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SubjectRe: [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7
On Mon, Jan 26, 2015 at 10:06:01AM +0000, Wenyou Yang wrote:

Commit log please.

> 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

You will have to explain why you need this, really.

> +
> +#if defined(CONFIG_CPU_V7)
> + /*
> + * Execute an ISB instruction to flush the pipeline to ensure
> + * that all of operations have beem completed.

s/beem/been

> + */
> + isb
> +
> + /*
> + * Execute an ISB instruction to ensure that all of the
> + * CP15 register changes have been committed.
> + */
> + dsb

This is a dsb not an isb.

> + dmb
You have to explain why you need every single one of these barriers,
otherwise I am NAKing this patch.

> +
> + /* Disable the processor's clock */
> + mov tmp1, #AT91_PMC_PCK
> + str tmp1, [pmc, #AT91_PMC_SCDR]
> +
> + /* Execute a WFI instruction */
> + wfi @ Wait For Interrupt

This one looks ok :)

> +
> + /*
> + * CPU can specualatively prefetch the instructions
> + * so add NOPs after WFI. Sixteen NOPs as Cortex-A5 pipeline.

So what ? I suspect your issue is related to wfi completion on pending
IRQ. I would like to know the details that describe the issue you are
trying to solve here please.

> + */
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> + nop
> +#else
> + mcr p15, 0, tmp1, c7, c0, 4
> +#endif

Tell us what's the problem you have to solve, first, then we will see how
to fix it.

Thanks,
Lorenzo

> +
> + .endm
> +
> .text
>
> /*
> @@ -181,7 +233,7 @@ sdr_sr_done:
>
> skip_disable_main_clock:
> /* Wait for interrupt */
> - mcr p15, 0, tmp1, c7, c0, 4
> + _do_wfi
>
> tst mode, #AT91_PM_SLOW_CLOCK
> beq skip_enable_main_clock
> --
> 1.7.9.5
>
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