drm/exynos: add DRM_EXYNOS_GEM_MAP ioctl

The commit d931589c01 ("drm/exynos: remove DRM_EXYNOS_GEM_MAP_OFFSET
ioctl") removed it same with the ioctl that this patch adds. The reason
that removed DRM_EXYNOS_GEM_MAP_OFFSET was we could use
DRM_IOCTL_MODE_MAP_DUMB. Both did exactly same thing.

Now we again will revive it as DRM_EXYNOS_GEM_MAP because of render
node. DRM_IOCTL_MODE_MAP_DUMB isn't permitted in render node.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_drv.c

@@ -370,6 +370,8 @@ static const struct vm_operations_struct exynos_drm_gem_vm_ops = {
 static const struct drm_ioctl_desc exynos_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(EXYNOS_GEM_CREATE, exynos_drm_gem_create_ioctl,
 			DRM_AUTH | DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(EXYNOS_GEM_MAP, exynos_drm_gem_map_ioctl,
+			DRM_AUTH | DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(EXYNOS_GEM_GET, exynos_drm_gem_get_ioctl,
 			DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(EXYNOS_VIDI_CONNECTION, vidi_connection_ioctl,

drivers/gpu/drm/exynos/exynos_drm_gem.c

@@ -280,6 +280,15 @@ int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
+int exynos_drm_gem_map_ioctl(struct drm_device *dev, void *data,
+			     struct drm_file *file_priv)
+{
+	struct drm_exynos_gem_map *args = data;
+
+	return exynos_drm_gem_dumb_map_offset(file_priv, dev, args->handle,
+					      &args->offset);
+}
+
 dma_addr_t *exynos_drm_gem_get_dma_addr(struct drm_device *dev,
 					unsigned int gem_handle,
 					struct drm_file *filp)

drivers/gpu/drm/exynos/exynos_drm_gem.h

@@ -71,6 +71,10 @@ struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
 int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
 				struct drm_file *file_priv);
 
+/* get fake-offset of gem object that can be used with mmap. */
+int exynos_drm_gem_map_ioctl(struct drm_device *dev, void *data,
+			     struct drm_file *file_priv);
+
 /*
  * get dma address from gem handle and this function could be used for
  * other drivers such as 2d/3d acceleration drivers.

include/uapi/drm/exynos_drm.h

@@ -32,6 +32,19 @@ struct drm_exynos_gem_create {
 	__u32 handle;
 };
 
+/**
+ * A structure for getting a fake-offset that can be used with mmap.
+ *
+ * @handle: handle of gem object.
+ * @reserved: just padding to be 64-bit aligned.
+ * @offset: a fake-offset of gem object.
+ */
+struct drm_exynos_gem_map {
+	__u32 handle;
+	__u32 reserved;
+	__u64 offset;
+};
+
 /**
  * A structure to gem information.
  *
@@ -284,6 +297,7 @@ struct drm_exynos_ipp_cmd_ctrl {
 };
 
 #define DRM_EXYNOS_GEM_CREATE		0x00
+#define DRM_EXYNOS_GEM_MAP		0x01
 /* Reserved 0x03 ~ 0x05 for exynos specific gem ioctl */
 #define DRM_EXYNOS_GEM_GET		0x04
 #define DRM_EXYNOS_VIDI_CONNECTION	0x07
@@ -301,7 +315,8 @@ struct drm_exynos_ipp_cmd_ctrl {
 
 #define DRM_IOCTL_EXYNOS_GEM_CREATE		DRM_IOWR(DRM_COMMAND_BASE + \
 		DRM_EXYNOS_GEM_CREATE, struct drm_exynos_gem_create)
-
+#define DRM_IOCTL_EXYNOS_GEM_MAP		DRM_IOWR(DRM_COMMAND_BASE + \
+		DRM_EXYNOS_GEM_MAP, struct drm_exynos_gem_map)
 #define DRM_IOCTL_EXYNOS_GEM_GET	DRM_IOWR(DRM_COMMAND_BASE + \
 		DRM_EXYNOS_GEM_GET,	struct drm_exynos_gem_info)