Re: [PATCH RESEND 1/5] ARM: BCM63XX: add basic support for the Broadcom BCM63138 DSL SoC

Arnd Bergmann
2014-05-02T07:55:23Z

On Thursday 01 May 2014 22:32:27 Florian Fainelli wrote:
> >> +#ifndef __ARM_BCM63XX_H
> >> +#define __ARM_BCM63XX_H
> >> +
> >> +#define IO_ADDRESS(x) (((x) & 0x00ffffff) + 0xfc000000)
> >> +
> >> +/* AHB register space */
> >> +#define BCM63XX_AHB_PHYS 0x80001000
> >> +#define BCM63XX_AHB_VIRT IO_ADDRESS(BCM63XX_AHB_PHYS)
> >> +#define BCM63XX_AHB_SIZE 0x800000
> >> +
> >> +/* PERIPH (legacy) register space */
> >> +#define BCM63XX_PERIPH_PHYS 0xfffe8000
> >> +#define BCM63XX_PERIPH_VIRT IO_ADDRESS(BCM63XX_PERIPH_PHYS)
> >> +#define BCM63XX_PERIPH_SIZE 0x10000
> >
> > You shouldn't need these any more. If you do, just move all of this
> > into the main file, to ensure no other file accidentally relies
> > on hardcoded values.
> >
> > Note that BCM63XX_AHB_PHYS is nor aligned, so AFAICT you don't
> > actually get a huge page entry for it, and there is no point
> > doing this at all, as it has neither functional nor performance
> > relevance.
> >
> > You may have out-of-tree drivers that you haven't cleaned up
> > or posted yet relying on specific static mappings, but that is
> > no reason to have these mappings in the mainline kernel.
>
> I tried without the iotable entries, and any register access to these
> regions did hang the system, I will check harder what was going on
> there.

Can you clarify what you mean with 'any register access to these
regions did hang the system'? If you remove the call to iotable_init,
you obviously can't access the registers through BCM63XX_{AHB,PERIPH}_VIRT
any longer, but accesses through a pointer returned from ioremap()
should keep working as before.

The DEBUG_LL early output is a special case here, these need one
of three options:

- .map_io is NULL (preferred)
- .map_io points to a function that calls debug_ll_io_init()
- .map_io points to a function that calls iotable_init with
an equivalent or larger mapping as debug_ll_io_init() would.

I suspect you were doing the third here for historic reasons.

Arnd