powerpc/powernv: Call opal_pci_poll() if needed

When issuing PHB reset, OPAL API opal_pci_poll() is called to drive
the state machine in OPAL forward. However, we needn't always call
the function under some circumstances like reset deassert.

This avoids calling opal_pci_poll() when OPAL_SUCCESS is returned
from opal_pci_reset(). Except the overhead introduced by additional
one unnecessary OPAL call, I didn't run into real issue because of
this.

Reported-by: Pridhiviraj Paidipeddi <ppaiddipe@in.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
index 68f1a85..995947d 100644 (file)
--- a/arch/powerpc/platforms/powernv/eeh-powernv.c
+++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
@@ -763,7 +763,8 @@ int pnv_eeh_phb_reset(struct pci_controller *hose, int option)
         * reset followed by hot reset on root bus. So we also
         * need the PCI bus settlement delay.
         */
-       rc = pnv_eeh_poll(phb->opal_id);
+       if (rc > 0)
+               rc = pnv_eeh_poll(phb->opal_id);
        if (option == EEH_RESET_DEACTIVATE) {
                if (system_state < SYSTEM_RUNNING)
                        udelay(1000 * EEH_PE_RST_SETTLE_TIME);
@@ -806,7 +807,8 @@ static int pnv_eeh_root_reset(struct pci_controller *hose, int option)
                goto out;
 
        /* Poll state of the PHB until the request is done */
-       rc = pnv_eeh_poll(phb->opal_id);
+       if (rc > 0)
+               rc = pnv_eeh_poll(phb->opal_id);
        if (option == EEH_RESET_DEACTIVATE)
                msleep(EEH_PE_RST_SETTLE_TIME);
 out: