[coreboot] option rom progress and some issues

Jason Wang wangqingpei at gmail.com
Tue Aug 11 21:59:02 CEST 2009

Hi all
    Since USB ROM has already added into the booting menu list(IPL table),
and the UHCI stack can be run well in usbrom now, i have some issues to
confirm, any advices are welcome.
1) <<Plug and Play BIOS Specification>>Page21, There is an r Return Status
from Initialization Call of OPTION ROM. Which used to let the bios know the
status. But it seems Seabios does not
   check the return code. Is that OK?
2) After Seabios make an far call into the BEV, the OPTION ROM should begin
to load OS.if it failed, it can return back to BIOS. But it can not return
back with my USB OPTION ROM, Is there any configuration
   I should set?
3) In my eyes, OPTION ROM hook int13 after jump into BEV, not in the
initialization.But after that how does it jump into the booting code which
located in the USB disk?

 Kevin: I looked the code of Seabios ata.c to learn how seabios booting OS
from ata disk. some question i have:
1) ATA used add_bcv_hd to add ata disk into IPL table. it's type is
IPL_TYPE_HARDDISK(0x02). It's vector is the driver id. how does seabios know
the bootstrap vector based the driver ID?
   what does ata fill FDPT area for? Should my usbrom do the same?
For my usbrom, i should not use add_bcv to add option rom into IPL ? or just
take the ata as example?

Jason Wang
Peking University
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