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1 | /* |
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 | */ | |
47 | int 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 | ||
d3599920 | 63 | freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC); |
a0dd7b79 NM |
64 | 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; | |
78 | } | |
79 | ||
80 | freq_table[i].driver_data = i; | |
81 | freq_table[i].frequency = CPUFREQ_TABLE_END; | |
82 | ||
83 | *table = &freq_table[0]; | |
84 | ||
85 | out: | |
86 | rcu_read_unlock(); | |
87 | if (ret) | |
88 | kfree(freq_table); | |
89 | ||
90 | return ret; | |
91 | } | |
92 | EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table); | |
93 | ||
94 | /** | |
95 | * dev_pm_opp_free_cpufreq_table() - free the cpufreq table | |
96 | * @dev: device for which we do this operation | |
97 | * @table: table to free | |
98 | * | |
99 | * Free up the table allocated by dev_pm_opp_init_cpufreq_table | |
100 | */ | |
101 | void dev_pm_opp_free_cpufreq_table(struct device *dev, | |
102 | struct cpufreq_frequency_table **table) | |
103 | { | |
104 | if (!table) | |
105 | return; | |
106 | ||
107 | kfree(*table); | |
108 | *table = NULL; | |
109 | } | |
110 | EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table); |