2 * Copyright (C) STMicroelectronics 2009
3 * Copyright (C) ST-Ericsson SA 2010
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>
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>
18 static struct cpufreq_frequency_table freq_table[] = {
28 /* Used for MAX_OPP, if available */
30 .frequency = CPUFREQ_TABLE_END,
34 .frequency = CPUFREQ_TABLE_END,
38 static enum arm_opp idx2opp[] = {
44 static struct freq_attr *db8500_cpufreq_attr[] = {
45 &cpufreq_freq_attr_scaling_available_freqs,
49 static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
51 return cpufreq_frequency_table_verify(policy, freq_table);
54 static int db8500_cpufreq_target(struct cpufreq_policy *policy,
55 unsigned int target_freq,
56 unsigned int relation)
58 struct cpufreq_freqs freqs;
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;
67 /* Lookup the next frequency */
68 if (cpufreq_frequency_table_target
69 (policy, freq_table, target_freq, relation, &idx)) {
73 freqs.old = policy->cur;
74 freqs.new = freq_table[idx].frequency;
75 freqs.cpu = policy->cpu;
77 if (freqs.old == freqs.new)
80 /* pre-change notification */
81 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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");
89 /* post change notification */
90 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
95 static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
98 /* request the prcm to get the current ARM opp */
99 for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++)
101 return freq_table[i].frequency;
104 static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
109 BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table));
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;
118 /* get policy fields based on the table */
119 res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
121 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
123 pr_err("db8500-cpufreq : Failed to read policy table\n");
127 policy->min = policy->cpuinfo.min_freq;
128 policy->max = policy->cpuinfo.max_freq;
129 policy->cur = db8500_cpufreq_getspeed(policy->cpu);
131 for (i = 0; freq_table[i].frequency != policy->cur; i++)
134 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
137 * FIXME : Need to take time measurement across the target()
138 * function with no/some/all drivers in the notification
141 policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
143 /* policy sharing between dual CPUs */
144 cpumask_copy(policy->cpus, &cpu_present_map);
146 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
151 static 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,
158 .attr = db8500_cpufreq_attr,
161 static int __init db8500_cpufreq_register(void)
163 if (!cpu_is_u8500v20_or_later())
166 pr_info("cpufreq for DB8500 started\n");
167 return cpufreq_register_driver(&db8500_cpufreq_driver);
169 device_initcall(db8500_cpufreq_register);