*BSD News Article 83404


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From: Frederic.Marand@osinet.fr (Frederic MARAND)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: DMA
Date: Thu, 21 Nov 1996 18:38:52 GMT
Organization: Groupe SEDI / Agorus SA / OSI SARL
Lines: 25
Message-ID: <572b5n$ilc@newsbr.eunet.fr>
References: <328C8861.48A3@mercurio.uc.pt> <56mjnr$b4a@uriah.heep.sax.de> <329083AC.7048@mercurio.uc.pt> <56vtd6$1mo@anorak.coverform.lan> <32946E0C.EF5@mercurio.uc.pt>
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Filipe Araujo <filipius@mercurio.uc.pt> wrote:
>Brian Somers wrote:
>> In article <329083AC.7048@mercurio.uc.pt>,
>>         Filipe Araujo <filipius@mercurio.uc.pt> writes:
>> :       - allocate contiguous memory under 16 MB;
>	The PCI local bus has 32 bits for addressing. The PCI local bus
> specification also defines a transparent extension to 64 bits. The same
>thing for data, because data and address lines are shared.
Has it really ? Or is it like the ISA bus with the low-order bits
truncated ?

>> kvm_alloc().  I'm no kernel hacker, but it seems that this allocates
>> the memory (returning a virtual pointer) and you can then use the
>> KVTOPHYS() macro to get a physical address to give to the hardware.
>	I didn't find the function kvm_alloc()...
I don't know about FreeBSD, but last time I saw it, it was only
available to programs in kernel space, not user space. It was defined
int sys/kvm.h, I believe.

-------------------------
   Frederic G. MARAND
  Agorus SA / OSI SARL
Frederic.Marand@osinet.fr
-------------------------