Re: [PATCH v6 05/10] cpufreq: mediatek: Add opp notification support

[Rex-BC Chen <rex-bc.chen@mediatek.com>]

On Fri, 2022-05-06 at 09:45 +0530, Viresh Kumar wrote:
> On 05-05-22, 19:52, Rex-BC Chen wrote:
> > > From this opp notifier, cpufreq should listen to opp notification
> > > and do
> > 
> > proper actions when receiving events of disable and voltage
> > adjustment.
> > 
> > One of the user for this opp notifier is MediaTek SVS.
> > The MediaTek Smart Voltage Scaling (SVS) is a hardware which
> > calculates
> > suitable SVS bank voltages to OPP voltage table.
> > 
> > Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@mediatek.com>
> > Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
> > Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> > Reviewed-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
> > ---
> >  drivers/cpufreq/mediatek-cpufreq.c | 91
> > +++++++++++++++++++++++++++---
> >  1 file changed, 83 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c
> > b/drivers/cpufreq/mediatek-cpufreq.c
> > index fe205eca657d..06d80ee06bbf 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
> > @@ -46,6 +46,11 @@ struct mtk_cpu_dvfs_info {
> >  	int intermediate_voltage;
> >  	bool need_voltage_tracking;
> >  	int pre_vproc;
> > +	/* Avoid race condition for regulators between notify and
> > policy */
> > +	struct mutex reg_lock;
> > +	struct notifier_block opp_nb;
> > +	unsigned int opp_cpu;
> > +	unsigned long opp_freq;
> 
> The name opp_freq doesn't fit well, I renamed it to current_freq.
> 
> >  	const struct mtk_cpufreq_platform_data *soc_data;
> >  	int vtrack_max;
> >  };
> > @@ -182,6 +187,8 @@ static int mtk_cpufreq_set_target(struct
> > cpufreq_policy *policy,
> >  
> >  	pre_freq_hz = clk_get_rate(cpu_clk);
> >  
> > +	mutex_lock(&info->reg_lock);
> > +
> >  	if (unlikely(info->pre_vproc <= 0))
> >  		pre_vproc = regulator_get_voltage(info->proc_reg);
> >  	else
> > @@ -214,7 +221,7 @@ static int mtk_cpufreq_set_target(struct
> > cpufreq_policy *policy,
> >  			dev_err(cpu_dev,
> >  				"cpu%d: failed to scale up voltage!\n",
> > policy->cpu);
> >  			mtk_cpufreq_set_voltage(info, pre_vproc);
> > -			return ret;
> > +			goto out;
> >  		}
> >  	}
> >  
> > @@ -224,8 +231,7 @@ static int mtk_cpufreq_set_target(struct
> > cpufreq_policy *policy,
> >  		dev_err(cpu_dev,
> >  			"cpu%d: failed to re-parent cpu clock!\n",
> > policy->cpu);
> >  		mtk_cpufreq_set_voltage(info, pre_vproc);
> > -		WARN_ON(1);
> > -		return ret;
> > +		goto out;
> >  	}
> >  
> >  	/* Set the original PLL to target rate. */
> > @@ -235,7 +241,7 @@ static int mtk_cpufreq_set_target(struct
> > cpufreq_policy *policy,
> >  			"cpu%d: failed to scale cpu clock rate!\n",
> > policy->cpu);
> >  		clk_set_parent(cpu_clk, armpll);
> >  		mtk_cpufreq_set_voltage(info, pre_vproc);
> > -		return ret;
> > +		goto out;
> >  	}
> >  
> >  	/* Set parent of CPU clock back to the original PLL. */
> > @@ -244,8 +250,7 @@ static int mtk_cpufreq_set_target(struct
> > cpufreq_policy *policy,
> >  		dev_err(cpu_dev,
> >  			"cpu%d: failed to re-parent cpu clock!\n",
> > policy->cpu);
> >  		mtk_cpufreq_set_voltage(info, inter_vproc);
> > -		WARN_ON(1);
> > -		return ret;
> > +		goto out;
> >  	}
> >  
> >  	/*
> > @@ -260,15 +265,72 @@ static int mtk_cpufreq_set_target(struct
> > cpufreq_policy *policy,
> >  			clk_set_parent(cpu_clk, info->inter_clk);
> >  			clk_set_rate(armpll, pre_freq_hz);
> >  			clk_set_parent(cpu_clk, armpll);
> > -			return ret;
> > +			goto out;
> >  		}
> >  	}
> >  
> > -	return 0;
> > +	info->opp_freq = freq_hz;
> > +
> > +out:
> > +	mutex_unlock(&info->reg_lock);
> > +
> > +	return ret;
> >  }
> >  
> >  #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 *new_opp;
> > +	struct mtk_cpu_dvfs_info *info;
> > +	unsigned long freq, volt;
> > +	struct cpufreq_policy *policy;
> > +	int ret = 0;
> > +
> > +	info = container_of(nb, struct mtk_cpu_dvfs_info, opp_nb);
> > +
> > +	if (event == OPP_EVENT_ADJUST_VOLTAGE) {
> > +		freq = dev_pm_opp_get_freq(opp);
> > +
> > +		mutex_lock(&info->reg_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->reg_lock);
> > +	} else if (event == OPP_EVENT_DISABLE) {
> > +		freq = dev_pm_opp_get_freq(opp);
> > +
> > +		/* case of current opp item is disabled */
> > +		if (info->opp_freq == freq) {
> > +			freq = 1;
> > +			new_opp = dev_pm_opp_find_freq_ceil(info-
> > >cpu_dev,
> > +							    &freq);
> > +			if (IS_ERR(new_opp)) {
> > +				dev_err(info->cpu_dev,
> > +					"all opp items are
> > disabled\n");
> > +				ret = PTR_ERR(new_opp);
> > +				return notifier_from_errno(ret);
> > +			}
> > +
> > +			dev_pm_opp_put(new_opp);
> > +			policy = cpufreq_cpu_get(info->opp_cpu);
> > +			if (policy) {
> > +				cpufreq_driver_target(policy, freq /
> > 1000,
> > +						      CPUFREQ_RELATION_
> > L);
> > +				cpufreq_cpu_put(policy);
> > +			}
> > +		}
> > +	}
> > +
> > +	return notifier_from_errno(ret);
> > +}
> > +
> >  static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info,
> > int cpu)
> >  {
> >  	struct device *cpu_dev;
> > @@ -357,6 +419,18 @@ 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);
> >  
> > +	mutex_init(&info->reg_lock);
> > +
> > +	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) {
> > +		dev_err(cpu_dev, "cpu%d: failed to register opp
> > notifier\n", cpu);
> > +		goto out_disable_inter_clock;
> > +	}
> > +
> > +	info->opp_freq = clk_get_rate(info->cpu_clk);
> 
> This is a resource as well, which should have been initialized before
> registering notifier.
> 
> Applied with above changes. Thanks.
> 

Hello Viresh,

Thanks for your help!

BRs,
Rex