[PATCH 4.19 100/168] PCI: cadence: Fix updating Vendor ID and Subsystem Vendor ID register

[Greg Kroah-Hartman]

From: Kishon Vijay Abraham I <kishon@xxxxxx>

[ Upstream commit e3bca37d15dca118f2ef1f0a068bb6e07846ea20 ]

Commit 1b79c5284439 ("PCI: cadence: Add host driver for Cadence PCIe
controller") in order to update Vendor ID, directly wrote to
PCI_VENDOR_ID register. However PCI_VENDOR_ID in root port configuration
space is read-only register and writing to it will have no effect.
Use local management register to configure Vendor ID and Subsystem Vendor
ID.

Link: https://lore.kernel.org/r/20200722110317.4744-10-kishon@xxxxxx
Fixes: 1b79c5284439 ("PCI: cadence: Add host driver for Cadence PCIe controller")
Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/pci/controller/pcie-cadence-host.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-cadence-host.c b/drivers/pci/controller/pcie-cadence-host.c
index ec394f6a19c8e..ae7affcb1a811 100644
--- a/drivers/pci/controller/pcie-cadence-host.c
+++ b/drivers/pci/controller/pcie-cadence-host.c
@@ -102,6 +102,7 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
 {
 	struct cdns_pcie *pcie = &rc->pcie;
 	u32 value, ctrl;
+	u32 id;
 
 	/*
 	 * Set the root complex BAR configuration register:
@@ -121,8 +122,12 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
 	cdns_pcie_writel(pcie, CDNS_PCIE_LM_RC_BAR_CFG, value);
 
 	/* Set root port configuration space */
-	if (rc->vendor_id != 0xffff)
-		cdns_pcie_rp_writew(pcie, PCI_VENDOR_ID, rc->vendor_id);
+	if (rc->vendor_id != 0xffff) {
+		id = CDNS_PCIE_LM_ID_VENDOR(rc->vendor_id) |
+			CDNS_PCIE_LM_ID_SUBSYS(rc->vendor_id);
+		cdns_pcie_writel(pcie, CDNS_PCIE_LM_ID, id);
+	}
+
 	if (rc->device_id != 0xffff)
 		cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, rc->device_id);
 
-- 
2.25.1