drm/radeon/kms: Make GPU/CPU page size handling consistent in blit code (v2)

The BO blit code inconsistenly handled the page size.  This wasn't
an issue on system with 4k pages since the GPU's page size is 4k as
well.  Switch the driver blit callbacks to take num pages in GPU
page units.

Fixes lemote mipsel systems using AMD rs780/rs880 chipsets.

v2: incorporate suggestions from Michel.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index a536505..5b1837b 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -721,11 +721,11 @@
 int r100_copy_blit(struct radeon_device *rdev,
 		   uint64_t src_offset,
 		   uint64_t dst_offset,
-		   unsigned num_pages,
+		   unsigned num_gpu_pages,
 		   struct radeon_fence *fence)
 {
 	uint32_t cur_pages;
-	uint32_t stride_bytes = PAGE_SIZE;
+	uint32_t stride_bytes = RADEON_GPU_PAGE_SIZE;
 	uint32_t pitch;
 	uint32_t stride_pixels;
 	unsigned ndw;
@@ -737,7 +737,7 @@
 	/* radeon pitch is /64 */
 	pitch = stride_bytes / 64;
 	stride_pixels = stride_bytes / 4;
-	num_loops = DIV_ROUND_UP(num_pages, 8191);
+	num_loops = DIV_ROUND_UP(num_gpu_pages, 8191);
 
 	/* Ask for enough room for blit + flush + fence */
 	ndw = 64 + (10 * num_loops);
@@ -746,12 +746,12 @@
 		DRM_ERROR("radeon: moving bo (%d) asking for %u dw.\n", r, ndw);
 		return -EINVAL;
 	}
-	while (num_pages > 0) {
-		cur_pages = num_pages;
+	while (num_gpu_pages > 0) {
+		cur_pages = num_gpu_pages;
 		if (cur_pages > 8191) {
 			cur_pages = 8191;
 		}
-		num_pages -= cur_pages;
+		num_gpu_pages -= cur_pages;
 
 		/* pages are in Y direction - height
 		   page width in X direction - width */