drivers/base/power/opp/opp.h

   1 /*
   2  * Generic OPP Interface
   3  *
   4  * Copyright (C) 2009-2010 Texas Instruments Incorporated.
   5  *      Nishanth Menon
   6  *      Romit Dasgupta
   7  *      Kevin Hilman
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #ifndef __DRIVER_OPP_H__
  15 #define __DRIVER_OPP_H__
  16
  17 #include <linux/device.h>
  18 #include <linux/kernel.h>
  19 #include <linux/list.h>
  20 #include <linux/limits.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/rculist.h>
  23 #include <linux/rcupdate.h>
  24
  25 struct clk;
  26 struct regulator;
  27
  28 /* Lock to allow exclusive modification to the device and opp lists */
  29 extern struct mutex opp_table_lock;
  30
  31 extern struct list_head opp_tables;
  32
  33 /*
  34  * Internal data structure organization with the OPP layer library is as
  35  * follows:
  36  * opp_tables (root)
  37  *      |- device 1 (represents voltage domain 1)
  38  *      |       |- opp 1 (availability, freq, voltage)
  39  *      |       |- opp 2 ..
  40  *      ...     ...
  41  *      |       `- opp n ..
  42  *      |- device 2 (represents the next voltage domain)
  43  *      ...
  44  *      `- device m (represents mth voltage domain)
  45  * device 1, 2.. are represented by opp_table structure while each opp
  46  * is represented by the opp structure.
  47  */
  48
  49 /**
  50  * struct dev_pm_opp - Generic OPP description structure
  51  * @node:       opp table node. The nodes are maintained throughout the lifetime
  52  *              of boot. It is expected only an optimal set of OPPs are
  53  *              added to the library by the SoC framework.
  54  *              RCU usage: opp table is traversed with RCU locks. node
  55  *              modification is possible realtime, hence the modifications
  56  *              are protected by the opp_table_lock for integrity.
  57  *              IMPORTANT: the opp nodes should be maintained in increasing
  58  *              order.
  59  * @available:  true/false - marks if this OPP as available or not
  60  * @dynamic:    not-created from static DT entries.
  61  * @turbo:      true if turbo (boost) OPP
  62  * @suspend:    true if suspend OPP
  63  * @rate:       Frequency in hertz
  64  * @supplies:   Power supplies voltage/current values
  65  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
  66  *              frequency from any other OPP's frequency.
  67  * @opp_table:  points back to the opp_table struct this opp belongs to
  68  * @rcu_head:   RCU callback head used for deferred freeing
  69  * @np:         OPP's device node.
  70  * @dentry:     debugfs dentry pointer (per opp)
  71  *
  72  * This structure stores the OPP information for a given device.
  73  */
  74 struct dev_pm_opp {
  75         struct list_head node;
  76
  77         bool available;
  78         bool dynamic;
  79         bool turbo;
  80         bool suspend;
  81         unsigned long rate;
  82
  83         struct dev_pm_opp_supply *supplies;
  84
  85         unsigned long clock_latency_ns;
  86
  87         struct opp_table *opp_table;
  88         struct rcu_head rcu_head;
  89
  90         struct device_node *np;
  91
  92 #ifdef CONFIG_DEBUG_FS
  93         struct dentry *dentry;
  94 #endif
  95 };
  96
  97 /**
  98  * struct opp_device - devices managed by 'struct opp_table'
  99  * @node:       list node
 100  * @dev:        device to which the struct object belongs
 101  * @rcu_head:   RCU callback head used for deferred freeing
 102  * @dentry:     debugfs dentry pointer (per device)
 103  *
 104  * This is an internal data structure maintaining the devices that are managed
 105  * by 'struct opp_table'.
 106  */
 107 struct opp_device {
 108         struct list_head node;
 109         const struct device *dev;
 110         struct rcu_head rcu_head;
 111
 112 #ifdef CONFIG_DEBUG_FS
 113         struct dentry *dentry;
 114 #endif
 115 };
 116
 117 enum opp_table_access {
 118         OPP_TABLE_ACCESS_UNKNOWN = 0,
 119         OPP_TABLE_ACCESS_EXCLUSIVE = 1,
 120         OPP_TABLE_ACCESS_SHARED = 2,
 121 };
 122
 123 /**
 124  * struct opp_table - Device opp structure
 125  * @node:       table node - contains the devices with OPPs that
 126  *              have been registered. Nodes once added are not modified in this
 127  *              table.
