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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> | |
f8ce2547 | 22 | #include <linux/clk.h> |
fced80c7 | 23 | #include <linux/io.h> |
ec6bced6 | 24 | |
a09e64fb | 25 | #include <mach/hardware.h> |
ec6bced6 TL |
26 | #include <asm/system.h> |
27 | ||
a7ca9d2b TL |
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 | ||
b8488fbe HD |
36 | static struct clk *mpu_clk; |
37 | ||
ec6bced6 TL |
38 | /* TODO: Add support for SDRAM timing changes */ |
39 | ||
40 | int omap_verify_speed(struct cpufreq_policy *policy) | |
41 | { | |
ec6bced6 TL |
42 | if (policy->cpu) |
43 | return -EINVAL; | |
44 | ||
45 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
46 | policy->cpuinfo.max_freq); | |
b8488fbe | 47 | |
ec6bced6 TL |
48 | policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000; |
49 | policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000; | |
50 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
51 | policy->cpuinfo.max_freq); | |
ec6bced6 TL |
52 | return 0; |
53 | } | |
54 | ||
55 | unsigned int omap_getspeed(unsigned int cpu) | |
56 | { | |
ec6bced6 TL |
57 | unsigned long rate; |
58 | ||
59 | if (cpu) | |
60 | return 0; | |
61 | ||
ec6bced6 | 62 | rate = clk_get_rate(mpu_clk) / 1000; |
ec6bced6 TL |
63 | return rate; |
64 | } | |
65 | ||
66 | static int omap_target(struct cpufreq_policy *policy, | |
67 | unsigned int target_freq, | |
68 | unsigned int relation) | |
69 | { | |
ec6bced6 TL |
70 | struct cpufreq_freqs freqs; |
71 | int ret = 0; | |
72 | ||
ec6bced6 TL |
73 | freqs.old = omap_getspeed(0); |
74 | freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000; | |
75 | freqs.cpu = 0; | |
76 | ||
77 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
78 | ret = clk_set_rate(mpu_clk, target_freq * 1000); | |
79 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
ec6bced6 TL |
80 | |
81 | return ret; | |
82 | } | |
83 | ||
84 | static int __init omap_cpu_init(struct cpufreq_policy *policy) | |
85 | { | |
a7ca9d2b | 86 | mpu_clk = clk_get(NULL, MPU_CLK); |
ec6bced6 TL |
87 | if (IS_ERR(mpu_clk)) |
88 | return PTR_ERR(mpu_clk); | |
89 | ||
90 | if (policy->cpu != 0) | |
91 | return -EINVAL; | |
92 | policy->cur = policy->min = policy->max = omap_getspeed(0); | |
ec6bced6 | 93 | policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000; |
a7ca9d2b | 94 | policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, VERY_HI_RATE) / 1000; |
ec6bced6 | 95 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
ec6bced6 TL |
96 | |
97 | return 0; | |
98 | } | |
99 | ||
b8488fbe HD |
100 | static int omap_cpu_exit(struct cpufreq_policy *policy) |
101 | { | |
102 | clk_put(mpu_clk); | |
103 | return 0; | |
104 | } | |
105 | ||
ec6bced6 TL |
106 | static struct cpufreq_driver omap_driver = { |
107 | .flags = CPUFREQ_STICKY, | |
108 | .verify = omap_verify_speed, | |
109 | .target = omap_target, | |
110 | .get = omap_getspeed, | |
111 | .init = omap_cpu_init, | |
b8488fbe | 112 | .exit = omap_cpu_exit, |
ec6bced6 TL |
113 | .name = "omap", |
114 | }; | |
115 | ||
116 | static int __init omap_cpufreq_init(void) | |
117 | { | |
118 | return cpufreq_register_driver(&omap_driver); | |
119 | } | |
120 | ||
121 | arch_initcall(omap_cpufreq_init); |