oom: fix integer overflow of points in oom_badness
[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/db8500-prcmu.h>
16 #include <mach/id.h>
17
18 static 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
38 static enum arm_opp idx2opp[] = {
39         ARM_50_OPP,
40         ARM_100_OPP,
41         ARM_MAX_OPP
42 };
43
44 static struct freq_attr *db8500_cpufreq_attr[] = {
45         &cpufreq_freq_attr_scaling_available_freqs,
46         NULL,
47 };
48
49 static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
50 {
51         return cpufreq_frequency_table_verify(policy, freq_table);
52 }
53
54 static 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
95 static 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
104 static 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
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,
157         .name   = "DB8500",
158         .attr   = db8500_cpufreq_attr,
159 };
160
161 static 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 }
169 device_initcall(db8500_cpufreq_register);