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List:       linux-arm-kernel
Subject:    RE: Direct-mapped Compact Flash on ARM9
From:       "Ranslam, Robert E" <robert.e.ranslam () intel ! com>
Date:       2004-07-02 17:20:11
Message-ID: 8D5F43CD1194B04CAD2AC656844E8F2B0178C1D4 () orsmsx409
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>-----Original Message-----
>From: linux-arm-kernel-bounces@lists.arm.linux.org.uk 
>[mailto:linux-arm-kernel-bounces@lists.arm.linux.org.uk] On 
>Behalf Of Deepak Saxena
>Sent: Friday, July 02, 2004 9:23 AM
>To: Greg Ungerer
>Cc: James Graves; linux-arm-kernel@lists.arm.linux.org.uk
>Subject: Re: Direct-mapped Compact Flash on ARM9
>
>On Jul 02 2004, at 14:57, Greg Ungerer was caught saying:
>> The one thing that has caused me grief though is that I need to use 
>> appropriate in/out calls now, for different drivers. For example the 
>> default in/out on the ixp425 architecture platforms point at the PCI 
>> bus. I want that for PCI drivers. But now I need the in/out 
>functions 
>> for any pcmcia/pccard drivers to point at the expansion bus space 
>> mapped in my simple pcmcia driver. Anyone have any comments 
>on a clean 
>> way to handle this?
>
>
>Unfortunately the whole read/write API is a mess b/c it is 
>supposedly ther only for PCI drivers but everthing from flash 
>to 8250.c uses it. :( I had a similar situation with the 
>IXDP2801 board where the serial driver does readl/writel and I 
>didn't want to swap the words. The only way to do this that I 
>could really think of was to static-map the serial ports and 
>then have my read/write macros check the address range of the 
>incoming address to determine how to handle it.  Since there 
>is no device context associated with the incoming address, it 
>seemed like the only way to really do it. 
>

I'm just chiming in because I think that there are a lot of folks 
that could benefit.  This would be a similar issue with handing
the CF connection on the Gateworks IXP425-based board. Connecting
the IDE Subsystem required replacing the io routines. 

I did spend a little time last year looking at this and concluded
that PCI is the sole focus in linux, a general solution for the
expansion bus probably deserved a new subsystem, but - at the time
 - was not worth the Effort.  I did not have the time or a project
To try it on either.  Although if I had at least Hacked something
to gether it may have ecouraged others.

You two guys are the best ones to maybe formulate a solution/less
ugly hack(IMHO).   Do we want to try to address it in this forum?

There are others out there that have been using the expansion bus
Varsious things. Meybe they would like to chime in too.

RR

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