[PATCH 2/2] arm: mvebu: Add hardware I/O Coherency support

[Andrew Lunn]

On Wed, Oct 24, 2012 at 10:04:01AM +0200, Gregory CLEMENT wrote:
> Armada 370 and XP come with an unit called coherency fabric. This unit
> allows to use the Armada XP as a nearly coherent architecture. The
> coherency mechanism uses snoop filters to ensure the coherency between
> caches, DRAM and devices. This mechanism needs a synchronization
> barrier which guarantees that all memory write initiated by the
> devices has reached their target and do not reside in intermediate
> write buffers. That's why the architecture is not totally coherent and
> we need to provide our own functions for some DMA operations.
> 
> Beside the use of the coherency fabric, the device units will have to
> set the attribute flag to select the accurate coherency process for
> the memory transaction. This is done each device driver programs the
> DRAM address windows. The value of the attribute set by the driver is
> retrieved through the orion_addr_map_cfg struct filled during the
> early initialization of the platform.
> 
> Signed-off-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
> Reviewed-by: Yehuda Yitschak <yehuday at marvell.com>
> ---
>  arch/arm/boot/dts/armada-370-xp.dtsi |    3 +-
>  arch/arm/mach-mvebu/addr-map.c       |    3 ++
>  arch/arm/mach-mvebu/armada-370-xp.c  |    1 +
>  arch/arm/mach-mvebu/coherency.c      |   87 ++++++++++++++++++++++++++++++++++
>  arch/arm/mach-mvebu/common.h         |    2 +
>  5 files changed, 95 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/armada-370-xp.dtsi b/arch/arm/boot/dts/armada-370-xp.dtsi
> index 18ba60b..af22e53 100644
> --- a/arch/arm/boot/dts/armada-370-xp.dtsi
> +++ b/arch/arm/boot/dts/armada-370-xp.dtsi
> @@ -38,7 +38,8 @@
>  
>  	coherency-fabric at d0020200 {
>  		compatible = "marvell,coherency-fabric";
> -		reg = <0xd0020200 0xb0>;
> +		reg = <0xd0020200 0xb0>,
> +		      <0xd0021010 0x1c>;
>  	};

...

>  int __init armada_370_xp_coherency_init(void)
>  {
>  	struct device_node *np;
> @@ -82,7 +159,17 @@ int __init armada_370_xp_coherency_init(void)
>  	if (np) {
>  		pr_info("Initializing Coherency fabric\n");
>  		coherency_base = of_iomap(np, 0);
> +		coherency_cpu_base = of_iomap(np, 1);

Is this already in the binding documentation?

   Thanks
	Andrew