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ec6bced6 TL |
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 | ||
23 | #include <asm/hardware.h> | |
ec6bced6 TL |
24 | #include <asm/io.h> |
25 | #include <asm/system.h> | |
26 | ||
27 | #include <asm/hardware/clock.h> | |
28 | ||
29 | /* TODO: Add support for SDRAM timing changes */ | |
30 | ||
31 | int omap_verify_speed(struct cpufreq_policy *policy) | |
32 | { | |
33 | struct clk * mpu_clk; | |
34 | ||
35 | if (policy->cpu) | |
36 | return -EINVAL; | |
37 | ||
38 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
39 | policy->cpuinfo.max_freq); | |
40 | mpu_clk = clk_get(NULL, "mpu"); | |
41 | if (IS_ERR(mpu_clk)) | |
42 | return PTR_ERR(mpu_clk); | |
43 | policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000; | |
44 | policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000; | |
45 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
46 | policy->cpuinfo.max_freq); | |
47 | clk_put(mpu_clk); | |
48 | ||
49 | return 0; | |
50 | } | |
51 | ||
52 | unsigned int omap_getspeed(unsigned int cpu) | |
53 | { | |
54 | struct clk * mpu_clk; | |
55 | unsigned long rate; | |
56 | ||
57 | if (cpu) | |
58 | return 0; | |
59 | ||
60 | mpu_clk = clk_get(NULL, "mpu"); | |
61 | if (IS_ERR(mpu_clk)) | |
62 | return 0; | |
63 | rate = clk_get_rate(mpu_clk) / 1000; | |
64 | clk_put(mpu_clk); | |
65 | ||
66 | return rate; | |
67 | } | |
68 | ||
69 | static int omap_target(struct cpufreq_policy *policy, | |
70 | unsigned int target_freq, | |
71 | unsigned int relation) | |
72 | { | |
73 | struct clk * mpu_clk; | |
74 | struct cpufreq_freqs freqs; | |
75 | int ret = 0; | |
76 | ||
77 | mpu_clk = clk_get(NULL, "mpu"); | |
78 | if (IS_ERR(mpu_clk)) | |
79 | return PTR_ERR(mpu_clk); | |
80 | ||
81 | freqs.old = omap_getspeed(0); | |
82 | freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000; | |
83 | freqs.cpu = 0; | |
84 | ||
85 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
86 | ret = clk_set_rate(mpu_clk, target_freq * 1000); | |
87 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
88 | clk_put(mpu_clk); | |
89 | ||
90 | return ret; | |
91 | } | |
92 | ||
93 | static int __init omap_cpu_init(struct cpufreq_policy *policy) | |
94 | { | |
95 | struct clk * mpu_clk; | |
96 | ||
97 | mpu_clk = clk_get(NULL, "mpu"); | |
98 | if (IS_ERR(mpu_clk)) | |
99 | return PTR_ERR(mpu_clk); | |
100 | ||
101 | if (policy->cpu != 0) | |
102 | return -EINVAL; | |
103 | policy->cur = policy->min = policy->max = omap_getspeed(0); | |
104 | policy->governor = CPUFREQ_DEFAULT_GOVERNOR; | |
105 | policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000; | |
106 | policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, 216000000) / 1000; | |
107 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; | |
108 | clk_put(mpu_clk); | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
113 | static struct cpufreq_driver omap_driver = { | |
114 | .flags = CPUFREQ_STICKY, | |
115 | .verify = omap_verify_speed, | |
116 | .target = omap_target, | |
117 | .get = omap_getspeed, | |
118 | .init = omap_cpu_init, | |
119 | .name = "omap", | |
120 | }; | |
121 | ||
122 | static int __init omap_cpufreq_init(void) | |
123 | { | |
124 | return cpufreq_register_driver(&omap_driver); | |
125 | } | |
126 | ||
127 | arch_initcall(omap_cpufreq_init); |