4.13.5. plane代码分析
4.13.5.1. struct drm_plane结构体
struct drm_plane {
/** @dev: DRM device this plane belongs to */
struct drm_device *dev;
struct list_head head;
char *name;
struct drm_modeset_lock mutex;
/** @base: base mode object */
struct drm_mode_object base;
//plane绑定的crtc
uint32_t possible_crtcs;
//plane支持的fb像素format类型数组，format类型如DRM_FORMAT_ARGB8888
uint32_t *format_types;
//plane支持的fb像素format类型数组大小
unsigned int format_count;
bool format_default;
//modifier数组，其存放的值DRM_FORMAT_MOD_LINEAR/DRM_FORMAT_MOD_X_TILED
uint64_t *modifiers;
//modifier数组大小
unsigned int modifier_count;
//d当前绑定的crtc
struct drm_crtc *crtc;
//no-atomic drivers用来标识当前绑定的fb
struct drm_framebuffer *fb;
//对于no-atomic drivers, old_fb用于在modeset操作时跟踪老的fb
struct drm_framebuffer *old_fb;
/** @funcs: plane control functions */
const struct drm_plane_funcs *funcs;
/** @properties: property tracking for this plane */
struct drm_object_properties properties;
/** @type: Type of plane, see &enum drm_plane_type for details. */
enum drm_plane_type type;
/**
* @index: Position inside the mode_config.list, can be used as an array
* index. It is invariant over the lifetime of the plane.
*/
unsigned index;
/** @helper_private: mid-layer private data */
const struct drm_plane_helper_funcs *helper_private;
//表示plane的各种状态，如其绑定的crtc/fb等，用于atomic操作
struct drm_plane_state *state;
/**
* @alpha_property:
* Optional alpha property for this plane. See
* drm_plane_create_alpha_property().
*/
struct drm_property *alpha_property;
/**
* @zpos_property:
* Optional zpos property for this plane. See
* drm_plane_create_zpos_property().
*/
struct drm_property *zpos_property;
/**
* @rotation_property:
* Optional rotation property for this plane. See
* drm_plane_create_rotation_property().
*/
struct drm_property *rotation_property;
/**
* @blend_mode_property:
* Optional "pixel blend mode" enum property for this plane.
* Blend mode property represents the alpha blending equation selection,
* describing how the pixels from the current plane are composited with
* the background.
*/
struct drm_property *blend_mode_property;
/**
* @color_encoding_property:
*
* Optional "COLOR_ENCODING" enum property for specifying
* color encoding for non RGB formats.
* See drm_plane_create_color_properties().
*/
struct drm_property *color_encoding_property;
/**
* @color_range_property:
*
* Optional "COLOR_RANGE" enum property for specifying
* color range for non RGB formats.
* See drm_plane_create_color_properties().
*/
struct drm_property *color_range_property;
};
4.13.5.2. drm_universal_plane_init
int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,
uint32_t possible_crtcs,
const struct drm_plane_funcs *funcs,
const uint32_t *formats, unsigned int format_count,
const uint64_t *format_modifiers,
enum drm_plane_type type,
const char *name, ...)
{
struct drm_mode_config *config = &dev->mode_config;
unsigned int format_modifier_count = 0;
int ret;
/* plane index is used with 32bit bitmasks */
if (WARN_ON(config->num_total_plane >= 32))
return -EINVAL;
WARN_ON(drm_drv_uses_atomic_modeset(dev) &&
(!funcs->atomic_destroy_state ||
!funcs->atomic_duplicate_state));
//创建一个类型为DRM_MODE_OBJECT_PLANE的
ret = drm_mode_object_add(dev, &plane->base, DRM_MODE_OBJECT_PLANE);
if (ret)
return ret;
drm_modeset_lock_init(&plane->mutex);
plane->base.properties = &plane->properties;
plane->dev = dev;
plane->funcs = funcs;
plane->format_types = kmalloc_array(format_count, sizeof(uint32_t),
GFP_KERNEL);
if (!plane->format_types) {
DRM_DEBUG_KMS("out of memory when allocating plane\n");
drm_mode_object_unregister(dev, &plane->base);
return -ENOMEM;
}
/*
* First driver to need more than 64 formats needs to fix this. Each
* format is encoded as a bit and the current code only supports a u64.
