• Andrew Morton's avatar
    [PATCH] add readX_relaxed() interface · 50f33737
    Andrew Morton authored
    From: jbarnes@sgi.com (Jesse Barnes)
    
    Here's the patch to add the new _relaxed variants for PIO read accesses.
    It's been ack'd by gregkh and Grant Grundler, and I think it's ready to
    go.
    
    PCI ordering rules also guarantee that PIO read responses arrive after any
    outstanding DMA writes on that bus, since for some devices the result of a
    readb() call may signal to the driver that a DMA transaction is complete.  In
    many cases, however, the driver may want to indicate that the next readb()
    call has no relation to any previous DMA writes performed by the device.  The
    driver can use the readb_relaxed() for these cases, although only some
    platforms will honor the relaxed semantics.
    50f33737
io.h 2.23 KB