cbe_cpufreq_pmi.c

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/*
 * pmi backend for the cbe_cpufreq driver
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
 *
 * Author: Christian Krafft <[email protected]>
 *
 * 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, 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/of_platform.h>

#include <asm/processor.h>
#include <asm/prom.h>
#include <asm/pmi.h>
#include <asm/cell-regs.h>

#ifdef DEBUG
#include <asm/time.h>
#endif

#include "cbe_cpufreq.h"

static u8 pmi_slow_mode_limit[MAX_CBE];

bool cbe_cpufreq_has_pmi = false;
EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);

/*
 * hardware specific functions
 */

int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode)
{
    int ret;
    pmi_message_t pmi_msg;
#ifdef DEBUG
    long time;
#endif
    pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
    pmi_msg.data1 = cbe_cpu_to_node(cpu);
    pmi_msg.data2 = pmode;

#ifdef DEBUG
    time = jiffies;
#endif
    pmi_send_message(pmi_msg);

#ifdef DEBUG
    time = jiffies  - time;
    time = jiffies_to_msecs(time);
    pr_debug("had to wait %lu ms for a transition using " \
         "PMI\n", time);
#endif
    ret = pmi_msg.data2;
    pr_debug("PMI returned slow mode %d\n", ret);

    return ret;
}
EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);


static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
{
    u8 node, slow_mode;

    BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);

    node = pmi_msg.data1;
    slow_mode = pmi_msg.data2;

    pmi_slow_mode_limit[node] = slow_mode;

    pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode);
}

static int pmi_notifier(struct notifier_block *nb,
                       unsigned long event, void *data)
{
    struct cpufreq_policy *policy = data;
    struct cpufreq_frequency_table *cbe_freqs;
    u8 node;

    /* Should this really be called for CPUFREQ_ADJUST, CPUFREQ_INCOMPATIBLE
     * and CPUFREQ_NOTIFY policy events?)
     */
    if (event == CPUFREQ_START)
        return 0;

    cbe_freqs = cpufreq_frequency_get_table(policy->cpu);
    node = cbe_cpu_to_node(policy->cpu);

    pr_debug("got notified, event=%lu, node=%u\n", event, node);

    if (pmi_slow_mode_limit[node] != 0) {
        pr_debug("limiting node %d to slow mode %d\n",
             node, pmi_slow_mode_limit[node]);

        cpufreq_verify_within_limits(policy, 0,

            cbe_freqs[pmi_slow_mode_limit[node]].frequency);
    }

    return 0;
}

static struct notifier_block pmi_notifier_block = {
    .notifier_call = pmi_notifier,
};

static struct pmi_handler cbe_pmi_handler = {
    .type           = PMI_TYPE_FREQ_CHANGE,
    .handle_pmi_message = cbe_cpufreq_handle_pmi,
};



static int __init cbe_cpufreq_pmi_init(void)
{
    cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0;

    if (!cbe_cpufreq_has_pmi)
        return -ENODEV;

    cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);

    return 0;
}

static void __exit cbe_cpufreq_pmi_exit(void)
{
    cpufreq_unregister_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
    pmi_unregister_handler(&cbe_pmi_handler);
}

module_init(cbe_cpufreq_pmi_init);
module_exit(cbe_cpufreq_pmi_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Krafft <[email protected]>");