Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 | /*
* arch/sh/kernel/cpufreq.c
*
* cpufreq driver for the SuperH processors.
*
* Copyright (C) 2002 - 2007 Paul Mundt
* Copyright (C) 2002 M. R. Brown
*
* Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
*
* Copyright (C) 2004-2007 Atmel Corporation
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/types.h>
#include <linux/cpufreq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/cpumask.h>
#include <linux/smp.h>
#include <linux/sched.h> /* set_cpus_allowed() */
#include <linux/clk.h>
static struct clk *cpuclk;
static unsigned int sh_cpufreq_get(unsigned int cpu)
{
return (clk_get_rate(cpuclk) + 500) / 1000;
}
/*
* Here we notify other drivers of the proposed change and the final change.
*/
static int sh_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int cpu = policy->cpu;
cpumask_t cpus_allowed;
struct cpufreq_freqs freqs;
long freq;
if (!cpu_online(cpu))
return -ENODEV;
cpus_allowed = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(cpu));
BUG_ON(smp_processor_id() != cpu);
/* Convert target_freq from kHz to Hz */
freq = clk_round_rate(cpuclk, target_freq * 1000);
if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
return -EINVAL;
pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
freqs.cpu = cpu;
freqs.old = sh_cpufreq_get(cpu);
freqs.new = (freq + 500) / 1000;
freqs.flags = 0;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
set_cpus_allowed(current, cpus_allowed);
clk_set_rate(cpuclk, freq);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
pr_debug("cpufreq: set frequency %lu Hz\n", freq);
return 0;
}
static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
if (!cpu_online(policy->cpu))
return -ENODEV;
cpuclk = clk_get(NULL, "cpu_clk");
if (IS_ERR(cpuclk)) {
printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
return PTR_ERR(cpuclk);
}
/* cpuinfo and default policy values */
policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
policy->cur = sh_cpufreq_get(policy->cpu);
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
/*
* Catch the cases where the clock framework hasn't been wired up
* properly to support scaling.
*/
if (unlikely(policy->min == policy->max)) {
printk(KERN_ERR "cpufreq: clock framework rate rounding "
"not supported on this CPU.\n");
clk_put(cpuclk);
return -EINVAL;
}
printk(KERN_INFO "cpufreq: Frequencies - Minimum %u.%03u MHz, "
"Maximum %u.%03u MHz.\n",
policy->min / 1000, policy->min % 1000,
policy->max / 1000, policy->max % 1000);
return 0;
}
static int sh_cpufreq_verify(struct cpufreq_policy *policy)
{
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
return 0;
}
static int sh_cpufreq_exit(struct cpufreq_policy *policy)
{
clk_put(cpuclk);
return 0;
}
static struct cpufreq_driver sh_cpufreq_driver = {
.owner = THIS_MODULE,
.name = "sh",
.init = sh_cpufreq_cpu_init,
.verify = sh_cpufreq_verify,
.target = sh_cpufreq_target,
.get = sh_cpufreq_get,
.exit = sh_cpufreq_exit,
};
static int __init sh_cpufreq_module_init(void)
{
printk(KERN_INFO "cpufreq: SuperH CPU frequency driver.\n");
return cpufreq_register_driver(&sh_cpufreq_driver);
}
static void __exit sh_cpufreq_module_exit(void)
{
cpufreq_unregister_driver(&sh_cpufreq_driver);
}
module_init(sh_cpufreq_module_init);
module_exit(sh_cpufreq_module_exit);
MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
MODULE_DESCRIPTION("cpufreq driver for SuperH");
MODULE_LICENSE("GPL");
|