From: "Zhuoyu.Zhang@freescale.com" <Zhuoyu.Zhang@freescale.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: "viresh.kumar@linaro.org" <viresh.kumar@linaro.org>,
"cpufreq@vger.kernel.org" <cpufreq@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Yuantian Tang <Yuantian.Tang@freescale.com>
Subject: RE: [PATCH] cpufreq: powerpc: replace CPUFREQ_ETERNAL with cpufreq transition latency for FSL e500mc Socs
Date: Wed, 19 Mar 2014 03:51:59 +0000 [thread overview]
Message-ID: <9ac578cdc68c41ef98e1639a57f2772f@BN1PR03MB154.namprd03.prod.outlook.com> (raw)
In-Reply-To: <2143464.l2G8tITm4N@vostro.rjw.lan>
> -----Original Message-----
> From: Rafael J. Wysocki [mailto:rjw@rjwysocki.net]
> Sent: Wednesday, March 19, 2014 9:42 AM
> To: Zhang Zhuoyu-B46552
> Cc: viresh.kumar@linaro.org; cpufreq@vger.kernel.org; linux-
> pm@vger.kernel.org; Tang Yuantian-B29983
> Subject: Re: [PATCH] cpufreq: powerpc: replace CPUFREQ_ETERNAL with
> cpufreq transition latency for FSL e500mc Socs
>
> On Monday, March 17, 2014 01:29:28 PM Zhuoyu Zhang wrote:
> > According to the data provided by HW Team, at least 12 internal
> > platform clock cycles are required to stabilize a DFS clock switch on
> > FSL e500mc Socs. This patch replaces the CPUFREQ_ETERNAL with
> appropriate HW clock transition latency to make DFS governors work
> normally on Freescale e500mc boards.
>
> Please sign off the patch. I can't apply it without your sign-off.
Sorry to miss the "sign-off", I already sent another version for your review.
--Zhuoyu
>
> > ---
> > drivers/cpufreq/ppc-corenet-cpufreq.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c
> > b/drivers/cpufreq/ppc-corenet-cpufreq.c
> > index 051000f..ff7b625 100644
> > --- a/drivers/cpufreq/ppc-corenet-cpufreq.c
> > +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
> > @@ -21,6 +21,7 @@
> > #include <linux/of.h>
> > #include <linux/slab.h>
> > #include <linux/smp.h>
> > +#include <sysdev/fsl_soc.h>
> >
> > /**
> > * struct cpu_data - per CPU data struct @@ -205,7 +206,7 @@ static
> > int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
> > for_each_cpu(i, per_cpu(cpu_mask, cpu))
> > per_cpu(cpu_data, i) = data;
> >
> > - policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
> > + policy->cpuinfo.transition_latency = (12 * NSEC_PER_SEC) /
> > +fsl_get_sys_freq();
> > of_node_put(np);
> >
> > return 0;
> >
>
> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.
>
prev parent reply other threads:[~2014-03-19 3:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-17 5:29 [PATCH] cpufreq: powerpc: replace CPUFREQ_ETERNAL with cpufreq transition latency for FSL e500mc Socs Zhuoyu Zhang
2014-03-19 1:42 ` Rafael J. Wysocki
2014-03-19 3:51 ` Zhuoyu.Zhang [this message]
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