tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) STMicroelectronics 2009
3 * Copyright (C) ST-Ericsson SA 2010
4 *
5 * License Terms: GNU General Public License v2
6 * Author: Sundar Iyer <sundar.iyer@stericsson.com>
7 * Author: Martin Persson <martin.persson@stericsson.com>
8 * Author: Jonas Aaberg <jonas.aberg@stericsson.com>
9 *
10 */
11#include <linux/kernel.h>
12#include <linux/cpufreq.h>
13#include <linux/delay.h>
14#include <linux/slab.h>
15#include <linux/mfd/db8500-prcmu.h>
16#include <mach/id.h>
17
18static struct cpufreq_frequency_table freq_table[] = {
19 [0] = {
20 .index = 0,
21 .frequency = 300000,
22 },
23 [1] = {
24 .index = 1,
25 .frequency = 600000,
26 },
27 [2] = {
28 /* Used for MAX_OPP, if available */
29 .index = 2,
30 .frequency = CPUFREQ_TABLE_END,
31 },
32 [3] = {
33 .index = 3,
34 .frequency = CPUFREQ_TABLE_END,
35 },
36};
37
38static enum arm_opp idx2opp[] = {
39 ARM_50_OPP,
40 ARM_100_OPP,
41 ARM_MAX_OPP
42};
43
44static struct freq_attr *db8500_cpufreq_attr[] = {
45 &cpufreq_freq_attr_scaling_available_freqs,
46 NULL,
47};
48
49static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
50{
51 return cpufreq_frequency_table_verify(policy, freq_table);
52}
53
54static int db8500_cpufreq_target(struct cpufreq_policy *policy,
55 unsigned int target_freq,
56 unsigned int relation)
57{
58 struct cpufreq_freqs freqs;
59 unsigned int idx;
60
61 /* scale the target frequency to one of the extremes supported */
62 if (target_freq < policy->cpuinfo.min_freq)
63 target_freq = policy->cpuinfo.min_freq;
64 if (target_freq > policy->cpuinfo.max_freq)
65 target_freq = policy->cpuinfo.max_freq;
66
67 /* Lookup the next frequency */
68 if (cpufreq_frequency_table_target
69 (policy, freq_table, target_freq, relation, &idx)) {
70 return -EINVAL;
71 }
72
73 freqs.old = policy->cur;
74 freqs.new = freq_table[idx].frequency;
75 freqs.cpu = policy->cpu;
76
77 if (freqs.old == freqs.new)
78 return 0;
79
80 /* pre-change notification */
81 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
82
83 /* request the PRCM unit for opp change */
84 if (prcmu_set_arm_opp(idx2opp[idx])) {
85 pr_err("db8500-cpufreq: Failed to set OPP level\n");
86 return -EINVAL;
87 }
88
89 /* post change notification */
90 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
91
92 return 0;
93}
94
95static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
96{
97 int i;
98 /* request the prcm to get the current ARM opp */
99 for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++)
100 ;
101 return freq_table[i].frequency;
102}
103
104static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
105{
106 int res;
107 int i;
108
109 BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table));
110
111 if (cpu_is_u8500v2() && !prcmu_is_u8400()) {
112 freq_table[0].frequency = 400000;
113 freq_table[1].frequency = 800000;
114 if (prcmu_has_arm_maxopp())
115 freq_table[2].frequency = 1000000;
116 }
117
118 /* get policy fields based on the table */
119 res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
120 if (!res)
121 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
122 else {
123 pr_err("db8500-cpufreq : Failed to read policy table\n");
124 return res;
125 }
126
127 policy->min = policy->cpuinfo.min_freq;
128 policy->max = policy->cpuinfo.max_freq;
129 policy->cur = db8500_cpufreq_getspeed(policy->cpu);
130
131 for (i = 0; freq_table[i].frequency != policy->cur; i++)
132 ;
133
134 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
135
136 /*
137 * FIXME : Need to take time measurement across the target()
138 * function with no/some/all drivers in the notification
139 * list.
140 */
141 policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
142
143 /* policy sharing between dual CPUs */
144 cpumask_copy(policy->cpus, &cpu_present_map);
145
146 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
147
148 return 0;
149}
150
151static struct cpufreq_driver db8500_cpufreq_driver = {
152 .flags = CPUFREQ_STICKY,
153 .verify = db8500_cpufreq_verify_speed,
154 .target = db8500_cpufreq_target,
155 .get = db8500_cpufreq_getspeed,
156 .init = db8500_cpufreq_init,
157 .name = "DB8500",
158 .attr = db8500_cpufreq_attr,
159};
160
161static int __init db8500_cpufreq_register(void)
162{
163 if (!cpu_is_u8500v20_or_later())
164 return -ENODEV;
165
166 pr_info("cpufreq for DB8500 started\n");
167 return cpufreq_register_driver(&db8500_cpufreq_driver);
168}
169device_initcall(db8500_cpufreq_register);