*/
if (WARN_ON(format_count > 64))
return -EINVAL;
if (format_modifiers) {
const uint64_t *temp_modifiers = format_modifiers;
while (*temp_modifiers++ != DRM_FORMAT_MOD_INVALID)
format_modifier_count++;
}
if (format_modifier_count)
config->allow_fb_modifiers = true;
plane->modifier_count = format_modifier_count;
plane->modifiers = kmalloc_array(format_modifier_count,
sizeof(format_modifiers[0]),
GFP_KERNEL);
if (format_modifier_count && !plane->modifiers) {
DRM_DEBUG_KMS("out of memory when allocating plane\n");
kfree(plane->format_types);
drm_mode_object_unregister(dev, &plane->base);
return -ENOMEM;
}
if (name) {
va_list ap;
va_start(ap, name);
plane->name = kvasprintf(GFP_KERNEL, name, ap);
va_end(ap);
} else {
plane->name = kasprintf(GFP_KERNEL, "plane-%d",
drm_num_planes(dev));
}
if (!plane->name) {
kfree(plane->format_types);
kfree(plane->modifiers);
drm_mode_object_unregister(dev, &plane->base);
return -ENOMEM;
}
memcpy(plane->format_types, formats, format_count * sizeof(uint32_t));
plane->format_count = format_count;
memcpy(plane->modifiers, format_modifiers,
format_modifier_count * sizeof(format_modifiers[0]));
plane->possible_crtcs = possible_crtcs;
plane->type = type;
list_add_tail(&plane->head, &config->plane_list);
plane->index = config->num_total_plane++;
drm_object_attach_property(&plane->base,
config->plane_type_property,
plane->type);
if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
drm_object_attach_property(&plane->base, config->prop_fb_id, 0);
drm_object_attach_property(&plane->base, config->prop_in_fence_fd, -1);
drm_object_attach_property(&plane->base, config->prop_crtc_id, 0);
drm_object_attach_property(&plane->base, config->prop_crtc_x, 0);
drm_object_attach_property(&plane->base, config->prop_crtc_y, 0);
drm_object_attach_property(&plane->base, config->prop_crtc_w, 0);
drm_object_attach_property(&plane->base, config->prop_crtc_h, 0);
drm_object_attach_property(&plane->base, config->prop_src_x, 0);
drm_object_attach_property(&plane->base, config->prop_src_y, 0);
drm_object_attach_property(&plane->base, config->prop_src_w, 0);
drm_object_attach_property(&plane->base, config->prop_src_h, 0);
}
if (config->allow_fb_modifiers)
create_in_format_blob(dev, plane);
return 0;
}
4.13.5.3. func
struct drm_plane_funcs
/**
* struct drm_plane_funcs - driver plane control functions
*/
struct drm_plane_funcs {
/*使能配置plane的crtc和framebuffer.src_x/src_y/src_w/src_h指定fb的源区域
*crtc_x/crtc_y/crtc_w/crtc_h指定其显示在crtc上的目标区域
*atomic操作使用drm_atomic_helper_update_plane实现
*/
int (*update_plane)(struct drm_plane *plane,
struct drm_crtc *crtc, struct drm_framebuffer *fb,
int crtc_x, int crtc_y,
unsigned int crtc_w, unsigned int crtc_h,
uint32_t src_x, uint32_t src_y,
uint32_t src_w, uint32_t src_h,
struct drm_modeset_acquire_ctx *ctx);
/*DRM_IOCTL_MODE_SETPLANE IOCTL调用时，fb id参数，如果为0，就会调用该接口
*关闭plane， atomic modeset使用drm_atomic_helper_disable_plane()实现该hook
*/
int (*disable_plane)(struct drm_plane *plane,
struct drm_modeset_acquire_ctx *ctx);
//该接口仅在driver卸载的时候通过drm_mode_config_cleanup()调用来清空plane资源
void (*destroy)(struct drm_plane *plane);
/*reset plane的软硬件状态， 通过drm_mode_config_reset接口调用
*atomic drivers 使用drm_atomic_helper_plane_reset()实现该hook*/
void (*reset)(struct drm_plane *plane);
/*设置属性的legacy入口， atomic drivers不使用*/
int (*set_property)(struct drm_plane *plane,
struct drm_property *property, uint64_t val);
/*复制plane state, atomic driver必须要有该接口
*drm_atomic_get_plane_state会调用到该hook*/
struct drm_plane_state *(*atomic_duplicate_state)(struct drm_plane *plane);
//销毁plane state
void (*atomic_destroy_state)(struct drm_plane *plane,
struct drm_plane_state *state);
/*设置驱动自定义的属性， 通过drm_atomic_plane_set_property调用*/
int (*atomic_set_property)(struct drm_plane *plane,
struct drm_plane_state *state,
struct drm_property *property,
uint64_t val);
//获取驱动自定义的属性， 通过drm_atomic_plane_get_property调用
int (*atomic_get_property)(struct drm_plane *plane,
const struct drm_plane_state *state,
struct drm_property *property,
uint64_t *val);
//drm_dev_register接口调用后，调用该hook注册额外的用户接口
int (*late_register)(struct drm_plane *plane);
//drm_dev_unregister()前调用，unregister用户空间接口
void (*early_unregister)(struct drm_plane *plane);
//打印plane state, drm_atomic_plane_print_state()会调用
void (*atomic_print_state)(struct drm_printer *p,
const struct drm_plane_state *state);
//检查format和modifier是否有效
bool (*format_mod_supported)(struct drm_plane *plane, uint32_t format,
uint64_t modifier);
};
struct drm_plane_helper_funcs
struct drm_plane_helper_funcs {
//准备fb，主要包括设置fb fence, 映射fb虚拟地址等
int (*prepare_fb)(struct drm_plane *plane,
struct drm_plane_state *new_state);
//和prepare_fb是相反的操作，比如解除fb虚拟地址的映射
void (*cleanup_fb)(struct drm_plane *plane,
struct drm_plane_state *old_state);
//可选的检查plane属性的约束项
int (*atomic_check)(struct drm_plane *plane,
struct drm_atomic_state *state);
/*更新plane的属性状态到软硬件中， 这个接口才是真正更新参数*/
void (*atomic_update)(struct drm_plane *plane,
struct drm_atomic_state *state);
//disable plane 非必需，不做介绍
void (*atomic_disable)(struct drm_plane *plane,
struct drm_atomic_state *state);
//异步检查 后续了解
int (*atomic_async_check)(struct drm_plane *plane,
struct drm_atomic_state *state);
//异步更新，后续了解
void (*atomic_async_update)(struct drm_plane *plane,
struct drm_atomic_state *state);
};