drm/fb-cma-helper: Add drm_fb_cma_get_gem_addr()

Add function drm_fb_cma_get_gem_addr() which return the physical address
of framebuffer (1st pixel). This function will usually be called by plane
callback (atomic_update).

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/1492164819-10513-3-git-send-email-yannick.fertre@st.com
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/drm_fb_cma_helper.c

@@ -259,6 +259,33 @@ struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
 }
 EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
 
+/**
+ * drm_fb_cma_get_gem_addr() - Get physical address for framebuffer
+ * @fb: The framebuffer
+ * @state: Which state of drm plane
+ * @plane: Which plane
+ * Return the CMA GEM address for given framebuffer.
+ *
+ * This function will usually be called from the PLANE callback functions.
+ */
+dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
+				   struct drm_plane_state *state,
+				   unsigned int plane)
+{
+	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
+	dma_addr_t paddr;
+
+	if (plane >= 4)
+		return 0;
+
+	paddr = fb_cma->obj[plane]->paddr + fb->offsets[plane];
+	paddr += fb->format->cpp[plane] * (state->src_x >> 16);
+	paddr += fb->pitches[plane] * (state->src_y >> 16);
+
+	return paddr;
+}
+EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_addr);
+
 /**
  * drm_fb_cma_prepare_fb() - Prepare CMA framebuffer
  * @plane: Which plane

include/drm/drm_fb_cma_helper.h

@@ -41,6 +41,10 @@ struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
 struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
 	unsigned int plane);
 
+dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
+				   struct drm_plane_state *state,
+				   unsigned int plane);
+
 int drm_fb_cma_prepare_fb(struct drm_plane *plane,
 			  struct drm_plane_state *state);