[Skiboot] [PATCH] phb4: Reset pfir and nfir if new errors reported during ETU reset

[Vasant Hegde]

On 08/30/2018 06:27 PM, Vaibhav Jain wrote:
> During fast-reboot a PCI device can continue sending requests even
> after ETU-Reset is asserted. This will cause new errors to be reported
> in ETU fir-registers and will result in values of variables nfir_cache
> and pfir_cache to be out of sync.
> 
> Presently during step-2 of CRESET nfir_cache and pfir_cache values are
> used to bring the PHB out of reset state. However if these variables
> are out of date the nfir/pfir registers are never reset completely and
> ETU still remains frozen.
> 
> Hence this patch updates step-2 of phb4_creset to re-read the values of
> nfir/pfir registers to check if any new errors were reported after
> ETU-reset was asserted, report these new errors and reset the
> nfir/pfir registers. This should bring the ETU out of reset
> successfully.
> 
> Signed-off-by: Vaibhav Jain <vaibhav at linux.ibm.com>

Tested-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>

-Vasant