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From: Frank Rowand <frank_rowand@mvista•com>
To: Dan Malek <dan@mvista•com>
Cc: linuxppc-dev <linuxppc-dev@lists•linuxppc.org>
Subject: Re: kernel mapping
Date: Mon, 15 Jan 2001 19:07:39 -0800	[thread overview]
Message-ID: <3A63BAFB.80E3980C@mvista.com> (raw)
In-Reply-To: 3A63840E.4C724E03@mvista.com


Dan Malek wrote:
>
> How come we don't use iopa() and friends for all kernel mapping
> information?  It is only defined for CONFIG_APUS, but is the right
> thing to use on 8xx and 4xx, and probably all processors.  The
> virt_to_bus/bus_to_virt contain the quickie arithmetic hack with
> KERNELBASE, but that isn't the right thing to do for any kmalloc()
> or valloc() space or if you don't have BAT mapping.
>
> I am considering making these functions more generic, removing the
> #ifdefs, and implementing "simulated" BAT mapping for processors
> like the 8xx and 4xx that don't have BATs (not for 2.4, of course :-).
>
> Why shouldn't I do this?
>
>         -- Dan

For the 405 I had to use iopa() for virt_to_bus() because there are
cases where I create a virtual address for IO buffers that is
uncached, and that virtual address is not (physical address + KERNELBASE).
I also have the beginnings of simulated BAT mapping for the 405
(not quite there, but part way).

-Frank
--
Frank Rowand <frank_rowand@mvista•com>
MontaVista Software, Inc

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2001-01-16  3:07 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-01-15 23:13 kernel mapping Dan Malek
2001-01-16  3:07 ` Frank Rowand [this message]
2001-01-16  3:55   ` Dan Malek
2001-01-16 11:37   ` Ralph Blach
2001-01-16 16:50     ` Dan Malek
2001-01-16 17:10       ` Ralph Blach
2001-01-16 17:47       ` David Edelsohn
2001-01-16 21:57         ` Dan Malek
2001-01-17 10:51         ` Gabriel Paubert
2001-01-17 17:45           ` David Edelsohn
2001-01-16 19:56       ` Frank Rowand
2001-01-16 22:13         ` Dan Malek
2001-01-17  0:04           ` Frank Rowand
2001-01-17  7:02             ` Dan Malek

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