[PATCH] drm/vkms: Optimize compute_crc(), blend()

[Sidong Yang]

Optimize looping pixels in compute_crc() and blend(). Calculate
src_offset in start of looping horizontally and increase it.
It's better than calculating in every pixels.

Cc: Rodrigo Siqueira <rodrigosiqueiram...@gmail.com>
Cc: David Airlie <airl...@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-ker...@vger.kernel.org
Signed-off-by: Sidong Yang <realwa...@gmail.com>
---
 drivers/gpu/drm/vkms/vkms_composer.c | 32 +++++++++++++++-------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_composer.c 
b/drivers/gpu/drm/vkms/vkms_composer.c
index 4af2f19480f4..9d2a765ca1fb 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -28,14 +28,14 @@ static uint32_t compute_crc(void *vaddr_out, struct 
vkms_composer *composer)
        u32 crc = 0;
 
        for (i = y_src; i < y_src + h_src; ++i) {
-               for (j = x_src; j < x_src + w_src; ++j) {
-                       src_offset = composer->offset
-                                    + (i * composer->pitch)
-                                    + (j * composer->cpp);
+               src_offset = composer->offset + (i * composer->pitch)
+                               + (x_src * composer->cpp);
+               for (j = 0 ; j < w_src; ++j) {
                        /* XRGB format ignores Alpha channel */
                        memset(vaddr_out + src_offset + 24, 0,  8);
                        crc = crc32_le(crc, vaddr_out + src_offset,
                                       sizeof(u32));
+                       src_offset += composer->cpp;
                }
        }
 
@@ -61,7 +61,7 @@ static void blend(void *vaddr_dst, void *vaddr_src,
                  struct vkms_composer *dest_composer,
                  struct vkms_composer *src_composer)
 {
-       int i, j, j_dst, i_dst;
+       int i, j, i_dst;
        int offset_src, offset_dst;
 
        int x_src = src_composer->src.x1 >> 16;
@@ -73,21 +73,23 @@ static void blend(void *vaddr_dst, void *vaddr_src,
        int w_dst = drm_rect_width(&src_composer->dst);
 
        int y_limit = y_src + h_dst;
-       int x_limit = x_src + w_dst;
 
-       for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
-               for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
-                       offset_dst = dest_composer->offset
-                                    + (i_dst * dest_composer->pitch)
-                                    + (j_dst++ * dest_composer->cpp);
-                       offset_src = src_composer->offset
-                                    + (i * src_composer->pitch)
-                                    + (j * src_composer->cpp);
+       for (i = y_src, i_dst = y_dst; i < y_limit; ++i, ++i_dst) {
+               offset_dst = dest_composer->offset
+                    + (i_dst * dest_composer->pitch)
+                    + (x_dst * dest_composer->cpp);
 
+               offset_src = src_composer->offset
+                    + (i * src_composer->pitch)
+                    + (x_src * src_composer->cpp);
+
+               for (j = 0; j < w_dst; ++j) {
                        memcpy(vaddr_dst + offset_dst,
                               vaddr_src + offset_src, sizeof(u32));
+
+                       offset_dst += dest_composer->cpp;
+                       offset_src += src_composer->cpp;
                }
-               i_dst++;
        }
 }
 
-- 
2.17.1

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