sandbox: video: Support 8bpp depth

At present sandbox only supports 16 and 32bpp depths, since those are the
easy ones with SDL.

We can support other depths by manually converting the pixel formats. Add
support for this, to enable an 8ppp (monochrome) format.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 60 insertions, 5 deletions

diff --git a/arch/sandbox/cpu/sdl.c b/arch/sandbox/cpu/sdl.c
index bef5abd..7ff0df2 100644
--- a/arch/sandbox/cpu/sdl.c
+++ b/arch/sandbox/cpu/sdl.c
@@ -44,6 +44,8 @@ struct buf_info {
  * @stopping: true if audio will stop once it runs out of data
  * @texture: SDL texture to use for U-Boot display contents
  * @renderer: SDL renderer to use
+ * @src_depth: Number of bits per pixel in the source frame buffer (that we read
+ * from and render to SDL)
  */
 static struct sdl_info {
 	int width;
@@ -61,6 +63,7 @@ static struct sdl_info {
 	bool stopping;
 	SDL_Texture *texture;
 	SDL_Renderer *renderer;
+	int src_depth;
 } sdl;
 
 static void sandbox_sdl_poll_events(void)
@@ -126,6 +129,9 @@ int sandbox_sdl_init_display(int width, int height, int log2_bpp,
 	if (!SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "1"))
 		printf("Unable to init hinting: %s", SDL_GetError());
 
+	sdl.src_depth = 1 << log2_bpp;
+	if (log2_bpp != 4 && log2_bpp != 5)
+		log2_bpp = 5;
 	sdl.depth = 1 << log2_bpp;
 	sdl.pitch = sdl.width * sdl.depth / 8;
 	SDL_Window *screen = SDL_CreateWindow("U-Boot", SDL_WINDOWPOS_UNDEFINED,
@@ -137,10 +143,6 @@ int sandbox_sdl_init_display(int width, int height, int log2_bpp,
 		       SDL_GetError());
 		return -EIO;
 	}
-	if (log2_bpp != 4 && log2_bpp != 5) {
-		printf("U-Boot SDL does not support depth %d\n", log2_bpp);
-		return -EINVAL;
-	}
 	sdl.renderer = SDL_CreateRenderer(screen, -1,
 					  SDL_RENDERER_ACCELERATED |
 					  SDL_RENDERER_PRESENTVSYNC);
@@ -165,6 +167,55 @@ int sandbox_sdl_init_display(int width, int height, int log2_bpp,
 	return 0;
 }
 
+static int copy_to_texture(void *lcd_base)
+{
+	char *dest;
+	int pitch, x, y;
+	int src_pitch;
+	void *pixels;
+	char *src;
+	int ret;
+
+	if (sdl.src_depth == sdl.depth) {
+		SDL_UpdateTexture(sdl.texture, NULL, lcd_base, sdl.pitch);
+		return 0;
+	}
+
+	/*
+	 * We only support copying from an 8bpp to a 32bpp texture since the
+	 * other cases are supported directly by the texture.
+	 */
+	if (sdl.depth != 32 && sdl.src_depth != 8) {
+		printf("Need depth 32bpp for copy\n");
+		return -EINVAL;
+	}
+
+	ret = SDL_LockTexture(sdl.texture, NULL, &pixels, &pitch);
+	if (ret) {
+		printf("SDL lock %d: %s\n", ret, SDL_GetError());
+		return ret;
+	}
+
+	/* Copy the pixels one by one */
+	src_pitch = sdl.width * sdl.src_depth / 8;
+	for (y = 0; y < sdl.height; y++) {
+		char val;
+
+		dest = pixels + y * pitch;
+		src = lcd_base + src_pitch * y;
+		for (x = 0; x < sdl.width; x++, dest += 4) {
+			val = *src++;
+			dest[0] = val;
+			dest[1] = val;
+			dest[2] = val;
+			dest[3] = 0;
+		}
+	}
+	SDL_UnlockTexture(sdl.texture);
+
+	return 0;
+}
+
 int sandbox_sdl_sync(void *lcd_base)
 {
 	struct SDL_Rect rect;
@@ -173,7 +224,11 @@ int sandbox_sdl_sync(void *lcd_base)
 	if (!sdl.texture)
 		return 0;
 	SDL_RenderClear(sdl.renderer);
-	SDL_UpdateTexture(sdl.texture, NULL, lcd_base, sdl.pitch);
+	ret = copy_to_texture(lcd_base);
+	if (ret) {
+		printf("copy_to_texture: %d: %s\n", ret, SDL_GetError());
+		return -EIO;
+	}
 	ret = SDL_RenderCopy(sdl.renderer, sdl.texture, NULL, NULL);
 	if (ret) {
 		printf("SDL copy %d: %s\n", ret, SDL_GetError());