From: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Date: Mon, 28 Sep 2015 16:03:10 +0000 (+0800)
Subject: PCI: designware: Make num-lanes an optional DT property
X-Git-Tag: KARO-TX6UL-2015-11-03~103^2~4^3
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=efe52075227729aa2a1ed55e34dd599b3bb0dbf1;p=karo-tx-linux.git

PCI: designware: Make num-lanes an optional DT property

Currently "num-lanes" is read in dw_pcie_host_init(), but it is only used
if we call dw_pcie_setup_rc() while bringing up the link.  If the link has
already been brought up by firmware, we need not call dw_pcie_setup_rc(),
and "num-lanes" is unnecessary.

Only complain about "num-lanes" if we actually need it and we didn't find a
valid value.

[bhelgaas: changelog]
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---

diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
index 9f4faa8e8d00..0036ab3065b8 100644
--- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
@@ -14,7 +14,6 @@ Required properties:
 - interrupt-map-mask and interrupt-map: standard PCI properties
 	to define the mapping of the PCIe interface to interrupt
 	numbers.
-- num-lanes: number of lanes to use
 - clocks: Must contain an entry for each entry in clock-names.
 	See ../clocks/clock-bindings.txt for details.
 - clock-names: Must include the following entries:
@@ -22,6 +21,8 @@ Required properties:
 	- "pcie_bus"
 
 Optional properties:
+- num-lanes: number of lanes to use (this property should be specified unless
+  the link is brought already up in BIOS)
 - reset-gpio: gpio pin number of power good signal
 - bus-range: PCI bus numbers covered (it is recommended for new devicetrees to
   specify this property, to keep backwards compatibility a range of 0x00-0xff
diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index b77535f3967b..fb89ca23d9a8 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -534,10 +534,9 @@ int dw_pcie_host_init(struct pcie_port *pp)
 		}
 	}
 
-	if (of_property_read_u32(np, "num-lanes", &pp->lanes)) {
-		dev_err(pp->dev, "Failed to parse the number of lanes\n");
-		return -EINVAL;
-	}
+	ret = of_property_read_u32(np, "num-lanes", &pp->lanes);
+	if (ret)
+		pp->lanes = 0;
 
 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
 		if (!pp->ops->msi_host_init) {
@@ -814,6 +813,9 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 	case 8:
 		val |= PORT_LINK_MODE_8_LANES;
 		break;
+	default:
+		dev_err(pp->dev, "num-lanes %u: invalid value\n", pp->lanes);
+		return;
 	}
 	dw_pcie_writel_rc(pp, val, PCIE_PORT_LINK_CONTROL);