Root/drivers/cpufreq/freq_table.c

1/*
2 * linux/drivers/cpufreq/freq_table.c
3 *
4 * Copyright (C) 2002 - 2003 Dominik Brodowski
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/cpufreq.h>
16
17/*********************************************************************
18 * FREQUENCY TABLE HELPERS *
19 *********************************************************************/
20
21int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
22                    struct cpufreq_frequency_table *table)
23{
24    unsigned int min_freq = ~0;
25    unsigned int max_freq = 0;
26    unsigned int i;
27
28    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
29        unsigned int freq = table[i].frequency;
30        if (freq == CPUFREQ_ENTRY_INVALID) {
31            pr_debug("table entry %u is invalid, skipping\n", i);
32
33            continue;
34        }
35        pr_debug("table entry %u: %u kHz, %u index\n",
36                    i, freq, table[i].index);
37        if (freq < min_freq)
38            min_freq = freq;
39        if (freq > max_freq)
40            max_freq = freq;
41    }
42
43    policy->min = policy->cpuinfo.min_freq = min_freq;
44    policy->max = policy->cpuinfo.max_freq = max_freq;
45
46    if (policy->min == ~0)
47        return -EINVAL;
48    else
49        return 0;
50}
51EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
52
53
54int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
55                   struct cpufreq_frequency_table *table)
56{
57    unsigned int next_larger = ~0;
58    unsigned int i;
59    unsigned int count = 0;
60
61    pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
62                    policy->min, policy->max, policy->cpu);
63
64    if (!cpu_online(policy->cpu))
65        return -EINVAL;
66
67    cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
68                     policy->cpuinfo.max_freq);
69
70    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
71        unsigned int freq = table[i].frequency;
72        if (freq == CPUFREQ_ENTRY_INVALID)
73            continue;
74        if ((freq >= policy->min) && (freq <= policy->max))
75            count++;
76        else if ((next_larger > freq) && (freq > policy->max))
77            next_larger = freq;
78    }
79
80    if (!count)
81        policy->max = next_larger;
82
83    cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
84                     policy->cpuinfo.max_freq);
85
86    pr_debug("verification lead to (%u - %u kHz) for cpu %u\n",
87                policy->min, policy->max, policy->cpu);
88
89    return 0;
90}
91EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
92
93
94int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
95                   struct cpufreq_frequency_table *table,
96                   unsigned int target_freq,
97                   unsigned int relation,
98                   unsigned int *index)
99{
100    struct cpufreq_frequency_table optimal = {
101        .index = ~0,
102        .frequency = 0,
103    };
104    struct cpufreq_frequency_table suboptimal = {
105        .index = ~0,
106        .frequency = 0,
107    };
108    unsigned int i;
109
110    pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
111                    target_freq, relation, policy->cpu);
112
113    switch (relation) {
114    case CPUFREQ_RELATION_H:
115        suboptimal.frequency = ~0;
116        break;
117    case CPUFREQ_RELATION_L:
118        optimal.frequency = ~0;
119        break;
120    }
121
122    if (!cpu_online(policy->cpu))
123        return -EINVAL;
124
125    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
126        unsigned int freq = table[i].frequency;
127        if (freq == CPUFREQ_ENTRY_INVALID)
128            continue;
129        if ((freq < policy->min) || (freq > policy->max))
130            continue;
131        switch (relation) {
132        case CPUFREQ_RELATION_H:
133            if (freq <= target_freq) {
134                if (freq >= optimal.frequency) {
135                    optimal.frequency = freq;
136                    optimal.index = i;
137                }
138            } else {
139                if (freq <= suboptimal.frequency) {
140                    suboptimal.frequency = freq;
141                    suboptimal.index = i;
142                }
143            }
144            break;
145        case CPUFREQ_RELATION_L:
146            if (freq >= target_freq) {
147                if (freq <= optimal.frequency) {
148                    optimal.frequency = freq;
149                    optimal.index = i;
150                }
151            } else {
152                if (freq >= suboptimal.frequency) {
153                    suboptimal.frequency = freq;
154                    suboptimal.index = i;
155                }
156            }
157            break;
158        }
159    }
160    if (optimal.index > i) {
161        if (suboptimal.index > i)
162            return -EINVAL;
163        *index = suboptimal.index;
164    } else
165        *index = optimal.index;
166
167    pr_debug("target is %u (%u kHz, %u)\n", *index, table[*index].frequency,
168        table[*index].index);
169
170    return 0;
171}
172EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
173
174static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
175/**
176 * show_available_freqs - show available frequencies for the specified CPU
177 */
178static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf)
179{
180    unsigned int i = 0;
181    unsigned int cpu = policy->cpu;
182    ssize_t count = 0;
183    struct cpufreq_frequency_table *table;
184
185    if (!per_cpu(cpufreq_show_table, cpu))
186        return -ENODEV;
187
188    table = per_cpu(cpufreq_show_table, cpu);
189
190    for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
191        if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
192            continue;
193        count += sprintf(&buf[count], "%d ", table[i].frequency);
194    }
195    count += sprintf(&buf[count], "\n");
196
197    return count;
198
199}
200
201struct freq_attr cpufreq_freq_attr_scaling_available_freqs = {
202    .attr = { .name = "scaling_available_frequencies",
203          .mode = 0444,
204        },
205    .show = show_available_freqs,
206};
207EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
208
209/*
210 * if you use these, you must assure that the frequency table is valid
211 * all the time between get_attr and put_attr!
212 */
213void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
214                      unsigned int cpu)
215{
216    pr_debug("setting show_table for cpu %u to %p\n", cpu, table);
217    per_cpu(cpufreq_show_table, cpu) = table;
218}
219EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_attr);
220
221void cpufreq_frequency_table_put_attr(unsigned int cpu)
222{
223    pr_debug("clearing show_table for cpu %u\n", cpu);
224    per_cpu(cpufreq_show_table, cpu) = NULL;
225}
226EXPORT_SYMBOL_GPL(cpufreq_frequency_table_put_attr);
227
228struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
229{
230    return per_cpu(cpufreq_show_table, cpu);
231}
232EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
233
234MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
235MODULE_DESCRIPTION("CPUfreq frequency table helpers");
236MODULE_LICENSE("GPL");
237

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