From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH 1/2] ARM: OMAP2+: Initialize timers later with late_time_init Date: Tue, 1 Dec 2015 07:47:05 -0800 Message-ID: <20151201154705.GP23396@atomide.com> References: <1448900789-4034-1-git-send-email-tony@atomide.com> <1448900789-4034-2-git-send-email-tony@atomide.com> <565DA609.2020204@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <565DA609.2020204@ti.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: Grygorii Strashko Cc: Tero Kristo , Paul Walmsley , linux-omap@vger.kernel.org, Felipe Balbi , linux-arm-kernel@lists.infradead.org List-Id: linux-omap@vger.kernel.org * Grygorii Strashko [151201 05:53]: > On 11/30/2015 06:26 PM, Tony Lindgren wrote: > > We don't need timers right away and initializing them later gives us few > > nice things like interrupts and kmalloc. As the timers have a dependency > > to the clock framework, we're better off initializing things later rather > > than early if things go wrong. And this allows us to make the mux clock > > driver needed for system timers into early_platform drivers. > > > > Note that smp_prepare_cpus() will get called later on during the init so > > we just need to local_irq_enable/disable for clocksource_probe(). > > > > Cc: Felipe Balbi > > Cc: Grygorii Strashko > > Cc: Paul Walmsley > > Cc: Tero Kristo > > Signed-off-by: Tony Lindgren > > --- > > arch/arm/mach-omap2/timer.c | 46 +++++++++++++++++++++++++++++++++++++++------ > > 1 file changed, 40 insertions(+), 6 deletions(-) > > > > diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c > > index b18ebbe..68bf482 100644 > > --- a/arch/arm/mach-omap2/timer.c > > +++ b/arch/arm/mach-omap2/timer.c > > @@ -478,36 +478,56 @@ static void __init __omap_sync32k_timer_init(int clkev_nr, const char *clkev_src > > omap2_gp_clockevent_init(clkev_nr, clkev_src, clkev_prop); > > > > /* Enable the use of clocksource="gp_timer" kernel parameter */ > > + local_irq_disable(); > > if (use_gptimer_clksrc || gptimer) > > omap2_gptimer_clocksource_init(clksrc_nr, clksrc_src, > > clksrc_prop); > > else > > omap2_sync32k_clocksource_init(); > > + local_irq_enable(); > > So, this will be called now after sched_clock_postinit() and to W/A warnings > you've added local_irq_disable()/local_irq_enable(). Am I right? > > Are you sure this is safe? Hmm good point, update_sched_clock() is never called again and so it's running on jiffies. We could separate out the sched_clock when the 32k source or a local timer is used. But that does allow initializing the gptimer later on. Anyways, clearly this needs more work. Regards, Tony