linux-mips
[Top] [All Lists]

Re: Modpost warning on Alchemy

To: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Subject: Re: Modpost warning on Alchemy
From: "Maciej W. Rozycki" <macro@linux-mips.org>
Date: Thu, 2 Aug 2007 14:27:29 +0100 (BST)
Cc: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
In-reply-to: <46B1D2F7.8000002@ru.mvista.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20070801115231.GA20323@linux-mips.org> <46B07B36.1000501@ru.mvista.com> <Pine.LNX.4.64N.0708011337390.20314@blysk.ds.pg.gda.pl> <46B086EB.2030101@ru.mvista.com> <46B0880B.2000009@ru.mvista.com> <Pine.LNX.4.64N.0708011629010.20314@blysk.ds.pg.gda.pl> <46B0AA74.7040100@ru.mvista.com> <Pine.LNX.4.64N.0708011708250.20314@blysk.ds.pg.gda.pl> <46B0B6B4.5090103@ru.mvista.com> <Pine.LNX.4.64N.0708011737170.20314@blysk.ds.pg.gda.pl> <46B0BD99.6070901@ru.mvista.com> <Pine.LNX.4.64N.0708020945020.22591@blysk.ds.pg.gda.pl> <46B1D2F7.8000002@ru.mvista.com>
Sender: linux-mips-bounce@linux-mips.org
Hi,

> > It does not help too much with a 32-bit virtual address space indeed.
> > Though I gather it has to be very sparsely populated as 16MiB is enough to
> > cover the whole configuration space of a single PCI bus tree.  Thus it has 
> 
>    Hm, maybe 16 MiB would be enough indeed, as the Alchemy CPUs are known to
> not support bus masters behind PCI bridges...

 That is unrelated -- for configuration accesses (assuming the basic 
configuration space) you need: 8 bits for the bus number + 5 bits for the 
device number + 3 bits for the function number + 8 bits for the register 
number.  The total is 24 bits.  It is up to hardware to sort it out and 
put the right bits on the bus.

  Maciej

<Prev in Thread] Current Thread [Next in Thread>