3 files changed, 99 insertions, 70 deletions

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index cc728e8c6ee6..25f37532093d 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -238,9 +238,13 @@ void eeh_slot_error_detail(struct eeh_pe *pe, int severity)
 	 * the data from PCI config space because it should return
 	 * 0xFF's. For ER, we still retrieve the data from the PCI
 	 * config space.
+	 *
+	 * For pHyp, we have to enable IO for log retrieval. Otherwise,
+	 * 0xFF's is always returned from PCI config space.
 	 */
 	if (!(pe->type & EEH_PE_PHB)) {
-		eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
+		if (eeh_probe_mode_devtree())
+			eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
 		eeh_ops->configure_bridge(pe);
 		eeh_pe_restore_bars(pe);
 
@@ -509,16 +513,42 @@ EXPORT_SYMBOL(eeh_check_failure);
  */
 int eeh_pci_enable(struct eeh_pe *pe, int function)
 {
-	int rc;
+	int rc, flags = (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE);
+
+	/*
+	 * pHyp doesn't allow to enable IO or DMA on unfrozen PE.
+	 * Also, it's pointless to enable them on unfrozen PE. So
+	 * we have the check here.
+	 */
+	if (function == EEH_OPT_THAW_MMIO ||
+	    function == EEH_OPT_THAW_DMA) {
+		rc = eeh_ops->get_state(pe, NULL);
+		if (rc < 0)
+			return rc;
+
+		/* Needn't to enable or already enabled */
+		if ((rc == EEH_STATE_NOT_SUPPORT) ||
+		    ((rc & flags) == flags))
+			return 0;
+	}
 
 	rc = eeh_ops->set_option(pe, function);
 	if (rc)
-		pr_warning("%s: Unexpected state change %d on PHB#%d-PE#%x, err=%d\n",
-			__func__, function, pe->phb->global_number, pe->addr, rc);
+		pr_warn("%s: Unexpected state change %d on "
+			"PHB#%d-PE#%x, err=%d\n",
+			__func__, function, pe->phb->global_number,
+			pe->addr, rc);
 
 	rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
-	if (rc > 0 && (rc & EEH_STATE_MMIO_ENABLED) &&
-	   (function == EEH_OPT_THAW_MMIO))
+	if (rc <= 0)
+		return rc;
+
+	if ((function == EEH_OPT_THAW_MMIO) &&
+	    (rc & EEH_STATE_MMIO_ENABLED))
+		return 0;
+
+	if ((function == EEH_OPT_THAW_DMA) &&
+	    (rc & EEH_STATE_DMA_ENABLED))
 		return 0;
 
 	return rc;
@@ -639,11 +669,13 @@ int eeh_reset_pe(struct eeh_pe *pe)
 	for (i=0; i<3; i++) {
 		eeh_reset_pe_once(pe);
 
+		/*
+		 * EEH_PE_ISOLATED is expected to be removed after
+		 * BAR restore.
+		 */
 		rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
-		if ((rc & flags) == flags) {
-			eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
+		if ((rc & flags) == flags)
 			return 0;
-		}
 
 		if (rc < 0) {
 			pr_err("%s: Unrecoverable slot failure on PHB#%d-PE#%x",
diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index 6d91b51a5ddb..1f1e2cc045a9 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -417,6 +417,36 @@ static void *eeh_pe_detach_dev(void *data, void *userdata)
 	return NULL;
 }
 
+/*
+ * Explicitly clear PE's frozen state for PowerNV where
+ * we have frozen PE until BAR restore is completed. It's
+ * harmless to clear it for pSeries. To be consistent with
+ * PE reset (for 3 times), we try to clear the frozen state
+ * for 3 times as well.
+ */
+static int eeh_clear_pe_frozen_state(struct eeh_pe *pe)
+{
+	int i, rc;
+
+	for (i = 0; i < 3; i++) {
+		rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
+		if (rc)
+			continue;
+		rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
+		if (!rc)
+			break;
+	}
+
+	/* The PE has been isolated, clear it */
+	if (rc)
+		pr_warn("%s: Can't clear frozen PHB#%x-PE#%x (%d)\n",
+			__func__, pe->phb->global_number, pe->addr, rc);
+	else
+		eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
+
+	return rc;
+}
+
 /**
  * eeh_reset_device - Perform actual reset of a pci slot
  * @pe: EEH PE
@@ -474,6 +504,11 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
 	eeh_pe_restore_bars(pe);
 	eeh_pe_state_clear(pe, EEH_PE_RESET);
 
