[PATCH 2/2] 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 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 <redacted>
Reviewed-by: Yehuda Yitschak <redacted>
---
 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);