These two patches enable qemu to use the recently added SeaBIOS bootsplash code. The first patch is for SeaBIOS - it enables finding the "bootsplash.jpg" file from either CBFS (on coreboot) or fw_cfg (on QEMU). The second patch is for qemu - it enables loading a "bootsplash.jpg" file into fw_cfg from the bios roms directory if the file is present.
Some notes:
This uses the qemu "rom" interface for loading the jpeg file. It seems to work, but I'm not sure if this is strictly correct.
The jpeg viewer in SeaBIOS will look at the image size and try to find a vesa graphics mode that supports that size. So, choose images that are exactly 640x480, 1024x768, etc. Also, the SeaBIOS viewer has stripped down support for jpegs - not all valid jpegs will work. Some quick tests with the netpbm tools worked okay for me.
SeaBIOS only shows the bootsplash during the interval between vgabios init and OS execution. This is generally too short a time to be seen. Add "-menu boot=on" to the qemu command line to have it shown longer.
Unfortunately, the vgabios doesn't support writing text to the screen while in a vesa video mode. So, this means that if a user selects F12 for the boot menu, they can't actually see the boot menu. This will need to be fixed in SeaBIOS in a follow up patch.
-Kevin