+	/* Clear frozen state */
+	rc = eeh_clear_pe_frozen_state(pe);
+	if (rc)
+		return rc;
+
 	/* Give the system 5 seconds to finish running the user-space
 	 * hotplug shutdown scripts, e.g. ifdown for ethernet.  Yes,
 	 * this is a hack, but if we don't do this, and try to bring
diff --git a/arch/powerpc/platforms/powernv/eeh-ioda.c b/arch/powerpc/platforms/powernv/eeh-ioda.c
index ed6c68634c9c..6bdae8d84463 100644
--- a/arch/powerpc/platforms/powernv/eeh-ioda.c
+++ b/arch/powerpc/platforms/powernv/eeh-ioda.c
@@ -268,6 +268,21 @@ static int ioda_eeh_get_state(struct eeh_pe *pe)
 		return EEH_STATE_NOT_SUPPORT;
 	}
 
+	/*
+	 * If we're in middle of PE reset, return normal
+	 * state to keep EEH core going. For PHB reset, we
+	 * still expect to have fenced PHB cleared with
+	 * PHB reset.
+	 */
+	if (!(pe->type & EEH_PE_PHB) &&
+	    (pe->state & EEH_PE_RESET)) {
+		result = (EEH_STATE_MMIO_ACTIVE |
+			  EEH_STATE_DMA_ACTIVE |
+			  EEH_STATE_MMIO_ENABLED |
+			  EEH_STATE_DMA_ENABLED);
+		return result;
+	}
+
 	/* Retrieve PE status through OPAL */
 	pe_no = pe->addr;
 	ret = opal_pci_eeh_freeze_status(phb->opal_id, pe_no,
@@ -347,52 +362,6 @@ static int ioda_eeh_get_state(struct eeh_pe *pe)
 	return result;
 }
 
-static int ioda_eeh_pe_clear(struct eeh_pe *pe)
-{
-	struct pci_controller *hose;
-	struct pnv_phb *phb;
-	u32 pe_no;
-	u8 fstate;
-	u16 pcierr;
-	s64 ret;
-
-	pe_no = pe->addr;
-	hose = pe->phb;
-	phb = pe->phb->private_data;
-
-	/* Clear the EEH error on the PE */
-	ret = opal_pci_eeh_freeze_clear(phb->opal_id,
-			pe_no, OPAL_EEH_ACTION_CLEAR_FREEZE_ALL);
-	if (ret) {
-		pr_err("%s: Failed to clear EEH error for "
-		       "PHB#%x-PE#%x, err=%lld\n",
-		       __func__, hose->global_number, pe_no, ret);
-		return -EIO;
-	}
-
-	/*
-	 * Read the PE state back and verify that the frozen
-	 * state has been removed.
-	 */
-	ret = opal_pci_eeh_freeze_status(phb->opal_id, pe_no,
-			&fstate, &pcierr, NULL);
-	if (ret) {
-		pr_err("%s: Failed to get EEH status on "
-		       "PHB#%x-PE#%x\n, err=%lld\n",
-		       __func__, hose->global_number, pe_no, ret);
-		return -EIO;
-	}
-
-	if (fstate != OPAL_EEH_STOPPED_NOT_FROZEN) {
-		pr_err("%s: Frozen state not cleared on "
-		       "PHB#%x-PE#%x, sts=%x\n",
-		       __func__, hose->global_number, pe_no, fstate);
-		return -EIO;
-	}
-
-	return 0;
-}
-
 static s64 ioda_eeh_phb_poll(struct pnv_phb *phb)
 {
 	s64 rc = OPAL_HARDWARE;
@@ -524,27 +493,20 @@ static int ioda_eeh_reset(struct eeh_pe *pe, int option)
 	int ret;
 
 	/*
-	 * Anyway, we have to clear the problematic state for the
-	 * corresponding PE. However, we needn't do it if the PE
-	 * is PHB associated. That means the PHB is having fatal
-	 * errors and it needs reset. Further more, the AIB interface
-	 * isn't reliable any more.
-	 */
-	if (!(pe->type & EEH_PE_PHB) &&
-	    (option == EEH_RESET_HOT ||
-	    option == EEH_RESET_FUNDAMENTAL)) {
-		ret = ioda_eeh_pe_clear(pe);
-		if (ret)
-			return -EIO;
-	}
-
-	/*
 	 * The rules applied to reset, either fundamental or hot reset:
 	 *
 	 * We always reset the direct upstream bridge of the PE. If the
 	 * direct upstream bridge isn't root bridge, we always take hot
 	 * reset no matter what option (fundamental or hot) is. Otherwise,
 	 * we should do the reset according to the required option.
+	 *
+	 * Here, we have different design to pHyp, which always clear the
+	 * frozen state during PE reset. However, the good idea here from
+	 * benh is to keep frozen state before we get PE reset done completely
+	 * (until BAR restore). With the frozen state, HW drops illegal IO
+	 * or MMIO access, which can incur recrusive frozen PE during PE
+	 * reset. The side effect is that EEH core has to clear the frozen
+	 * state explicitly after BAR restore.
 	 */
 	if (pe->type & EEH_PE_PHB) {
 		ret = ioda_eeh_phb_reset(hose, option);