powerpc/eeh: Fix PE#0 check in eeh_add_to_parent_pe()

The function eeh_add_parent_pe() is used to create a PE or add one
edev to its parent PE. Current code checks if PE#0 is valid for the
later case. Actually, we should validate PE#0 for both cases when
EEH core regards PE#0 as invalid one (without flag EEH_VALID_PE_ZERO).
Otherwise, not all EEH devices can be added to its parent PE#0 for
EEH on P7IOC.

The patch fixes the issue by validating PE#0 for the two cases. So far,
we don't have PE#0 for EEH on P7IOC, but it will show up when we enable
M64 for P7IOC. The patch also makes the error message more meaningful.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/eeh_pe.c

@@ -328,6 +328,13 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 {
 	struct eeh_pe *pe, *parent;
 
+	/* Check if the PE number is valid */
+	if (!eeh_has_flag(EEH_VALID_PE_ZERO) && !edev->pe_config_addr) {
+		pr_err("%s: Invalid PE#0 for edev 0x%x on PHB#%d\n",
+		       __func__, edev->config_addr, edev->phb->global_number);
+		return -EINVAL;
+	}
+
 	/*
 	 * Search the PE has been existing or not according
 	 * to the PE address. If that has been existing, the
@@ -336,12 +343,6 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	 */
 	pe = eeh_pe_get(edev);
 	if (pe && !(pe->type & EEH_PE_INVALID)) {
-		if (!edev->pe_config_addr) {
-			pr_err("%s: PE with addr 0x%x already exists\n",
-				__func__, edev->config_addr);
-			return -EEXIST;
-		}
-
 		/* Mark the PE as type of PCI bus */
 		pe->type = EEH_PE_BUS;
 		edev->pe = pe;