[PATCH weston v2 1/3] gl-renderer: Add EGLDevice enumeration support

[Miguel A. Vico]

EGLDevice provides means to enumerate native devices.

In preparation for follow-on changes to support frame presentation
through EGLDevice+EGLOutput, this change adds both
gl_renderer_get_devices() and gl_renderer_get_drm_device_file()
functions which will help to enumerate EGLDevices and match them to DRM
devices.

Signed-off-by: Miguel A Vico Moya <mvicomoya at nvidia.com>
Reviewed-by: Andy Ritger <aritger at nvidia.com>
Reviewed-by: Adam Cheney <acheney at nvidia.com>
Reviewed-by: James Jones <jajones at nvidia.com>
---
 src/gl-renderer.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/gl-renderer.h |  7 +++++
 2 files changed, 95 insertions(+), 1 deletion(-)

diff --git a/src/gl-renderer.c b/src/gl-renderer.c
index db5f53d..e11db9e 100644
--- a/src/gl-renderer.c
+++ b/src/gl-renderer.c
@@ -3175,6 +3175,90 @@ gl_renderer_setup(struct weston_compositor *ec, EGLSurface egl_surface)
 	return 0;
 }
 
+static int
+gl_renderer_get_devices(EGLint max_devices, EGLDeviceEXT *devices,
+			EGLint *num_devices)
+{
+	const char *extensions;
+	PFNEGLQUERYDEVICESEXTPROC query_devices;
+
+	extensions = (const char *)eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
+	if (!extensions) {
+		weston_log("Retrieving EGL extension string failed.\n");
+		return -1;
+	}
+
+	if (!check_extension(extensions, "EGL_EXT_device_base") &&
+	    (!check_extension(extensions, "EGL_EXT_device_query") ||
+	     !check_extension(extensions, "EGL_EXT_device_enumeration"))) {
+		weston_log("EGL_EXT_device_base not supported\n");
+		return -1;
+	}
+
+	query_devices = (void *) eglGetProcAddress("eglQueryDevicesEXT");
+	if (!query_devices) {
+		weston_log("Failed to get eglQueryDevicesEXT function\n");
+		return -1;
+	}
+
+	if (query_devices(max_devices, devices, num_devices) != EGL_TRUE) {
+		weston_log("Failed to query EGL Devices\n");
+		gl_renderer_print_egl_error_state();
+		return -1;
+	}
+
+	return 0;
+}
+
+static int
+gl_renderer_get_drm_device_file(EGLDeviceEXT device,
+				const char **drm_device_file)
+{
+	const char *exts;
+	PFNEGLQUERYDEVICESTRINGEXTPROC query_device_string;
+
+	exts = (const char *)eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
+	if (!exts) {
+		weston_log("Retrieving EGL extension string failed.\n");
+		return -1;
+	}
+
+	if (!check_extension(exts, "EGL_EXT_device_base") &&
+	    (!check_extension(exts, "EGL_EXT_device_query") ||
+	     !check_extension(exts, "EGL_EXT_device_enumeration"))) {
+		weston_log("EGL_EXT_device_base not supported.\n");
+		return -1;
+	}
+
+	query_device_string =
+		(void *) eglGetProcAddress("eglQueryDeviceStringEXT");
+	if (!query_device_string) {
+		weston_log("Failed to get eglQueryDeviceStringEXT function\n");
+		return -1;
+	}
+
+	exts = query_device_string(device, EGL_EXTENSIONS);
+	if (!exts) {
+		weston_log("Retrieving EGL extension string failed.\n");
+		return -1;
+	}
+
+	if (!check_extension(exts, "EGL_EXT_device_drm")) {
+		weston_log("EGL_EXT_device_drm not supported.\n");
+		return -1;
+	}
+
+	(*drm_device_file) = query_device_string(device,
+						 EGL_DRM_DEVICE_FILE_EXT);
+	if (*drm_device_file == NULL) {
+		weston_log("Failed to query DRM device name.\n");
+		gl_renderer_print_egl_error_state();
+		return -1;
+	}
+
+	return 0;
+}
+
 WL_EXPORT struct gl_renderer_interface gl_renderer_interface = {
 	.opaque_attribs = gl_renderer_opaque_attribs,
 	.alpha_attribs = gl_renderer_alpha_attribs,
@@ -3185,5 +3269,8 @@ WL_EXPORT struct gl_renderer_interface gl_renderer_interface = {
 	.output_destroy = gl_renderer_output_destroy,
 	.output_surface = gl_renderer_output_surface,
 	.output_set_border = gl_renderer_output_set_border,
-	.print_egl_error_state = gl_renderer_print_egl_error_state
+	.print_egl_error_state = gl_renderer_print_egl_error_state,
+
+	.get_devices = gl_renderer_get_devices,
+	.get_drm_device_file = gl_renderer_get_drm_device_file
 };
diff --git a/src/gl-renderer.h b/src/gl-renderer.h
index ecd2168..4d8a98e 100644
--- a/src/gl-renderer.h
+++ b/src/gl-renderer.h
@@ -129,5 +129,12 @@ struct gl_renderer_interface {
 				  int32_t tex_width, unsigned char *data);
 
 	void (*print_egl_error_state)(void);
+
+	int (*get_devices)(EGLint max_devices,
+			   EGLDeviceEXT *devices,
+			   EGLint *num_devices);
+
+	int (*get_drm_device_file)(EGLDeviceEXT device,
+				   const char **drm_device_file);
 };
 
-- 
2.8.0