• Gregory CLEMENT's avatar
    arm: mvebu: Add hardware I/O Coherency support · e60304f8
    Gregory CLEMENT authored
    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: default avatarGregory CLEMENT <gregory.clement@free-electrons.com>
    Reviewed-by: default avatarYehuda Yitschak <yehuday@marvell.com>
    Acked-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
    e60304f8
addr-map.c 3.75 KB