video: sandbox: Set a maximum frame-buffer size

If U-Boot starts with the frame buffer set to 16bpp but then runs a test
that uses 32bpp, there is not enough space. Update the driver to use the
maximum possible frame-buffer size, to avoid this.

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

diff --git a/drivers/video/sandbox_sdl.c b/drivers/video/sandbox_sdl.c
index 6e430b2..de8c660 100644 (file)
--- a/drivers/video/sandbox_sdl.c
+++ b/drivers/video/sandbox_sdl.c
@@ -55,10 +55,26 @@ static void set_bpp(struct udevice *dev, enum video_log2_bpp l2bpp)
 
        plat->bpix = l2bpp;
 
-       uc_plat->size = plat->xres * plat->yres * (1 << plat->bpix) / 8;
+       uc_plat->size = plat->xres * plat->yres * VNBYTES(plat->bpix);
+
+       /*
+        * Set up to the maximum size we'll ever need. This is a strange case.
+        * The video memory is allocated by video_post_bind() called from
+        * board_init_r(). If a test changes the reoslution so it needs more
+        * memory later (with sandbox_sdl_set_bpp()), it is too late to make
+        * the frame buffer larger.
+        *
+        * So use a maximum size here.
+        */
+       uc_plat->size = max(uc_plat->size, 1920U * 1080 * VNBYTES(VIDEO_BPP32));
 
        /* Allow space for two buffers, the lower one being the copy buffer */
        log_debug("Frame buffer size %x\n", uc_plat->size);
+
+       /*
+        * If a copy framebuffer is used, double the size and use the last half
+        * as the copy, with the first half as the normal frame buffer.
+        */
        if (IS_ENABLED(CONFIG_VIDEO_COPY))
                uc_plat->size *= 2;
 }