From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 2/4] ARM: tegra: pmc: add power on function for secondary CPUs Date: Fri, 22 Feb 2013 21:32:32 -0700 Message-ID: <51284660.8060002@wwwdotorg.org> References: <1361515491-16199-1-git-send-email-josephl@nvidia.com> <1361515491-16199-3-git-send-email-josephl@nvidia.com> <20130222130051.GV23234@tbergstrom-lnx.Nvidia.com> <1361587135.1804.16.camel@jlo-ubuntu-64.nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1361587135.1804.16.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Joseph Lo Cc: Peter De Schrijver , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On 02/22/2013 07:38 PM, Joseph Lo wrote: > On Fri, 2013-02-22 at 21:00 +0800, Peter De Schrijver wrote: >> On Fri, Feb 22, 2013 at 07:44:49AM +0100, Joseph Lo wrote: >>> Adding the power on function for secondary CPUs in PMC driver, this can >>> help us to remove legacy powergate driver and add generic power domain >>> support later. >>> diff --git a/arch/arm/mach-tegra/pmc.c b/arch/arm/mach-tegra/pmc.c >>> +static u8 tegra_cpu_domains[] = { >>> + 0xFF, /* not available for CPU0 */ >> >> On Tegra114 we can also powergate CPU0, so this needs to be defined then. >> > No, DON'T DO THAT!! > We don't allow any code to power gate CPU0 manually here or elsewhere. > > The function here only for SMP and hotplug bring up for secondary CPU. Doesn't Tegra114 have improved HW that does actually allow power-gating/hot-unplugging/... CPU 0, even though older HW didn't?