phb4: Reset pfir and nfir if new errors reported during ETU reset
phb4: Reset pfir and nfir if new errors reported during ETU reset

During fast-reboot new PEC errors can be latched even after ETU-Reset
is asserted. This will result in values of variables nfir_cache and
pfir_cache to be out of sync.

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
as noted above 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 <e78384dfaa97bf0f3945c4da4075af8ac33ade0a@linux.ibm.com>
Tested-By: Vasant Hegde <a6d753843573f7bfed5075c1e875b0be8007a0ab@linux.vnet.ibm.com>
Reviewed-by: Oliver O'Halloran <3dfaff8fa6ae977f042064a112a6aac576279b9b@gmail.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.ibm.com>

legoater/skiboot,shenki/skiboot,legoater/skiboot,stewart-ibm/skiboot,qemu/skiboot,qemu/skiboot,legoater/skiboot,shenki/skiboot,open-power/skiboot,open-power/skiboot,qemu/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,legoater/skiboot,shenki/skiboot,legoater/skiboot,stewart-ibm/skiboot,qemu/skiboot,shenki/skiboot,stewart-ibm/skiboot,open-power/skiboot,open-power/skiboot