[CPUFREQ] move policy's governor initialisation out of low-level drivers into cpufreq...
[linux-3.10.git] / arch / arm / plat-omap / cpu-omap.c
1 /*
2  *  linux/arch/arm/plat-omap/cpu-omap.c
3  *
4  *  CPU frequency scaling for OMAP
5  *
6  *  Copyright (C) 2005 Nokia Corporation
7  *  Written by Tony Lindgren <tony@atomide.com>
8  *
9  *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  */
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <linux/cpufreq.h>
19 #include <linux/delay.h>
20 #include <linux/init.h>
21 #include <linux/err.h>
22 #include <linux/clk.h>
23
24 #include <asm/hardware.h>
25 #include <asm/io.h>
26 #include <asm/system.h>
27
28 #define VERY_HI_RATE    900000000
29
30 #ifdef CONFIG_ARCH_OMAP1
31 #define MPU_CLK         "mpu"
32 #else
33 #define MPU_CLK         "virt_prcm_set"
34 #endif
35
36 /* TODO: Add support for SDRAM timing changes */
37
38 int omap_verify_speed(struct cpufreq_policy *policy)
39 {
40         struct clk * mpu_clk;
41
42         if (policy->cpu)
43                 return -EINVAL;
44
45         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
46                                      policy->cpuinfo.max_freq);
47         mpu_clk = clk_get(NULL, MPU_CLK);
48         if (IS_ERR(mpu_clk))
49                 return PTR_ERR(mpu_clk);
50         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
51         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
52         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
53                                      policy->cpuinfo.max_freq);
54         clk_put(mpu_clk);
55
56         return 0;
57 }
58
59 unsigned int omap_getspeed(unsigned int cpu)
60 {
61         struct clk * mpu_clk;
62         unsigned long rate;
63
64         if (cpu)
65                 return 0;
66
67         mpu_clk = clk_get(NULL, MPU_CLK);
68         if (IS_ERR(mpu_clk))
69                 return 0;
70         rate = clk_get_rate(mpu_clk) / 1000;
71         clk_put(mpu_clk);
72
73         return rate;
74 }
75
76 static int omap_target(struct cpufreq_policy *policy,
77                        unsigned int target_freq,
78                        unsigned int relation)
79 {
80         struct clk * mpu_clk;
81         struct cpufreq_freqs freqs;
82         int ret = 0;
83
84         mpu_clk = clk_get(NULL, MPU_CLK);
85         if (IS_ERR(mpu_clk))
86                 return PTR_ERR(mpu_clk);
87
88         freqs.old = omap_getspeed(0);
89         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
90         freqs.cpu = 0;
91
92         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
93         ret = clk_set_rate(mpu_clk, target_freq * 1000);
94         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
95         clk_put(mpu_clk);
96
97         return ret;
98 }
99
100 static int __init omap_cpu_init(struct cpufreq_policy *policy)
101 {
102         struct clk * mpu_clk;
103
104         mpu_clk = clk_get(NULL, MPU_CLK);
105         if (IS_ERR(mpu_clk))
106                 return PTR_ERR(mpu_clk);
107
108         if (policy->cpu != 0)
109                 return -EINVAL;
110         policy->cur = policy->min = policy->max = omap_getspeed(0);
111         policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
112         policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, VERY_HI_RATE) / 1000;
113         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
114         clk_put(mpu_clk);
115
116         return 0;
117 }
118
119 static struct cpufreq_driver omap_driver = {
120         .flags          = CPUFREQ_STICKY,
121         .verify         = omap_verify_speed,
122         .target         = omap_target,
123         .get            = omap_getspeed,
124         .init           = omap_cpu_init,
125         .name           = "omap",
126 };
127
128 static int __init omap_cpufreq_init(void)
129 {
130         return cpufreq_register_driver(&omap_driver);
131 }
132
133 arch_initcall(omap_cpufreq_init);