🚀 go-pugleaf

In article <144400004@hpcupt3.cup.hp.com> sbmn@hpcupt3.cup.hp.com (S.Subramanian(contr)) writes:
>/ hpcupt3:comp.unix.internals / hausler@aldetec.oz.au (Graham Hausler) / 12:45 am  Nov 20, 1992 /
>> 1. Can I access physical memory (not in IO space) directly from a
>>   device driver, assumming I have removed this memory from usage by unix?
>>    I want the physical memory at a fixed address, and hence cannot
>>    allocate in virtual address space and then derive the physical address
>>    (assuming I can even manage that !!)
>
>If your kernel has a sptalloc() / ptalloc() routine, you can make use of it.
>It takes a base physical address maps it to a kernel virtual address and
>returns this address.



All you need to do is choose a physical address range (not used by
UNIX) and plunk in a value in the TTRs (Transparent Translation
Registers) so that the physical addresses are directly accessible from
the driver. Pretty cool. I am assuming of course that you are using a
68040...

Krishna

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