From e60304f8cb7bb545e79fe62d9b9762460c254ec2 Mon Sep 17 00:00:00 2001 From: Gregory CLEMENT Date: Fri, 12 Oct 2012 19:20:36 +0200 Subject: arm: mvebu: Add hardware I/O Coherency support Armada 370 and XP come with an unit called coherency fabric. This unit allows to use the Armada 370/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 the memory writes initiated by the devices have 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 of the decoding address window 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 Reviewed-by: Yehuda Yitschak Acked-by: Marek Szyprowski --- arch/arm/mach-mvebu/addr-map.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/arm/mach-mvebu/addr-map.c') diff --git a/arch/arm/mach-mvebu/addr-map.c b/arch/arm/mach-mvebu/addr-map.c index fe454a4430be..595f6b722a8f 100644 --- a/arch/arm/mach-mvebu/addr-map.c +++ b/arch/arm/mach-mvebu/addr-map.c @@ -108,6 +108,9 @@ static int __init armada_setup_cpu_mbus(void) addr_map_cfg.bridge_virt_base = mbus_unit_addr_decoding_base; + if (of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric")) + addr_map_cfg.hw_io_coherency = 1; + /* * Disable, clear and configure windows. */ -- cgit v1.2.3