Import minigbm

Minigbm is a gbm implementation for a few DRM targets. Currently the
targets are:
- cirrus
- exynos
- gma500
- i915
- rockchip
- tegra
- udl

Right some targets are controlled with GBM_{TARGET} flags. I would
like to get to a place where we can just build all the targets in a
single library, but we need the drm headers for all targets for that
to happen so this needs more thinking.

BUG=chromium:394868,chromium:402597,chromium:413947,chromium:412508
TEST=unit tests, which I will need to import later

Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Change-Id: I36ae07f2a59827a807e19e1432891ca196b28803
Reviewed-on: https://chromium-review.googlesource.com/218030

gbm_priv.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GBM_PRIV_H
+#define GBM_PRIV_H
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include "gbm.h"
+
+struct gbm_device
+{
+	int fd;
+	struct gbm_driver *driver;
+	void *priv;
+};
+
+struct gbm_surface
+{
+};
+
+struct gbm_bo
+{
+	struct gbm_device *gbm;
+	uint32_t width;
+	uint32_t height;
+	uint32_t size;
+	uint32_t stride;
+	uint32_t format;
+	union gbm_bo_handle handle;
+	void *priv;
+	void *user_data;
+	void (*destroy_user_data)(struct gbm_bo *, void *);
+};
+
+struct gbm_driver
+{
+	char *name;
+	int (*init)(struct gbm_device *gbm);
+	void (*close)(struct gbm_device *gbm);
+	int (*bo_create)(struct gbm_bo *bo, uint32_t width, uint32_t height, uint32_t format, uint32_t flags);
+	int (*bo_destroy)(struct gbm_bo *bo);
+	struct format_supported {
+		uint32_t format;
+		enum gbm_bo_flags usage;
+	}
+	format_list[10];
+};
+
+#endif