Santosh Shilimkar <santosh.shilim...@ti.com> writes:

> From: Russell King <rmk+ker...@arm.linux.org.uk>
>
> Adjust _both_ the per-cpu loops_per_jiffy and global lpj. Calibrate them
> with with reference to the initial values to avoid a progressively
> bigger and bigger error in the value over time.
>
> While at this, re-use the notifiers for UP/SMP since on
> UP machine or UP_ON_SMP policy->cpus mask would contain only
> the boot CPU.
>
> Signed-off-by: Santosh Shilimkar <santosh.shilim...@ti.com>
> [santosh.shilim...@ti.com: re-based against omap cpufreq
> upstream branch and fixed notifiers]
> Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk>
> Cc: Kevin Hilman <khil...@ti.com>

Thanks, applied to pm-wip/cpufreq branch.

Kevin

> ---
> Patch is outcome of below discussion.
> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg51559.html
>
>  arch/arm/mach-omap2/omap2plus-cpufreq.c |   50 ++++++++++++++++--------------
>  1 files changed, 27 insertions(+), 23 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap2plus-cpufreq.c 
> b/arch/arm/mach-omap2/omap2plus-cpufreq.c
> index 1f3b2e1..de82e87 100644
> --- a/arch/arm/mach-omap2/omap2plus-cpufreq.c
> +++ b/arch/arm/mach-omap2/omap2plus-cpufreq.c
> @@ -38,6 +38,16 @@
>  
>  #include <mach/hardware.h>
>  
> +#ifdef CONFIG_SMP
> +struct lpj_info {
> +     unsigned long   ref;
> +     unsigned int    freq;
> +};
> +
> +static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
> +static struct lpj_info global_lpj_ref;
> +#endif
> +
>  static struct cpufreq_frequency_table *freq_table;
>  static atomic_t freq_table_users = ATOMIC_INIT(0);
>  static struct clk *mpu_clk;
> @@ -96,37 +106,18 @@ static int omap_target(struct cpufreq_policy *policy,
>       if (freqs.old == freqs.new && policy->cur == freqs.new)
>               return ret;
>  
> -     if (!is_smp()) {
> -             cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> -             goto set_freq;
> -     }
> -
>       /* notifiers */
>       for_each_cpu(i, policy->cpus) {
>               freqs.cpu = i;
>               cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
>       }
>  
> -set_freq:
>  #ifdef CONFIG_CPU_FREQ_DEBUG
>       pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
>  #endif
>  
>       ret = clk_set_rate(mpu_clk, freqs.new * 1000);
> -
> -     /*
> -      * Generic CPUFREQ driver jiffy update is under !SMP. So jiffies
> -      * won't get updated when UP machine cpufreq build with
> -      * CONFIG_SMP enabled. Below code is added only to manage that
> -      * scenario
> -      */
>       freqs.new = omap_getspeed(policy->cpu);
> -     if (!is_smp()) {
> -             loops_per_jiffy =
> -                      cpufreq_scale(loops_per_jiffy, freqs.old, freqs.new);
> -             cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> -             goto skip_lpj;
> -     }
>  
>  #ifdef CONFIG_SMP
>       /*
> @@ -134,10 +125,24 @@ set_freq:
>        * cpufreq driver. So, update the per-CPU loops_per_jiffy value
>        * on frequency transition. We need to update all dependent CPUs.
>        */
> -     for_each_cpu(i, policy->cpus)
> +     for_each_cpu(i, policy->cpus) {
> +             struct lpj_info *lpj = &per_cpu(lpj_ref, i);
> +             if (!lpj->freq) {
> +                     lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
> +                     lpj->freq = freqs.old;
> +             }
> +
>               per_cpu(cpu_data, i).loops_per_jiffy =
> -                     cpufreq_scale(per_cpu(cpu_data, i).loops_per_jiffy,
> -                                     freqs.old, freqs.new);
> +                     cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
> +     }
> +
> +     /* And don't forget to adjust the global one */
> +     if (!global_lpj_ref.freq) {
> +             global_lpj_ref.ref = loops_per_jiffy;
> +             global_lpj_ref.freq = freqs.old;
> +     }
> +     loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
> +                                     freqs.new);
>  #endif
>  
>       /* notifiers */
> @@ -146,7 +151,6 @@ set_freq:
>               cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
>       }
>  
> -skip_lpj:
>       return ret;
>  }
--
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