[SeaBIOS] [PATCH] Seabios: allow mapping of multiple PCI option ROMs to one

[Dave Frodin]

----- Original Message -----
> From: "Kevin O'Connor" <kevin at koconnor.net>
> To: "Dave Frodin" <dave.frodin at se-eng.com>
> Cc: "seabios" <seabios at seabios.org>
> Sent: Saturday, May 25, 2013 10:47:42 AM
> Subject: Re: [SeaBIOS] [PATCH] Seabios: allow mapping of multiple PCI option ROMs to one
> 
> On Fri, May 24, 2013 at 09:06:54AM -0500, Dave Frodin wrote:
> > Kevin,
> > 
> > Thanks.
> > The new patch that I've attached no longer alters the pci device struct.
> > I also no longer repeatedly read the file in from CBFS, but keep the
> > pointer to it around for the next time the function is called.
> > 
> > As far as the use case is concerned. We (or a client) will often have
> > several of
> > the same mainboard (e.g. persimmon), but the graphics ID will vary
> > depending on
> > which version of the cpu is installed. Previously, we would have to figure
> > out
> > what the PCI ID of the graphics devices was, adjust the ID in coreboot's
> > config,
> > build/flash the new rom image. This seabios change along with a change to
> > coreboot to set the ID and stuff the correct vendev mapping file into CBFS
> > will allow a single coreboot/seabios image to be used on any particular
> > mainboard independent of what cpu was installed. This change won't be
> > useful
> > to someone who is using a single board who's graphics ID would never
> > change.
> > For that case they wouldn't need to do anything. If the vendev mapping file
> > doesn't get added they would see no difference.
> 
> Thanks.
> 
> Why not just place the rom in "vgaroms/" directory where it will
> always be run?

That is an option but I was hoping to reduce the number of configuration
differences between having coreboot vs seabios load/run the vga option rom.
Currently, coreboot has vendor/device ID mapping functions for the family14,
family15tn northbridges.

> Also, I think we could avoid the binary structure in CBFS.  Something
> like the below (totally untested).
> 
> -Kevin
> 
> 
> --- a/src/optionroms.c
> +++ b/src/optionroms.c
> @@ -178,10 +178,19 @@ deploy_romfile(struct romfile_s *file)
>  static struct rom_header *
>  lookup_hardcode(struct pci_device *pci)
>  {
> -    char fname[17];
> -    snprintf(fname, sizeof(fname), "pci%04x,%04x.rom"
> +    struct romfile_s *file;
> +    char fname[19];
> +    snprintf(fname, sizeof(fname), "alias%04x,%04x.rom"
>               , pci->vendor, pci->device);
> -    struct romfile_s *file = romfile_find(fname);
> +    char *alias = romfile_loadfile(fname, NULL);
> +    if (alias) {
> +        file = romfile_find(alias);
> +        free(alias);
> +    } else {
> +        snprintf(fname, sizeof(fname), "pci%04x,%04x.rom"
> +                 , pci->vendor, pci->device);
> +        file = romfile_find(fname);
> +    }
>      if (file)
>          return deploy_romfile(file);
>      return NULL;
>

In your sample code above, I don't see where any pci ID translation (mapping) occurs.

As an example we could have a family14 mainboard with a coreboot .config that generates
a vga option rom with the name "pci1002,9802.rom". The actual mainboard could have a
graphics chip with the id of 1002,9804 (which is 1 of 8 possible IDs). So there needs
to be some sort of mapping function (in SeaBIOS) that maps the ID of 1002,9804 to 1002,9802.

Thanks again,
Dave