LXR linux/arch/powerpc/platforms/cell/cbe_cpufreq

   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/of_platform.h>
  27
  28#include <asm/processor.h>
  29#include <asm/prom.h>
  30#include <asm/pmi.h>
  31#include <asm/cell-regs.h>
  32
  33#ifdef DEBUG
  34#include <asm/time.h>
  35#endif
  36
  37#include "cbe_cpufreq.h"
  38
  39static u8 pmi_slow_mode_limit[MAX_CBE];
  40
  41bool cbe_cpufreq_has_pmi = false;
  42EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
  43
  44/*
  45 * hardware specific functions
  46 */
  47
  48int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode)
  49{
  50        int ret;
  51        pmi_message_t pmi_msg;
  52#ifdef DEBUG
  53        long time;
  54#endif
  55        pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
  56        pmi_msg.data1 = cbe_cpu_to_node(cpu);
  57        pmi_msg.data2 = pmode;
  58
  59#ifdef DEBUG
  60        time = jiffies;
  61#endif
  62        pmi_send_message(pmi_msg);
  63
  64#ifdef DEBUG
  65        time = jiffies  - time;
  66        time = jiffies_to_msecs(time);
  67        pr_debug("had to wait %lu ms for a transition using " \
  68                 "PMI\n", time);
  69#endif
  70        ret = pmi_msg.data2;
  71        pr_debug("PMI returned slow mode %d\n", ret);
  72
  73        return ret;
  74}
  75EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
  76
  77
  78static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
  79{
  80        u8 node, slow_mode;
  81
  82        BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
  83
  84        node = pmi_msg.data1;
  85        slow_mode = pmi_msg.data2;
  86
  87        pmi_slow_mode_limit[node] = slow_mode;
  88
  89        pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode);
  90}
  91
  92static int pmi_notifier(struct notifier_block *nb,
  93                                       unsigned long event, void *data)
  94{
  95        struct cpufreq_policy *policy = data;
  96        struct cpufreq_frequency_table *cbe_freqs;
  97        u8 node;
  98
  99        /* Should this really be called for CPUFREQ_ADJUST, CPUFREQ_INCOMPATIBLE
 100         * and CPUFREQ_NOTIFY policy events?)
 101         */
 102        if (event == CPUFREQ_START)
 103                return 0;
 104
 105        cbe_freqs = cpufreq_frequency_get_table(policy->cpu);
 106        node = cbe_cpu_to_node(policy->cpu);
 107
 108        pr_debug("got notified, event=%lu, node=%u\n", event, node);
 109
 110        if (pmi_slow_mode_limit[node] != 0) {
 111                pr_debug("limiting node %d to slow mode %d\n",
 112                         node, pmi_slow_mode_limit[node]);
 113
 114                cpufreq_verify_within_limits(policy, 0,
 115
 116                        cbe_freqs[pmi_slow_mode_limit[node]].frequency);
 117        }
 118
 119        return 0;
 120}
 121
 122static struct notifier_block pmi_notifier_block = {
 123        .notifier_call = pmi_notifier,
 124};
 125
 126static struct pmi_handler cbe_pmi_handler = {
 127        .type                   = PMI_TYPE_FREQ_CHANGE,
 128        .handle_pmi_message     = cbe_cpufreq_handle_pmi,
 129};
 130
 131
 132
 133static int __init cbe_cpufreq_pmi_init(void)
 134{
 135        cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0;
 136
 137        if (!cbe_cpufreq_has_pmi)
 138                return -ENODEV;
 139
 140        cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
 141
 142        return 0;
 143}
 144
 145static void __exit cbe_cpufreq_pmi_exit(void)
 146{
 147        cpufreq_unregister_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
 148        pmi_unregister_handler(&cbe_pmi_handler);
 149}
 150
 151module_init(cbe_cpufreq_pmi_init);
 152module_exit(cbe_cpufreq_pmi_exit);
 153
 154MODULE_LICENSE("GPL");
 155MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
 156