• Thomas Petazzoni's avatar
    ARM: 8060/1: mm: allow sub-architectures to override PCI I/O memory type · 1c8c3cf0
    Thomas Petazzoni authored
    Due to a design incompatibility between the PCIe Marvell controller
    and the Cortex-A9, stressing PCIe devices with a lot of traffic
    quickly causes a deadlock.
    
    One part of the workaround for this is to have all PCIe regions mapped
    as strongly-ordered (MT_UNCACHED) instead of the default
    MT_DEVICE. While the arch_ioremap_caller() mechanism allows
    sub-architecture code to override ioremap(), used to map PCIe memory
    regions, there isn't such a mechanism to override the behavior of
    pci_ioremap_io().
    
    This commit adds the arch_pci_ioremap_mem_type variable, initialized
    to MT_DEVICE by default, and that sub-architecture code can
    override. We have chosen to expose a single variable rather than
    offering the possibility of overriding the entire pci_ioremap_io(),
    because implementing pci_ioremap_io() requires calling functions
    (get_mem_type()) that are private to the arch/arm/mm/ code.
    Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
    Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
    1c8c3cf0
ioremap.c 11.2 KB