Re: [PATCH] ARM: Update SMP_ON_UP code to detect A9MPCore with 1 CPU devices

[Sekhar Nori <nsekhar@ti.com>]

On 8/13/2013 7:01 PM, Santosh Shilimkar wrote:
> On Tuesday 13 August 2013 07:19 AM, Will Deacon wrote:
>> On Mon, Aug 12, 2013 at 07:34:13PM +0100, Santosh Shilimkar wrote:
>>> On Friday 02 August 2013 11:48 AM, Will Deacon wrote:
>>>> I think this an A9-specific register, which reads as 0 on UP A9 and reads as
>>>> some form of PERIPH_BASE for SMP parts. The issue I have is when PERIPH_BASE
>>>> is zero.
>>>>
>>> What do we do here ? Should we document this in the code and proceed ?
>>> Mostly there is no platform with PERIPH_BASE = 0, so its should be fine but
>>> I am open for any other alternative.
>>
>> The only other alternative I can think of is forcing people to have
>> CONFIG_SMP=n, but that blows away single zImage for your platform.
>>
> Yep which surely we don't want considering after so much effort we
> have it working first place. How about going ahead with assumption
> that PERIPH_BASE = 0 case doesn't work.

I must be missing something but why cannot we use the SCU configuration
register "CPU number" field to determine that its a UP? I do not have an
OMAP4 board, but on AM437x, it certainly indicates only CPU0 present.

Thanks,
Sekhar