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Tony Lindgrenec6bced2005-07-10 19:58:20 +01001/*
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>
Russell Kingf8ce2542006-01-07 16:15:52 +000022#include <linux/clk.h>
Russell Kingfced80c2008-09-06 12:10:45 +010023#include <linux/io.h>
Tony Lindgrenec6bced2005-07-10 19:58:20 +010024
Russell Kinga09e64f2008-08-05 16:14:15 +010025#include <mach/hardware.h>
Tony Lindgrenec6bced2005-07-10 19:58:20 +010026#include <asm/system.h>
27
Tony Lindgrena7ca9d22006-06-26 16:16:17 -070028#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
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +030036static struct clk *mpu_clk;
37
Tony Lindgrenec6bced2005-07-10 19:58:20 +010038/* TODO: Add support for SDRAM timing changes */
39
40int omap_verify_speed(struct cpufreq_policy *policy)
41{
Tony Lindgrenec6bced2005-07-10 19:58:20 +010042 if (policy->cpu)
43 return -EINVAL;
44
45 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
46 policy->cpuinfo.max_freq);
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +030047
Tony Lindgrenec6bced2005-07-10 19:58:20 +010048 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);
Tony Lindgrenec6bced2005-07-10 19:58:20 +010052 return 0;
53}
54
55unsigned int omap_getspeed(unsigned int cpu)
56{
Tony Lindgrenec6bced2005-07-10 19:58:20 +010057 unsigned long rate;
58
59 if (cpu)
60 return 0;
61
Tony Lindgrenec6bced2005-07-10 19:58:20 +010062 rate = clk_get_rate(mpu_clk) / 1000;
Tony Lindgrenec6bced2005-07-10 19:58:20 +010063 return rate;
64}
65
66static int omap_target(struct cpufreq_policy *policy,
67 unsigned int target_freq,
68 unsigned int relation)
69{
Tony Lindgrenec6bced2005-07-10 19:58:20 +010070 struct cpufreq_freqs freqs;
71 int ret = 0;
72
Tony Lindgrenec6bced2005-07-10 19:58:20 +010073 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);
Tony Lindgrenec6bced2005-07-10 19:58:20 +010080
81 return ret;
82}
83
84static int __init omap_cpu_init(struct cpufreq_policy *policy)
85{
Tony Lindgrena7ca9d22006-06-26 16:16:17 -070086 mpu_clk = clk_get(NULL, MPU_CLK);
Tony Lindgrenec6bced2005-07-10 19:58:20 +010087 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);
Tony Lindgrenec6bced2005-07-10 19:58:20 +010093 policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
Tony Lindgrena7ca9d22006-06-26 16:16:17 -070094 policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, VERY_HI_RATE) / 1000;
Tony Lindgrenec6bced2005-07-10 19:58:20 +010095 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
Tony Lindgrenec6bced2005-07-10 19:58:20 +010096
97 return 0;
98}
99
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +0300100static int omap_cpu_exit(struct cpufreq_policy *policy)
101{
102 clk_put(mpu_clk);
103 return 0;
104}
105
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100106static 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,
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +0300112 .exit = omap_cpu_exit,
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100113 .name = "omap",
114};
115
116static int __init omap_cpufreq_init(void)
117{
118 return cpufreq_register_driver(&omap_driver);
119}
120
121arch_initcall(omap_cpufreq_init);