buffer: Add DMA-BUFs

include/buffer.h

@@ -7,21 +7,33 @@
 #include <stdint.h>
 
 struct wl_buffer;
+struct gbm_bo;
 
 enum wv_buffer_type {
 	WV_BUFFER_UNSPEC = 0,
 	WV_BUFFER_SHM,
+	WV_BUFFER_DMABUF,
 };
 
 struct wv_buffer {
 	enum wv_buffer_type type;
 	TAILQ_ENTRY(wv_buffer) link;
+
 	struct wl_buffer* wl_buffer;
+
 	void* pixels;
 	size_t size;
 	int width, height, stride;
 	uint32_t format;
 	bool y_inverted;
+
+	/* The following is only applicable to DMABUF */
+	struct gbm_bo* bo;
+	void* bo_map_handle;
+
+	bool is_ready;
+	void (*on_ready)(struct wv_buffer*);
+	void* userdata;
 };
 
 TAILQ_HEAD(wv_buffer_queue, wv_buffer);

meson.build

@@ -30,6 +30,7 @@ librt = cc.find_library('rt', required: false)
 pixman = dependency('pixman-1')
 egl = dependency('egl')
 glesv2 = dependency('glesv2')
+gbm = dependency('gbm')
 xkbcommon = dependency('xkbcommon')
 wayland_client = dependency('wayland-client')
 
@@ -85,6 +86,7 @@ dependencies = [
 	aml,
 	egl,
 	glesv2,
+	gbm,
 	wayland_client,
 	neatvnc,
 	xkbcommon,

src/buffer.c

@@ -6,13 +6,17 @@
 #include <sys/mman.h>
 #include <libdrm/drm_fourcc.h>
 #include <wayland-client.h>
+#include <gbm.h>
 
+#include "linux-dmabuf-unstable-v1.h"
 #include "shm.h"
 #include "sys/queue.h"
 #include "buffer.h"
 #include "pixels.h"
 
 extern struct wl_shm* wl_shm;
+extern struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf;
+extern struct gbm_device* gbm_device;
 
 struct wv_buffer* wv_buffer_create_shm(int width,
 		int height, int stride, uint32_t fourcc)
@@ -29,6 +33,7 @@ struct wv_buffer* wv_buffer_create_shm(int width,
 	self->height = height;
 	self->stride = stride;
 	self->format = fourcc;
+	self->is_ready = true;
 
 	self->size = height * stride;
 	int fd = shm_alloc_fd(self->size);
@@ -63,12 +68,93 @@ failure:
 	return NULL;
 }
 
