drm/vgem: implement virtual GEM

This patch implements the virtual GEM driver with PRIME sharing which
allows vgem to import a gem object from other drivers for the purpose
of mmap-ing them to userspace. The mmap is done using the mmap
operation exported by other drivers.

v2: remove platform_device and do not attach to dma bufs
v3: use drm helpers for get/put pages
v4: correct dumb create pitch

Reviewed-by: Rob Clark <robdclark@gmail.com> (v3)
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org> (v3)
Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Zach Reizner <zachr@google.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/vgem/vgem_drv.h

@@ -0,0 +1,57 @@
+/*
+ * Copyright © 2012 Intel Corporation
+ * Copyright © 2014 The Chromium OS Authors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Ben Widawsky <ben@bwidawsk.net>
+ *
+ */
+
+#ifndef _VGEM_DRV_H_
+#define _VGEM_DRV_H_
+
+#include <drm/drmP.h>
+#include <drm/drm_gem.h>
+
+#define to_vgem_bo(x) container_of(x, struct drm_vgem_gem_object, base)
+struct drm_vgem_gem_object {
+	struct drm_gem_object base;
+	struct page **pages;
+	bool use_dma_buf;
+};
+
+/* vgem_drv.c */
+extern void vgem_gem_put_pages(struct drm_vgem_gem_object *obj);
+extern int vgem_gem_get_pages(struct drm_vgem_gem_object *obj);
+
+/* vgem_dma_buf.c */
+extern struct sg_table *vgem_gem_prime_get_sg_table(
+			struct drm_gem_object *gobj);
+extern int vgem_gem_prime_pin(struct drm_gem_object *gobj);
+extern void vgem_gem_prime_unpin(struct drm_gem_object *gobj);
+extern void *vgem_gem_prime_vmap(struct drm_gem_object *gobj);
+extern void vgem_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
+extern struct drm_gem_object *vgem_gem_prime_import(struct drm_device *dev,
+						    struct dma_buf *dma_buf);
+
+
+#endif