From: andrew-sh.cheng <andrew-sh.cheng@mediatek.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>, Nishanth Menon <nm@ti.com>,
devicetree@vger.kernel.org, srv_heupstream@mediatek.com,
linux-pm@vger.kernel.org, Stephen Boyd <sboyd@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-kernel@vger.kernel.org,
Chanwoo Choi <cw00.choi@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Rob Herring <robh+dt@kernel.org>,
linux-mediatek@lists.infradead.org,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
fan.chen@mediatek.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [v5, PATCH 4/5] cpufreq: mediatek: add opp notification for SVS support
Date: Mon, 9 Dec 2019 14:56:28 +0800 [thread overview]
Message-ID: <1575874588.13494.4.camel@mtksdaap41> (raw)
In-Reply-To: <20191127083619.etocnhpyyut3hzwq@vireshk-i7>
On Wed, 2019-11-27 at 14:06 +0530, Viresh Kumar wrote:
> On 26-11-19, 19:50, Andrew-sh.Cheng wrote:
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> > index 4b0cc50dd93b..7c37ab31230a 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
> > @@ -42,6 +42,10 @@ struct mtk_cpu_dvfs_info {
> > struct list_head list_head;
> > int intermediate_voltage;
> > bool need_voltage_tracking;
> > + struct mutex lock; /* avoid notify and policy race condition */
>
> Will a read-write lock be better suited here for performance reasons ?
Thank you for advice, I will check it.
>
> > + struct notifier_block opp_nb;
> > + int opp_cpu;
> > + unsigned long opp_freq;
> > };
> >
> > static LIST_HEAD(dvfs_info_list);
> > @@ -231,6 +235,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> > vproc = dev_pm_opp_get_voltage(opp);
> > dev_pm_opp_put(opp);
> >
> > + mutex_lock(&info->lock);
> > /*
> > * If the new voltage or the intermediate voltage is higher than the
> > * current voltage, scale up voltage first.
> > @@ -242,6 +247,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> > pr_err("cpu%d: failed to scale up voltage!\n",
> > policy->cpu);
> > mtk_cpufreq_set_voltage(info, old_vproc);
> > + mutex_unlock(&info->lock);
> > return ret;
> > }
> > }
> > @@ -253,6 +259,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> > policy->cpu);
> > mtk_cpufreq_set_voltage(info, old_vproc);
> > WARN_ON(1);
> > + mutex_unlock(&info->lock);
> > return ret;
> > }
> >
> > @@ -263,6 +270,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> > policy->cpu);
> > clk_set_parent(cpu_clk, armpll);
> > mtk_cpufreq_set_voltage(info, old_vproc);
> > + mutex_unlock(&info->lock);
> > return ret;
> > }
> >
> > @@ -273,6 +281,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> > policy->cpu);
> > mtk_cpufreq_set_voltage(info, inter_vproc);
> > WARN_ON(1);
> > + mutex_unlock(&info->lock);
> > return ret;
> > }
> >
> > @@ -288,15 +297,75 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> > clk_set_parent(cpu_clk, info->inter_clk);
> > clk_set_rate(armpll, old_freq_hz);
> > clk_set_parent(cpu_clk, armpll);
> > + mutex_unlock(&info->lock);
> > return ret;
> > }
> > }
> >
> > + info->opp_freq = freq_hz;
> > + mutex_unlock(&info->lock);
> > +
> > return 0;
> > }
> >
> > #define DYNAMIC_POWER "dynamic-power-coefficient"
> >
> > +static int mtk_cpufreq_opp_notifier(struct notifier_block *nb,
> > + unsigned long event, void *data)
> > +{
> > + struct dev_pm_opp *opp = data;
> > + struct dev_pm_opp *opp_item;
> > + struct mtk_cpu_dvfs_info *info =
> > + container_of(nb, struct mtk_cpu_dvfs_info, opp_nb);
>
> Do the assignment after all definitions, instead of awkwardly breaking
> the line here.
Got it, will change it.
>
> > + unsigned long freq, volt;
> > + struct cpufreq_policy *policy;
> > + int ret = 0;
> > +
> > + if (event == OPP_EVENT_ADJUST_VOLTAGE) {
> > + freq = dev_pm_opp_get_freq(opp);
> > +
> > + mutex_lock(&info->lock);
> > + if (info->opp_freq == freq) {
> > + volt = dev_pm_opp_get_voltage(opp);
> > + ret = mtk_cpufreq_set_voltage(info, volt);
> > + if (ret)
> > + dev_err(info->cpu_dev, "failed to scale voltage: %d\n",
> > + ret);
> > + }
> > + mutex_unlock(&info->lock);
> > + } else if (event == OPP_EVENT_DISABLE) {
> > + freq = info->opp_freq;
> > + opp_item = dev_pm_opp_find_freq_ceil(info->cpu_dev, &freq);
>
> name it new_opp instead of opp_item.
