[coreboot] [PATCH] workaround v2 VIA ROMCC breakage

[Carl-Daniel Hailfinger]

On 17.10.2008 01:32, Carl-Daniel Hailfinger wrote:
> On 17.10.2008 01:14, Eric W. Biederman wrote:
>   
>> 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.
>>   
>>     
>
> That indeed sounds like a solution, thanks. The code in question is
> sometimes compiled with ROMCC and sometimes with GCC. Fortunately, the
> only case where the code is called is a single mainboard which uses CAR
> and GCC anyway.
>   

The function is hidden from ROMCC since revision 3664.

That leaves us with the segfault problem, but I'm confident your
wizardry will fix that.

Regards,
Carl-Daniel

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