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

Marcin Wojtas
2015-11-22T21:24:04Z

Arnd,

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.

Best regards,
Marcin