• Arnd Bergmann's avatar
    hwmon: (xgene) access mailbox as RAM · c7cefce0
    Arnd Bergmann authored
    The newly added hwmon driver fails to build in an allmodconfig
    kernel:
    
          ERROR: "memblock_is_memory" [drivers/hwmon/xgene-hwmon.ko] undefined!
    
    According to comments in the code, the mailbox is a shared memory region,
    not a set of MMIO registers, so we should use memremap() for mapping it
    instead of ioremap or acpi_os_ioremap, and pointer dereferences instead
    of readl/writel.
    
    The driver already uses plain kernel pointers, so it's a bit unusual
    to work with functions that operate on __iomem pointers, and this
    fixes that part too.
    
    I'm using READ_ONCE/WRITE_ONCE here to keep the existing behavior
    regarding the ordering of the accesses from the CPU, but note that
    there are no barriers (also unchanged from before).
    
    I'm also keeping the endianness behavior, though I'm unsure whether
    the message data was supposed to be in LE32 format in the first
    place, it's possible this was meant to be interpreted as a byte
    stream instead.
    Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    Acked-by: default avatarHoan Tran <hotran@apm.com>
    Tested-by: default avatarHoan Tran <hotran@apm.com>
    Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
    c7cefce0
xgene-hwmon.c 19.5 KB