[PATCH v6 17/17] drm/vkms: Add support for DRM_FORMAT_R*

[Louis Chauvet <louis.chauvet@bootlin.com>]

This add the support for:
- R1/R2/R4/R8

R1 format was tested with [1] and [2].

[1]: https://lore.kernel.org/r/20240313-new_rotation-v2-0-6230fd5cae59@bootlin.com
[2]: https://lore.kernel.org/igt-dev/20240306-b4-kms_tests-v1-0-8fe451efd2ac@bootlin.com/

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_formats.c | 101 ++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_plane.c   |   4 ++
 2 files changed, 105 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index ca9028c1ef1a..7f49995686fd 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -237,6 +237,11 @@ static struct pixel_argb_u16 argb_u16_from_RGB565(const u16 *pixel)
 	return out_pixel;
 }
 
+static struct pixel_argb_u16 argb_u16_from_gray8(u8 gray)
+{
+	return argb_u16_from_u8888(255, gray, gray, gray);
+}
+
 VISIBLE_IF_KUNIT struct pixel_argb_u16 argb_u16_from_yuv888(u8 y, u8 channel_1, u8 channel_2,
 							   const struct conversion_matrix *matrix)
 {
@@ -302,6 +307,94 @@ static void magenta_to_argb_u16(const struct vkms_plane_state *plane, int x_star
 	}
 }
 
+static void Rx_read_line(const struct vkms_plane_state *plane, int x_start,
+			 int y_start, enum pixel_read_direction direction, int count,
+			 struct pixel_argb_u16 out_pixel[], u8 bit_per_pixel, u8 lum_per_level)
+{
+	struct pixel_argb_u16 *end = out_pixel + count;
+	u8 *src_pixels;
+	int rem_x, rem_y;
+
+	WARN_ONCE(drm_format_info_block_height(plane->frame_info->fb->format, 0) != 1,
+		  "%s() only support formats with block_h == 1", __func__);
+
+	packed_pixels_addr(plane->frame_info, x_start, y_start, 0, &src_pixels, &rem_x, &rem_y);
+	int bit_offset = (8-bit_per_pixel) - rem_x * bit_per_pixel;
+	int step = get_block_step_byte(plane->frame_info->fb, direction, 0);
+	int mask = (0x1 << bit_per_pixel) - 1;
+
+	if (direction == READ_LEFT_TO_RIGHT || direction == READ_RIGHT_TO_LEFT) {
+		int restart_bit_offset;
+		int step_bit_offset;
+
+		if (direction == READ_LEFT_TO_RIGHT) {
+			restart_bit_offset = 8 - bit_per_pixel;
+			step_bit_offset = -bit_per_pixel;
+		} else {
+			restart_bit_offset = 0;
+			step_bit_offset = bit_per_pixel;
+		}
+
+		while (out_pixel < end) {
+			u8 val = ((*src_pixels) >> bit_offset) & mask;
+
+			*out_pixel = argb_u16_from_gray8(val * lum_per_level);
+
+			bit_offset += step_bit_offset;
+			if (bit_offset < 0 || 8 <= bit_offset) {
+				bit_offset = restart_bit_offset;
+				src_pixels += step;
+			}
+			out_pixel += 1;
+		}
+	} else if (direction == READ_TOP_TO_BOTTOM || direction == READ_BOTTOM_TO_TOP) {
+		while (out_pixel < end) {
+			u8 val = (*src_pixels >> bit_offset) & mask;
+			*out_pixel = argb_u16_from_gray8(val * lum_per_level);
+			src_pixels += step;
+			out_pixel += 1;
+		}
+	}
+}
+
+static void R1_read_line(const struct vkms_plane_state *plane, int x_start,
+			 int y_start, enum pixel_read_direction direction, int count,
+			 struct pixel_argb_u16 out_pixel[])
+{
+	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel, 1, 0xFF);
+}
+
+static void R2_read_line(const struct vkms_plane_state *plane, int x_start,
+			 int y_start, enum pixel_read_direction direction, int count,
+			 struct pixel_argb_u16 out_pixel[])
+{
+	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel, 2, 0x55);
+}
+
+static void R4_read_line(const struct vkms_plane_state *plane, int x_start,
+			 int y_start, enum pixel_read_direction direction, int count,
+			 struct pixel_argb_u16 out_pixel[])
+{
+	Rx_read_line(plane, x_start, y_start, direction, count, out_pixel, 4, 0x11);
+}
+
+static void R8_read_line(const struct vkms_plane_state *plane, int x_start,
+			 int y_start, enum pixel_read_direction direction, int count,
+			 struct pixel_argb_u16 out_pixel[])
+{
+	struct pixel_argb_u16 *end = out_pixel + count;
+	u8 *src_pixels;
+	int step = get_block_step_byte(plane->frame_info->fb, direction, 0);
+
+	packed_pixels_addr_1x1(plane->frame_info, x_start, y_start, 0, &src_pixels);
+
+	while (out_pixel < end) {
+		*out_pixel = argb_u16_from_gray8(*src_pixels);
+		src_pixels += step;
+		out_pixel += 1;
+	}
+}
+
 static void ARGB8888_read_line(const struct vkms_plane_state *plane, int x_start, int y_start,
 			       enum pixel_read_direction direction, int count,
 			       struct pixel_argb_u16 out_pixel[])
@@ -625,6 +718,14 @@ pixel_read_line_t get_pixel_read_line_function(u32 format)
 	case DRM_FORMAT_YVU422:
 	case DRM_FORMAT_YVU444:
 		return &planar_yuv_read_line;
+	case DRM_FORMAT_R1:
+		return &R1_read_line;
+	case DRM_FORMAT_R2:
+		return &R2_read_line;
+	case DRM_FORMAT_R4:
+		return &R4_read_line;
+	case DRM_FORMAT_R8:
+		return &R8_read_line;
 	default:
 		/*
 		 * This is a bug in vkms_plane_atomic_check(). All the supported
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 8f764a108b00..67f891e7ac58 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -30,6 +30,10 @@ static const u32 vkms_formats[] = {
 	DRM_FORMAT_YVU420,
 	DRM_FORMAT_YVU422,
 	DRM_FORMAT_YVU444,
+	DRM_FORMAT_R1,
+	DRM_FORMAT_R2,
+	DRM_FORMAT_R4,
+	DRM_FORMAT_R8,
 };
 
 static struct drm_plane_state *

-- 
2.43.0