linux-imx

/*

 *  sc520_freq.c: cpufreq driver for the AMD Elan sc520

 *

 *  Copyright (C) 2005 Sean Young <sean@mess.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.

 *

 *  Based on elanfreq.c

 *

 *  2005-03-30: - initial revision

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

​

#include <linux/delay.h>

#include <linux/cpufreq.h>

#include <linux/timex.h>

#include <linux/io.h>

​

#include <asm/cpu_device_id.h>

#include <asm/msr.h>

​

#define MMCR_BASE   0xfffef000  /* The default base address */

#define OFFS_CPUCTL 0x2   /* CPU Control Register */

​

static __u8 __iomem *cpuctl;

​

static struct cpufreq_frequency_table sc520_freq_table[] = {

    {0, 0x01,   100000},

    {0, 0x02,   133000},

    {0, 0,  CPUFREQ_TABLE_END},

};

​

static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu)

{

    u8 clockspeed_reg = *cpuctl;

​

    switch (clockspeed_reg & 0x03) {

    default:

        pr_err("error: cpuctl register has unexpected value %02x\n",

               clockspeed_reg);

    case 0x01:

        return 100000;

    case 0x02:

        return 133000;

    }

}

​

static int sc520_freq_target(struct cpufreq_policy *policy, unsigned int state)

{

​

    u8 clockspeed_reg;

​

    local_irq_disable();

​

    clockspeed_reg = *cpuctl & ~0x03;