[coreboot] [PATCH] workaround v2 VIA ROMCC breakage

[Eric W. Biederman]

Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net> writes:

> Hi Eric,
>
> I'm copying you on this mail because we managed to have ROMCC segfault
> reliably and choke on another piece of code.
>
>
> On 16.10.2008 18:36, Rudolf Marek wrote:
>>
>>> +#if 0
>>>      /* Set SPI clock to 33MHz. */
>>>      spireg = (u16 *) (VT8237S_SPI_MEM_BASE + 0x6c);
>>>      (*spireg) &= 0xff00;
>>> +#endif
>>>   
>>
>> This is OK because default is 16MHz, mtrr should handle caching for us.
>
> ROMCC segfaulted on the code above, so a small rewrite may also fix this
> problem. Or we could fix ROMCC.
>
>
>>> +#if 0
>>>      if (rom == NULL) {
>>>          print_err("No config data specified, using default MAC!\n");
>>>          n.mac_address[0] = 0x0;
>>> @@ -443,6 +446,7 @@
>>>          n.checksum = 0x0;
>>>          rom = &n;
>>>      }
>>> +#endif
>> The reason why exactly this needs to be handled in rom stage is that
>> the shadow registers needs to be filled _before_ PCI reset, because
>> PCI reset will force the internal microcontroller to reload with this
>> configuration. Its not much documented, only in programming guide,
>> and there is just assembly code and some strange English ;) they
>> really mention that the controller should be reloaded when the device
>> enters D0 via PCIRST#. Dont know if for example some ->D3 and ->D0
>> transition will work or not.
>
> Oh my. That's quite strange hardware. Anyway, it seems that romcc mainly
> barfs on the
> if (rom == NULL)
> check due to unexpected typing. It should be possible to fix this.

Likely.  I'm not certain because that function is never called in the output
you sent me.

I was going to suggest changing it to just if (!rom) and then it started
complaining about addresses of auto variables not being supported.

So ultimately putting #ifndef ROMCC around that whole function looks
like the right thing to do.

Eric