cb5ec75b8b
This gets the SH cpufreq working again. We follow the changes in the AVR32 implementation for wrapping in to the clock framework. CPUs that wish to use this are required to define rate rounding primitives in order to satisfy clk_round_rate(). This works well enough for the common case, though we should look at unifying this driver across all of the platforms that implement clock framework support in one capacity or another. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
166 lines
4.1 KiB
C
166 lines
4.1 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/io.h>
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#include <linux/clk.h>
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#include <asm/processor.h>
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#include <asm/watchdog.h>
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#include <asm/freq.h>
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#include <asm/clock.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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printk(KERN_INFO "cpufreq: SuperH CPU frequency driver.\n");
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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->governor = CPUFREQ_DEFAULT_GOVERNOR;
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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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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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