Re: [PATCH, RFC 2/8] ARM: twd: register clock event for 1 core SMP

From: Felipe Balbi
Date: Tue Feb 19 2013 - 07:14:37 EST


On Tue, Feb 19, 2013 at 03:44:14PM +0530, Santosh Shilimkar wrote:
> On Monday 18 February 2013 05:07 PM, Afzal Mohammed wrote:
> >Register percpu local timer for scheduler tick in the case of one core
> >SMP configuration. In other cases - secondary cpu's as well as boot
> >cpu's having more than one core, this is being registered as per
> >existing boot flow, with a difference that they happens after delay
> >calibration. Registering the clock for tick in case of one core should
> >be done before Kernel calibrates delay (this is required to boot,
> >unless local timer is the only one registered for tick). Registering
> >twd local timer at init_time (which platforms are doing now) helps
> >achieve that with the proposed change.
> >
> >This helps in an almost booting Kernel (minimal) by only relying on
> >ARM parts for an A9 one core SMP.
> >
> >Signed-off-by: Afzal Mohammed <afzal@xxxxxx>
> >---
> As mentioned in cover-letter, I don't think we have good
> reasoning to make TWD to work with UP configuration. Even
> you fix the timer code, there are more cascaded dependencies
> which is not worth the effort.

if CONFIG_SMP_ON_UP is enabled, smp_twd.c can still be compiled, right ?

--
balbi

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