Logo Search packages:      
Sourcecode: linux version File versions  Download package

cpu.c

/*
 * File:         arch/blackfin/mach-bf533/cpu.c
 * Based on:
 * Author:       michael.kang@analog.com
 *
 * Created:
 * Description:  clock scaling for the bf533
 *
 * Modified:
 *               Copyright 2004-2006 Analog Devices Inc.
 *
 * Bugs:         Enter bugs at http://blackfin.uclinux.org/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <asm/dpmc.h>
#include <linux/fs.h>
#include <asm/bfin-global.h>

/* CONFIG_CLKIN_HZ=11059200 */
#define VCO5 (CONFIG_CLKIN_HZ*45)   /*497664000 */
#define VCO4 (CONFIG_CLKIN_HZ*36)   /*398131200 */
#define VCO3 (CONFIG_CLKIN_HZ*27)   /*298598400 */
#define VCO2 (CONFIG_CLKIN_HZ*18)   /*199065600 */
#define VCO1 (CONFIG_CLKIN_HZ*9)    /*99532800 */
#define VCO(x) VCO##x

#define FREQ(x) {VCO(x),VCO(x)/4},{VCO(x),VCO(x)/2},{VCO(x),VCO(x)}
/* frequency */
static struct cpufreq_frequency_table bf533_freq_table[] = {
      FREQ(1),
      FREQ(3),
      {VCO4, VCO4 / 2}, {VCO4, VCO4},
      FREQ(5),
      {0, CPUFREQ_TABLE_END},
};

/*
 * dpmc_fops->ioctl()
 * static int dpmc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 */
static int bf533_getfreq(unsigned int cpu)
{
      unsigned long cclk_mhz, vco_mhz;

      /* The driver only support single cpu */
      if (cpu == 0)
            dpmc_fops.ioctl(NULL, NULL, IOCTL_GET_CORECLOCK, &cclk_mhz);
      else
            cclk_mhz = -1;
      return cclk_mhz;
}

static int bf533_target(struct cpufreq_policy *policy,
                      unsigned int target_freq, unsigned int relation)
{
      unsigned long cclk_mhz;
      unsigned long vco_mhz;
      unsigned long flags;
      unsigned int index, vco_index;
      int i;

      struct cpufreq_freqs freqs;
      if (cpufreq_frequency_table_target(policy, bf533_freq_table, target_freq, relation, &index))
            return -EINVAL;
      cclk_mhz = bf533_freq_table[index].frequency;
      vco_mhz = bf533_freq_table[index].index;

      dpmc_fops.ioctl(NULL, NULL, IOCTL_CHANGE_FREQUENCY, &vco_mhz);
      freqs.old = bf533_getfreq(0);
      freqs.new = cclk_mhz;
      freqs.cpu = 0;

      pr_debug("cclk begin change to cclk %d,vco=%d,index=%d,target=%d,oldfreq=%d\n",
               cclk_mhz, vco_mhz, index, target_freq, freqs.old);

      cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
      local_irq_save(flags);
      dpmc_fops.ioctl(NULL, NULL, IOCTL_SET_CCLK, &cclk_mhz);
      local_irq_restore(flags);
      cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

      vco_mhz = get_vco();
      cclk_mhz = get_cclk();
      return 0;
}

/* make sure that only the "userspace" governor is run -- anything else wouldn't make sense on
 * this platform, anyway.
 */
static int bf533_verify_speed(struct cpufreq_policy *policy)
{
      return cpufreq_frequency_table_verify(policy, &bf533_freq_table);
}

static int __init __bf533_cpu_init(struct cpufreq_policy *policy)
{
      int result;

      if (policy->cpu != 0)
            return -EINVAL;

      policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
      /*Now ,only support one cpu */
      policy->cur = bf533_getfreq(0);
      cpufreq_frequency_table_get_attr(bf533_freq_table, policy->cpu);
      return cpufreq_frequency_table_cpuinfo(policy, bf533_freq_table);
}

static struct freq_attr *bf533_freq_attr[] = {
      &cpufreq_freq_attr_scaling_available_freqs,
      NULL,
};

static struct cpufreq_driver bf533_driver = {
      .verify = bf533_verify_speed,
      .target = bf533_target,
      .get = bf533_getfreq,
      .init = __bf533_cpu_init,
      .name = "bf533",
      .owner = THIS_MODULE,
      .attr = bf533_freq_attr,
};

static int __init bf533_cpu_init(void)
{
      return cpufreq_register_driver(&bf533_driver);
}

static void __exit bf533_cpu_exit(void)
{
      cpufreq_unregister_driver(&bf533_driver);
}

MODULE_AUTHOR("Mickael Kang");
MODULE_DESCRIPTION("cpufreq driver for BF533 CPU");
MODULE_LICENSE("GPL");

module_init(bf533_cpu_init);
module_exit(bf533_cpu_exit);

Generated by  Doxygen 1.6.0   Back to index