[PATCH v7 6/8] cpufreq: mediatek: add opp notification for SVS support

[Andrew-sh.Cheng]

From: "Andrew-sh.Cheng" <andrew-sh.cheng at 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.

Change-Id: Icf7807fdebc312dfcea4c98487fe4f79a08459ce
Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng at mediatek.com>
---
 drivers/cpufreq/mediatek-cpufreq.c | 89 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 85 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 4b479c110cc9..71395ab87ac7 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -42,6 +42,11 @@ 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;
+	int old_vproc;
 };
 
 static LIST_HEAD(dvfs_info_list);
@@ -192,11 +197,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
 
 static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
 {
+	int ret;
+
 	if (info->need_voltage_tracking)
-		return mtk_cpufreq_voltage_tracking(info, vproc);
+		ret = mtk_cpufreq_voltage_tracking(info, vproc);
 	else
-		return regulator_set_voltage(info->proc_reg, vproc,
-					     vproc + VOLT_TOL);
+		ret = regulator_set_voltage(info->proc_reg, vproc,
+					    MAX_VOLT_LIMIT);
+	if (!ret)
+		info->old_vproc = vproc;
+	return ret;
 }
 
 static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
@@ -214,7 +224,9 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
 	inter_vproc = info->intermediate_voltage;
 
 	old_freq_hz = clk_get_rate(cpu_clk);
-	old_vproc = regulator_get_voltage(info->proc_reg);
+	old_vproc = info->old_vproc;
+	if (old_vproc == 0)
+		old_vproc = regulator_get_voltage(info->proc_reg);
 	if (old_vproc < 0) {
 		pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
 		return old_vproc;
@@ -231,6 +243,7 @@ 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 +255,7 @@ 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 +267,7 @@ 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 +278,7 @@ 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 +289,7 @@ 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 +305,69 @@ 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 *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->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 = 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_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);
+				}
+			} 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;
@@ -392,11 +463,21 @@ 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_disable_inter_clock;
+	}
+
+	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