drivers/cpufreq/ppc_cbe_cpufreq_pmi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * pmi backend for the cbe_cpufreq driver
   4  *
   5  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
   6  *
   7  * Author: Christian Krafft <krafft@de.ibm.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/types.h>
  12 #include <linux/timer.h>
  13 #include <linux/init.h>
  14 #include <linux/pm_qos.h>
  15 #include <linux/slab.h>
  16
  17 #include <asm/processor.h>
  18 #include <asm/pmi.h>
  19 #include <asm/cell-regs.h>
  20
  21 #ifdef DEBUG
  22 #include <asm/time.h>
  23 #endif
  24
  25 #include "ppc_cbe_cpufreq.h"
  26
  27 bool cbe_cpufreq_has_pmi = false;
  28 EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
  29
  30 /*
  31  * hardware specific functions
  32  */
  33
  34 int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode)
  35 {
  36         int ret;
  37         pmi_message_t pmi_msg;
  38 #ifdef DEBUG
  39         long time;
  40 #endif
  41         pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
  42         pmi_msg.data1 = cbe_cpu_to_node(cpu);
  43         pmi_msg.data2 = pmode;
  44
  45 #ifdef DEBUG
  46         time = jiffies;
  47 #endif
  48         pmi_send_message(pmi_msg);
  49
  50 #ifdef DEBUG
  51         time = jiffies  - time;
  52         time = jiffies_to_msecs(time);
  53         pr_debug("had to wait %lu ms for a transition using " \
  54                  "PMI\n", time);
  55 #endif
  56         ret = pmi_msg.data2;
  57         pr_debug("PMI returned slow mode %d\n", ret);
  58
  59         return ret;
  60 }
  61 EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
  62
  63
  64 static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
  65 {
  66         struct cpufreq_policy *policy;
  67         struct freq_qos_request *req;
  68         u8 node, slow_mode;
  69         int cpu, ret;
  70
  71         BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
  72
  73         node = pmi_msg.data1;
  74         slow_mode = pmi_msg.data2;
  75
  76         cpu = cbe_node_to_cpu(node);
  77
  78         pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode);
  79
  80         policy = cpufreq_cpu_get(cpu);
  81         if (!policy) {
  82                 pr_warn("cpufreq policy not found cpu%d\n", cpu);
  83                 return;
  84         }
  85
  86         req = policy->driver_data;
  87
  88         ret = freq_qos_update_request(req,
  89                         policy->freq_table[slow_mode].frequency);
  90         if (ret < 0)
  91                 pr_warn("Failed to update freq constraint: %d\n", ret);
  92         else
  93                 pr_debug("limiting node %d to slow mode %d\n", node, slow_mode);
  94
  95         cpufreq_cpu_put(policy);
  96 }
  97
  98 static struct pmi_handler cbe_pmi_handler = {
  99         .type                   = PMI_TYPE_FREQ_CHANGE,
 100         .handle_pmi_message     = cbe_cpufreq_handle_pmi,
 101 };
 102
 103 void cbe_cpufreq_pmi_policy_init(struct cpufreq_policy *policy)
 104 {
 105         struct freq_qos_request *req;
 106         int ret;
 107
 108         if (!cbe_cpufreq_has_pmi)
 109                 return;
 110
 111         req = kzalloc(sizeof(*req), GFP_KERNEL);
 112         if (!req)
 113                 return;
 114
 115         ret = freq_qos_add_request(&policy->constraints, req, FREQ_QOS_MAX,
 116                                    policy->freq_table[0].frequency);
 117         if (ret < 0) {
 118                 pr_err("Failed to add freq constraint (%d)\n", ret);
 119                 kfree(req);
 120                 return;
 121         }
 122
 123         policy->driver_data = req;
 124 }
 125 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_init);
 126
 127 void cbe_cpufreq_pmi_policy_exit(struct cpufreq_policy *policy)
 128 {
 129         struct freq_qos_request *req = policy->driver_data;
 130
 131         if (cbe_cpufreq_has_pmi) {
 132                 freq_qos_remove_request(req);
 133                 kfree(req);
 134         }
 135 }
 136 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_exit);
 137
 138 void cbe_cpufreq_pmi_init(void)
 139 {
 140         if (!pmi_register_handler(&cbe_pmi_handler))
 141                 cbe_cpufreq_has_pmi = true;
 142 }
 143 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_init);
 144
 145 void cbe_cpufreq_pmi_exit(void)
 146 {
 147         pmi_unregister_handler(&cbe_pmi_handler);
 148         cbe_cpufreq_has_pmi = false;
 149 }
 150 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_exit);