[PATCH 4.16 069/113] PCI: aardvark: Fix logic in advk_pcie_{rd,wr}_conf()

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Victor Gu <xigu@xxxxxxxxxxx>

commit 660661afcd40ed7f515ef3369721ed58e80c0fc5 upstream.

The PCI configuration space read/write functions were special casing
the situation where PCI_SLOT(devfn) != 0, and returned
PCIBIOS_DEVICE_NOT_FOUND in this case.

However, while this is what is intended for the root bus, it is not
intended for the child busses, as it prevents discovering devices with
PCI_SLOT(x) != 0. Therefore, we return PCIBIOS_DEVICE_NOT_FOUND only
if we're on the root bus.

Fixes: 8c39d710363c1 ("PCI: aardvark: Add Aardvark PCI host controller driver")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Victor Gu <xigu@xxxxxxxxxxx>
Reviewed-by: Wilson Ding <dingwei@xxxxxxxxxxx>
Reviewed-by: Nadav Haklai <nadavh@xxxxxxxxxxx>
[Thomas: tweak commit log.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/pci/host/pci-aardvark.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/pci/host/pci-aardvark.c
+++ b/drivers/pci/host/pci-aardvark.c
@@ -437,7 +437,7 @@ static int advk_pcie_rd_conf(struct pci_
 	u32 reg;
 	int ret;
 
-	if (PCI_SLOT(devfn) != 0) {
+	if ((bus->number == pcie->root_bus_nr) && PCI_SLOT(devfn) != 0) {
 		*val = 0xffffffff;
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
@@ -491,7 +491,7 @@ static int advk_pcie_wr_conf(struct pci_
 	int offset;
 	int ret;
 
-	if (PCI_SLOT(devfn) != 0)
+	if ((bus->number == pcie->root_bus_nr) && PCI_SLOT(devfn) != 0)
 		return PCIBIOS_DEVICE_NOT_FOUND;
 
 	if (where % size)