Messages in this thread Patch in this message | | | Date | Thu, 19 May 2011 19:32:22 +0200 | Subject | Re: [PATCH] ARM: smp_twd: Reconfigure clockevents after cpufreq change | From | Linus Walleij <> |
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2011/5/17 Colin Cross <ccross@android.com>:
> This patch depends on Thomas Gleixner's patch to add clockevents_reconfigure > See: https://lkml.org/lkml/2011/5/13/122
Patch set has evolved, see below. Also note that you more or less reimplement Rob Herrings patch: http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=6802/1 (no big deal I guess, give him a nod)
To work with Thomas full changeset just create a fresh branch and: git pull git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip.git timers/clockevents
Pls change subject from ARM: to clockevents: and merge through Thomas tree (IMHO).
> diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c > index 60636f4..dbf58d4 100644 > --- a/arch/arm/kernel/smp_twd.c > +++ b/arch/arm/kernel/smp_twd.c > @@ -10,21 +10,29 @@ > */ > #include <linux/init.h> > #include <linux/kernel.h> > +#include <linux/clk.h> > +#include <linux/cpufreq.h> > #include <linux/delay.h> > #include <linux/device.h> > +#include <linux/err.h> > #include <linux/smp.h> > #include <linux/jiffies.h> > #include <linux/clockchips.h> > #include <linux/irq.h> > #include <linux/io.h> > +#include <linux/percpu.h> > > #include <asm/smp_twd.h> > #include <asm/hardware/gic.h> > > +#define TWD_MIN_RANGE 4 > +
Loose this. Let the framework decide using the function below.
> /* set up by the platform code */ > void __iomem *twd_base; > > +static struct clk *twd_clk; > static unsigned long twd_timer_rate; > +static DEFINE_PER_CPU(struct clock_event_device *, twd_ce); > > static void twd_set_mode(enum clock_event_mode mode, > struct clock_event_device *clk) > @@ -80,6 +88,49 @@ int twd_timer_ack(void) > return 0; > } > > +/* > + * Updates clockevent frequency when the cpu frequency changes. > + * Called on the cpu that is changing frequency with interrupts disabled. > + */ > +static void twd_update_frequency(void *data) > +{ > + twd_timer_rate = clk_get_rate(twd_clk); > + > + clockevents_reconfigure(__get_cpu_var(twd_ce), twd_timer_rate, > + TWD_MIN_RANGE);
Changed name to clockevents_update_freq(), dropped range argument.
> +} > + > +static int twd_cpufreq_transition(struct notifier_block *nb, > + unsigned long state, void *data) > +{ > + struct cpufreq_freqs *freqs = data; > + > + /* > + * The twd clock events must be reprogrammed to account for the new > + * frequency. The timer is local to a cpu, so cross-call to the > + * changing cpu. > + */ > + if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE) > + smp_call_function_single(freqs->cpu, twd_update_frequency, > + NULL, 1); > + > + return NOTIFY_OK; > +} > + > +static struct notifier_block twd_cpufreq_nb = { > + .notifier_call = twd_cpufreq_transition, > +}; > + > +static int twd_cpufreq_init(void) > +{ > + if (!IS_ERR_OR_NULL(twd_clk)) > + return cpufreq_register_notifier(&twd_cpufreq_nb, > + CPUFREQ_TRANSITION_NOTIFIER); > + > + return 0; > +} > +core_initcall(twd_cpufreq_init); > + > static void __cpuinit twd_calibrate_rate(void) > { > unsigned long count; > @@ -124,7 +175,16 @@ static void __cpuinit twd_calibrate_rate(void) > */ > void __cpuinit twd_timer_setup(struct clock_event_device *clk) > { > - twd_calibrate_rate(); > + if (twd_clk == NULL) { > + twd_clk = clk_get_sys("smp_twd", NULL); > + if (IS_ERR_OR_NULL(twd_clk)) > + pr_warn("%s: no clock found\n", __func__); > + } > + > + if (!IS_ERR_OR_NULL(twd_clk)) > + twd_timer_rate = clk_get_rate(twd_clk); > + else > + twd_calibrate_rate(); > > clk->name = "local_timer"; > clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | > @@ -132,13 +192,16 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk) > clk->rating = 350; > clk->set_mode = twd_set_mode; > clk->set_next_event = twd_set_next_event; > - clk->shift = 20; > - clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift); > + > + clockevents_calc_mult_shift(clk, twd_timer_rate, TWD_MIN_RANGE); > + > clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); > clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
Get rid of everything between clk->shift ... and here and replace it with:
clockevents_config_and_register(clk, twd_timer_rate, 0xf, 0xffffffff);
> /* Make sure our local interrupt controller has this enabled */ > gic_enable_ppi(clk->irq); > > + __get_cpu_var(twd_ce) = clk; > + > clockevents_register_device(clk); > }
Or just smack in this patch on top:
From fd546090b8f0cb5df06103c014466c86cf58b73a Mon Sep 17 00:00:00 2001 From: Linus Walleij <linus.walleij@stericsson.com> Date: Thu, 19 May 2011 18:55:22 +0200 Subject: [PATCH] Fix smallish cleanup
--- arch/arm/kernel/smp_twd.c | 13 +++---------- 1 files changed, 3 insertions(+), 10 deletions(-)
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c index dbf58d4..968f298 100644 --- a/arch/arm/kernel/smp_twd.c +++ b/arch/arm/kernel/smp_twd.c @@ -25,8 +25,6 @@ #include <asm/smp_twd.h> #include <asm/hardware/gic.h>
-#define TWD_MIN_RANGE 4 - /* set up by the platform code */ void __iomem *twd_base;
@@ -96,8 +94,7 @@ static void twd_update_frequency(void *data) { twd_timer_rate = clk_get_rate(twd_clk);
- clockevents_reconfigure(__get_cpu_var(twd_ce), twd_timer_rate, - TWD_MIN_RANGE); + clockevents_update_freq(__get_cpu_var(twd_ce), twd_timer_rate); }
static int twd_cpufreq_transition(struct notifier_block *nb, @@ -193,15 +190,11 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk) clk->set_mode = twd_set_mode; clk->set_next_event = twd_set_next_event;
- clockevents_calc_mult_shift(clk, twd_timer_rate, TWD_MIN_RANGE); - - clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); - clk->min_delta_ns = clockevent_delta2ns(0xf, clk); - /* Make sure our local interrupt controller has this enabled */ gic_enable_ppi(clk->irq);
__get_cpu_var(twd_ce) = clk;
- clockevents_register_device(clk); + clockevents_config_and_register(clk, twd_timer_rate, + 0xf, 0xffffffff); } -- 1.7.3.2
With these changes (provided they work) all should be well, so: Tested-by: Linus Walleij <linus.walleij@linaro.org>
If all is well on your side as well, ask Thomas to take this into the timers/clockevents branch where all dependencies are.
Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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