159 lines
4.0 KiB
C
159 lines
4.0 KiB
C
/*
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* arch/sh/kernel/cpufreq.c
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*
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* cpufreq driver for the SuperH processors.
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*
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* Copyright (C) 2002 - 2007 Paul Mundt
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* Copyright (C) 2002 M. R. Brown
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*
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* Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
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*
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* Copyright (C) 2004-2007 Atmel Corporation
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/types.h>
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#include <linux/cpufreq.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/cpumask.h>
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#include <linux/smp.h>
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#include <linux/sched.h> /* set_cpus_allowed() */
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#include <linux/clk.h>
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static struct clk *cpuclk;
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static unsigned int sh_cpufreq_get(unsigned int cpu)
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{
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return (clk_get_rate(cpuclk) + 500) / 1000;
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}
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/*
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* Here we notify other drivers of the proposed change and the final change.
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*/
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static int sh_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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unsigned int cpu = policy->cpu;
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cpumask_t cpus_allowed;
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struct cpufreq_freqs freqs;
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long freq;
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if (!cpu_online(cpu))
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return -ENODEV;
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cpus_allowed = current->cpus_allowed;
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set_cpus_allowed(current, cpumask_of_cpu(cpu));
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BUG_ON(smp_processor_id() != cpu);
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/* Convert target_freq from kHz to Hz */
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freq = clk_round_rate(cpuclk, target_freq * 1000);
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if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
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return -EINVAL;
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pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
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freqs.cpu = cpu;
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freqs.old = sh_cpufreq_get(cpu);
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freqs.new = (freq + 500) / 1000;
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freqs.flags = 0;
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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set_cpus_allowed(current, cpus_allowed);
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clk_set_rate(cpuclk, freq);
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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pr_debug("cpufreq: set frequency %lu Hz\n", freq);
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return 0;
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}
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static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
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{
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if (!cpu_online(policy->cpu))
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return -ENODEV;
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cpuclk = clk_get(NULL, "cpu_clk");
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if (IS_ERR(cpuclk)) {
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printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
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return PTR_ERR(cpuclk);
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}
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/* cpuinfo and default policy values */
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policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
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policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
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policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
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policy->cur = sh_cpufreq_get(policy->cpu);
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policy->min = policy->cpuinfo.min_freq;
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policy->max = policy->cpuinfo.max_freq;
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/*
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* Catch the cases where the clock framework hasn't been wired up
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* properly to support scaling.
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*/
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if (unlikely(policy->min == policy->max)) {
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printk(KERN_ERR "cpufreq: clock framework rate rounding "
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"not supported on this CPU.\n");
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clk_put(cpuclk);
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return -EINVAL;
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}
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printk(KERN_INFO "cpufreq: Frequencies - Minimum %u.%03u MHz, "
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"Maximum %u.%03u MHz.\n",
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policy->min / 1000, policy->min % 1000,
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policy->max / 1000, policy->max % 1000);
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return 0;
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}
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static int sh_cpufreq_verify(struct cpufreq_policy *policy)
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{
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cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
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policy->cpuinfo.max_freq);
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return 0;
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}
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static int sh_cpufreq_exit(struct cpufreq_policy *policy)
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{
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clk_put(cpuclk);
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return 0;
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}
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static struct cpufreq_driver sh_cpufreq_driver = {
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.owner = THIS_MODULE,
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.name = "sh",
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.init = sh_cpufreq_cpu_init,
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.verify = sh_cpufreq_verify,
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.target = sh_cpufreq_target,
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.get = sh_cpufreq_get,
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.exit = sh_cpufreq_exit,
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};
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static int __init sh_cpufreq_module_init(void)
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{
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printk(KERN_INFO "cpufreq: SuperH CPU frequency driver.\n");
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return cpufreq_register_driver(&sh_cpufreq_driver);
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}
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static void __exit sh_cpufreq_module_exit(void)
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{
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cpufreq_unregister_driver(&sh_cpufreq_driver);
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}
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module_init(sh_cpufreq_module_init);
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module_exit(sh_cpufreq_module_exit);
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MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
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MODULE_DESCRIPTION("cpufreq driver for SuperH");
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MODULE_LICENSE("GPL");
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