[PATCH 1/4] drm/fb-dma-helper: Add drm_fb_dma_get_gem_clipped_addr()

[Chen-Yu Tsai]

drm_fb_dma_get_gem_addr() returns the DMA address to the "unclipped"
framebuffer. However some display drivers want the "clipped" framebuffer
instead, as they are also using the clipped coordinates to program the
hardware.

Some of these drivers are open-coding drm_fb_dma_get_gem_addr() with
the source coordinates replaced, while others have been incorrectly
converted to using drm_fb_dma_get_gem_addr(), which would end up
causing incorrect parts of the framebuffer to be displayed if it were
somehow clipped.

Add drm_fb_dma_get_gem_clipped_addr(), a "clipped" version of
drm_fb_dma_get_gem_addr() for these drivers to use.

Cc: <stable at vger.kernel.org> # dependency for next patch
Signed-off-by: Chen-Yu Tsai <wenst at chromium.org>
---
 drivers/gpu/drm/drm_fb_dma_helper.c | 63 +++++++++++++++++++++--------
 include/drm/drm_fb_dma_helper.h     |  4 ++
 2 files changed, 51 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/drm_fb_dma_helper.c b/drivers/gpu/drm/drm_fb_dma_helper.c
index fd71969d2fb1..a260e7cd5667 100644
--- a/drivers/gpu/drm/drm_fb_dma_helper.c
+++ b/drivers/gpu/drm/drm_fb_dma_helper.c
@@ -59,20 +59,10 @@ struct drm_gem_dma_object *drm_fb_dma_get_gem_obj(struct drm_framebuffer *fb,
 }
 EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_obj);
 
-/**
- * drm_fb_dma_get_gem_addr() - Get DMA (bus) address for framebuffer, for pixel
- * formats where values are grouped in blocks this will get you the beginning of
- * the block
- * @fb: The framebuffer
- * @state: Which state of drm plane
- * @plane: Which plane
- * Return the DMA GEM address for given framebuffer.
- *
- * This function will usually be called from the PLANE callback functions.
- */
-dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,
-				   struct drm_plane_state *state,
-				   unsigned int plane)
+static dma_addr_t _drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,
+					   unsigned int plane,
+					   unsigned int x,
+					   unsigned int y)
 {
 	struct drm_gem_dma_object *obj;
 	dma_addr_t dma_addr;
@@ -96,8 +86,8 @@ dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,
 		v_div = fb->format->vsub;
 	}
 
-	sample_x = (state->src_x >> 16) / h_div;
-	sample_y = (state->src_y >> 16) / v_div;
+	sample_x = x / h_div;
+	sample_y = y / v_div;
 	block_start_y = (sample_y / block_h) * block_h;
 	num_hblocks = sample_x / block_w;
 
@@ -106,8 +96,49 @@ dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,
 
 	return dma_addr;
 }
+
+/**
+ * drm_fb_dma_get_gem_addr() - Get DMA (bus) address for unclipped framebuffer,
+ * for pixel formats where values are grouped in blocks this will get you the
+ * beginning of the block
+ * @fb: The framebuffer
+ * @state: Which state of drm plane
+ * @plane: Which plane
+ *
+ * This function will usually be called from the PLANE callback functions.
+ *
+ * Return: GEM DMA address for given framebuffer, unclipped.
+ */
+dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,
+				   struct drm_plane_state *state,
+				   unsigned int plane)
+{
+	return _drm_fb_dma_get_gem_addr(fb, plane, state->src_x >> 16,
+					state->src_y >> 16);
+}
 EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_addr);
 
+/**
+ * drm_fb_dma_get_gem_clipped_addr() - Get DMA (bus) address for clipped
+ * framebuffer, for pixel formats where values are grouped in blocks this
+ * will get you the beginning of the block
+ * @fb: The framebuffer
+ * @state: Which state of drm plane
+ * @plane: Which plane
+ *
+ * This function will usually be called from the PLANE callback functions.
+ *
+ * Return: GEM DMA address for given framebuffer, clipped.
+ */
+dma_addr_t drm_fb_dma_get_gem_clipped_addr(struct drm_framebuffer *fb,
+					   struct drm_plane_state *state,
+					   unsigned int plane)
+{
+	return _drm_fb_dma_get_gem_addr(fb, plane, state->src.x1 >> 16,
+					state->src.y1 >> 16);
+}
+EXPORT_SYMBOL_GPL(drm_fb_dma_get_gem_clipped_addr);
+
 /**
  * drm_fb_dma_sync_non_coherent - Sync GEM object to non-coherent backing
  *	memory
diff --git a/include/drm/drm_fb_dma_helper.h b/include/drm/drm_fb_dma_helper.h
index c950732c6d36..b2a0bd7ef9d0 100644
--- a/include/drm/drm_fb_dma_helper.h
+++ b/include/drm/drm_fb_dma_helper.h
@@ -17,6 +17,10 @@ dma_addr_t drm_fb_dma_get_gem_addr(struct drm_framebuffer *fb,
 				   struct drm_plane_state *state,
 				   unsigned int plane);
 
+dma_addr_t drm_fb_dma_get_gem_clipped_addr(struct drm_framebuffer *fb,
+					   struct drm_plane_state *state,
+					   unsigned int plane);
+
 void drm_fb_dma_sync_non_coherent(struct drm_device *drm,
 				  struct drm_plane_state *old_state,
 				  struct drm_plane_state *state);
-- 
2.55.0.979.g7e5102b832-goog