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From: Laurent Pinchart <laurent.pinchart@tbox.biz>
To: Vitaly Bordug <vbordug@ru.mvista.com>
Subject: Re: Accessing the CPM2 on an MPC82xx : CPM_MAP_ADDR or cpm2_immr ?
Date: Thu, 2 Feb 2006 16:42:49 +0100
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> > I noticed that the CPM2 module is accessed both through CPM_MAP_ADDR
> > (physical address) and cpm2_immr (ioremap()ed address). For instance, the
> > fec_enet driver configures the IO ports using (cpm2_map_t*)CPM_MAP_ADDR.
>
> Mentioned driver is deprecated.

It has been replaced by drivers/net/fs_enet, right ? The new driver doesn't 
support the LXT971/LXT971A PHY chipsets yet, so I'm still using the old one.

> > What's the correct way to access the CPM2 module ? Does ioremap() map
> > CPM_MAP_ADDR to itself so that both ways are correct ?
>
> Even direct cpm2_immr usage is not a good thing, but I cannot tell more
> without knowing your concerns. Can you please describe what you are
> planning to implement, prolly we can advice how to do that proper way.

I'm currently just hacking IDMA transfers to make sure the signals we plan to 
use on a custom design work as expected. I will later work on the USB host 
controller driver.

The new fs_enet driver internally maps CPM_MAP_ADDR. Should every driver 
create an internal CPM mapping ? Why was the old fec_enet driver able to 
access the CPM through CPM_MAP_ADDR without ioremap()ing it first ?

Laurent Pinchart