target/linux/ipq806x/patches-4.9/0054-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch

   1 From 10577f74c35bd395951d1b2382c8d821089b5745 Mon Sep 17 00:00:00 2001
   2 From: Stephen Boyd <sboyd@codeaurora.org>
   3 Date: Fri, 18 Sep 2015 17:52:08 -0700
   4 Subject: [PATCH 54/69] cpufreq-dt: Handle OPP voltage adjust events
   5
   6 On some SoCs the Adaptive Voltage Scaling (AVS) technique is
   7 employed to optimize the operating voltage of a device. At a
   8 given frequency, the hardware monitors dynamic factors and either
   9 makes a suggestion for how much to adjust a voltage for the
  10 current frequency, or it automatically adjusts the voltage
  11 without software intervention.
  12
  13 In the former case, an AVS driver will call
  14 dev_pm_opp_modify_voltage() and update the voltage for the
  15 particular OPP the CPUs are using. Add an OPP notifier to
  16 cpufreq-dt so that we can adjust the voltage of the CPU when AVS
  17 updates the OPP.
  18
  19 Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
  20 Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
  21 Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
  22 ---
  23  drivers/cpufreq/cpufreq-dt.c | 68 ++++++++++++++++++++++++++++++++++++++++++--
  24  1 file changed, 65 insertions(+), 3 deletions(-)
  25
  26 --- a/drivers/cpufreq/cpufreq-dt.c
  27 +++ b/drivers/cpufreq/cpufreq-dt.c
  28 @@ -32,6 +32,9 @@ struct private_data {
  29         struct device *cpu_dev;
  30         struct thermal_cooling_device *cdev;
  31         const char *reg_name;
  32 +       struct notifier_block opp_nb;
  33 +       struct mutex lock;
  34 +       unsigned long opp_freq;
  35  };
  36
  37  static struct freq_attr *cpufreq_dt_attr[] = {
  38 @@ -43,9 +46,16 @@ static struct freq_attr *cpufreq_dt_attr
  39  static int set_target(struct cpufreq_policy *policy, unsigned int index)
  40  {
  41         struct private_data *priv = policy->driver_data;
  42 +       int ret;
  43 +       unsigned long target_freq = policy->freq_table[index].frequency * 1000;
  44 +
  45 +       mutex_lock(&priv->lock);
  46 +       ret = dev_pm_opp_set_rate(priv->cpu_dev, target_freq);
  47 +       if (!ret)
  48 +               priv->opp_freq = target_freq;
  49 +       mutex_unlock(&priv->lock);
  50
  51 -       return dev_pm_opp_set_rate(priv->cpu_dev,
  52 -                                  policy->freq_table[index].frequency * 1000);
  53 +       return ret;
  54  }
  55
  56  /*
  57 @@ -86,6 +96,39 @@ node_put:
  58         return name;
  59  }
  60
  61 +static int opp_notifier(struct notifier_block *nb, unsigned long event,
  62 +                       void *data)
  63 +{
  64 +       struct dev_pm_opp *opp = data;
  65 +       struct private_data *priv = container_of(nb, struct private_data,
  66 +                                                opp_nb);
  67 +       struct device *cpu_dev = priv->cpu_dev;
  68 +       struct regulator *cpu_reg;
  69 +       unsigned long volt, freq;
  70 +       int ret = 0;
  71 +
  72 +       if (event == OPP_EVENT_ADJUST_VOLTAGE) {
  73 +               cpu_reg = dev_pm_opp_get_regulator(cpu_dev);
  74 +               if (IS_ERR(cpu_reg)) {
  75 +                       ret = PTR_ERR(cpu_reg);
  76 +                       goto out;
  77 +               }
  78 +               volt = dev_pm_opp_get_voltage(opp);
  79 +               freq = dev_pm_opp_get_freq(opp);
  80 +
  81 +               mutex_lock(&priv->lock);
  82 +               if (freq == priv->opp_freq) {
  83 +                       ret = regulator_set_voltage_triplet(cpu_reg, volt, volt, volt);
  84 +               }
  85 +               mutex_unlock(&priv->lock);
  86 +               if (ret)
  87 +                       dev_err(cpu_dev, "failed to scale voltage: %d\n", ret);
  88 +       }
  89 +
  90 +out:
  91 +       return notifier_from_errno(ret);
  92 +}
  93 +
  94  static int resources_available(void)
  95  {
  96         struct device *cpu_dev;
  97 @@ -153,6 +196,7 @@ static int cpufreq_init(struct cpufreq_p
  98         bool fallback = false;
  99         const char *name;
 100         int ret;
 101 +       struct srcu_notifier_head *opp_srcu_head;
 102
 103         cpu_dev = get_cpu_device(policy->cpu);
 104         if (!cpu_dev) {
 105 @@ -239,13 +283,29 @@ static int cpufreq_init(struct cpufreq_p
 106                 goto out_free_opp;
 107         }
 108
 109 +       mutex_init(&priv->lock);
 110 +
 111 +       rcu_read_lock();
 112 +       opp_srcu_head = dev_pm_opp_get_notifier(cpu_dev);
 113 +       if (IS_ERR(opp_srcu_head)) {
 114 +               ret = PTR_ERR(opp_srcu_head);
 115 +               rcu_read_unlock();
 116 +               goto out_free_priv;
 117 +       }
 118 +
 119 +       priv->opp_nb.notifier_call = opp_notifier;
 120 +       ret = srcu_notifier_chain_register(opp_srcu_head, &priv->opp_nb);
 121 +       rcu_read_unlock();
 122 +       if (ret)
 123 +               goto out_free_priv;
 124 +
 125         priv->reg_name = name;
 126         priv->opp_table = opp_table;
 127
 128         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 129         if (ret) {
 130                 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 131 -               goto out_free_priv;
 132 +               goto out_unregister_nb;
 133         }
 134
 135         priv->cpu_dev = cpu_dev;
 136 @@ -284,6 +344,8 @@ static int cpufreq_init(struct cpufreq_p
 137
 138  out_free_cpufreq_table:
 139         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 140 +out_unregister_nb:
 141 +       srcu_notifier_chain_unregister(opp_srcu_head, &priv->opp_nb);
 142  out_free_priv:
 143         kfree(priv);
 144  out_free_opp: