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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>
This commit is contained in:
Gabriele Paoloni 2015-09-29 00:03:10 +08:00 committed by Bjorn Helgaas
parent b6b18f589e
commit 907fce0902
2 changed files with 8 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Documentation/devicetree/bindings/pci/designware-pcie.txt
View File

@ -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

10
drivers/pci/host/pcie-designware.c
View File

@ -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);