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 /*
  32  * Internal data structure organization with the OPP layer library is as
  33  * follows:
  34  * opp_tables (root)
  35  *      |- device 1 (represents voltage domain 1)
  36  *      |       |- opp 1 (availability, freq, voltage)
  37  *      |       |- opp 2 ..
  38  *      ...     ...
  39  *      |       `- opp n ..
  40  *      |- device 2 (represents the next voltage domain)
  41  *      ...
  42  *      `- device m (represents mth voltage domain)
  43  * device 1, 2.. are represented by opp_table structure while each opp
  44  * is represented by the opp structure.
  45  */
  46
  47 /**
  48  * struct dev_pm_opp - Generic OPP description structure
  49  * @node:       opp table node. The nodes are maintained throughout the lifetime
  50  *              of boot. It is expected only an optimal set of OPPs are
  51  *              added to the library by the SoC framework.
  52  *              RCU usage: opp table is traversed with RCU locks. node
  53  *              modification is possible realtime, hence the modifications
  54  *              are protected by the opp_table_lock for integrity.
  55  *              IMPORTANT: the opp nodes should be maintained in increasing
  56  *              order.
  57  * @available:  true/false - marks if this OPP as available or not
  58  * @dynamic:    not-created from static DT entries.
  59  * @turbo:      true if turbo (boost) OPP
  60  * @suspend:    true if suspend OPP
  61  * @rate:       Frequency in hertz
  62  * @u_volt:     Target voltage in microvolts corresponding to this OPP
  63  * @u_volt_min: Minimum voltage in microvolts corresponding to this OPP
  64  * @u_volt_max: Maximum voltage in microvolts corresponding to this OPP
  65  * @u_amp:      Maximum current drawn by the device in microamperes
  66  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
  67  *              frequency from any other OPP's frequency.
  68  * @opp_table:  points back to the opp_table struct this opp belongs to
  69  * @rcu_head:   RCU callback head used for deferred freeing
  70  * @np:         OPP's device node.
  71  * @dentry:     debugfs dentry pointer (per opp)
  72  *
  73  * This structure stores the OPP information for a given device.
  74  */
  75 struct dev_pm_opp {
  76         struct list_head node;
  77
  78         bool available;
  79         bool dynamic;
  80         bool turbo;
  81         bool suspend;
  82         unsigned long rate;
  83
  84         unsigned long u_volt;
  85         unsigned long u_volt_min;
  86         unsigned long u_volt_max;
  87         unsigned long u_amp;
  88         unsigned long clock_latency_ns;
  89
  90         struct opp_table *opp_table;
  91         struct rcu_head rcu_head;
  92
  93         struct device_node *np;
  94
  95 #ifdef CONFIG_DEBUG_FS
  96         struct dentry *dentry;
  97 #endif
  98 };
  99
 100 /**
 101  * struct opp_device - devices managed by 'struct opp_table'
 102  * @node:       list node
 103  * @dev:        device to which the struct object belongs
 104  * @rcu_head:   RCU callback head used for deferred freeing
 105  * @dentry:     debugfs dentry pointer (per device)
 106  *
 107  * This is an internal data structure maintaining the devices that are managed
 108  * by 'struct opp_table'.
 109  */
 110 struct opp_device {
 111         struct list_head node;
 112         const struct device *dev;
 113         struct rcu_head rcu_head;
 114
 115 #ifdef CONFIG_DEBUG_FS
 116         struct dentry *dentry;
 117 #endif
 118 };
 119
 120 /**
 121  * struct opp_table - Device opp structure
 122  * @node:       table node - contains the devices with OPPs that
 123  *              have been registered. Nodes once added are not modified in this
 124  *              table.
 125  *              RCU usage: nodes are not modified in the table of opp_table,
 126  *              however addition is possible and is secured by opp_table_lock
 127  * @srcu_head:  notifier head to notify the OPP availability changes.
 128  * @rcu_head:   RCU callback head used for deferred freeing
 129  * @dev_list:   list of devices that share these OPPs
 130  * @opp_list:   table of opps
 131  * @np:         struct device_node pointer for opp's DT node.
 132  * @clock_latency_ns_max: Max clock latency in nanoseconds.
 133  * @shared_opp: OPP is shared between multiple devices.
 134  * @suspend_opp: Pointer to OPP to be used during device suspend.
 135  * @supported_hw: Array of version number to support.
 136  * @supported_hw_count: Number of elements in supported_hw array.
 137  * @prop_name: A name to postfix to many DT properties, while parsing them.
 138  * @clk: Device's clock handle
 139  * @regulator: Supply regulator
 140  * @dentry:     debugfs dentry pointer of the real device directory (not links).
 141  * @dentry_name: Name of the real dentry.
 142  *
 143  * @voltage_tolerance_v1: In percentage, for v1 bindings only.
 144  *
 145  * This is an internal data structure maintaining the link to opps attached to
 146  * a device. This structure is not meant to be shared to users as it is
 147  * meant for book keeping and private to OPP library.
 148  *
 149  * Because the opp structures can be used from both rcu and srcu readers, we
 150  * need to wait for the grace period of both of them before freeing any
 151  * resources. And so we have used kfree_rcu() from within call_srcu() handlers.
 152  */
 153 struct opp_table {
 154         struct list_head node;
 155
 156         struct srcu_notifier_head srcu_head;
 157         struct rcu_head rcu_head;
 158         struct list_head dev_list;
 159         struct list_head opp_list;
 160
 161         struct device_node *np;
 162         unsigned long clock_latency_ns_max;
 163
 164         /* For backward compatibility with v1 bindings */
 165         unsigned int voltage_tolerance_v1;
 166
 167         bool shared_opp;
 168         struct dev_pm_opp *suspend_opp;
 169
 170         unsigned int *supported_hw;
 171         unsigned int supported_hw_count;
 172         const char *prop_name;
 173         struct clk *clk;
 174         struct regulator *regulator;
 175
 176 #ifdef CONFIG_DEBUG_FS
 177         struct dentry *dentry;
 178         char dentry_name[NAME_MAX];
 179 #endif
 180 };
 181
 182 /* Routines internal to opp core */
 183 struct opp_table *_find_opp_table(struct device *dev);
 184 struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);
 185 struct device_node *_of_get_opp_desc_node(struct device *dev);
 186
 187 #ifdef CONFIG_DEBUG_FS
 188 void opp_debug_remove_one(struct dev_pm_opp *opp);
 189 int opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table);
 190 int opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table);
 191 void opp_debug_unregister(struct opp_device *opp_dev, struct opp_table *opp_table);
 192 #else
 193 static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
 194
 195 static inline int opp_debug_create_one(struct dev_pm_opp *opp,
 196                                        struct opp_table *opp_table)
 197 { return 0; }
 198 static inline int opp_debug_register(struct opp_device *opp_dev,
 199                                      struct opp_table *opp_table)
 200 { return 0; }
 201
 202 static inline void opp_debug_unregister(struct opp_device *opp_dev,
 203                                         struct opp_table *opp_table)
 204 { }
 205 #endif          /* DEBUG_FS */
 206
 207 #endif          /* __DRIVER_OPP_H__ */