ARM: smp_twd: Reconfigure clockevents after cpufreq change
diff mbox

Message ID BANLkTim4U-CJ_D3VSNzwd23XL3fDXT7onQ@mail.gmail.com
State New, archived
Headers show

Commit Message

Linus Walleij May 19, 2011, 5:32 p.m. UTC
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(-)

 }

Comments

Colin Cross May 19, 2011, 11:26 p.m. UTC | #1
On Thu, May 19, 2011 at 10:32 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> 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).

I don't think the subject should change - the patch is to ARM code,
not clockevent code, it's named for what the patch does, not whose
tree it goes through.

>> 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>

Thanks, I'll squash your fixes in.

> 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
>

Patch
diff mbox

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);