[coreboot] BDX-DE PCI init fail

[David Hendricks]

Hi Hilbert,

On Wed, Jan 3, 2018 at 12:56 AM, Hilbert Tu(杜睿哲_Pegatron) <
Hilbert_Tu at pegatroncorp.com> wrote:

> Hi Zoran,
>
> I have changed to maximal log level and found SMBus init was failed when
> enabling clock gating. Do you have any comments about this? Thanks.
>

Yes, looking back at my notes from earlier that is also how I got past the
issue - by commenting out the following lines in
src/soc/intel/fsp_broadwell_de/smbus.c:
        /* Enable clock gating */
       reg32 =read32(rcba + 0x341c);
       reg32 |= (1 << 5);
       write32(rcba + 0x341c, reg32);

I suspected that reading the register is where it hung, however I did not
have a chance to root cause the issue or try to enable clock gating
elsewhere. The system worked without clock gating enabled, though.

I also tested another Broadwell-DE device that did not require the same
hack, but it used different memory and a different processor stepping
(stepping 3 instead of stepping 4) which may have made a difference.
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