Got it, will change it.
>
> > + if (!IS_ERR(opp_item))
> > + dev_pm_opp_put(opp_item);
> > + else
> > + freq = 0;
> > +
>
> What is the purpose of the above code ?
When dev_pm_opp_find_freq_ceil() doesn't find matching opp item, freq
value won't be set.
Set it as 0 for below checking
>
> > + /* case of current opp is disabled */
> > + if (freq == 0 || freq != info->opp_freq) {
> > + // find an enable opp item
>
> Use proper commenting style please.
Got it, will change it.
>
> > + freq = 1;
> > + opp_item = dev_pm_opp_find_freq_ceil(info->cpu_dev,
> > + &freq);
> > + if (!IS_ERR(opp_item)) {
> > + dev_pm_opp_put(opp_item);
> > + policy = cpufreq_cpu_get(info->opp_cpu);
> > + if (policy) {
> > + cpufreq_driver_target(policy,
> > + freq / 1000,
> > + CPUFREQ_RELATION_L);
>
> Why don't you simply call this instead of all the code in the else
> block ?
These else code is used to check "current opp item is disabled or not".
If not, do nothing.
If current opp item is disabled, need to find an not-disabled opp item,
and set frequency to it.
>
> > + cpufreq_cpu_put(policy);
> > + }
> > + } else {
> > + pr_err("%s: all opp items are disabled\n",
> > + __func__);
> > + }
> > + }
> > + }
> > +
> > + return notifier_from_errno(ret);
> > +}
> > +
> > static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
> > {
> > struct device *cpu_dev;
> > @@ -383,11 +452,21 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
> > info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
> > dev_pm_opp_put(opp);
> >
> > + info->opp_cpu = cpu;
> > + info->opp_nb.notifier_call = mtk_cpufreq_opp_notifier;
> > + ret = dev_pm_opp_register_notifier(cpu_dev, &info->opp_nb);
> > + if (ret) {
> > + pr_warn("cannot register opp notification\n");
> > + goto out_free_opp_table;
> > + }
> > +
> > + mutex_init(&info->lock);
> > info->cpu_dev = cpu_dev;
> > info->proc_reg = proc_reg;
> > info->sram_reg = IS_ERR(sram_reg) ? NULL : sram_reg;
> > info->cpu_clk = cpu_clk;
> > info->inter_clk = inter_clk;
> > + info->opp_freq = clk_get_rate(cpu_clk);
> >
> > /*
> > * If SRAM regulator is present, software "voltage tracking" is needed
> > --
> > 2.12.5
>
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next prev parent reply other threads:[~2019-12-09 6:56 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20191126115058epcas1p3caa6da2508caa5fbe71c202834184b15@epcas1p3.samsung.com>
2019-11-26 11:50 ` [v5, PATCH 0/5] Add cpufreq and cci devfreq for mt8183, and SVS support Andrew-sh.Cheng
2019-11-26 11:50 ` [v5, PATCH 1/5] cpufreq: mediatek: add clock enable for intermediate clock Andrew-sh.Cheng
2019-11-26 11:50 ` [v5, PATCH 2/5] dt-bindings: devfreq: add compatible for mt8183 cci devfreq Andrew-sh.Cheng
2019-12-17 2:38 ` Chanwoo Choi
2019-11-26 11:50 ` [v5, PATCH 3/5] devfreq: add mediatek " Andrew-sh.Cheng
2019-12-17 10:08 ` Chanwoo Choi
2019-11-26 11:50 ` [v5, PATCH 4/5] cpufreq: mediatek: add opp notification for SVS support Andrew-sh.Cheng
2019-11-27 8:36 ` Viresh Kumar
2019-12-09 6:56 ` andrew-sh.cheng [this message]
2019-12-10 6:43 ` Viresh Kumar
2020-03-10 8:11 ` andrew-sh.cheng
2020-03-11 6:06 ` Viresh Kumar
2020-03-12 9:12 ` andrew-sh.cheng
2020-03-13 7:22 ` andrew-sh.cheng
2020-03-13 9:10 ` Viresh Kumar
2020-04-06 9:12 ` andrew-sh.cheng
2020-04-06 9:29 ` Viresh Kumar
2020-04-07 6:54 ` andrew-sh.cheng
2020-04-07 8:29 ` Viresh Kumar
2020-04-07 9:09 ` andrew-sh.cheng
2019-11-26 11:50 ` [v5, PATCH 5/5] devfreq: mediatek: cci devfreq register " Andrew-sh.Cheng
2019-12-17 7:31 ` [v5, PATCH 0/5] Add cpufreq and cci devfreq for mt8183, and " Chanwoo Choi
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