From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Wenyou Yang <wenyou.yang@atmel.com>
Cc: "nicolas.ferre@atmel.com" <nicolas.ferre@atmel.com>,
"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"alexandre.belloni@free-electrons.com"
<alexandre.belloni@free-electrons.com>,
"sylvain.rochet@finsecur.com" <sylvain.rochet@finsecur.com>,
"peda@axentia.se" <peda@axentia.se>,
"Patrice.VILCHEZ@atmel.com" <Patrice.VILCHEZ@atmel.com>
Subject: Re: [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7
Date: Wed, 28 Jan 2015 11:25:52 +0000 [thread overview]
Message-ID: <20150128112551.GA13253@e102568-lin.cambridge.arm.com> (raw)
In-Reply-To: <1422266761-24487-1-git-send-email-wenyou.yang@atmel.com>
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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next prev parent reply other threads:[~2015-01-28 20:26 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-26 10:03 [PATCH 0/7] AT91 pm improvements for 3.20 Wenyou Yang
2015-01-26 10:04 ` [PATCH 1/7] pm: at91: achieve the memory controller's type from the dts file Wenyou Yang
2015-01-26 10:06 ` [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7 Wenyou Yang
2015-01-26 13:05 ` Sergei Shtylyov
2015-01-27 4:44 ` Yang, Wenyou
2015-01-28 11:25 ` Lorenzo Pieralisi [this message]
2015-01-29 2:36 ` Yang, Wenyou
2015-01-29 12:22 ` Lorenzo Pieralisi
2015-01-30 7:23 ` Yang, Wenyou
2015-01-30 10:17 ` Lorenzo Pieralisi
2015-01-30 10:44 ` Lorenzo Pieralisi
2015-01-26 10:06 ` [PATCH 3/7] pm: at91: pm_suspend: MOR register KEY was missing Wenyou Yang
2015-01-26 10:07 ` [PATCH 4/7] ARM: at91: enable the L2 Cache controller Wenyou Yang
2015-01-26 11:46 ` Mark Rutland
2015-01-26 12:45 ` Russell King - ARM Linux
2015-01-26 22:36 ` Alexandre Belloni
2015-01-27 5:11 ` Yang, Wenyou
2015-01-26 10:07 ` [PATCH 5/7] pm: at91: add disable/enable the L1/L2 cache while suspend/resume Wenyou Yang
2015-01-26 10:08 ` [PATCH 6/7] pm: at91: add achieve the mpddrc peripheral ID and the DDR clock ID support Wenyou Yang
2015-01-26 11:49 ` Mark Rutland
2015-01-27 5:24 ` Yang, Wenyou
2015-01-26 10:08 ` [PATCH 7/7] pm: at91: add disable/enable the mpddrc's clock and DDR clock support Wenyou Yang
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