powerpc/eeh: Fix fenced PHB caused by eeh_slot_error_detail()
powerpc/eeh: Fix fenced PHB caused by eeh_slot_error_detail()

The config space of some PCI devices can't be accessed when their
PEs are in frozen state. Otherwise, fenced PHB might be seen.
Those PEs are identified with flag EEH_PE_CFG_RESTRICTED, meaing
EEH_PE_CFG_BLOCKED is set automatically when the PE is put to
frozen state (EEH_PE_ISOLATED). eeh_slot_error_detail() restores
PCI device BARs with eeh_pe_restore_bars(), which then calls
eeh_ops->restore_config() to reinitialize the PCI device in
(OPAL) firmware. eeh_ops->restore_config() produces PCI config
access that causes fenced PHB. The problem was reported on below
adapter:

   0001:01:00.0 0200: 14e4:168e (rev 10)
   0001:01:00.0 Ethernet controller: Broadcom Corporation \
                NetXtreme II BCM57810 10 Gigabit Ethernet (rev 10)

This fixes the issue by skipping eeh_pe_restore_bars() in
eeh_slot_error_detail() when EEH_PE_CFG_BLOCKED is set for the PE.

Fixes: b6541db1 ("powerpc/eeh: Block PCI config access upon frozen PE")
Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org # v4.0+
Reported-by: Manvanthara B. Puttashankar <9dd9ac1da023962a275aa7bd4e5b66707ca772be@in.ibm.com>
Signed-off-by: Gavin Shan <0398910e4f4970259b451f0f9d0686cc5e961b81@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <864f124608374e06e4da1fa5d2e47ed839b95411@ellerman.id.au>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs