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SubjectRE: [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7
Date
Hi Sergei,

Thank you for your review.

> -----Original Message-----
> From: Sergei Shtylyov [mailto:sergei.shtylyov@cogentembedded.com]
> Sent: Monday, January 26, 2015 9:05 PM
> To: Yang, Wenyou; Ferre, Nicolas; linux@arm.linux.org.uk
> Cc: sylvain.rochet@finsecur.com; Vilchez, Patrice; linux-kernel@vger.kernel.org;
> alexandre.belloni@free-electrons.com; peda@axentia.se; linux-arm-
> kernel@lists.infradead.org
> Subject: Re: [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7
>
> Hello.
>
> On 1/26/2015 1:06 PM, Wenyou Yang wrote:
>
> > Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> > ---
> > arch/arm/mach-at91/pm_suspend.S | 54
> ++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 53 insertions(+), 1 deletion(-)
>
> > diff --git a/arch/arm/mach-at91/pm_suspend.S
> > b/arch/arm/mach-at91/pm_suspend.S index 122a3f1..e796722 100644
> > --- a/arch/arm/mach-at91/pm_suspend.S
> > +++ b/arch/arm/mach-at91/pm_suspend.S
> > @@ -53,6 +53,58 @@ mode .req r6
> > beq 1b
> > .endm
> >
> > +/*
> > + * Put the processor to enter the WFI state */
> > + .macro _do_wfi
> > +
> > +#if defined(CONFIG_CPU_V7)
> > + /*
> > + * Execute an ISB instruction to flush the pipeline to ensure
> > + * that all of operations have beem completed.
>
> Been.
>
> > + */
> > + isb
> > +
> > + /*
> > + * Execute an ISB instruction to ensure that all of the
>
> ISB again, while you're executing DSB/DMB?
>
Thank you for your pointing.

> > + * CP15 register changes have been committed.
> > + */
> > + dsb
> > + dmb
> > +
> > + /* Disable the processor's clock */
> > + mov tmp1, #AT91_PMC_PCK
>
> What's 'tmp1'? Is that a register name?
Yes, a register name defined at the head of file.

>
> > + str tmp1, [pmc, #AT91_PMC_SCDR]
> > +
> > + /* Execute a WFI instruction */
>
> Self-obvious comment, I'd say...
>
> > + wfi @ Wait For Interrupt
> > +
> > + /*
> > + * CPU can specualatively prefetch the instructions
>
> Speculatively.
Thanks.
>
> [...]
>
> WBR, Sergei


Best Regards,
Wenyou Yang


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