cpu-freq.c

Go to the documentation of this file.

/* linux/arch/arm/mach-s3c2410/cpu-freq.c
 *
 * Copyright (c) 2006-2008 Simtec Electronics
 *  http://armlinux.simtec.co.uk/
 *  Ben Dooks <[email protected]>
 *
 * S3C2410 CPU Frequency scaling
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>

#include <asm/mach/arch.h>
#include <asm/mach/map.h>

#include <mach/regs-clock.h>

#include <plat/cpu.h>
#include <plat/clock.h>
#include <plat/cpu-freq-core.h>

/* Note, 2410A has an extra mode for 1:4:4 ratio, bit 2 of CLKDIV */

static void s3c2410_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
{
    u32 clkdiv = 0;

    if (cfg->divs.h_divisor == 2)
        clkdiv |= S3C2410_CLKDIVN_HDIVN;

    if (cfg->divs.p_divisor != cfg->divs.h_divisor)
        clkdiv |= S3C2410_CLKDIVN_PDIVN;

    __raw_writel(clkdiv, S3C2410_CLKDIVN);
}

static int s3c2410_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
{
    unsigned long hclk, fclk, pclk;
    unsigned int hdiv, pdiv;
    unsigned long hclk_max;

    fclk = cfg->freq.fclk;
    hclk_max = cfg->max.hclk;

    cfg->freq.armclk = fclk;

    s3c_freq_dbg("%s: fclk is %lu, max hclk %lu\n",
              __func__, fclk, hclk_max);

    hdiv = (fclk > cfg->max.hclk) ? 2 : 1;
    hclk = fclk / hdiv;

    if (hclk > cfg->max.hclk) {
        s3c_freq_dbg("%s: hclk too big\n", __func__);
        return -EINVAL;
    }

    pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
    pclk = hclk / pdiv;

    if (pclk > cfg->max.pclk) {
        s3c_freq_dbg("%s: pclk too big\n", __func__);
        return -EINVAL;
    }

    pdiv *= hdiv;

    /* record the result */
    cfg->divs.p_divisor = pdiv;
    cfg->divs.h_divisor = hdiv;

    return 0      ;
}

static struct s3c_cpufreq_info s3c2410_cpufreq_info = {
    .max        = {
        .fclk   = 200000000,
        .hclk   = 100000000,
        .pclk   =  50000000,
    },

    /* transition latency is about 5ms worst-case, so
     * set 10ms to be sure */
    .latency    = 10000000,

    .locktime_m = 150,
    .locktime_u = 150,
    .locktime_bits  = 12,

    .need_pll   = 1,

    .name       = "s3c2410",
    .calc_iotiming  = s3c2410_iotiming_calc,
    .set_iotiming   = s3c2410_iotiming_set,
    .get_iotiming   = s3c2410_iotiming_get,
    .resume_clocks  = s3c2410_setup_clocks,

    .set_fvco   = s3c2410_set_fvco,
    .set_refresh    = s3c2410_cpufreq_setrefresh,
    .set_divs   = s3c2410_cpufreq_setdivs,
    .calc_divs  = s3c2410_cpufreq_calcdivs,

    .debug_io_show  = s3c_cpufreq_debugfs_call(s3c2410_iotiming_debugfs),
};

static int s3c2410_cpufreq_add(struct device *dev,
                   struct subsys_interface *sif)
{
    return s3c_cpufreq_register(&s3c2410_cpufreq_info);
}

static struct subsys_interface s3c2410_cpufreq_interface = {
    .name       = "s3c2410_cpufreq",
    .subsys     = &s3c2410_subsys,
    .add_dev    = s3c2410_cpufreq_add,
};

static int __init s3c2410_cpufreq_init(void)
{
    return subsys_interface_register(&s3c2410_cpufreq_interface);
}

arch_initcall(s3c2410_cpufreq_init);

static int s3c2410a_cpufreq_add(struct device *dev,
                struct subsys_interface *sif)
{
    /* alter the maximum freq settings for S3C2410A. If a board knows
     * it only has a maximum of 200, then it should register its own
     * limits. */

    s3c2410_cpufreq_info.max.fclk = 266000000;
    s3c2410_cpufreq_info.max.hclk = 133000000;
    s3c2410_cpufreq_info.max.pclk =  66500000;
    s3c2410_cpufreq_info.name = "s3c2410a";

    return s3c2410_cpufreq_add(dev, sif);
}

static struct subsys_interface s3c2410a_cpufreq_interface = {
    .name       = "s3c2410a_cpufreq",
    .subsys     = &s3c2410a_subsys,
    .add_dev    = s3c2410a_cpufreq_add,
};

static int __init s3c2410a_cpufreq_init(void)
{
    return subsys_interface_register(&s3c2410a_cpufreq_interface);
}

arch_initcall(s3c2410a_cpufreq_init);