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  * @u_volt:     Target voltage in microvolts corresponding to this OPP
  65  * @u_volt_min: Minimum voltage in microvolts corresponding to this OPP
  66  * @u_volt_max: Maximum voltage in microvolts corresponding to this OPP
  67  * @u_amp:      Maximum current drawn by the device in microamperes
  68  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
  69  *              frequency from any other OPP's frequency.
  70  * @opp_table:  points back to the opp_table struct this opp belongs to
  71  * @rcu_head:   RCU callback head used for deferred freeing
  72  * @np:         OPP's device node.
  73  * @dentry:     debugfs dentry pointer (per opp)
  74  *
  75  * This structure stores the OPP information for a given device.
  76  */
  77 struct dev_pm_opp {
  78         struct list_head node;
  79
  80         bool available;
  81         bool dynamic;
  82         bool turbo;
  83         bool suspend;
  84         unsigned long rate;
  85
  86         unsigned long u_volt;
  87         unsigned long u_volt_min;
  88         unsigned long u_volt_max;
  89         unsigned long u_amp;
  90         unsigned long clock_latency_ns;
  91
  92         struct opp_table *opp_table;
  93         struct rcu_head rcu_head;
  94
  95         struct device_node *np;
  96
  97 #ifdef CONFIG_DEBUG_FS
  98         struct dentry *dentry;
  99 #endif
 100 };
 101
 102 /**
 103  * struct opp_device - devices managed by 'struct opp_table'
 104  * @node:       list node
 105  * @dev:        device to which the struct object belongs
 106  * @rcu_head:   RCU callback head used for deferred freeing
 107  * @dentry:     debugfs dentry pointer (per device)
 108  *
 109  * This is an internal data structure maintaining the devices that are managed
 110  * by 'struct opp_table'.
 111  */
 112 struct opp_device {
 113         struct list_head node;
 114         const struct device *dev;
 115         struct rcu_head rcu_head;
 116
 117 #ifdef CONFIG_DEBUG_FS
 118         struct dentry *dentry;
 119 #endif
 120 };
 121
 122 enum opp_table_access {
 123         OPP_TABLE_ACCESS_UNKNOWN = 0,
 124         OPP_TABLE_ACCESS_EXCLUSIVE = 1,
 125         OPP_TABLE_ACCESS_SHARED = 2,
 126 };
 127
 128 /**
 129  * struct opp_table - Device opp structure
 130  * @node:       table node - contains the devices with OPPs that
 131  *              have been registered. Nodes once added are not modified in this
 132  *              table.
 133  *              RCU usage: nodes are not modified in the table of opp_table,
 134  *              however addition is possible and is secured by opp_table_lock
 135  * @srcu_head:  notifier head to notify the OPP availability changes.
 136  * @rcu_head:   RCU callback head used for deferred freeing
 137  * @dev_list:   list of devices that share these OPPs
 138  * @opp_list:   table of opps
 139  * @np:         struct device_node pointer for opp's DT node.
 140  * @clock_latency_ns_max: Max clock latency in nanoseconds.
 141  * @shared_opp: OPP is shared between multiple devices.
 142  * @suspend_opp: Pointer to OPP to be used during device suspend.
 143  * @supported_hw: Array of version number to support.
 144  * @supported_hw_count: Number of elements in supported_hw array.
 145  * @prop_name: A name to postfix to many DT properties, while parsing them.
 146  * @clk: Device's clock handle
 147  * @regulator: Supply regulator
 148  * @dentry:     debugfs dentry pointer of the real device directory (not links).
 149  * @dentry_name: Name of the real dentry.
 150  *
 151  * @voltage_tolerance_v1: In percentage, for v1 bindings only.
 152  *
 153  * This is an internal data structure maintaining the link to opps attached to
 154  * a device. This structure is not meant to be shared to users as it is
 155  * meant for book keeping and private to OPP library.
 156  *
 157  * Because the opp structures can be used from both rcu and srcu readers, we
 158  * need to wait for the grace period of both of them before freeing any
 159  * resources. And so we have used kfree_rcu() from within call_srcu() handlers.
 160  */
 161 struct opp_table {
 162         struct list_head node;
 163
 164         struct srcu_notifier_head srcu_head;
 165         struct rcu_head rcu_head;
 166         struct list_head dev_list;
 167         struct list_head opp_list;
 168
 169         struct device_node *np;
 170         unsigned long clock_latency_ns_max;
 171
 172         /* For backward compatibility with v1 bindings */
 173         unsigned int voltage_tolerance_v1;
 174
 175         enum opp_table_access shared_opp;
 176         struct dev_pm_opp *suspend_opp;
 177
 178         unsigned int *supported_hw;
 179         unsigned int supported_hw_count;
 180         const char *prop_name;
 181         struct clk *clk;
 182         struct regulator *regulator;
 183
 184 #ifdef CONFIG_DEBUG_FS
 185         struct dentry *dentry;
 186         char dentry_name[NAME_MAX];
 187 #endif
 188 };
 189
 190 /* Routines internal to opp core */
 191 struct opp_table *_find_opp_table(struct device *dev);
 192 struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);
 193 struct device_node *_of_get_opp_desc_node(struct device *dev);
 194 void _dev_pm_opp_remove_table(struct device *dev, bool remove_all);
 195 struct dev_pm_opp *_allocate_opp(struct device *dev, struct opp_table **opp_table);
 196 int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table);
 197 void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp, bool notify);
 198 int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt, bool dynamic);
 199 void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, bool of);
 200
 201 #ifdef CONFIG_OF
 202 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev);
 203 #else
 204 static inline void _of_init_opp_table(struct opp_table *opp_table, struct device *dev) {}
 205 #endif
 206
 207 #ifdef CONFIG_DEBUG_FS
 208 void opp_debug_remove_one(struct dev_pm_opp *opp);
 209 int opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table);
 210 int opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table);
 211 void opp_debug_unregister(struct opp_device *opp_dev, struct opp_table *opp_table);
 212 #else
 213 static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
 214
 215 static inline int opp_debug_create_one(struct dev_pm_opp *opp,
 216                                        struct opp_table *opp_table)
 217 { return 0; }
 218 static inline int opp_debug_register(struct opp_device *opp_dev,
 219                                      struct opp_table *opp_table)
 220 { return 0; }
 221
 222 static inline void opp_debug_unregister(struct opp_device *opp_dev,
 223                                         struct opp_table *opp_table)
 224 { }
 225 #endif          /* DEBUG_FS */
 226
 227 #endif          /* __DRIVER_OPP_H__ */