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/dbx500-prcmu.h>
16 #include <mach/id.h>
17
18 static struct cpufreq_frequency_table freq_table[] = {
19 [0] = {
20 .index = 0,
21 .frequency = 200000,
22 },
23 [1] = {
24 .index = 1,
25 .frequency = 300000,
26 },
27 [2] = {
28 .index = 2,
29 .frequency = 600000,
30 },
31 [3] = {
32 /* Used for MAX_OPP, if available */
33 .index = 3,
34 .frequency = CPUFREQ_TABLE_END,
35 },
36 [4] = {
37 .index = 4,
38 .frequency = CPUFREQ_TABLE_END,
39 },
40 };
41
42 static enum arm_opp idx2opp[] = {
43 ARM_EXTCLK,
44 ARM_50_OPP,
45 ARM_100_OPP,
46 ARM_MAX_OPP
47 };
48
49 static struct freq_attr *db8500_cpufreq_attr[] = {
50 &cpufreq_freq_attr_scaling_available_freqs,
51 NULL,
52 };
53
db8500_cpufreq_verify_speed(struct cpufreq_policy * policy)54 static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
55 {
56 return cpufreq_frequency_table_verify(policy, freq_table);
57 }
58
db8500_cpufreq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)59 static int db8500_cpufreq_target(struct cpufreq_policy *policy,
60 unsigned int target_freq,
61 unsigned int relation)
62 {
63 struct cpufreq_freqs freqs;
64 unsigned int idx;
65
66 /* scale the target frequency to one of the extremes supported */
67 if (target_freq < policy->cpuinfo.min_freq)
68 target_freq = policy->cpuinfo.min_freq;
69 if (target_freq > policy->cpuinfo.max_freq)
70 target_freq = policy->cpuinfo.max_freq;
71
72 /* Lookup the next frequency */
73 if (cpufreq_frequency_table_target
74 (policy, freq_table, target_freq, relation, &idx)) {
75 return -EINVAL;
76 }
77
78 freqs.old = policy->cur;
79 freqs.new = freq_table[idx].frequency;
80
81 if (freqs.old == freqs.new)
82 return 0;
83
84 /* pre-change notification */
85 for_each_cpu(freqs.cpu, policy->cpus)
86 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
87
88 /* request the PRCM unit for opp change */
89 if (prcmu_set_arm_opp(idx2opp[idx])) {
90 pr_err("db8500-cpufreq: Failed to set OPP level\n");
91 return -EINVAL;
92 }
93
94 /* post change notification */
95 for_each_cpu(freqs.cpu, policy->cpus)
96 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
97
98 return 0;
99 }
100
db8500_cpufreq_getspeed(unsigned int cpu)101 static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
102 {
103 int i;
104 /* request the prcm to get the current ARM opp */
105 for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++)
106 ;
107 return freq_table[i].frequency;
108 }
109
db8500_cpufreq_init(struct cpufreq_policy * policy)110 static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
111 {
112 int i, res;
113
114 BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table));
115
116 if (!prcmu_is_u8400()) {
117 freq_table[1].frequency = 400000;
118 freq_table[2].frequency = 800000;
119 if (prcmu_has_arm_maxopp())
120 freq_table[3].frequency = 1000000;
121 }
122 pr_info("db8500-cpufreq : Available frequencies:\n");
123 for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
124 pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
125
126 /* get policy fields based on the table */
127 res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
128 if (!res)
129 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
130 else {
131 pr_err("db8500-cpufreq : Failed to read policy table\n");
132 return res;
133 }
134
135 policy->min = policy->cpuinfo.min_freq;
136 policy->max = policy->cpuinfo.max_freq;
137 policy->cur = db8500_cpufreq_getspeed(policy->cpu);
138 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
139
140 /*
141 * FIXME : Need to take time measurement across the target()
142 * function with no/some/all drivers in the notification
143 * list.
144 */
145 policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
146
147 /* policy sharing between dual CPUs */
148 cpumask_copy(policy->cpus, &cpu_present_map);
149
150 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
151
152 return 0;
153 }
154
155 static struct cpufreq_driver db8500_cpufreq_driver = {
156 .flags = CPUFREQ_STICKY,
157 .verify = db8500_cpufreq_verify_speed,
158 .target = db8500_cpufreq_target,
159 .get = db8500_cpufreq_getspeed,
160 .init = db8500_cpufreq_init,
161 .name = "DB8500",
162 .attr = db8500_cpufreq_attr,
163 };
164
db8500_cpufreq_register(void)165 static int __init db8500_cpufreq_register(void)
166 {
167 if (!cpu_is_u8500v20_or_later())
168 return -ENODEV;
169
170 pr_info("cpufreq for DB8500 started\n");
171 return cpufreq_register_driver(&db8500_cpufreq_driver);
172 }
173 device_initcall(db8500_cpufreq_register);
174