From f9df74dfce542ad2aea2e601ef1a1281e01fad6a Mon Sep 17 00:00:00 2001
From: "Bryant G. Ly" <bryantly@linux.vnet.ibm.com>
Date: Tue, 29 Aug 2017 08:11:51 -0500
Subject: [PATCH] powerpc/kernel: Change retrieval of pci_dn

References: bsc#1078720
Patch-mainline: v4.14-rc1
Git-commit: f9df74dfce542ad2aea2e601ef1a1281e01fad6a

For a PCI device it's pci_dn can be retrieved from
pdev->dev.archdata.firmware_data, PCI_DN(devnode), or parent's list.
Thus, we should just use the existing function pci_get_pdn_by_devfn
to get the pci_dn.

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Reviewed-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/rtas_pci.c | 33 ++++-----------------------------
 1 file changed, 4 insertions(+), 29 deletions(-)

diff --git a/arch/powerpc/kernel/rtas_pci.c b/arch/powerpc/kernel/rtas_pci.c
index 73f1934582c2..c2b148b1634a 100644
--- a/arch/powerpc/kernel/rtas_pci.c
+++ b/arch/powerpc/kernel/rtas_pci.c
@@ -91,26 +91,14 @@ static int rtas_pci_read_config(struct pci_bus *bus,
 				unsigned int devfn,
 				int where, int size, u32 *val)
 {
-	struct device_node *busdn, *dn;
 	struct pci_dn *pdn;
-	bool found = false;
 	int ret;
 
-	/* Search only direct children of the bus */
 	*val = 0xFFFFFFFF;
-	busdn = pci_bus_to_OF_node(bus);
-	for (dn = busdn->child; dn; dn = dn->sibling) {
-		pdn = PCI_DN(dn);
-		if (pdn && pdn->devfn == devfn
-		    && of_device_is_available(dn)) {
-			found = true;
-			break;
-		}
-	}
 
-	if (!found)
-		return PCIBIOS_DEVICE_NOT_FOUND;
+	pdn = pci_get_pdn_by_devfn(bus, devfn);
 
+	/* Validity of pdn is checked in here */
 	ret = rtas_read_config(pdn, where, size, val);
 	if (*val == EEH_IO_ERROR_VALUE(size) &&
 	    eeh_dev_check_failure(pdn_to_eeh_dev(pdn)))
@@ -153,24 +141,11 @@ static int rtas_pci_write_config(struct pci_bus *bus,
 				 unsigned int devfn,
 				 int where, int size, u32 val)
 {
-	struct device_node *busdn, *dn;
 	struct pci_dn *pdn;
-	bool found = false;
-
-	/* Search only direct children of the bus */
-	busdn = pci_bus_to_OF_node(bus);
-	for (dn = busdn->child; dn; dn = dn->sibling) {
-		pdn = PCI_DN(dn);
-		if (pdn && pdn->devfn == devfn
-		    && of_device_is_available(dn)) {
-			found = true;
-			break;
-		}
-	}
 
-	if (!found)
-		return PCIBIOS_DEVICE_NOT_FOUND;
+	pdn = pci_get_pdn_by_devfn(bus, devfn);
 
+	/* Validity of pdn is checked in here. */
 	return rtas_write_config(pdn, where, size, val);
 }
 
-- 
2.13.6