The pixel_read_direction enum is useful to describe the reading direction in a plane. It avoids using the rotation property of DRM, which not practical to know the direction of reading. This patch also introduce two helpers, one to compute the pixel_read_direction from the DRM rotation property, and one to compute the step, in byte, between two successive pixel in a specific direction. Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx> --- drivers/gpu/drm/vkms/vkms_composer.c | 36 ++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/vkms/vkms_drv.h | 11 +++++++++++ drivers/gpu/drm/vkms/vkms_formats.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 77 insertions(+) diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c index 9254086f23ff..989bcf59f375 100644 --- a/drivers/gpu/drm/vkms/vkms_composer.c +++ b/drivers/gpu/drm/vkms/vkms_composer.c @@ -159,6 +159,42 @@ static void apply_lut(const struct vkms_crtc_state *crtc_state, struct line_buff } } +/** + * direction_for_rotation() - Get the correct reading direction for a given rotation + * + * This function will use the @rotation setting of a source plane to compute the reading + * direction in this plane which correspond to a "left to right writing" in the CRTC. + * For example, if the buffer is reflected on X axis, the pixel must be read from right to left + * to be written from left to right on the CRTC. + * + * @rotation: Rotation to analyze. It correspond the field @frame_info.rotation. + */ +static enum pixel_read_direction direction_for_rotation(unsigned int rotation) +{ + if (rotation & DRM_MODE_ROTATE_0) { + if (rotation & DRM_MODE_REFLECT_X) + return READ_RIGHT_TO_LEFT; + else + return READ_LEFT_TO_RIGHT; + } else if (rotation & DRM_MODE_ROTATE_90) { + if (rotation & DRM_MODE_REFLECT_Y) + return READ_BOTTOM_TO_TOP; + else + return READ_TOP_TO_BOTTOM; + } else if (rotation & DRM_MODE_ROTATE_180) { + if (rotation & DRM_MODE_REFLECT_X) + return READ_LEFT_TO_RIGHT; + else + return READ_RIGHT_TO_LEFT; + } else if (rotation & DRM_MODE_ROTATE_270) { + if (rotation & DRM_MODE_REFLECT_Y) + return READ_TOP_TO_BOTTOM; + else + return READ_BOTTOM_TO_TOP; + } + return READ_LEFT_TO_RIGHT; +} + /** * blend - blend the pixels from all planes and compute crc * @wb: The writeback frame buffer metadata diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h index 3ead8b39af4a..985e7a92b7bc 100644 --- a/drivers/gpu/drm/vkms/vkms_drv.h +++ b/drivers/gpu/drm/vkms/vkms_drv.h @@ -69,6 +69,17 @@ struct vkms_writeback_job { pixel_write_t pixel_write; }; +/** + * enum pixel_read_direction - Enum used internaly by VKMS to represent a reading direction in a + * plane. + */ +enum pixel_read_direction { + READ_BOTTOM_TO_TOP, + READ_TOP_TO_BOTTOM, + READ_RIGHT_TO_LEFT, + READ_LEFT_TO_RIGHT +}; + /** * typedef pixel_read_t - These functions are used to read a pixel in the source frame, * convert it to `struct pixel_argb_u16` and write it to @out_pixel. diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c index 649d75d05b1f..743b6fd06db5 100644 --- a/drivers/gpu/drm/vkms/vkms_formats.c +++ b/drivers/gpu/drm/vkms/vkms_formats.c @@ -75,6 +75,36 @@ static void packed_pixels_addr(const struct vkms_frame_info *frame_info, *addr = (u8 *)frame_info->map[0].vaddr + offset; } +/** + * get_step_next_block() - Common helper to compute the correct step value between each pixel block + * to read in a certain direction. + * + * As the returned offset is the number of bytes between two consecutive blocks in a direction, + * the caller may have to read multiple pixel 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. + * + * @fb: Framebuffer to iter on + * @direction: Direction of the reading + * @plane_index: Plane to get the step from + */ +static int get_step_next_block(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]; + case READ_BOTTOM_TO_TOP: + return -(int)fb->pitches[plane_index]; + } + + return 0; +} + static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y, int plane_index) { -- 2.43.0