From: David Hawkins <dwh@ovro•caltech.edu>
To: Bruce_Leonard@selinc•com
Cc: linuxppc-embedded@ozlabs•org
Subject: Re: How do I access nvRAM from user space?
Date: Thu, 25 Sep 2008 08:53:38 -0700 [thread overview]
Message-ID: <48DBB402.8090402@ovro.caltech.edu> (raw)
In-Reply-To: <OFFC64870C.57753273-ON882574CF.001088E7-882574CF.001228E4@selinc.com>
Hi Bruce,
> Sorry for the dumb question, I just can figure out the right google search
> to find what I'm trying to do. I'm running 2.6.27-rc4 on an mpc8347 with
> a 32KiB nvSRAM (Cypress CY14B256L) on the local bus. We just want to be
> able to access this memory from user space seperately from "main" memory.
> We've got a process that needs to be able to remember info through power
> cycles. Can anyone point me to an article or some code snippet that does
> something like this so I can sink my teeth into it?
Assuming your bootloader sets up the local bus access windows
(physical address of the SRAM) and timing so that you can
read/write to the SRAM, then once Linux boots, you should be
able to just use /dev/mem as you would to access any other
device registers at a specific address.
Cheers,
Dave
next prev parent reply other threads:[~2008-09-25 16:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-25 3:18 How do I access nvRAM from user space? Bruce_Leonard
2008-09-25 5:45 ` yanjun.luo
2008-09-25 15:53 ` David Hawkins [this message]
2008-09-25 17:18 ` Bruce_Leonard
2008-09-25 18:13 ` Bruce_Leonard
2008-09-25 18:14 ` David Hawkins
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