linux/drivers/cpufreq/ppc_cbe_cpufreq_pmi.c
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   1/*
   2 * pmi backend for the cbe_cpufreq driver
   3 *
   4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
   5 *
   6 * Author: Christian Krafft <krafft@de.ibm.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2, or (at your option)
  11 * any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23#include <linux/kernel.h>
  24#include <linux/types.h>
  25#include <linux/timer.h>
  26#include <linux/module.h>
  27#include <linux/of_platform.h>
  28
  29#include <asm/processor.h>
  30#include <asm/prom.h>
  31#include <asm/pmi.h>
  32#include <asm/cell-regs.h>
  33
  34#ifdef DEBUG
  35#include <asm/time.h>
  36#endif
  37
  38#include "ppc_cbe_cpufreq.h"
  39
  40static u8 pmi_slow_mode_limit[MAX_CBE];
  41
  42bool cbe_cpufreq_has_pmi = false;
  43EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
  44
  45/*
  46 * hardware specific functions
  47 */
  48
  49int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode)
  50{
  51        int ret;
  52        pmi_message_t pmi_msg;
  53#ifdef DEBUG
  54        long time;
  55#endif
  56        pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
  57        pmi_msg.data1 = cbe_cpu_to_node(cpu);
  58        pmi_msg.data2 = pmode;
  59
  60#ifdef DEBUG
  61        time = jiffies;
  62#endif
  63        pmi_send_message(pmi_msg);
  64
  65#ifdef DEBUG
  66        time = jiffies  - time;
  67        time = jiffies_to_msecs(time);
  68        pr_debug("had to wait %lu ms for a transition using " \
  69                 "PMI\n", time);
  70#endif
  71        ret = pmi_msg.data2;
  72        pr_debug("PMI returned slow mode %d\n", ret);
  73
  74        return ret;
  75}
  76EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
  77
  78
  79static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
  80{
  81        u8 node, slow_mode;
  82
  83        BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
  84
  85        node = pmi_msg.data1;
  86        slow_mode = pmi_msg.data2;
  87
  88        pmi_slow_mode_limit[node] = slow_mode;
  89
  90        pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode);
  91}
  92
  93static int pmi_notifier(struct notifier_block *nb,
  94                                       unsigned long event, void *data)
  95{
  96        struct cpufreq_policy *policy = data;
  97        struct cpufreq_frequency_table *cbe_freqs;
  98        u8 node;
  99
 100        /* Should this really be called for CPUFREQ_ADJUST, CPUFREQ_INCOMPATIBLE
 101         * and CPUFREQ_NOTIFY policy events?)
 102         */
 103        if (event == CPUFREQ_START)
 104                return 0;
 105
 106        cbe_freqs = cpufreq_frequency_get_table(policy->cpu);
 107        node = cbe_cpu_to_node(policy->cpu);
 108
 109        pr_debug("got notified, event=%lu, node=%u\n", event, node);
 110
 111        if (pmi_slow_mode_limit[node] != 0) {
 112                pr_debug("limiting node %d to slow mode %d\n",
 113                         node, pmi_slow_mode_limit[node]);
 114
 115                cpufreq_verify_within_limits(policy, 0,
 116
 117                        cbe_freqs[pmi_slow_mode_limit[node]].frequency);
 118        }
 119
 120        return 0;
 121}
 122
 123static struct notifier_block pmi_notifier_block = {
 124        .notifier_call = pmi_notifier,
 125};
 126
 127static struct pmi_handler cbe_pmi_handler = {
 128        .type                   = PMI_TYPE_FREQ_CHANGE,
 129        .handle_pmi_message     = cbe_cpufreq_handle_pmi,
 130};
 131
 132
 133
 134static int __init cbe_cpufreq_pmi_init(void)
 135{
 136        cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0;
 137
 138        if (!cbe_cpufreq_has_pmi)
 139                return -ENODEV;
 140
 141        cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
 142
 143        return 0;
 144}
 145
 146static void __exit cbe_cpufreq_pmi_exit(void)
 147{
 148        cpufreq_unregister_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
 149        pmi_unregister_handler(&cbe_pmi_handler);
 150}
 151
 152module_init(cbe_cpufreq_pmi_init);
 153module_exit(cbe_cpufreq_pmi_exit);
 154
 155MODULE_LICENSE("GPL");
 156MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
 157
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