UPSTREAM: Documentation/devicetree: Add new property to specify the max link speed

[firefly-linux-kernel-4.4.55.git] / Documentation / devicetree / bindings / pci / pci.txt

diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
index f8fbe9af7b2f276350426b299c6030adb9464640..e7d97a3bd17f3e2778c9a71e8d655caebf9fb35d 100644 (file)
--- a/Documentation/devicetree/bindings/pci/pci.txt
+++ b/Documentation/devicetree/bindings/pci/pci.txt
@@ -1,12 +1,12 @@
 PCI bus bridges have standardized Device Tree bindings:
 
 PCI Bus Binding to: IEEE Std 1275-1994
-http://www.openfirmware.org/ofwg/bindings/pci/pci2_1.pdf
+http://www.firmware.org/1275/bindings/pci/pci2_1.pdf
 
 And for the interrupt mapping part:
 
 Open Firmware Recommended Practice: Interrupt Mapping
-http://www.openfirmware.org/1275/practice/imap/imap0_9d.pdf
+http://www.firmware.org/1275/practice/imap/imap0_9d.pdf
 
 Additionally to the properties specified in the above standards a host bridge
 driver implementation may support the following properties:
@@ -18,3 +18,9 @@ driver implementation may support the following properties:
    host bridges in the system, otherwise potentially conflicting domain numbers
    may be assigned to root buses behind different host bridges.  The domain
    number for each host bridge in the system must be unique.
+- max-link-speed:
+   If present this property specifies PCI gen for link capability. The host drivers
+   could add this as a strategy to avoid unnecessary operation for unsupported
+   link speed, for instance, trying to do training for unsupported link speed, etc.
+   Must be '4' for gen4, '3' for gen3, '2' for gen2, and '1' for gen1. Any other
+   values are invalid.