blob: 0f5e6d5f6da0a6d29788a79eb37cc51d2430140b [file] [log] [blame]
Nishanth Menona0dd7b72014-05-05 08:33:50 -05001/*
2 * Generic OPP helper interface for CPUFreq drivers
3 *
4 * Copyright (C) 2009-2014 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#include <linux/cpufreq.h>
14#include <linux/device.h>
15#include <linux/err.h>
16#include <linux/errno.h>
17#include <linux/export.h>
18#include <linux/kernel.h>
19#include <linux/pm_opp.h>
20#include <linux/rcupdate.h>
21#include <linux/slab.h>
22
23/**
24 * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
25 * @dev: device for which we do this operation
26 * @table: Cpufreq table returned back to caller
27 *
28 * Generate a cpufreq table for a provided device- this assumes that the
29 * opp list is already initialized and ready for usage.
30 *
31 * This function allocates required memory for the cpufreq table. It is
32 * expected that the caller does the required maintenance such as freeing
33 * the table as required.
34 *
35 * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
36 * if no memory available for the operation (table is not populated), returns 0
37 * if successful and table is populated.
38 *
39 * WARNING: It is important for the callers to ensure refreshing their copy of
40 * the table if any of the mentioned functions have been invoked in the interim.
41 *
42 * Locking: The internal device_opp and opp structures are RCU protected.
43 * Since we just use the regular accessor functions to access the internal data
44 * structures, we use RCU read lock inside this function. As a result, users of
45 * this function DONOT need to use explicit locks for invoking.
46 */
47int dev_pm_opp_init_cpufreq_table(struct device *dev,
48 struct cpufreq_frequency_table **table)
49{
50 struct dev_pm_opp *opp;
51 struct cpufreq_frequency_table *freq_table = NULL;
52 int i, max_opps, ret = 0;
53 unsigned long rate;
54
55 rcu_read_lock();
56
57 max_opps = dev_pm_opp_get_opp_count(dev);
58 if (max_opps <= 0) {
59 ret = max_opps ? max_opps : -ENODATA;
60 goto out;
61 }
62
Anand Moond3599922014-09-05 08:38:30 +053063 freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
Nishanth Menona0dd7b72014-05-05 08:33:50 -050064 if (!freq_table) {
65 ret = -ENOMEM;
66 goto out;
67 }
68
69 for (i = 0, rate = 0; i < max_opps; i++, rate++) {
70 /* find next rate */
71 opp = dev_pm_opp_find_freq_ceil(dev, &rate);
72 if (IS_ERR(opp)) {
73 ret = PTR_ERR(opp);
74 goto out;
75 }
76 freq_table[i].driver_data = i;
77 freq_table[i].frequency = rate / 1000;
Bartlomiej Zolnierkiewicz79eea442015-07-29 16:23:08 +053078
79 /* Is Boost/turbo opp ? */
80 if (dev_pm_opp_is_turbo(opp))
81 freq_table[i].flags = CPUFREQ_BOOST_FREQ;
Nishanth Menona0dd7b72014-05-05 08:33:50 -050082 }
83
84 freq_table[i].driver_data = i;
85 freq_table[i].frequency = CPUFREQ_TABLE_END;
86
87 *table = &freq_table[0];
88
89out:
90 rcu_read_unlock();
91 if (ret)
92 kfree(freq_table);
93
94 return ret;
95}
96EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
97
98/**
99 * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
100 * @dev: device for which we do this operation
101 * @table: table to free
102 *
103 * Free up the table allocated by dev_pm_opp_init_cpufreq_table
104 */
105void dev_pm_opp_free_cpufreq_table(struct device *dev,
106 struct cpufreq_frequency_table **table)
107{
108 if (!table)
109 return;
110
111 kfree(*table);
112 *table = NULL;
113}
114EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);