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- /*
- * 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_ptr(current, cpumask_of(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_ptr(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#%d clk\n",
- policy->cpu);
- 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 CPU#%d.\n", policy->cpu);
- clk_put(cpuclk);
- return -EINVAL;
- }
- printk(KERN_INFO "cpufreq: CPU#%d Frequencies - Minimum %u.%03u MHz, "
- "Maximum %u.%03u MHz.\n",
- policy->cpu, 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");
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