From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: [PATCH 1/3] ARM: at91: flush the L2 cache before entering cpu idle Date: Fri, 6 Jan 2017 10:05:17 +0100 Message-ID: <20170106090517.txcoukisnx43cfqq@piout.net> References: <20170106065947.30631-1-wenyou.yang@atmel.com> <20170106065947.30631-2-wenyou.yang@atmel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20170106065947.30631-2-wenyou.yang@atmel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Wenyou Yang Cc: Mark Rutland , devicetree@vger.kernel.org, Russell King , Wenyou Yang , Nicolas Ferre , linux-kernel@vger.kernel.org, Rob Herring , linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org Hi, On 06/01/2017 at 14:59:45 +0800, Wenyou Yang wrote : > For the SoCs such as SAMA5D2 and SAMA5D4 which have L2 cache, > flush the L2 cache first before entering the cpu idle. > > Signed-off-by: Wenyou Yang > --- > > arch/arm/mach-at91/pm.c | 19 +++++++++++++++++++ > drivers/memory/atmel-sdramc.c | 1 + > 2 files changed, 20 insertions(+) > > diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c > index b4332b727e9c..1a60dede1a01 100644 > --- a/arch/arm/mach-at91/pm.c > +++ b/arch/arm/mach-at91/pm.c > @@ -289,6 +289,24 @@ static void at91_ddr_standby(void) > at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1); > } > > +static void at91_ddr_cache_standby(void) > +{ > + u32 saved_lpr; > + > + flush_cache_all(); > + outer_disable(); > + > + saved_lpr = at91_ramc_read(0, AT91_DDRSDRC_LPR); > + at91_ramc_write(0, AT91_DDRSDRC_LPR, (saved_lpr & > + (~AT91_DDRSDRC_LPCB)) | AT91_DDRSDRC_LPCB_SELF_REFRESH); > + > + cpu_do_idle(); > + > + at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr); > + > + outer_resume(); > +} > + Seems good to me. Did you measure the added latency on sama5d3 if you add the cache operations in at91_ddr_standby instead of having a new function? -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com