Nishanth Menon | a0dd7b7 | 2014-05-05 08:33:50 -0500 | [diff] [blame] | 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 | |
Stephen Boyd | 3c5445c | 2014-08-06 22:04:58 +0200 | [diff] [blame] | 63 | freq_table = kcalloc(sizeof(*freq_table), (max_opps + 1), GFP_ATOMIC); |
Nishanth Menon | a0dd7b7 | 2014-05-05 08:33:50 -0500 | [diff] [blame] | 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); |