diff options
Diffstat (limited to 'drivers/gpu/drm/vkms/vkms_formats.c')
| -rw-r--r-- | drivers/gpu/drm/vkms/vkms_formats.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c index f9045a80aceb..5dad7bcec0a6 100644 --- a/drivers/gpu/drm/vkms/vkms_formats.c +++ b/drivers/gpu/drm/vkms/vkms_formats.c @@ -80,6 +80,38 @@ static void packed_pixels_addr(const struct vkms_frame_info *frame_info, } /** + * get_block_step_bytes() - Common helper to compute the correct step value between each pixel block + * to read in a certain direction. + * + * @fb: Framebuffer to iter on + * @direction: Direction of the reading + * @plane_index: Plane to get the step from + * + * As the returned count is the number of bytes between two consecutive blocks in a direction, + * the caller may have to read multiple pixels before using the next one (for example, to read from + * left to right in a DRM_FORMAT_R1 plane, each block contains 8 pixels, so the step must be used + * only every 8 pixels). + */ +static int get_block_step_bytes(struct drm_framebuffer *fb, enum pixel_read_direction direction, + int plane_index) +{ + switch (direction) { + case READ_LEFT_TO_RIGHT: + return fb->format->char_per_block[plane_index]; + case READ_RIGHT_TO_LEFT: + return -fb->format->char_per_block[plane_index]; + case READ_TOP_TO_BOTTOM: + return (int)fb->pitches[plane_index] * drm_format_info_block_width(fb->format, + plane_index); + case READ_BOTTOM_TO_TOP: + return -(int)fb->pitches[plane_index] * drm_format_info_block_width(fb->format, + plane_index); + } + + return 0; +} + +/** * packed_pixels_addr_1x1() - Get the pointer to the block containing the pixel at the given * coordinates * |