[Skiboot] [PATCH 2/2] pci: Make fast reboot creset PHBs in parallel

[Nicholas Piggin]

On Thu, 22 Feb 2018 11:26:52 +1100
Michael Neuling <mikey at neuling.org> wrote:

> In this patch, we added a creset to the fast reboot path:
> 
>   commit a1eba9d29d17ff44fca1293b071023a9fbf4b938
>   Author: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
>   fast-reboot: creset PHBs on fast reboot
> 
> Unfortunately, this does the creset in serial rather than in
> parallel.
> 
> This patch changes the creset on fast reboot to operate in
> parallel. It simplifies the code by abstracting pci_init_slots() so
> that it can be used on boot and fast reboot to perform all the PCI
> retraining.
> 
> This improves fast reboot PCI training on a dual chip P9 from ~12
> seconds down to ~2 seconds. Similar improvements for P8 are achieved
> as well.

Very nice result!