 128  *              RCU usage: nodes are not modified in the table of opp_table,
 129  *              however addition is possible and is secured by opp_table_lock
 130  * @srcu_head:  notifier head to notify the OPP availability changes.
 131  * @rcu_head:   RCU callback head used for deferred freeing
 132  * @dev_list:   list of devices that share these OPPs
 133  * @opp_list:   table of opps
 134  * @np:         struct device_node pointer for opp's DT node.
 135  * @clock_latency_ns_max: Max clock latency in nanoseconds.
 136  * @shared_opp: OPP is shared between multiple devices.
 137  * @suspend_opp: Pointer to OPP to be used during device suspend.
 138  * @supported_hw: Array of version number to support.
 139  * @supported_hw_count: Number of elements in supported_hw array.
 140  * @prop_name: A name to postfix to many DT properties, while parsing them.
 141  * @clk: Device's clock handle
 142  * @regulators: Supply regulators
 143  * @regulator_count: Number of power supply regulators
 144  * @set_opp: Platform specific set_opp callback
 145  * @set_opp_data: Data to be passed to set_opp callback
 146  * @dentry:     debugfs dentry pointer of the real device directory (not links).
 147  * @dentry_name: Name of the real dentry.
 148  *
 149  * @voltage_tolerance_v1: In percentage, for v1 bindings only.
 150  *
 151  * This is an internal data structure maintaining the link to opps attached to
 152  * a device. This structure is not meant to be shared to users as it is
 153  * meant for book keeping and private to OPP library.
 154  *
 155  * Because the opp structures can be used from both rcu and srcu readers, we
 156  * need to wait for the grace period of both of them before freeing any
 157  * resources. And so we have used kfree_rcu() from within call_srcu() handlers.
 158  */
 159 struct opp_table {
 160         struct list_head node;
 161
 162         struct srcu_notifier_head srcu_head;
 163         struct rcu_head rcu_head;
 164         struct list_head dev_list;
 165         struct list_head opp_list;
 166
 167         struct device_node *np;
 168         unsigned long clock_latency_ns_max;
 169
 170         /* For backward compatibility with v1 bindings */
 171         unsigned int voltage_tolerance_v1;
 172
 173         enum opp_table_access shared_opp;
 174         struct dev_pm_opp *suspend_opp;
 175
 176         unsigned int *supported_hw;
 177         unsigned int supported_hw_count;
 178         const char *prop_name;
 179         struct clk *clk;
 180         struct regulator **regulators;
 181         unsigned int regulator_count;
 182
 183         int (*set_opp)(struct dev_pm_set_opp_data *data);
 184         struct dev_pm_set_opp_data *set_opp_data;
 185
 186 #ifdef CONFIG_DEBUG_FS
 187         struct dentry *dentry;
 188         char dentry_name[NAME_MAX];
 189 #endif
 190 };
 191
 192 /* Routines internal to opp core */
 193 struct opp_table *_find_opp_table(struct device *dev);
 194 struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);
 195 void _dev_pm_opp_remove_table(struct device *dev, bool remove_all);
 196 struct dev_pm_opp *_allocate_opp(struct device *dev, struct opp_table **opp_table);
 197 int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table);
 198 void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp, bool notify);
 199 int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt, bool dynamic);
 200 void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, bool of);
 201
 202 #ifdef CONFIG_OF
 203 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev);
 204 #else
 205 static inline void _of_init_opp_table(struct opp_table *opp_table, struct device *dev) {}
 206 #endif
 207
 208 #ifdef CONFIG_DEBUG_FS
 209 void opp_debug_remove_one(struct dev_pm_opp *opp);
 210 int opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table);
 211 int opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table);
 212 void opp_debug_unregister(struct opp_device *opp_dev, struct opp_table *opp_table);
 213 #else
 214 static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
 215
 216 static inline int opp_debug_create_one(struct dev_pm_opp *opp,
 217                                        struct opp_table *opp_table)
 218 { return 0; }
 219 static inline int opp_debug_register(struct opp_device *opp_dev,
 220                                      struct opp_table *opp_table)
 221 { return 0; }
 222
 223 static inline void opp_debug_unregister(struct opp_device *opp_dev,
 224                                         struct opp_table *opp_table)
 225 { }
 226 #endif          /* DEBUG_FS */
 227
 228 #endif          /* __DRIVER_OPP_H__ */