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
_of_init_opp_table(struct opp_table * opp_table,struct device * dev)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
opp_debug_remove_one(struct dev_pm_opp * opp)213 static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
214
opp_debug_create_one(struct dev_pm_opp * opp,struct opp_table * opp_table)215 static inline int opp_debug_create_one(struct dev_pm_opp *opp,
216 struct opp_table *opp_table)
217 { return 0; }
opp_debug_register(struct opp_device * opp_dev,struct opp_table * opp_table)218 static inline int opp_debug_register(struct opp_device *opp_dev,
219 struct opp_table *opp_table)
220 { return 0; }
221
opp_debug_unregister(struct opp_device * opp_dev,struct opp_table * opp_table)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__ */
228