Re: [PATCH] PCI: layerscape: Add 'dma-coherent' property

[Rob Herring <robh@kernel.org>]

On Tue, Jun 07, 2016 at 02:55:45PM +0800, Liu Gang wrote:
> 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>
> ---
>  Documentation/devicetree/bindings/pci/layerscape-pci.txt | 4 ++++
>  1 file changed, 4 insertions(+)

Acked-by: Rob Herring <robh@kernel.org>

> 
> diff --git a/Documentation/devicetree/bindings/pci/layerscape-pci.txt b/Documentation/devicetree/bindings/pci/layerscape-pci.txt
> index ef683b2..41e9f55 100644
> --- a/Documentation/devicetree/bindings/pci/layerscape-pci.txt
> +++ b/Documentation/devicetree/bindings/pci/layerscape-pci.txt
> @@ -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 */
> -- 
> 2.1.0.27.g96db324
>