target/linux/ipq806x/patches-4.19/0049-PM-OPP-Support-adjusting-OPP-voltages-at-runtime.patch

   1 From: Sylwester Nawrocki <s.nawrocki@samsung.com>
   2 To: krzk@kernel.org, vireshk@kernel.org, robh+dt@kernel.org
   3 Cc: sboyd@kernel.org, roger.lu@mediatek.com,
   4         linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
   5         linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org,
   6         b.zolnierkie@samsung.com, m.szyprowski@samsung.com,
   7         Stephen Boyd <sboyd@codeaurora.org>,
   8         Sylwester Nawrocki <s.nawrocki@samsung.com>
   9 Subject: [PATCH v5 1/4] PM / OPP: Support adjusting OPP voltages at runtime
  10 Date: Wed, 16 Oct 2019 16:57:53 +0200
  11 Message-ID: <20191016145756.16004-2-s.nawrocki@samsung.com> (raw)
  12 In-Reply-To: <20191016145756.16004-1-s.nawrocki@samsung.com>
  13
  14 From: Stephen Boyd <sboyd@codeaurora.org>
  15
  16 On some SoCs the Adaptive Voltage Scaling (AVS) technique is
  17 employed to optimize the operating voltage of a device. At a
  18 given frequency, the hardware monitors dynamic factors and either
  19 makes a suggestion for how much to adjust a voltage for the
  20 current frequency, or it automatically adjusts the voltage
  21 without software intervention. Add an API to the OPP library for
  22 the former case, so that AVS type devices can update the voltages
  23 for an OPP when the hardware determines the voltage should
  24 change. The assumption is that drivers like CPUfreq or devfreq
  25 will register for the OPP notifiers and adjust the voltage
  26 according to suggestions that AVS makes.
  27
  28 This patch is derived from [1] submitted by Stephen.
  29 [1] https://lore.kernel.org/patchwork/patch/599279/
  30
  31 Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
  32 Signed-off-by: Roger Lu <roger.lu@mediatek.com>
  33 [s.nawrocki@samsung.com: added handling of OPP min/max voltage]
  34 Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
  35 ---
  36  drivers/opp/core.c     | 69 ++++++++++++++++++++++++++++++++++++++++++
  37  include/linux/pm_opp.h | 13 ++++++++
  38  2 files changed, 82 insertions(+)
  39
  40 diff --git a/drivers/opp/core.c b/drivers/opp/core.c
  41 index 3b7ffd0234e9..f38b3be85072 100644
  42 --- a/drivers/opp/core.c
  43 +++ b/drivers/opp/core.c
  44 @@ -2112,6 +2112,75 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
  45         return r;
  46  }
  47
  48 +/**
  49 + * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP
  50 + * @dev:               device for which we do this operation
  51 + * @freq:              OPP frequency to adjust voltage of
  52 + * @u_volt:            new OPP target voltage
  53 + * @u_volt_min:                new OPP min voltage
  54 + * @u_volt_max:                new OPP max voltage
  55 + *
  56 + * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
  57 + * copy operation, returns 0 if no modifcation was done OR modification was
  58 + * successful.
  59 + */
  60 +int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
  61 +                             unsigned long u_volt, unsigned long u_volt_min,
  62 +                             unsigned long u_volt_max)
  63 +
  64 +{
  65 +       struct opp_table *opp_table;
  66 +       struct dev_pm_opp *tmp_opp, *opp = ERR_PTR(-ENODEV);
  67 +       int r = 0;
  68 +
  69 +       /* Find the opp_table */
  70 +       opp_table = _find_opp_table(dev);
  71 +       if (IS_ERR(opp_table)) {
  72 +               r = PTR_ERR(opp_table);
  73 +               dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
  74 +               return r;
  75 +       }
  76 +
  77 +       mutex_lock(&opp_table->lock);
  78 +
  79 +       /* Do we have the frequency? */
  80 +       list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
  81 +               if (tmp_opp->rate == freq) {
  82 +                       opp = tmp_opp;
  83 +                       break;
  84 +               }
  85 +       }
  86 +
  87 +       if (IS_ERR(opp)) {
  88 +               r = PTR_ERR(opp);
  89 +               goto adjust_unlock;
  90 +       }
  91 +
  92 +       /* Is update really needed? */
  93 +       if (opp->supplies->u_volt == u_volt)
  94 +               goto adjust_unlock;
  95 +
  96 +       opp->supplies->u_volt = u_volt;
  97 +       opp->supplies->u_volt_min = u_volt_min;
  98 +       opp->supplies->u_volt_max = u_volt_max;
  99 +
 100 +       dev_pm_opp_get(opp);
 101 +       mutex_unlock(&opp_table->lock);
 102 +
 103 +       /* Notify the voltage change of the OPP */
 104 +       blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADJUST_VOLTAGE,
 105 +                                    opp);
 106 +
 107 +       dev_pm_opp_put(opp);
 108 +       goto adjust_put_table;
 109 +
 110 +adjust_unlock:
 111 +       mutex_unlock(&opp_table->lock);
 112 +adjust_put_table:
 113 +       dev_pm_opp_put_opp_table(opp_table);
 114 +       return r;
 115 +}
 116 +
 117  /**
 118   * dev_pm_opp_enable() - Enable a specific OPP
 119   * @dev:       device for which we do this operation
 120 diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
 121 index b8197ab014f2..747861816f4f 100644
 122 --- a/include/linux/pm_opp.h
 123 +++ b/include/linux/pm_opp.h
 124 @@ -22,6 +22,7 @@ struct opp_table;
 125
 126  enum dev_pm_opp_event {
 127         OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
 128 +       OPP_EVENT_ADJUST_VOLTAGE,
 129  };
 130
 131  /**
 132 @@ -113,6 +114,10 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq,
 133  void dev_pm_opp_remove(struct device *dev, unsigned long freq);
 134  void dev_pm_opp_remove_all_dynamic(struct device *dev);
 135
 136 +int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
 137 +                             unsigned long u_volt, unsigned long u_volt_min,
 138 +                             unsigned long u_volt_max);
 139 +
 140  int dev_pm_opp_enable(struct device *dev, unsigned long freq);
 141
 142  int dev_pm_opp_disable(struct device *dev, unsigned long freq);
 143 @@ -242,6 +247,14 @@ static inline void dev_pm_opp_remove_all_dynamic(struct device *dev)
 144  {
 145  }
 146
 147 +static inline int
 148 +dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
 149 +                         unsigned long u_volt, unsigned long u_volt_min,
 150 +                         unsigned long u_volt_max)
 151 +{
 152 +       return 0;
 153 +}
 154 +
 155  static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)
 156  {
 157         return 0;