Linux 2.6.25-rc4
[linux-2.6/next.git] / arch / arm / plat-omap / cpu-omap.c
blobc0d63b0c61c9c5a54a11a298ea0f8d7334444e58
1 /*
2 * linux/arch/arm/plat-omap/cpu-omap.c
4 * CPU frequency scaling for OMAP
6 * Copyright (C) 2005 Nokia Corporation
7 * Written by Tony Lindgren <tony@atomide.com>
9 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
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.
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>
24 #include <asm/hardware.h>
25 #include <asm/io.h>
26 #include <asm/system.h>
28 #define VERY_HI_RATE 900000000
30 #ifdef CONFIG_ARCH_OMAP1
31 #define MPU_CLK "mpu"
32 #else
33 #define MPU_CLK "virt_prcm_set"
34 #endif
36 /* TODO: Add support for SDRAM timing changes */
38 int omap_verify_speed(struct cpufreq_policy *policy)
40 struct clk * mpu_clk;
42 if (policy->cpu)
43 return -EINVAL;
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);
56 return 0;
59 unsigned int omap_getspeed(unsigned int cpu)
61 struct clk * mpu_clk;
62 unsigned long rate;
64 if (cpu)
65 return 0;
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);
73 return rate;
76 static int omap_target(struct cpufreq_policy *policy,
77 unsigned int target_freq,
78 unsigned int relation)
80 struct clk * mpu_clk;
81 struct cpufreq_freqs freqs;
82 int ret = 0;
84 mpu_clk = clk_get(NULL, MPU_CLK);
85 if (IS_ERR(mpu_clk))
86 return PTR_ERR(mpu_clk);
88 freqs.old = omap_getspeed(0);
89 freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
90 freqs.cpu = 0;
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);
97 return ret;
100 static int __init omap_cpu_init(struct cpufreq_policy *policy)
102 struct clk * mpu_clk;
104 mpu_clk = clk_get(NULL, MPU_CLK);
105 if (IS_ERR(mpu_clk))
106 return PTR_ERR(mpu_clk);
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);
116 return 0;
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",
128 static int __init omap_cpufreq_init(void)
130 return cpufreq_register_driver(&omap_driver);
133 arch_initcall(omap_cpufreq_init);