[U-Boot] [PATCH V2] cfb_console: force natural alignment of 32-bit fields in gzipped .bmp files
Eric Nelson
eric.nelson at boundarydevices.com
Fri Feb 28 22:06:12 CET 2014
.bmp files contain 32-bit integers aligned at offsets of +2, +6,
et cetera within the bmp_header structure (see include/bmp_layout.h).
Support for gzip-compressed .bmp files is present in the cfb_console
display subsystem by uncompressing them prior to use.
This patch forces the in-memory header to be aligned properly
for these compressed images by extracting them to a 2-byte
offset in the memory returned by malloc. Since malloc will always
return a 4-byte aligned value, this forces the .bmp header
fields to be naturally aligned on 4-byte addresses.
Refer to these files for more details:
doc/README.displaying-bmps
doc/README.arm-unaligned-accesses
Signed-off-by: Eric Nelson <eric.nelson at boundarydevices.com>
---
drivers/video/cfb_console.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/video/cfb_console.c b/drivers/video/cfb_console.c
index 6db4073..2209148 100644
--- a/drivers/video/cfb_console.c
+++ b/drivers/video/cfb_console.c
@@ -1473,7 +1473,10 @@ int video_display_bitmap(ulong bmp_image, int x, int y)
printf("Error: malloc in gunzip failed!\n");
return 1;
}
- if (gunzip(dst, CONFIG_SYS_VIDEO_LOGO_MAX_SIZE,
+ /* NB: we need to force offset of +2
+ * See doc/README.displaying-bmps
+ */
+ if (gunzip(dst+2, CONFIG_SYS_VIDEO_LOGO_MAX_SIZE-2,
(uchar *) bmp_image,
&len) != 0) {
printf("Error: no valid bmp or bmp.gz image at %lx\n",
@@ -1489,7 +1492,7 @@ int video_display_bitmap(ulong bmp_image, int x, int y)
/*
* Set addr to decompressed image
*/
- bmp = (bmp_image_t *) dst;
+ bmp = (bmp_image_t *)(dst+2);
if (!((bmp->header.signature[0] == 'B') &&
(bmp->header.signature[1] == 'M'))) {
--
1.8.3.2
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