lkml.org 
[lkml]   [1997]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: pre2.0.31-2


    On 6 Jun 1997, Jes Degn Soerensen wrote:

    > But! Yeah here it comes, I do think it would be a good idea to add an
    > extra parameter to vremap() which specifies the cache-mode that is
    > supposed to be used for the mapping. We do need this for the m68k and
    > so we currently use our own kernel_map() rather than vremap(), and I
    > think some other architectures might need it as well.

    Agree. Furthermore broken PPro Bioses who forget to set up correctly MTRR
    do exist. I had the proof last night after a few mail exchanges with
    Patrick St. Jean <psj@cgmlarson.com>. He had to switch to v2.1 and use
    ioremap_nocache.

    Pentia are much more reliable in this respect since cache disabling is
    done by chipset hardware as a function of the physical address.

    > I would like to have a function with the same name for all archs so
    > one wont have to dig half way through the kernel to figure out what is
    > going on in some other driver when you want to clone it. Architectures
    > which do not need this can just ignore the extra parameter, but maybe
    > this really indicates that vremap() is really an architecture specific
    > thing and should be moved to arch/foo/mm/?

    Same function for all architectures with one additional parameter is best
    IMO. Mapping devices in kernel space is a quite generic need and should
    not be architecture specific. Anyway the architecture dependance can
    be hidden in #include <linux/mm.h> to try to avoid #ifdef's in drivers.

    >
    > Jes
    >
    > PS: Besides vremap() is really one of those functions where you cannot
    > figure out from its name what it is actually doing, so maybe a
    > renaming was a good idea as well.
    >

    Done in V2.1, it's called ioremap and has the additional ioremap_nocache
    version to explicitly disable caching.

    Gabriel

    \
     
     \ /
      Last update: 2005-03-22 13:39    [W:0.022 / U:1.048 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site