From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCH] ARM: exynos4212: hotplug: Fix CPU idle clock down after CPU1 off Date: Fri, 30 May 2014 16:43:59 +0200 Message-ID: <1401461039.11651.6.camel@AMDC1943> References: <1399990378-7023-1-git-send-email-k.kozlowski@samsung.com> <53887095.7090108@gmail.com> <1401453990.11651.2.camel@AMDC1943> <53888008.5020108@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-reply-to: <53888008.5020108@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Tomasz Figa Cc: Russell King , Kukjin Kim , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Kyungmin Park , Marek Szyprowski , Bartlomiej Zolnierkiewicz , Tomasz Figa List-Id: linux-samsung-soc@vger.kernel.org On pi=C4=85, 2014-05-30 at 14:56 +0200, Tomasz Figa wrote: > On 30.05.2014 14:46, Krzysztof Kozlowski wrote: > > On pi=C4=85, 2014-05-30 at 13:50 +0200, Tomasz Figa wrote: > >> Hi Krzysztof, > >> > >> On 13.05.2014 16:12, Krzysztof Kozlowski wrote: > >>> On Exynos4212 USE_DELAYED_RESET_ASSERTION must be set in > >>> ARM_CORE1_OPTION register during CPU power down. This is the prop= er way > >>> of powering down CPU. Additionally without this the CPU clock dow= n won't > >>> work after powering down CPU1 and CPU will work at full frequency= chosen > >>> by CPUfreq governor. > >>> > >>> Signed-off-by: Krzysztof Kozlowski > >>> --- > >>> arch/arm/mach-exynos/hotplug.c | 28 +++++++++++++++++++++++++--= - > >>> arch/arm/mach-exynos/regs-pmu.h | 2 ++ > >>> 2 files changed, 27 insertions(+), 3 deletions(-) > >>> > >>> diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exyno= s/hotplug.c > >>> index 5eead530c6f8..59b813e74558 100644 > >>> --- a/arch/arm/mach-exynos/hotplug.c > >>> +++ b/arch/arm/mach-exynos/hotplug.c > >>> @@ -74,7 +74,7 @@ static inline void cpu_enter_lowpower_a15(void) > >>> dsb(); > >>> } > >>> =20 > >>> -static inline void cpu_leave_lowpower(void) > >>> +static inline void cpu_leave_lowpower(unsigned int cpu) > >>> { > >>> unsigned int v; > >>> =20 > >>> @@ -88,6 +88,14 @@ static inline void cpu_leave_lowpower(void) > >>> : "=3D&r" (v) > >>> : "Ir" (CR_C), "Ir" (0x40) > >>> : "cc"); > >>> + > >>> + if (cpu =3D=3D 1 && soc_is_exynos4212()) { > >> > >> AFAIK this is needed not only on Exynos4x12, but at least also on = 4412. > >> Also I don't think the (cpu =3D=3D 1) condition is necessary. See = below. > >=20 > > I'll test it on Exynos4412. > >=20 > >> > >>> + unsigned int tmp; > >>> + > >>> + tmp =3D __raw_readl(S5P_ARM_CORE1_OPTION); > >>> + tmp &=3D ~(S5P_USE_DELAYED_RESET_ASSERTION); > >>> + __raw_writel(tmp, S5P_ARM_CORE1_OPTION); > >>> + } > >>> } > >>> =20 > >>> static inline void platform_do_lowpower(unsigned int cpu, int *s= purious) > >>> @@ -95,8 +103,22 @@ static inline void platform_do_lowpower(unsig= ned int cpu, int *spurious) > >>> for (;;) { > >>> =20 > >>> /* make cpu1 to be turned off at next WFI command */ > >>> - if (cpu =3D=3D 1) > >>> + if (cpu =3D=3D 1) { > >> > >> I think this patch should be rebased on top of my "[PATCH] ARM: EX= YNOS: > >> Fix core ID used by platsmp and hotplug code". Then instead of if = (cpu > >> =3D=3D 1) you would just use EXYNOS_ARM_CORE_OPTION(core_id). > >> > >> Also same comment as above, I believe this is also needed on Exyno= s4412. > >=20 > > Probably your patch needs rebasing too. I couldn't apply (cleanly) = on > > current Linus' tree and on Kukjin's for-next. What are the requirem= ents > > for it? >=20 > Hmm, I based it on Kukjin's for-next from the day I sent the patch, > 23.05 if I remember correctly. AFAICT everything needed by this patch= is > already merged in Kukjin's tree (and I believe already was when I sen= t > that patch). >=20 > To make sure, I'm talking about this patch: > http://www.spinics.net/lists/linux-samsung-soc/msg31604.html Yep, that's the patch but still it does not apply cleanly :). Anyway I'll send next version of my patch reflecting your comments: 1. Limit to all Exynos4 SoCs. 2. Rebase on your patch to utilize EXYNOS_ARM_CORE_OPTION(core_id). Best regards, Krzysztof