common/lcd: add protection from null bmp pointer

If the bmp pointer is null (for example because the environment variable "splashimage" was not defined) then U-Boot will get stuck when trying to load the image.
What's worse, it will get stuck before the U-Boot shell becomes available to the user, thus making it difficult to correct the situation.

To protect from the above scenario, check if the pointer is valid.

---
This patch depends on the following patch:

	patchwork.ozlabs.org/patch/176058/

 common/lcd.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 88dfa51..fcc09ac 100644
@@ -674,7 +674,7 @@ int lcd_display_bitmap(ulong bmp_image, int x, int y)
 	unsigned long pwidth = panel_info.vl_col;
 	unsigned colors, bpix, bmp_bpix;
 
-	if (!((bmp->header.signature[0] == 'B') &&
+	if (!bmp || !((bmp->header.signature[0] == 'B') &&
 		(bmp->header.signature[1] == 'M'))) {
 		printf("Error: no valid bmp image at %lx\n", bmp_image);
 

1.7.5.4

Hello Nikita,

Which branch is this? At [1] there is a check for this..

1600 s = getenv("splashimage");
1601 if (s != NULL) {
...

Regards,
Jeroen

[1]
http://git.denx.de/?p=u-boot.git;a=blob;f=drivers/video/cfb_console.c;h=19d061f6cbec31615c3193f59a27895f203e959f;hb=HEAD

Hi,

Just ignore above, since there are apparently more BMP drawing routines, and I mentioned the wrong one. The same check is in lcd.c though:

822: if (do_splash && (s = getenv("splashimage")) != NULL) {

Regards,
Jeroen

You are right; the null splashimage scenario was apparently a bad choice of example. However, lcd_display_bitmap is not a static function, and it appears
in lcd.h. This means that someone might use it outside of common/lcd.c context,
and for that reason it should be made more fault tolerant.

I'll resubmit the patch without the splashimage example in the commit message.