Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * 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");