drm/gem: Provide drm_gem_fb_{vmap,vunmap}()

Move framebuffer vmap code from shadow-buffered plane state into the new
interfaces drm_gem_fb_vmap() and drm_gem_fb_vunmap(). These functions
provide mappings of a framebuffer's BOs into kernel address space. No
functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

drivers/gpu/drm/drm_gem_atomic_helper.c

@@ -281,10 +281,7 @@ int drm_gem_prepare_shadow_fb(struct drm_plane *plane, struct drm_plane_state *p
 {
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	struct drm_gem_object *obj;
-	struct dma_buf_map map;
 	int ret;
-	size_t i;
 
 	if (!fb)
 		return 0;
@@ -293,27 +290,7 @@ int drm_gem_prepare_shadow_fb(struct drm_plane *plane, struct drm_plane_state *p
 	if (ret)
 		return ret;
 
-	for (i = 0; i < ARRAY_SIZE(shadow_plane_state->map); ++i) {
-		obj = drm_gem_fb_get_obj(fb, i);
-		if (!obj)
-			continue;
-		ret = drm_gem_vmap(obj, &map);
-		if (ret)
-			goto err_drm_gem_vunmap;
-		shadow_plane_state->map[i] = map;
-	}
-
-	return 0;
-
-err_drm_gem_vunmap:
-	while (i) {
-		--i;
-		obj = drm_gem_fb_get_obj(fb, i);
-		if (!obj)
-			continue;
-		drm_gem_vunmap(obj, &shadow_plane_state->map[i]);
-	}
-	return ret;
+	return drm_gem_fb_vmap(fb, shadow_plane_state->map);
 }
 EXPORT_SYMBOL(drm_gem_prepare_shadow_fb);
 
@@ -325,25 +302,17 @@ EXPORT_SYMBOL(drm_gem_prepare_shadow_fb);
  * This function implements struct &drm_plane_helper_funcs.cleanup_fb.
  * This function unmaps all buffer objects of the plane's framebuffer.
  *
- * See drm_gem_prepare_shadow_fb() for more inforamtion.
+ * See drm_gem_prepare_shadow_fb() for more information.
  */
 void drm_gem_cleanup_shadow_fb(struct drm_plane *plane, struct drm_plane_state *plane_state)
 {
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	size_t i = ARRAY_SIZE(shadow_plane_state->map);
-	struct drm_gem_object *obj;
 
 	if (!fb)
 		return;
 
-	while (i) {
-		--i;
-		obj = drm_gem_fb_get_obj(fb, i);
-		if (!obj)
-			continue;
-		drm_gem_vunmap(obj, &shadow_plane_state->map[i]);
-	}
+	drm_gem_fb_vunmap(fb, shadow_plane_state->map);
 }
 EXPORT_SYMBOL(drm_gem_cleanup_shadow_fb);
 

drivers/gpu/drm/drm_gem_framebuffer_helper.c

@@ -15,6 +15,8 @@
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_modeset_helper.h>
 
+#include "drm_internal.h"
+
 #define AFBC_HEADER_SIZE		16
 #define AFBC_TH_LAYOUT_ALIGNMENT	8
 #define AFBC_HDR_ALIGN			64
@@ -308,6 +310,74 @@ drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
 }
 EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
 
+/**
+ * drm_gem_fb_vmap - maps all framebuffer BOs into kernel address space
+ * @fb: the framebuffer
+ * @map: returns the mapping's address for each BO
+ *
+ * This function maps all buffer objects of the given framebuffer into
+ * kernel address space and stores them in struct dma_buf_map. If the
+ * mapping operation fails for one of the BOs, the function unmaps the
+ * already established mappings automatically.
+ *
+ * See drm_gem_fb_vunmap() for unmapping.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int drm_gem_fb_vmap(struct drm_framebuffer *fb, struct dma_buf_map map[DRM_FORMAT_MAX_PLANES])
+{
+	struct drm_gem_object *obj;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < DRM_FORMAT_MAX_PLANES; ++i) {
+		obj = drm_gem_fb_get_obj(fb, i);
+		if (!obj)
+			continue;
+		ret = drm_gem_vmap(obj, &map[i]);
+		if (ret)
+			goto err_drm_gem_vunmap;
+	}
+
+	return 0;
+
+err_drm_gem_vunmap:
+	while (i) {
+		--i;
+		obj = drm_gem_fb_get_obj(fb, i);
+		if (!obj)
+			continue;
+		drm_gem_vunmap(obj, &map[i]);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(drm_gem_fb_vmap);
+
+/**
+ * drm_gem_fb_vunmap - unmaps framebuffer BOs from kernel address space
+ * @fb: the framebuffer
+ * @map: mapping addresses as returned by drm_gem_fb_vmap()
+ *
+ * This function unmaps all buffer objects of the given framebuffer.
+ *
+ * See drm_gem_fb_vmap() for more information.
+ */
+void drm_gem_fb_vunmap(struct drm_framebuffer *fb, struct dma_buf_map map[DRM_FORMAT_MAX_PLANES])
+{
+	unsigned int i = DRM_FORMAT_MAX_PLANES;
+	struct drm_gem_object *obj;
+
+	while (i) {
+		--i;
+		obj = drm_gem_fb_get_obj(fb, i);
+		if (!obj)
+			continue;
+		drm_gem_vunmap(obj, &map[i]);
+	}
+}
+EXPORT_SYMBOL(drm_gem_fb_vunmap);
+
 static __u32 drm_gem_afbc_get_bpp(struct drm_device *dev,
 				  const struct drm_mode_fb_cmd2 *mode_cmd)
 {

include/drm/drm_gem_atomic_helper.h

@@ -5,6 +5,7 @@
 
 #include <linux/dma-buf-map.h>
 
+#include <drm/drm_fourcc.h>
 #include <drm/drm_plane.h>
 
 struct drm_simple_display_pipe;

include/drm/drm_gem_framebuffer_helper.h

@@ -1,6 +1,8 @@
 #ifndef __DRM_GEM_FB_HELPER_H__
 #define __DRM_GEM_FB_HELPER_H__
 
+#include <linux/dma-buf-map.h>
+
 struct drm_afbc_framebuffer;
 struct drm_device;
 struct drm_fb_helper_surface_size;
@@ -34,6 +36,9 @@ struct drm_framebuffer *
 drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
 			     const struct drm_mode_fb_cmd2 *mode_cmd);
 
+int drm_gem_fb_vmap(struct drm_framebuffer *fb, struct dma_buf_map map[DRM_FORMAT_MAX_PLANES]);
+void drm_gem_fb_vunmap(struct drm_framebuffer *fb, struct dma_buf_map map[DRM_FORMAT_MAX_PLANES]);
+
 #define drm_is_afbc(modifier) \
 	(((modifier) & AFBC_VENDOR_AND_TYPE_MASK) == DRM_FORMAT_MOD_ARM_AFBC(0))