cpufreq: OMAP: notify even with bad boot frequency
[linux-2.6.git] / drivers / cpufreq / db8500-cpufreq.c
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
54 static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
55 {
56         return cpufreq_frequency_table_verify(policy, freq_table);
57 }
58
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
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
110 static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
111 {
112         int 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         while (freq_table[i].frequency != CPUFREQ_TABLE_END)
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
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);