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cbe_cpufreq_pmi.c

/*
 * pmi backend for the cbe_cpufreq driver
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
 *
 * Author: Christian Krafft <krafft@de.ibm.com>
 *
 * 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/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 <krafft@de.ibm.com>");

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