cpu.c

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/*
 *  linux/arch/arm/mach-integrator/cpu.c
 *
 *  Copyright (C) 2001-2002 Deep Blue Solutions Ltd.
 *
 * 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.
 *
 * CPU support functions
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <mach/platform.h>
#include <asm/mach-types.h>
#include <asm/hardware/icst.h>

static struct cpufreq_driver integrator_driver;

#define CM_ID   __io_address(INTEGRATOR_HDR_ID)
#define CM_OSC  __io_address(INTEGRATOR_HDR_OSC)
#define CM_STAT __io_address(INTEGRATOR_HDR_STAT)
#define CM_LOCK __io_address(INTEGRATOR_HDR_LOCK)

static const struct icst_params lclk_params = {
    .ref        = 24000000,
    .vco_max    = ICST525_VCO_MAX_5V,
    .vco_min    = ICST525_VCO_MIN,
    .vd_min     = 8,
    .vd_max     = 132,
    .rd_min     = 24,
    .rd_max     = 24,
    .s2div      = icst525_s2div,
    .idx2s      = icst525_idx2s,
};

static const struct icst_params cclk_params = {
    .ref        = 24000000,
    .vco_max    = ICST525_VCO_MAX_5V,
    .vco_min    = ICST525_VCO_MIN,
    .vd_min     = 12,
    .vd_max     = 160,
    .rd_min     = 24,
    .rd_max     = 24,
    .s2div      = icst525_s2div,
    .idx2s      = icst525_idx2s,
};

/*
 * Validate the speed policy.
 */
static int integrator_verify_policy(struct cpufreq_policy *policy)
{
    struct icst_vco vco;

    cpufreq_verify_within_limits(policy, 
                     policy->cpuinfo.min_freq, 
                     policy->cpuinfo.max_freq);

    vco = icst_hz_to_vco(&cclk_params, policy->max * 1000);
    policy->max = icst_hz(&cclk_params, vco) / 1000;

    vco = icst_hz_to_vco(&cclk_params, policy->min * 1000);
    policy->min = icst_hz(&cclk_params, vco) / 1000;

    cpufreq_verify_within_limits(policy, 
                     policy->cpuinfo.min_freq, 
                     policy->cpuinfo.max_freq);

    return 0;
}


static int integrator_set_target(struct cpufreq_policy *policy,
                 unsigned int target_freq,
                 unsigned int relation)
{
    cpumask_t cpus_allowed;
    int cpu = policy->cpu;
    struct icst_vco vco;
    struct cpufreq_freqs freqs;
    u_int cm_osc;

    /*
     * Save this threads cpus_allowed mask.
     */
    cpus_allowed = current->cpus_allowed;

    /*
     * Bind to the specified CPU.  When this call returns,
     * we should be running on the right CPU.
     */
    set_cpus_allowed(current, cpumask_of_cpu(cpu));
    BUG_ON(cpu != smp_processor_id());

    /* get current setting */
    cm_osc = __raw_readl(CM_OSC);

    if (machine_is_integrator()) {
        vco.s = (cm_osc >> 8) & 7;
    } else if (machine_is_cintegrator()) {
        vco.s = 1;
    }
    vco.v = cm_osc & 255;
    vco.r = 22;
    freqs.old = icst_hz(&cclk_params, vco) / 1000;

    /* icst_hz_to_vco rounds down -- so we need the next
     * larger freq in case of CPUFREQ_RELATION_L.
     */
    if (relation == CPUFREQ_RELATION_L)
        target_freq += 999;
    if (target_freq > policy->max)
        target_freq = policy->max;
    vco = icst_hz_to_vco(&cclk_params, target_freq * 1000);
    freqs.new = icst_hz(&cclk_params, vco) / 1000;

    freqs.cpu = policy->cpu;

    if (freqs.old == freqs.new) {
        set_cpus_allowed(current, cpus_allowed);
        return 0;
    }

    cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

    cm_osc = __raw_readl(CM_OSC);

    if (machine_is_integrator()) {
        cm_osc &= 0xfffff800;
        cm_osc |= vco.s << 8;
    } else if (machine_is_cintegrator()) {
        cm_osc &= 0xffffff00;
    }
    cm_osc |= vco.v;

    __raw_writel(0xa05f, CM_LOCK);
    __raw_writel(cm_osc, CM_OSC);
    __raw_writel(0, CM_LOCK);

    /*
     * Restore the CPUs allowed mask.
     */
    set_cpus_allowed(current, cpus_allowed);

    cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

    return 0;
}

static unsigned int integrator_get(unsigned int cpu)
{
    cpumask_t cpus_allowed;
    unsigned int current_freq;
    u_int cm_osc;
    struct icst_vco vco;

    cpus_allowed = current->cpus_allowed;

    set_cpus_allowed(current, cpumask_of_cpu(cpu));
    BUG_ON(cpu != smp_processor_id());

    /* detect memory etc. */
    cm_osc = __raw_readl(CM_OSC);

    if (machine_is_integrator()) {
        vco.s = (cm_osc >> 8) & 7;
    } else {
        vco.s = 1;
    }
    vco.v = cm_osc & 255;
    vco.r = 22;

    current_freq = icst_hz(&cclk_params, vco) / 1000; /* current freq */

    set_cpus_allowed(current, cpus_allowed);

    return current_freq;
}

static int integrator_cpufreq_init(struct cpufreq_policy *policy)
{

    /* set default policy and cpuinfo */
    policy->cpuinfo.max_freq = 160000;
    policy->cpuinfo.min_freq = 12000;
    policy->cpuinfo.transition_latency = 1000000; /* 1 ms, assumed */
    policy->cur = policy->min = policy->max = integrator_get(policy->cpu);

    return 0;
}

static struct cpufreq_driver integrator_driver = {
    .verify     = integrator_verify_policy,
    .target     = integrator_set_target,
    .get        = integrator_get,
    .init       = integrator_cpufreq_init,
    .name       = "integrator",
};

static int __init integrator_cpu_init(void)
{
    return cpufreq_register_driver(&integrator_driver);
}

static void __exit integrator_cpu_exit(void)
{
    cpufreq_unregister_driver(&integrator_driver);
}

MODULE_AUTHOR ("Russell M. King");
MODULE_DESCRIPTION ("cpufreq driver for ARM Integrator CPUs");
MODULE_LICENSE ("GPL");

module_init(integrator_cpu_init);
module_exit(integrator_cpu_exit);