[U-Boot] [RFC PATCH] x86: Support booting SeaBIOS

[Simon Glass]

Hi Bin,

On 10 October 2015 at 02:57, Bin Meng <bmeng.cn at gmail.com> wrote:
> Hi Simon,
>
> On Sat, Oct 3, 2015 at 10:29 PM, Simon Glass <sjg at chromium.org> wrote:
>> Hi Bin,
>>
>> On 29 September 2015 at 11:17, Bin Meng <bmeng.cn at gmail.com> wrote:
>>> SeaBIOS is an open source implementation of a 16-bit X86 BIOS.
>>> It can run in an emulator or natively on X86 hardware with the
>>> use of coreboot. With SeaBIOS's help, we can boot some OSes
>>> that require 16-bit BIOS services like Windows/DOS.
>>>
>>> As U-Boot, we have to manually create a table where SeaBIOS gets
>>> system information (eg: E820) from. The table unfortunately has
>>> to follow the coreboot table format as SeaBIOS currently supports
>>> booting as a coreboot payload. No U-Boot native support there.
>>>
>>> Booting SeaBIOS is done via U-Boot's bootelf command.
>>>
>>> This is the initial attempt to support booting SeaBIOS from U-Boot.
>>> If the basic concept is good, I can spend time working on follow-on
>>> patches to enable BIOS tables as well as graphics support. One issue
>>> is that U-Boot x86 does not has a ROM file system like coreboot.
>>> This brings difficulities to pass PCI option ROM to SeaBIOS, if we
>>> don't modify SeaBIOS's source codes. Maybe we should promote CBFS
>>> in U-Boot x86?
>>>
>>> This is tested on an Intel Crown Bay board with VGA card, booting
>>> SeaBIOS then chain loading a GRUB on a USB drive, then Linux kernel
>>> finally.
>>
>> Looks good to me. I think it is OK to use CBFS if needed - are you
>> thinking of an option to build u-boot.rom as a CBFS filesystem?
>
> If using CBFS, that means we may have to abandon ifdtool? Or maybe
> mixed usage of both tools?

So far I'm not sure of the best approach. At present we have the ROM
offsets stored mostly in Kconfig, with the MRC area in the SPI flash
device tree node. The environment is also in Kconfig.

What sort of option ROMs do you want to support? What other options
does seabios provide?

What does SEA stand for?

[snip]

Regards,
Simon