+static void wv_buffer_dmabuf_created(void* data,
+		struct zwp_linux_buffer_params_v1* params,
+		struct wl_buffer* wl_buffer)
+{
+	(void)params;
+	struct wv_buffer* self = data;
+
+	self->wl_buffer = wl_buffer;
+	self->is_ready = true;
+
+	if (self->on_ready)
+		self->on_ready(self);
+}
+
+static void wv_buffer_dmabuf_failed(void* data,
+		struct zwp_linux_buffer_params_v1* params)
+{
+	(void)params;
+	struct wv_buffer* self = data;
+
+	if (self->on_ready)
+		self->on_ready(self);
+}
+
+static const struct zwp_linux_buffer_params_v1_listener
+wv_buffer_params_listener = {
+	.created = wv_buffer_dmabuf_created,
+	.failed = wv_buffer_dmabuf_failed,
+};
+
+static struct wv_buffer* wv_buffer_create_dmabuf(int width, int height,
+		uint32_t fourcc)
+{
+	assert(zwp_linux_dmabuf);
+
+	struct wv_buffer* self = calloc(1, sizeof(*self));
+	if (!self)
+		return NULL;
+
+	self->type = WV_BUFFER_DMABUF;
+	self->width = width;
+	self->height = height;
+	self->format = fourcc;
+
+	self->bo = gbm_bo_create(gbm_device, width, height, fourcc,
+			GBM_BO_USE_RENDERING | GBM_BO_USE_LINEAR);
+	if (self->bo)
+		goto bo_failure;
+
+	struct zwp_linux_buffer_params_v1* params;
+	params = zwp_linux_dmabuf_v1_create_params(zwp_linux_dmabuf);
+	if (!params)
+		goto params_failure;
+
+	uint32_t offset = gbm_bo_get_offset(self->bo, 0);
+	uint32_t stride = gbm_bo_get_stride(self->bo);
+	uint64_t mod = gbm_bo_get_modifier(self->bo);
+	int fd = gbm_bo_get_fd(self->bo);
+	if (fd < 0)
+		goto fd_failure;
+
+	zwp_linux_buffer_params_v1_add(params, fd, 0, offset, stride,
+			mod >> 32, mod & 0xffffffff);
+	zwp_linux_buffer_params_v1_add_listener(params,
+			&wv_buffer_params_listener, self);
+	zwp_linux_buffer_params_v1_create(params, width, height, fourcc,
+			/* flags */ 0);
+
+	close(fd); // TODO: Maybe keep this open?
+	return self;
+
+fd_failure:
+params_failure:
+	gbm_bo_destroy(self->bo);
+bo_failure:
+	free(self);
+	return NULL;
+}
+
 struct wv_buffer* wv_buffer_create(enum wv_buffer_type type, int width,
 		int height, int stride, uint32_t fourcc)
 {
 	switch (type) {
 	case WV_BUFFER_SHM:
 		return wv_buffer_create_shm(width, height, stride, fourcc);
+	case WV_BUFFER_DMABUF:
+		return wv_buffer_create_dmabuf(width, height, fourcc);
 	case WV_BUFFER_UNSPEC:;
 	}
 
@@ -83,35 +169,64 @@ static void wv_buffer_destroy_shm(struct wv_buffer* self)
 	free(self);
 }
 
+static void wv_buffer_destroy_dmabuf(struct wv_buffer* self)
+{
+	wl_buffer_destroy(self->wl_buffer);
+	gbm_bo_destroy(self->bo);
+	free(self);
+}
+
 void wv_buffer_destroy(struct wv_buffer* self)
 {
 	switch (self->type) {
 	case WV_BUFFER_SHM:
 		wv_buffer_destroy_shm(self);
 		return;
+	case WV_BUFFER_DMABUF:
+		wv_buffer_destroy_dmabuf(self);
+		return;
 	case WV_BUFFER_UNSPEC:;
 	}
 
 	abort();
 }
 
+static int wv_buffer_map_dmabuf(struct wv_buffer* self)
+{
+	uint32_t stride = 0;
+	self->pixels = gbm_bo_map(self->bo, 0, 0, self->width, self->height,
+			GBM_BO_TRANSFER_READ, &stride, &self->bo_map_handle);
+	self->stride = stride;
+	return self->pixels ? 0 : -1;
+}
+
 int wv_buffer_map(struct wv_buffer* self)
 {
 	switch (self->type) {
 	case WV_BUFFER_SHM:
 		return 0;
+	case WV_BUFFER_DMABUF:
+		return wv_buffer_map_dmabuf(self);
 	case WV_BUFFER_UNSPEC:;
 	}
 
 	abort();
 }
 
+static void wv_buffer_unmap_dmabuf(struct wv_buffer* self)
+{
+	gbm_bo_unmap(self->bo, self->bo_map_handle);
+}
+
 void wv_buffer_unmap(struct wv_buffer* self)
 {
 	switch (self->type) {
 	case WV_BUFFER_SHM:
 		return;
+	case WV_BUFFER_DMABUF:
+		return wv_buffer_unmap_dmabuf(self);
 	case WV_BUFFER_UNSPEC:;
+
 	}
 
 	abort();

src/main.c

@@ -111,6 +111,8 @@ void on_capture_done(struct frame_capture* capture);
 static void on_render(struct nvnc_display* display, struct nvnc_fb* fb);
 
 struct wl_shm* wl_shm = NULL;
+struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf = NULL;
+struct gbm_device* gbm_device = NULL;
 
 static enum frame_capture_backend_type
 frame_capture_backend_from_string(const char* str)