[coreboot] Dealing with PCI reset

[Nico Huber]

Hi Paul,

sorry for the late reply.

On 11.12.2016 22:48, Paul Menzel via coreboot wrote:
> Dear coreboot folks,
> 
> 
> Several devices using the Intel 945 chipset copied code for PCI reset,
> costing 200 ms of boot time.
> 
> ```
>         /* Force PCIRST# */
>         pci_write_config16(PCI_DEV(0, 0x1e, 0), BCTRL, SBR);
>         udelay(200 * 1000);
>         pci_write_config16(PCI_DEV(0, 0x1e, 0), BCTRL, 0);
> ```
> 
> The change-set Ia37d9f0ecf5655531616edb20b53757d5d47b42f [1] removes
> that code from the Lenovo X60.
> 
> That code was added for some crypto card on a Roda device.

According to Stepan, this was a security measure to make sure the card
is always reset on a reboot.

> 
> My question is, if removing that code is fine, or if it should be left
> in and be made configurable (Kconfig/NVRAM)?

I don't think it's worth any hassle. We have our own branches locally
anyway, I can place it there.

> 
> Are there often cases where there are extensions card with problems,
> that need such a PCI reset?

If Stepan is right, there were no functionality problems at all.

Nico

> 
> 
> Thanks,
> 
> Paul
> 
> 
> [1] https://review.coreboot.org/17703
> 
> 
>