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bindings: PCI: layerscape: Add 'dma-coherent' property

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Add 'dma-coherent' description for PCI nodes.

The 'dma-coherent' indicates that the hardware IP block can ensure
the coherency of the data transferred from/to the IP block. This
can avoid the software cache flush/invalid actions, and improve
the performance significantly.

The PCI IP block of ls1043a has this capability, so adding
this feature to improve the PCI performance.

Signed-off-by: Liu Gang <Gang.Liu@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This commit is contained in:
Liu Gang 2016-06-07 14:55:45 +08:00 committed by Shawn Guo
parent bf26225fc6
commit 2f082b13f2
1 changed files with 4 additions and 0 deletions
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4
Documentation/devicetree/bindings/pci/layerscape-pci.txt
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@ -24,6 +24,9 @@ Required properties:
The first entry must be a link to the SCFG device node
The second entry must be '0' or '1' based on physical PCIe controller index.
This is used to get SCFG PEXN registers
- dma-coherent: Indicates that the hardware IP block can ensure the coherency
of the data transferred from/to the IP block. This can avoid the software
cache flush/invalid actions, and improve the performance significantly.
Example:
@ -38,6 +41,7 @@ Example:
#address-cells = <3>;
#size-cells = <2>;
device_type = "pci";
dma-coherent;
num-lanes = <4>;
bus-range = <0x0 0xff>;
ranges = <0x81000000 0x0 0x00000000 0x40 0x00010000 0x0 0x00010000 /* downstream I/O */