diff mbox series

[v4,7/8] cpufreq: mediatek: add opp notification for SVS support

Message ID 1565703113-31479-8-git-send-email-andrew-sh.cheng@mediatek.com (mailing list archive)
State New, archived
Headers show
Series Add cpufreq and cci devfreq for mt8183, and SVS support | expand

Commit Message

andrew-sh.cheng Aug. 13, 2019, 1:31 p.m. UTC 
From: "Andrew-sh.Cheng" <andrew-sh.cheng@mediatek.com>

cpufreq should listen opp notification and do proper actions
when receiving disable and voltage adjustment events,
which are triggered when SVS is enabled.

Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@mediatek.com>
---
 drivers/cpufreq/mediatek-cpufreq.c | 78 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

Comments

Viresh Kumar Aug. 20, 2019, 3:39 a.m. UTC | #1 
On 13-08-19, 21:31, Andrew-sh.Cheng wrote:
> From: "Andrew-sh.Cheng" <andrew-sh.cheng@mediatek.com>
> 
> cpufreq should listen opp notification and do proper actions
> when receiving disable and voltage adjustment events,
> which are triggered when SVS is enabled.
> 
> Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@mediatek.com>
> ---
>  drivers/cpufreq/mediatek-cpufreq.c | 78 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 78 insertions(+)
> 
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index 4dce41b18369..9820c8003507 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 */
> +	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 +297,74 @@ 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);
> +	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) {

Does this ever get called for your platform ? Why are you using opp disable ?
Maybe we can avoid it completely.

> +		freq = info->opp_freq;
> +		opp_item = dev_pm_opp_find_freq_ceil(info->cpu_dev, &freq);
> +		if (!IS_ERR(opp_item))
> +			dev_pm_opp_put(opp_item);
> +		else
> +			freq = 0;
> +
> +		/* case of current opp is disabled */
> +		if (freq == 0 || freq != info->opp_freq) {
> +			// find an enable opp item
> +			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);
> +					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 +451,21 @@ 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
andrew-sh.cheng Oct. 16, 2019, 2:43 a.m. UTC | #2 
On Tue, 2019-08-20 at 11:39 +0800, Viresh Kumar wrote:
> On 13-08-19, 21:31, Andrew-sh.Cheng wrote:
> > From: "Andrew-sh.Cheng" <andrew-sh.cheng@mediatek.com>
> > 
> > cpufreq should listen opp notification and do proper actions
> > when receiving disable and voltage adjustment events,
> > which are triggered when SVS is enabled.
> > 
> > Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@mediatek.com>
> > ---
> >  drivers/cpufreq/mediatek-cpufreq.c | 78 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 78 insertions(+)
> > 
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> > index 4dce41b18369..9820c8003507 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 */
> > +	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 +297,74 @@ 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);
> > +	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) {
> 
> Does this ever get called for your platform ? Why are you using opp disable ?
> Maybe we can avoid it completely.
Hi Viresh~
This is due to SVS feature need to fix Vproc for calibration.
When SVS calibration, it want to disable all opp items, except one with
voltae 1.0V. (SVS will change the voltage field of that opp item, if the
corresponding voltage is not 1.0V)
In this way, SVS can make sure there is no other module, include
thermal, will change Vproc by DVFS driver.
After SVS calibration done, SVS will enable those disabled opp items
back.

> 
> > +		freq = info->opp_freq;
> > +		opp_item = dev_pm_opp_find_freq_ceil(info->cpu_dev, &freq);
> > +		if (!IS_ERR(opp_item))
> > +			dev_pm_opp_put(opp_item);
> > +		else
> > +			freq = 0;
> > +
> > +		/* case of current opp is disabled */
> > +		if (freq == 0 || freq != info->opp_freq) {
> > +			// find an enable opp item
> > +			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);
> > +					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 +451,21 @@ 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
>
Viresh Kumar Oct. 17, 2019, 6:31 a.m. UTC | #3 
On 16-10-19, 10:43, andrew-sh.cheng wrote:
> This is due to SVS feature need to fix Vproc for calibration.
> When SVS calibration, it want to disable all opp items, except one with
> voltae 1.0V. (SVS will change the voltage field of that opp item, if the
> corresponding voltage is not 1.0V)
> In this way, SVS can make sure there is no other module, include
> thermal, will change Vproc by DVFS driver.
> After SVS calibration done, SVS will enable those disabled opp items
> back.

But why is this required to be done this way ? Why can't we just update the
voltages without doing this disable/enable dance ?
andrew-sh.cheng Oct. 18, 2019, 9:03 a.m. UTC | #4 
On Thu, 2019-10-17 at 12:01 +0530, Viresh Kumar wrote:
> On 16-10-19, 10:43, andrew-sh.cheng wrote:
> > This is due to SVS feature need to fix Vproc for calibration.
> > When SVS calibration, it want to disable all opp items, except one with
> > voltae 1.0V. (SVS will change the voltage field of that opp item, if the
> > corresponding voltage is not 1.0V)
> > In this way, SVS can make sure there is no other module, include
> > thermal, will change Vproc by DVFS driver.
> > After SVS calibration done, SVS will enable those disabled opp items
> > back.
> 
> But why is this required to be done this way ? Why can't we just update the
> voltages without doing this disable/enable dance ?
> 
This is because some opp items need voltage larger than 1.0V.
We cannot update the voltage to 1.0V.

If we don't disable these opp items, and DVFS policy want to set these
high frequencies, dvfs driver will set higher voltage to Vproc and SVS
calibration will be fail.
Viresh Kumar Oct. 18, 2019, 9:53 a.m. UTC | #5 
On 18-10-19, 17:03, andrew-sh.cheng wrote:
> On Thu, 2019-10-17 at 12:01 +0530, Viresh Kumar wrote:
> > On 16-10-19, 10:43, andrew-sh.cheng wrote:
> > > This is due to SVS feature need to fix Vproc for calibration.
> > > When SVS calibration, it want to disable all opp items, except one with
> > > voltae 1.0V. (SVS will change the voltage field of that opp item, if the
> > > corresponding voltage is not 1.0V)
> > > In this way, SVS can make sure there is no other module, include
> > > thermal, will change Vproc by DVFS driver.
> > > After SVS calibration done, SVS will enable those disabled opp items
> > > back.
> > 
> > But why is this required to be done this way ? Why can't we just update the
> > voltages without doing this disable/enable dance ?
> > 
> This is because some opp items need voltage larger than 1.0V.
> We cannot update the voltage to 1.0V.
> 
> If we don't disable these opp items, and DVFS policy want to set these
> high frequencies, dvfs driver will set higher voltage to Vproc and SVS
> calibration will be fail.

Okay.
diff mbox series

Patch

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 4dce41b18369..9820c8003507 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 */
+	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 +297,74 @@  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);
+	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);
+		if (!IS_ERR(opp_item))
+			dev_pm_opp_put(opp_item);
+		else
+			freq = 0;
+
+		/* case of current opp is disabled */
+		if (freq == 0 || freq != info->opp_freq) {
+			// find an enable opp item
+			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);
+					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 +451,21 @@  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