target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch

   1 From 175329015c8a0b480240da222822d2f8316f074d Mon Sep 17 00:00:00 2001
   2 From: Stephen Boyd <sboyd@codeaurora.org>
   3 Date: Mon, 1 Jun 2015 18:47:58 -0700
   4 Subject: 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 ---
  21  drivers/cpufreq/cpufreq-dt.c | 72 ++++++++++++++++++++++++++++++++++++++++----
  22  1 file changed, 66 insertions(+), 6 deletions(-)
  23
  24 --- a/drivers/cpufreq/cpufreq-dt.c
  25 +++ b/drivers/cpufreq/cpufreq-dt.c
  26 @@ -34,6 +34,9 @@ struct private_data {
  27         struct regulator *cpu_reg;
  28         struct thermal_cooling_device *cdev;
  29         unsigned int voltage_tolerance; /* in percentage */
  30 +       struct notifier_block opp_nb;
  31 +       struct mutex lock;
  32 +       unsigned long opp_freq;
  33  };
  34
  35  static struct freq_attr *cpufreq_dt_attr[] = {
  36 @@ -42,6 +45,42 @@ static struct freq_attr *cpufreq_dt_attr
  37         NULL,
  38  };
  39
  40 +static int opp_notifier(struct notifier_block *nb, unsigned long event,
  41 +                       void *data)
  42 +{
  43 +       struct dev_pm_opp *opp = data;
  44 +       struct private_data *priv = container_of(nb, struct private_data,
  45 +                                                opp_nb);
  46 +       struct device *cpu_dev = priv->cpu_dev;
  47 +       struct regulator *cpu_reg = priv->cpu_reg;
  48 +       unsigned long volt, tol, freq;
  49 +       int ret = 0;
  50 +
  51 +       switch (event) {
  52 +               case OPP_EVENT_ADJUST_VOLTAGE:
  53 +                       volt = dev_pm_opp_get_voltage(opp);
  54 +                       freq = dev_pm_opp_get_freq(opp);
  55 +                       tol = volt * priv->voltage_tolerance / 100;
  56 +
  57 +                       mutex_lock(&priv->lock);
  58 +                       if (freq == priv->opp_freq)
  59 +                               ret = regulator_set_voltage_tol(cpu_reg, volt,
  60 +                                                               tol);
  61 +                       mutex_unlock(&priv->lock);
  62 +                       if (ret) {
  63 +                               dev_err(cpu_dev,
  64 +                                       "failed to scale voltage up: %d\n",
  65 +                                       ret);
  66 +                               return ret;
  67 +                       }
  68 +                       break;
  69 +               default:
  70 +                       break;
  71 +       }
  72 +
  73 +       return 0;
  74 +}
  75 +
  76  static int set_target(struct cpufreq_policy *policy, unsigned int index)
  77  {
  78         struct dev_pm_opp *opp;
  79 @@ -53,6 +92,7 @@ static int set_target(struct cpufreq_pol
  80         unsigned long volt = 0, volt_old = 0, tol = 0;
  81         unsigned int old_freq, new_freq;
  82         long freq_Hz, freq_exact;
  83 +       unsigned long opp_freq = 0;
  84         int ret;
  85
  86         freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
  87 @@ -63,8 +103,8 @@ static int set_target(struct cpufreq_pol
  88         new_freq = freq_Hz / 1000;
  89         old_freq = clk_get_rate(cpu_clk) / 1000;
  90
  91 +       mutex_lock(&priv->lock);
  92         if (!IS_ERR(cpu_reg)) {
  93 -               unsigned long opp_freq;
  94
  95                 rcu_read_lock();
  96                 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
  97 @@ -72,7 +112,8 @@ static int set_target(struct cpufreq_pol
  98                         rcu_read_unlock();
  99                         dev_err(cpu_dev, "failed to find OPP for %ld\n",
 100                                 freq_Hz);
 101 -                       return PTR_ERR(opp);
 102 +                       ret = PTR_ERR(opp);
 103 +                       goto out;
 104                 }
 105                 volt = dev_pm_opp_get_voltage(opp);
 106                 opp_freq = dev_pm_opp_get_freq(opp);
 107 @@ -93,7 +134,7 @@ static int set_target(struct cpufreq_pol
 108                 if (ret) {
 109                         dev_err(cpu_dev, "failed to scale voltage up: %d\n",
 110                                 ret);
 111 -                       return ret;
 112 +                       goto out;
 113                 }
 114         }
 115
 116 @@ -102,7 +143,7 @@ static int set_target(struct cpufreq_pol
 117                 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
 118                 if (!IS_ERR(cpu_reg) && volt_old > 0)
 119                         regulator_set_voltage_tol(cpu_reg, volt_old, tol);
 120 -               return ret;
 121 +               goto out;
 122         }
 123
 124         /* scaling down?  scale voltage after frequency */
 125 @@ -112,9 +153,12 @@ static int set_target(struct cpufreq_pol
 126                         dev_err(cpu_dev, "failed to scale voltage down: %d\n",
 127                                 ret);
 128                         clk_set_rate(cpu_clk, old_freq * 1000);
 129 +                       goto out;
 130                 }
 131         }
 132 -
 133 +       priv->opp_freq = opp_freq;
 134 +out:
 135 +       mutex_unlock(&priv->lock);
 136         return ret;
 137  }
 138
 139 @@ -201,6 +245,7 @@ static int cpufreq_init(struct cpufreq_p
 140         unsigned int transition_latency;
 141         bool need_update = false;
 142         int ret;
 143 +       struct srcu_notifier_head *opp_srcu_head;
 144
 145         ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
 146         if (ret) {
 147 @@ -277,6 +322,19 @@ static int cpufreq_init(struct cpufreq_p
 148                 goto out_free_opp;
 149         }
 150
 151 +       mutex_init(&priv->lock);
 152 +
 153 +       opp_srcu_head = dev_pm_opp_get_notifier(cpu_dev);
 154 +       if (IS_ERR(opp_srcu_head)) {
 155 +               ret = PTR_ERR(opp_srcu_head);
 156 +               goto out_free_priv;
 157 +       }
 158 +
 159 +       priv->opp_nb.notifier_call = opp_notifier;
 160 +       ret = srcu_notifier_chain_register(opp_srcu_head, &priv->opp_nb);
 161 +       if (ret)
 162 +               goto out_free_priv;
 163 +
 164         of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
 165
 166         if (!transition_latency)
 167 @@ -326,7 +384,7 @@ static int cpufreq_init(struct cpufreq_p
 168         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 169         if (ret) {
 170                 pr_err("failed to init cpufreq table: %d\n", ret);
 171 -               goto out_free_priv;
 172 +               goto out_unregister_nb;
 173         }
 174
 175         priv->cpu_dev = cpu_dev;
 176 @@ -365,6 +423,8 @@ static int cpufreq_init(struct cpufreq_p
 177
 178  out_free_cpufreq_table:
 179         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
 180 +out_unregister_nb:
 181 +       srcu_notifier_chain_unregister(opp_srcu_head, &priv->opp_nb);
 182  out_free_priv:
 183         kfree(priv);
 184  out_free_opp: