2 * Generic OPP Interface
4 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
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.
14 #ifndef __DRIVER_OPP_H__
15 #define __DRIVER_OPP_H__
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>
25 /* Lock to allow exclusive modification to the device and opp lists */
26 extern struct mutex dev_opp_list_lock;
29 * Internal data structure organization with the OPP layer library is as
32 * |- device 1 (represents voltage domain 1)
33 * | |- opp 1 (availability, freq, voltage)
37 * |- device 2 (represents the next voltage domain)
39 * `- device m (represents mth voltage domain)
40 * device 1, 2.. are represented by dev_opp structure while each opp
41 * is represented by the opp structure.
45 * struct dev_pm_opp - Generic OPP description structure
46 * @node: opp list node. The nodes are maintained throughout the lifetime
47 * of boot. It is expected only an optimal set of OPPs are
48 * added to the library by the SoC framework.
49 * RCU usage: opp list is traversed with RCU locks. node
50 * modification is possible realtime, hence the modifications
51 * are protected by the dev_opp_list_lock for integrity.
52 * IMPORTANT: the opp nodes should be maintained in increasing
54 * @available: true/false - marks if this OPP as available or not
55 * @dynamic: not-created from static DT entries.
56 * @turbo: true if turbo (boost) OPP
57 * @suspend: true if suspend OPP
58 * @rate: Frequency in hertz
59 * @u_volt: Target voltage in microvolts corresponding to this OPP
60 * @u_volt_min: Minimum voltage in microvolts corresponding to this OPP
61 * @u_volt_max: Maximum voltage in microvolts corresponding to this OPP
62 * @u_amp: Maximum current drawn by the device in microamperes
63 * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
64 * frequency from any other OPP's frequency.
65 * @dev_opp: points back to the device_opp struct this opp belongs to
66 * @rcu_head: RCU callback head used for deferred freeing
67 * @np: OPP's device node.
68 * @dentry: debugfs dentry pointer (per opp)
70 * This structure stores the OPP information for a given device.
73 struct list_head node;
82 unsigned long u_volt_min;
83 unsigned long u_volt_max;
85 unsigned long clock_latency_ns;
87 struct device_opp *dev_opp;
88 struct rcu_head rcu_head;
90 struct device_node *np;
92 #ifdef CONFIG_DEBUG_FS
93 struct dentry *dentry;
98 * struct device_list_opp - devices managed by 'struct device_opp'
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)
104 * This is an internal data structure maintaining the list of devices that are
105 * managed by 'struct device_opp'.
107 struct device_list_opp {
108 struct list_head node;
109 const struct device *dev;
110 struct rcu_head rcu_head;
112 #ifdef CONFIG_DEBUG_FS
113 struct dentry *dentry;
118 * struct device_opp - Device opp structure
119 * @node: list node - contains the devices with OPPs that
120 * have been registered. Nodes once added are not modified in this
122 * RCU usage: nodes are not modified in the list of device_opp,
123 * however addition is possible and is secured by dev_opp_list_lock
124 * @srcu_head: notifier head to notify the OPP availability changes.
125 * @rcu_head: RCU callback head used for deferred freeing
126 * @dev_list: list of devices that share these OPPs
127 * @opp_list: list of opps
128 * @np: struct device_node pointer for opp's DT node.
129 * @clock_latency_ns_max: Max clock latency in nanoseconds.
130 * @shared_opp: OPP is shared between multiple devices.
131 * @suspend_opp: Pointer to OPP to be used during device suspend.
132 * @supported_hw: Array of version number to support.
133 * @supported_hw_count: Number of elements in supported_hw array.
134 * @prop_name: A name to postfix to many DT properties, while parsing them.
135 * @dentry: debugfs dentry pointer of the real device directory (not links).
136 * @dentry_name: Name of the real dentry.
138 * This is an internal data structure maintaining the link to opps attached to
139 * a device. This structure is not meant to be shared to users as it is
140 * meant for book keeping and private to OPP library.
142 * Because the opp structures can be used from both rcu and srcu readers, we
143 * need to wait for the grace period of both of them before freeing any
144 * resources. And so we have used kfree_rcu() from within call_srcu() handlers.
147 struct list_head node;
149 struct srcu_notifier_head srcu_head;
150 struct rcu_head rcu_head;
151 struct list_head dev_list;
152 struct list_head opp_list;
154 struct device_node *np;
155 unsigned long clock_latency_ns_max;
157 struct dev_pm_opp *suspend_opp;
159 unsigned int *supported_hw;
160 unsigned int supported_hw_count;
161 const char *prop_name;
163 #ifdef CONFIG_DEBUG_FS
164 struct dentry *dentry;
165 char dentry_name[NAME_MAX];
169 /* Routines internal to opp core */
170 struct device_opp *_find_device_opp(struct device *dev);
171 struct device_list_opp *_add_list_dev(const struct device *dev,
172 struct device_opp *dev_opp);
173 struct device_node *_of_get_opp_desc_node(struct device *dev);
175 #ifdef CONFIG_DEBUG_FS
176 void opp_debug_remove_one(struct dev_pm_opp *opp);
177 int opp_debug_create_one(struct dev_pm_opp *opp, struct device_opp *dev_opp);
178 int opp_debug_register(struct device_list_opp *list_dev,
179 struct device_opp *dev_opp);
180 void opp_debug_unregister(struct device_list_opp *list_dev,
181 struct device_opp *dev_opp);
183 static inline void opp_debug_remove_one(struct dev_pm_opp *opp) {}
185 static inline int opp_debug_create_one(struct dev_pm_opp *opp,
186 struct device_opp *dev_opp)
188 static inline int opp_debug_register(struct device_list_opp *list_dev,
189 struct device_opp *dev_opp)
192 static inline void opp_debug_unregister(struct device_list_opp *list_dev,
193 struct device_opp *dev_opp)
195 #endif /* DEBUG_FS */
197 #endif /* __DRIVER_OPP_H__ */