[PATCH v2 1/2] ARM: IMX5: cpuidle driver

[s.hauer@pengutronix.de (Sascha Hauer)]

On Wed, Feb 16, 2011 at 09:37:47AM +0100, Yong Shen wrote:
> Hi Sascha,
> 
> 
> > > +     local_irq_disable();
> > > +     do_gettimeofday(&before);
> > > +
> > > +     plat_lpc = __raw_readl(MXC_CORTEXA8_PLAT_LPC) &
> > > +         ~(MXC_CORTEXA8_PLAT_LPC_DSM);
> >
> > One thing that strikes me here is the fact that this code can probably
> > run on i.MX53 aswell, right? It's only that these registers have
> > different addresses on i.MX53. The MXC_ prefix is therefore not a good
> > idea. Switching this to MX51_ and having an additional MX53_ register
> > leads to code duplication. This shows that it's a bad idea to code
> > fixed addresses in the code. We should go for base + offset instead
> > so that this code will have a better start on i.MX53. This of course
> > needs changes in the current crm_regs.h and probably in the i.MX51/53
> > clock code.
> >
> Yes, for mx53, it is similar.
> But for the case you are talking about, is it easier that we keep MXC_
> prefix in this file and define MXC_ to MX51 or MX53 in crm_regs.h according
> to which board is running?

I don't understand. How can we 'define' (which is compile time) to
something depending on the board (which is runtime)?

> In addition, registers for this code are not in one section, which means
> many BASEx + offset there, if I understand right. Do you have a sample for
> 'base + offset' case? since mx53 just came in, I am not sure about such
> case.

Forget it. I just realized that more or less by accident the virtual
addresses for the i.MX51 and i.MX53 are the same.

Sascha


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