From: "David S. Miller" <davem@redhat.com>
To: mdaljeet@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: virt_to_bus and virt_to_phys on Apple G4 target
Date: Tue, 3 Jul 2001 00:18:58 -0700 (PDT) [thread overview]
Message-ID: <15169.29154.670946.785981@pizda.ninka.net> (raw)
In-Reply-To: <CA256A7E.0020F52C.00@d73mta01.au.ibm.com>
In-Reply-To: <CA256A7E.0020F52C.00@d73mta01.au.ibm.com>
mdaljeet@in.ibm.com writes:
> I am running linux 2.4.2 on Apple G4 machine. I think the 'PCI bus
> addresses' and 'physical addresses' are same on this architecture. I
> expected the two be different but according to asm/io.h 'virt_to_bus(addr)
> = virt_to_phys(addr) + PCI_DRAM_OFFSET'. I printed the value of
> 'PCI_DRAM_OFFSET' and that come out to be zero. Is this correct?
>
> If I somehow get the physical address of a user space buffer in a module
> and take this as a PCI bus address, will I be able to do DMA properly?
virt_to_bus() and bus_to_virt() are deprecated interfaces and should
not be used by anything new. See Documentation/DMA-mapping.txt for
details.
Later,
David S. Miller
davem@redhat.com
next prev parent reply other threads:[~2001-07-03 7:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-03 5:57 mdaljeet
2001-07-03 7:18 ` David S. Miller [this message]
2001-07-04 22:03 ` acmay
2001-07-04 7:56 ` Paul Mackerras
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