[PATCH] fsl/smp: add low power boot support to replace spin boot

[Dongsheng.Wang at freescale.com]

Thanks for your review.

> -----Original Message-----
> From: Sun York-R58495
> Sent: Friday, January 16, 2015 1:09 AM
> To: Wang Dongsheng-B40534; Wood Scott-B07421; Li Yang-Leo-R58472
> Cc: linuxppc-dev at lists.ozlabs.org
> Subject: Re: [PATCH] fsl/smp: add low power boot support to replace spin boot
> 
> 
> 
> On 01/14/2015 10:05 PM, Dongsheng Wang wrote:
> > From: Wang Dongsheng <dongsheng.wang at freescale.com>
> >
> > U-boot put non-boot cpus into an low power state(PW10/PW20 or DOZE)
> > when cpu powered up. To exit low power state kernel will send DOORBELL
> > or MPIC-IPI signal to all those CPUs.
> >
> > e500/e500v2 use mpic to send IPI signal.
> > e500mc and later use doorbell to send IPI signal.
> >
> > This feature tested on:
> > POWER UP TEST:
> > P1022DS(e500v2),96k times.
> > P4080(e500mc),  110k times.
> > T1024(e5500),   83k times.
> > T4240(e6500),   150k times.
> >
> > CPU HOTPLUG TEST:
> > P1022DS(e500v2),1.4 million times.
> > P4080(e500mc),  1.8 million times.
> > T1024(e5500),   1.3 million times.
> > T4240(e6500),   1.1 million times.
> >
> > Signed-off-by: Wang Dongsheng <dongsheng.wang at freescale.com>
> >
> 
> This is a very good move. Can you explain what has been tested for 100K times,
> or over a million times?
> 
Thanks, I tested linux boot process and cpu hotplug.

For Linux boot process test:
Each CPU can normally be started and random run an application, the application
works well.

For cpu hotplug test:
Just plug out and plug in for each cpu. Cpu hotplug test works well.

If I missed some case please let me know.

> Have you verified on older e500v2 platforms, such as MPC8572?
> 
I haven't tested MPC8572 and Just test P1022DS. Because is e500 and e500v2 use the same
Low power boot codes.

I will test this feature on MPC8572 platform. 

Regards,
-Dongsheng