Add initial linux_dmabuf protocol support

Tested with

    ./weston-simple-dmabuf-drm
    ./weston-simple-dmabuf-drm --import-immediate=1
    ./weston-simple-dmabuf-drm --y-inverted=1
    (and combinations)

Supports only single plane XRGB dmabufs for now.

include/wlr/render.h

@@ -123,6 +123,8 @@ bool wlr_texture_upload_drm(struct wlr_texture *tex,
 bool wlr_texture_upload_eglimage(struct wlr_texture *tex,
 	EGLImageKHR image, uint32_t width, uint32_t height);
 
+bool wlr_texture_upload_dmabuf(struct wlr_texture *tex,
+	struct wl_resource *dmabuf_resource);
 /**
  * Copies a rectangle of pixels from a wl_shm_buffer onto the texture. The
  * buffer is not accessed after this function returns. Under some circumstances,

include/wlr/render/egl.h

@@ -6,6 +6,7 @@
 #include <pixman.h>
 #include <stdbool.h>
 #include <wayland-server.h>
+#include <wlr/types/wlr_linux_dmabuf.h>
 
 struct wlr_egl {
 	EGLDisplay display;
@@ -18,6 +19,8 @@ struct wlr_egl {
 	struct {
 		bool buffer_age;
 		bool swap_buffers_with_damage;
+		bool dmabuf_import;
+		bool dmabuf_import_modifiers;
 	} egl_exts;
 
 	struct wl_display *wl_display;
@@ -61,6 +64,31 @@ EGLSurface wlr_egl_create_surface(struct wlr_egl *egl, void *window);
 EGLImageKHR wlr_egl_create_image(struct wlr_egl *egl,
 		EGLenum target, EGLClientBuffer buffer, const EGLint *attribs);
 
+/**
+ * Creates an egl image from the given dmabuf attributes. Check usability
+ * of the dmabuf with wlr_egl_check_import_dmabuf once first.
+ */
+EGLImageKHR wlr_egl_create_image_from_dmabuf(struct wlr_egl *egl,
+		struct wlr_dmabuf_buffer_attribs *attributes);
+
+/**
+ * Try to import the given dmabuf. On success return true false otherwise.
+ * If this succeeds the dmabuf can be used for rendering on a texture
+ */
+bool wlr_egl_check_import_dmabuf(struct wlr_egl *egl,
+		struct wlr_dmabuf_buffer *dmabuf);
+
+/**
+ * Get the available dmabuf formats
+ */
+int wlr_egl_get_dmabuf_formats(struct wlr_egl *egl, int **formats);
+
+/**
+ * Get the available dmabuf modifiers for a given format
+ */
+int wlr_egl_get_dmabuf_modifiers(struct wlr_egl *egl, int format,
+		uint64_t **modifiers);
+
 /**
  * Destroys an egl image created with the given wlr_egl.
  */

include/wlr/render/interface.h

@@ -8,6 +8,7 @@
 #include <wlr/render.h>
 #include <wlr/types/wlr_box.h>
 #include <wlr/types/wlr_output.h>
+#include <wlr/types/wlr_linux_dmabuf.h>
 
 struct wlr_renderer_impl;
 
@@ -58,6 +59,8 @@ struct wlr_texture_impl {
 		struct wl_resource *drm_buf);
 	bool (*upload_eglimage)(struct wlr_texture *texture, EGLImageKHR image,
 		uint32_t width, uint32_t height);
+	bool (*upload_dmabuf)(struct wlr_texture *texture,
+		struct wl_resource *dmabuf_resource);
 	void (*get_matrix)(struct wlr_texture *state,
 		float (*matrix)[16], const float (*projection)[16], int x, int y);
 	void (*get_buffer_size)(struct wlr_texture *texture,

include/wlr/types/wlr_linux_dmabuf.h

@@ -0,0 +1,84 @@
+#ifndef WLR_TYPES_WLR_LINUX_DMABUF_H
+#define WLR_TYPES_WLR_LINUX_DMABUF_H
+
+#define WLR_LINUX_DMABUF_MAX_PLANES 4
+
+#include <stdint.h>
+#include <wayland-server-protocol.h>
+
+/* So we don't have to pull in linux specific drm headers */
+#ifndef DRM_FORMAT_MOD_INVALID
+#define DRM_FORMAT_MOD_INVALID ((1ULL<<56) - 1)
+#endif
+
+struct wlr_dmabuf_buffer_attribs {
+	/* set via params_add */
+	int n_planes;
+	uint32_t offset[WLR_LINUX_DMABUF_MAX_PLANES];
+	uint32_t stride[WLR_LINUX_DMABUF_MAX_PLANES];
+	uint64_t modifier[WLR_LINUX_DMABUF_MAX_PLANES];
+	int fd[WLR_LINUX_DMABUF_MAX_PLANES];
+	/* set via params_create */
+	int32_t width;
+	int32_t height;
+	uint32_t format;
+	uint32_t flags; /* enum zlinux_buffer_params_flags */
+};
+
+struct wlr_dmabuf_buffer {
+	struct wlr_egl *egl;
+	struct wl_resource *buffer_resource;
+	struct wl_resource *params_resource;
+	struct wlr_dmabuf_buffer_attribs attributes;
+};
+
+/**
+ * Returns true if the given resource was created via the linux-dmabuf
+ * buffer protocol, false otherwise
+ */
+bool wlr_dmabuf_resource_is_buffer(struct wl_resource *buffer_resource);
+
+/**
+ * Returns the wlr_dmabuf_buffer if the given resource was created
+ * via the linux-dmabuf buffer protocol
+ */
+struct wlr_dmabuf_buffer *wlr_dmabuf_buffer_from_buffer_resource(
+	struct wl_resource *buffer_resource);
+
+/**
+ * Returns the wlr_dmabuf_buffer if the given resource was created
+ * via the linux-dmabuf params protocol
+ */
+struct wlr_dmabuf_buffer *wlr_dmabuf_buffer_from_params_resource(
+	struct wl_resource *params_resource);
+
+/**
+ * Returns true if the given dmabuf has y-axis inverted, false otherwise
+ */
+bool wlr_dmabuf_buffer_has_inverted_y(struct wlr_dmabuf_buffer *dmabuf);
+
+/* the protocol interface */
+struct wlr_linux_dmabuf {
+	struct wl_global *wl_global;
+	struct wl_listener display_destroy;
+	struct wlr_egl *egl;
+};
+
+/**
+ * Create linux-dmabuf interface
+ */
+struct wlr_linux_dmabuf *wlr_linux_dmabuf_create(struct wl_display *display,
+	struct wlr_egl *egl);
+/**
+ * Destroy the linux-dmabuf interface
+ */
+void wlr_linux_dmabuf_destroy(struct wlr_linux_dmabuf *linux_dmabuf);
+
+/**
+ * Returns the wlr_linux_dmabuf if the given resource was created
+ * via the linux_dmabuf protocol
+ */
+struct wlr_linux_dmabuf *wlr_linux_dmabuf_from_resource(
+	struct wl_resource *resource);
+
+#endif