Re: [PATCH 07/13] bus: mvebu-mbus: provide api for obtaining IO and DRAM window information

Arnd Bergmann
2015-11-23T16:59:41Z

On Sunday 22 November 2015 22:24:01 Marcin Wojtas wrote:
>
> 2015-11-22 21:02 GMT+01:00 Arnd Bergmann <arnd@arndb.de>:
> > On Sunday 22 November 2015 08:53:53 Marcin Wojtas wrote:
> >> This commit enables finding appropriate mbus window and obtaining its
> >> target id and attribute for given physical address in two separate
> >> routines, both for IO and DRAM windows. This functionality
> >> is needed for Armada XP/38x Network Controller's Buffer Manager and
> >> PnC configuration.
> >>
> >> Signed-off-by: Marcin Wojtas <mw@semihalf.com>
> >>
> >> [DRAM window information reference in LKv3.10]
> >> Signed-off-by: Evan Wang <xswang@marvell.com>
> >>
> >
> > It's too long ago to remember all the details, but I thought we
> > had designed this so the configuration can just be done by
> > describing it in DT. What am I missing?
> >
>
> And those functions do not break this approach. They just enable
> finding and reading the settings of MBUS windows done during initial
> configuration. Please remember that mvebu-mbus driver fills the MBUS
> windows registers basing on DT, however it just configures access CPU
> - DRAM/perfipheral.
>
> In this particular case only physical adresses of buffers are known
> and we have to 'open windows' between BM <-> DRAM and NETA <-> BM
> internal memory. Hence instead of hardcoding size/target/attribute, we
> can take information stored in CPU DRAM/IO windows registers.
>
>

Ok, got it. Thanks for the explanation.

Arnd