[coreboot] option rom progress and some issues

[Jason Wang]

On Thu, Aug 13, 2009 at 7:24 AM, Kevin O'Connor <kevin at koconnor.net> wrote:

> On Thu, Aug 13, 2009 at 02:22:05AM +0800, Jason Wang wrote:
> > On Wed, Aug 12, 2009 at 9:17 PM, Kevin O'Connor <kevin at koconnor.net>
> wrote:
> >
> > > On Wed, Aug 12, 2009 at 03:29:06PM +0800, Jason Wang wrote:
> > > > Hi Kevin,
> > > >     The Seabios try to booting usbrom with IPL_TYPE_BEV, which i
> think
> > > > should use IPL_TYPE_HARDDISK, right? Followed by BIOS BOOT
> Specification
> > > > I think it can add
> > > > #define IPL_TYPE_USBROM 0x05 to support BCV, how do you think about
> that?
> > >
> > > SeaBIOS is overloading those flags, and I agree it's confusing.  The
> > > flags for BCV tables are only used in run_bcv(), add_bcv(), and
> > > add_bcv_hd().  It's not necessary to add a new flag.
> >
> > I find that handle_19, do_boot only seek the BEV devices
>
> That is correct.
>
> The BEVs are the ways one can boot the machine and the BCVs are the
> drives in the machine.
>
> SeaBIOS has a BEV for booting off of a drive (see boot_disk()).  You
> should not add a new way to boot from a drive - instead you want to
> add a new drive.
>
> The BCV list is executed during post (see boot_prep()).  SeaBIOS will
> call all the optionroms that have BCVs and they can then hook int13.
> Once int13 has been properly hooked, the existing SeaBIOS drive
> booting code will work.

I still have questions about the BCVs.
1) The BCVs is used to hook int13 while being called by optionrom.What if
the usbrom failed,and system should
restore int13. Or the BCVs should do that?
2)As you mentioned the BCVs are the drivers in the machine. How does the BCV
save the drives in the memroy which
can be used by Seabios? Since after BCVs turning back to Seabios, it can
leave some data to Seabios?
3) i want to know if the int13 should initialize the USB stack each time it
is called?

>
>
> -Kevin
>



-- 
Jason Wang
Peking University
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