Re: [PATCH] fix ppc ioremap prototype

[Paul Mackerras]

Christoph Hellwig writes:

> ioremap_resource() looks like a fine idea.  It's cleaner, easily
> emulateable on <= 2.4 and solves the problem this hack wanted to
> work around properly.

I agree.

> This still doesn't make the phys_addr_t a good interims solution,
> though.  Just use ioremap_resource from the beginning for those
> drivers that care for the bigger address space on ppc44x.
> 
> Paul, what does actually use this higher addresses?

We have drivers for on-chip peripherals that work from a struct
ocp_device and call ioremap on the ocp_dev->paddr value, which is a
phys_addr_t (although some of them use __ioremap instead).  These
drivers are used on 405-based systems (with 32-bit phys_addr_t) as
well as on 440-based systems.

These drivers are in the linuxppc-2.{4,5} trees but most of them
haven't made it into the official trees yet.  They could all be
audited and converted to use __ioremap, although it seems a bit
arbitrary to say that you can't use ioremap in a an ocp driver if
you're going to use it on a 440.  I wouldn't expect it to be
immediately obvious to a driver author just why you have to use
__ioremap rather than ioremap in an ocp driver.  The ioremap_resource
idea would solve that problem of course, we would put a resource in
the struct ocp_device instead of the physical address.

Paul.

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