Firstly, you need download two patchs:the Kevin's for using Seabios as payload, and Rudolf's for s3.
http://www.coreboot.org/pipermail/coreboot/2008-September/038551.html
www.coreboot.org/pipermail/coreboot/2008-January/028787.html
Then there are two steps to do (Rudolf gave me much advice on IRC :-) , he is a good teacher)
#1 Since OS put some realmode code to the s3 resume vector before it demands the mainboard to enter sleep,
we need to backup the resume code before coreboot using real memory(may destroy the resume code) and recovery it before Coreboot jumps into the resume vector.
In the main()of cache_as_ram_auto.c, just before the stack switching code, add this:
if( (bootmode == 3){
print_debug("copy memory to high memory to protect s3 wakeup vector code \r\n");
memcpy((unsigned char *)(highmem_bakaddress),(unsigned char *)0, 0x100000);//highmem_bakaddress=512M-xxM
}
In the acpi_jump_wake() of wakeup.c, add this:
memcpy((unsigned char *)(resumevector), (unsigned char *)(highmem_bakaddress+resumevector), 0x1000);
//(ubuntu's vector=0x2000, XP's =0x1c000, but you should just get this from the FACS table as in Kevin's patch, even he move the FACS to the highend memory)
#2 Since when resume from S3, coreboot do not go into payload, so in vga driver codes need be added to do vga init after it judged that this is a boot waked from s3.
if(acpi_sleep_type==3)
{printk_debug("Enable VGA console\n");
vga_enable_console();}
if(acpi_sleep_type==3)
{xxxxxx}
if(acpi_sleep_type==3)
{xxxxxx}