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 10:14:49 +0100 (BST)
Cc: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
In-reply-to: <46B0BD99.6070901@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>
Sender: linux-mips-bounce@linux-mips.org
On Wed, 1 Aug 2007, Sergei Shtylyov wrote:

> > So what is the issue with the size then?  How big is the area?
> 
>    I've already said: 4 gigs! At least in theory, actually it's 2 gigs due to

 Oh, I mistook it for the base physical address, sorry.

> a device # being limited to 0 thru 19 (address bits 11 thru 30 are used as
> IDSELx).

 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 
to be another example where the chip designer "forgot" to talk to software 
people.  Or a shifter was traded for software performance and complexity. 
;-)

>    I meant that the implementation "caches" the 8 KiB mapping used for the
> last config. access.

 Ah, that can certainly be done with ioremap().

>    There was no need to tell me about how KSEG0/1/2 work -- that's why I
> cosidered it wasting time. :-)

 As I say -- the key is how you look at it.  There are other readers on 
the list who may benefit; it is archived too.  In this sense I can hardly 
consider it a waste of time.  And it was fun to explain and no fun shall 
be ever considered of no use. :-)

  Maciej

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