OpenWrt – Blame information for rev 3
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1 | office | 1 | From c949f08cf20fe82971fbdb4015daa38210da492e Mon Sep 17 00:00:00 2001 |
2 | From: Stephen Boyd <sboyd@codeaurora.org> |
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3 | Date: Fri, 18 Sep 2015 17:52:06 -0700 |
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4 | Subject: [PATCH 49/69] PM / OPP: Support adjusting OPP voltages at runtime |
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5 | |||
6 | On some SoCs the Adaptive Voltage Scaling (AVS) technique is |
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7 | employed to optimize the operating voltage of a device. At a |
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8 | given frequency, the hardware monitors dynamic factors and either |
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9 | makes a suggestion for how much to adjust a voltage for the |
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10 | current frequency, or it automatically adjusts the voltage |
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11 | without software intervention. Add an API to the OPP library for |
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12 | the former case, so that AVS type devices can update the voltages |
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13 | for an OPP when the hardware determines the voltage should |
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14 | change. The assumption is that drivers like CPUfreq or devfreq |
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15 | will register for the OPP notifiers and adjust the voltage |
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16 | according to suggestions that AVS makes. |
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17 | |||
18 | Cc: Nishanth Menon <nm@ti.com> |
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19 | Acked-by: Viresh Kumar <viresh.kumar@linaro.org> |
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20 | Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> |
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21 | Acked-by: Viresh Kumar <viresh.kumar@linaro.org> |
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22 | Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> |
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23 | --- |
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24 | drivers/base/power/opp/core.c | 77 +++++++++++++++++++++++++++++++++++++++++++ |
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25 | include/linux/pm_opp.h | 11 +++++++ |
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26 | 2 files changed, 88 insertions(+) |
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27 | |||
28 | --- a/drivers/base/power/opp/core.c |
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29 | +++ b/drivers/base/power/opp/core.c |
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3 | office | 30 | @@ -1605,6 +1605,83 @@ put_table: |
1 | office | 31 | } |
32 | |||
33 | /** |
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34 | + * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP |
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35 | + * @dev: device for which we do this operation |
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36 | + * @freq: OPP frequency to adjust voltage of |
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37 | + * @u_volt: new OPP voltage |
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38 | + * |
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39 | + * Change the voltage of an OPP with an RCU operation. |
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40 | + * |
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41 | + * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the |
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42 | + * copy operation, returns 0 if no modifcation was done OR modification was |
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43 | + * successful. |
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44 | + * |
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45 | + * Locking: The internal device_opp and opp structures are RCU protected. |
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46 | + * Hence this function internally uses RCU updater strategy with mutex locks to |
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47 | + * keep the integrity of the internal data structures. Callers should ensure |
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48 | + * that this function is *NOT* called under RCU protection or in contexts where |
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49 | + * mutex locking or synchronize_rcu() blocking calls cannot be used. |
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50 | + */ |
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51 | +int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, |
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52 | + unsigned long u_volt) |
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53 | +{ |
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54 | + struct opp_table *opp_table; |
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55 | + struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV); |
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56 | + int r = 0; |
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57 | + |
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58 | + /* keep the node allocated */ |
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59 | + new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL); |
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60 | + if (!new_opp) |
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61 | + return -ENOMEM; |
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62 | + |
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63 | + mutex_lock(&opp_table_lock); |
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64 | + |
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65 | + /* Find the opp_table */ |
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66 | + opp_table = _find_opp_table(dev); |
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67 | + if (IS_ERR(opp_table)) { |
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68 | + r = PTR_ERR(opp_table); |
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69 | + dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r); |
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70 | + goto unlock; |
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71 | + } |
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72 | + |
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73 | + /* Do we have the frequency? */ |
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74 | + list_for_each_entry(tmp_opp, &opp_table->opp_list, node) { |
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75 | + if (tmp_opp->rate == freq) { |
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76 | + opp = tmp_opp; |
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77 | + break; |
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78 | + } |
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79 | + } |
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80 | + if (IS_ERR(opp)) { |
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81 | + r = PTR_ERR(opp); |
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82 | + goto unlock; |
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83 | + } |
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84 | + |
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85 | + /* Is update really needed? */ |
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86 | + if (opp->supplies[0].u_volt == u_volt) |
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87 | + goto unlock; |
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88 | + /* copy the old data over */ |
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89 | + *new_opp = *opp; |
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90 | + |
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91 | + /* plug in new node */ |
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92 | + new_opp->supplies[0].u_volt = u_volt; |
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93 | + |
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94 | + list_replace(&opp->node, &new_opp->node); |
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95 | + mutex_unlock(&opp_table_lock); |
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96 | + kfree(opp); |
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97 | + |
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98 | + /* Notify the change of the OPP */ |
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99 | + blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADJUST_VOLTAGE, |
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100 | + new_opp); |
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101 | + |
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102 | + return 0; |
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103 | + |
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104 | +unlock: |
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105 | + mutex_unlock(&opp_table_lock); |
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106 | + kfree(new_opp); |
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107 | + return r; |
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108 | +} |
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109 | + |
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110 | +/** |
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111 | * dev_pm_opp_enable() - Enable a specific OPP |
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112 | * @dev: device for which we do this operation |
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113 | * @freq: OPP frequency to enable |
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114 | --- a/include/linux/pm_opp.h |
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115 | +++ b/include/linux/pm_opp.h |
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116 | @@ -25,6 +25,7 @@ struct opp_table; |
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117 | |||
118 | enum dev_pm_opp_event { |
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119 | OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE, |
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120 | + OPP_EVENT_ADJUST_VOLTAGE, |
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121 | }; |
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122 | |||
123 | /** |
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124 | @@ -108,6 +109,9 @@ int dev_pm_opp_add(struct device *dev, u |
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125 | unsigned long u_volt); |
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126 | void dev_pm_opp_remove(struct device *dev, unsigned long freq); |
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127 | |||
128 | +int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, |
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129 | + unsigned long u_volt); |
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130 | + |
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131 | int dev_pm_opp_enable(struct device *dev, unsigned long freq); |
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132 | |||
133 | int dev_pm_opp_disable(struct device *dev, unsigned long freq); |
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134 | @@ -208,6 +212,13 @@ static inline void dev_pm_opp_remove(str |
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135 | { |
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136 | } |
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137 | |||
138 | +static inline int |
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139 | +dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, |
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140 | + unsigned long u_volt) |
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141 | +{ |
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142 | + return 0; |
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143 | +} |
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144 | + |
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145 | static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq) |
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146 | { |
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147 | return 0; |