powerpc/eeh: Fix missed PE#0 on P7IOC

PE#0 should be regarded as valid for P7IOC, while it's invalid for
PHB3. The patch adds flag EEH_VALID_PE_ZERO to differentiate those
two cases. Without the patch, we possibly see frozen PE#0 state is
cleared without EEH recovery taken on P7IOC as following kernel logs
indicate:

[root@ltcfbl8eb ~]# dmesg
       :
pci 0000:00     : [PE# 000] Secondary bus 0 associated with PE#0
pci 0000:01     : [PE# 001] Secondary bus 1 associated with PE#1
pci 0001:00     : [PE# 000] Secondary bus 0 associated with PE#0
pci 0001:01     : [PE# 001] Secondary bus 1 associated with PE#1
pci 0002:00     : [PE# 000] Secondary bus 0 associated with PE#0
pci 0002:01     : [PE# 001] Secondary bus 1 associated with PE#1
pci 0003:00     : [PE# 000] Secondary bus 0 associated with PE#0
pci 0003:01     : [PE# 001] Secondary bus 1 associated with PE#1
pci 0003:20     : [PE# 002] Secondary bus 32..63 associated with PE#2
       :
EEH: Clear non-existing PHB#3-PE#0
EEH: PHB location: U78AE.001.WZS00M9-P1-002
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/eeh.h

@@ -38,8 +38,9 @@ struct device_node;
 #define EEH_FORCE_DISABLED	0x02	/* EEH disabled		*/
 #define EEH_PROBE_MODE_DEV	0x04	/* From PCI device	*/
 #define EEH_PROBE_MODE_DEVTREE	0x08	/* From device tree	*/
-#define EEH_ENABLE_IO_FOR_LOG	0x10	/* Enable IO for log	*/
-#define EEH_EARLY_DUMP_LOG	0x20	/* Dump log immediately	*/
+#define EEH_VALID_PE_ZERO	0x10	/* PE#0 is valid	*/
+#define EEH_ENABLE_IO_FOR_LOG	0x20	/* Enable IO for log	*/
+#define EEH_EARLY_DUMP_LOG	0x40	/* Dump log immediately	*/
 
 /*
  * Delay for PE reset, all in ms

arch/powerpc/kernel/eeh_pe.c

@@ -239,10 +239,18 @@ static void *__eeh_pe_get(void *data, void *flag)
 	if (pe->type & EEH_PE_PHB)
 		return NULL;
 
-	/* We prefer PE address */
-	if (edev->pe_config_addr &&
-	   (edev->pe_config_addr == pe->addr))
+	/*
+	 * We prefer PE address. For most cases, we should
+	 * have non-zero PE address
+	 */
+	if (eeh_has_flag(EEH_VALID_PE_ZERO)) {
+		if (edev->pe_config_addr == pe->addr)
+			return pe;
+	} else {
+		if (edev->pe_config_addr &&
+		    (edev->pe_config_addr == pe->addr))
 		return pe;
+	}
 
 	/* Try BDF address */
 	if (edev->config_addr &&

arch/powerpc/platforms/powernv/eeh-powernv.c

@@ -68,6 +68,17 @@ static int powernv_eeh_init(void)
 
 		if (phb->model == PNV_PHB_MODEL_P7IOC)
 			eeh_add_flag(EEH_ENABLE_IO_FOR_LOG);
+
+		/*
+		 * PE#0 should be regarded as valid by EEH core
+		 * if it's not the reserved one. Currently, we
+		 * have the reserved PE#0 and PE#127 for PHB3
+		 * and P7IOC separately. So we should regard
+		 * PE#0 as valid for P7IOC.
+		 */
+		if (phb->ioda.reserved_pe != 0)
+			eeh_add_flag(EEH_VALID_PE_ZERO);
+
 		break;
 	}