm_plane *plane,
+ struct drm_plane *parent,
+ unsigned long possible_crtcs,
+ const struct drm_plane_funcs *funcs,
+ const uint32_t *formats,
+ unsigned int format_count,
+ enum drm_plane_type type);
extern void drm_plane_cleanup(struct drm_plane *plane);
/**
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 452675f..01979a4 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -677,6 +677,13 @@ struct drm_get_cap {
*/
#define DRM_CLIENT_CAP_ATOMIC 3
+/**
+ * DRM_CLIENT_CAP_SHARE_PLANES
+ *
+ * If set to 1, the DRM core will expose share planes to userspace.
+ */
+#define DRM_CLIENT_CAP_SHARE_PLANES 4
+
/** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
struct drm_set_client_cap {
__u64 capability;
--
1.9.1
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