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RE: Battery powered ram


ioremap() is your friend here.

Something like this in a driver should do it:

unsigned long* mem;
mem = ioremap(MEM_CSR0_START, MAP_SIZE);

where MAP_SIZE is the size of the area you want to map

You can then access mem with e.g. mem[30] = 3 or with
memory to memory DMA (remember that DMA requires 
physical addresses and that all pages are present
in memory etc).

If you need the SRAM to be uncached you should 

-----Original Message-----
From: owner-dev-etrax@xxxxxxx.com]On">mailto:owner-dev-etrax@xxxxxxx.com]On
Behalf Of Pieter Grimmerink
Sent: Thursday, December 05, 2002 10:29 AM
To: dev-etrax
Subject: Battery powered ram

I would like to connect a small battery powered SRAM chip to the etrax100LX, 
and use that for non volatile storage.
Now I'm wondering how I should reserve its physical address range at bootup, 
in order to be able to map it as a device (like /dev/mem).
Could this be done in a kernel driver, or is that already too late (memory 
might already be in use?)

Best regards,