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    SubjectRe: [PATCH 3/3] arch/tile: tilegx PCI root complex support
    On 4/9/2012 9:59 AM, Arnd Bergmann wrote:
    > On Saturday 07 April 2012, Chris Metcalf wrote:
    >> This change implements PCIe root complex support for tilegx using
    >> the kernel support layer for accessing the TRIO hardware shim.
    >> Signed-off-by: Chris Metcalf <>
    > Hi Chris,
    > I don't know if we discussed it during the initial merge, but I notice that the PIO
    > accessors (inb/outb and friends) are still not implemented in this patch. Normally
    > PIO can just be mapped into the MMIO address space, so that inb() becomes
    > a call to readb() with an offset on the address.

    I asked our PCI expert here, who said, "My understanding is that if someone
    wants to use inb/outb to access MMIO space, he'll get the MMIO, as opposed
    to methods implemented with I/O instructions which are not supported by
    TILE. If the driver is dependent on the I/O instructions, it won't work on
    TILE. These drivers are legacy PC drivers, e.g. ATA devices, which are not
    supported by TILE."

    Should we just arrange to #include <asm-generic/io.h> to pick up inb/outb
    et al? Any reason to think a non-zero offset should be part of the
    solution? (I don't really understand how inb/outb are used by modern drivers.)

    > Using mdelay is generally considered very rude. Since you are not in
    > atomic context here, just use msleep() instead.


    Thanks for all your reviews!

    Chris Metcalf, Tilera Corp.

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