From: Adrian Cox <adrian@humboldt.co.uk>
To: "David Müller (ELSOFT AG)" <d.mueller@elsoft.ch>
Cc: linuxppc-dev@lists.linuxppc.org
Subject: Re: ISA DMA
Date: Thu, 20 Dec 2001 09:50:28 +0000 [thread overview]
Message-ID: <3C21B464.4030509@humboldt.co.uk> (raw)
In-Reply-To: 3C21A301.2080204@elsoft.ch
David Müller (ELSOFT AG) wrote:
> Seems like you are facing the same problem as i do. But IIRC i think you
> have to adjust the code in include/asm/dma.h (and possibly other places)
> as well (at least in 2.4.14, not sure about the later kernels).
The main problem I can see is that the code always writes to the
DMA_HI_PAGE_x registers, irrespective of whether they actually exist.
This should be harmless, as nothing else is mapped to those locations.
> What south bridge do you use? Some of the newer ones offer 32bit
> addressing capability for DMA.
Via686a. As I understand it, 32-bit DMA uses the DMA_HI_PAGE_x registers
from 0x487 to 0x48a, and the Via manual doesn't claim to have any
registers in that range. The only 32-bit DMA southbridge I've
encountered is the Winbond chip on the Sandpoint, and that chip doesn't
have UDMA66, USB, and audio.
--
Adrian Cox http://www.humboldt.co.uk/
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2001-12-20 9:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-19 10:21 ISA DMA Adrian Cox
2001-12-20 8:36 ` David Müller (ELSOFT AG)
2001-12-20 9:50 ` Adrian Cox [this message]
2001-12-20 10:09 ` Geert Uytterhoeven
-- strict thread matches above, loose matches on Subject: below --
2001-12-20 16:42 Michael Sokolov
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