drivers/cpufreq/ppc_cbe_cpufreq_pmi.c

   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/init.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
  40 static u8 pmi_slow_mode_limit[MAX_CBE];
  41
  42 bool cbe_cpufreq_has_pmi = false;
  43 EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
  44
  45 /*
  46  * hardware specific functions
  47  */
  48
  49 int 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 }
  76 EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
  77
  78
  79 static 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
  93 static 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 = policy->freq_table;
  98         u8 node;
  99
 100         /* Should this really be called for CPUFREQ_ADJUST and CPUFREQ_NOTIFY
 101          * policy events?)
 102          */
 103         if (event == CPUFREQ_START)
 104                 return 0;
 105
 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
 122 static struct notifier_block pmi_notifier_block = {
 123         .notifier_call = pmi_notifier,
 124 };
 125
 126 static struct pmi_handler cbe_pmi_handler = {
 127         .type                   = PMI_TYPE_FREQ_CHANGE,
 128         .handle_pmi_message     = cbe_cpufreq_handle_pmi,
 129 };
 130
 131
 132
 133 static 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 device_initcall(cbe_cpufreq_pmi_init);