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/of_platform.h>
  15 #include <linux/pm_qos.h>
  16
  17 #include <asm/processor.h>
  18 #include <asm/prom.h>
  19 #include <asm/pmi.h>
  20 #include <asm/cell-regs.h>
  21
  22 #ifdef DEBUG
  23 #include <asm/time.h>
  24 #endif
  25
  26 #include "ppc_cbe_cpufreq.h"
  27
  28 bool cbe_cpufreq_has_pmi = false;
  29 EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
  30
  31 /*
  32  * hardware specific functions
  33  */
  34
  35 int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode)
  36 {
  37         int ret;
  38         pmi_message_t pmi_msg;
  39 #ifdef DEBUG
  40         long time;
  41 #endif
  42         pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
  43         pmi_msg.data1 = cbe_cpu_to_node(cpu);
  44         pmi_msg.data2 = pmode;
  45
  46 #ifdef DEBUG
  47         time = jiffies;
  48 #endif
  49         pmi_send_message(pmi_msg);
  50
  51 #ifdef DEBUG
  52         time = jiffies  - time;
  53         time = jiffies_to_msecs(time);
  54         pr_debug("had to wait %lu ms for a transition using " \
  55                  "PMI\n", time);
  56 #endif
  57         ret = pmi_msg.data2;
  58         pr_debug("PMI returned slow mode %d\n", ret);
  59
  60         return ret;
  61 }
  62 EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
  63
  64
  65 static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
  66 {
  67         struct cpufreq_policy *policy;
  68         struct dev_pm_qos_request *req;
  69         u8 node, slow_mode;
  70         int cpu, ret;
  71
  72         BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
  73
  74         node = pmi_msg.data1;
  75         slow_mode = pmi_msg.data2;
  76
  77         cpu = cbe_node_to_cpu(node);
  78
  79         pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode);
  80
  81         policy = cpufreq_cpu_get(cpu);
  82         if (!policy) {
  83                 pr_warn("cpufreq policy not found cpu%d\n", cpu);
  84                 return;
  85         }
  86
  87         req = policy->driver_data;
  88
  89         ret = dev_pm_qos_update_request(req,
  90                         policy->freq_table[slow_mode].frequency);
  91         if (ret < 0)
  92                 pr_warn("Failed to update freq constraint: %d\n", ret);
  93         else
  94                 pr_debug("limiting node %d to slow mode %d\n", node, slow_mode);
  95
  96         cpufreq_cpu_put(policy);
  97 }
  98
  99 static struct pmi_handler cbe_pmi_handler = {
 100         .type                   = PMI_TYPE_FREQ_CHANGE,
 101         .handle_pmi_message     = cbe_cpufreq_handle_pmi,
 102 };
 103
 104 void cbe_cpufreq_pmi_policy_init(struct cpufreq_policy *policy)
 105 {
 106         struct dev_pm_qos_request *req;
 107         int ret;
 108
 109         if (!cbe_cpufreq_has_pmi)
 110                 return;
 111
 112         req = kzalloc(sizeof(*req), GFP_KERNEL);
 113         if (!req)
 114                 return;
 115
 116         ret = dev_pm_qos_add_request(get_cpu_device(policy->cpu), req,
 117                                      DEV_PM_QOS_MAX_FREQUENCY,
 118                                      policy->freq_table[0].frequency);
 119         if (ret < 0) {
 120                 pr_err("Failed to add freq constraint (%d)\n", ret);
 121                 kfree(req);
 122                 return;
 123         }
 124
 125         policy->driver_data = req;
 126 }
 127 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_init);
 128
 129 void cbe_cpufreq_pmi_policy_exit(struct cpufreq_policy *policy)
 130 {
 131         struct dev_pm_qos_request *req = policy->driver_data;
 132
 133         if (cbe_cpufreq_has_pmi) {
 134                 dev_pm_qos_remove_request(req);
 135                 kfree(req);
 136         }
 137 }
 138 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_exit);
 139
 140 void cbe_cpufreq_pmi_init(void)
 141 {
 142         if (!pmi_register_handler(&cbe_pmi_handler))
 143                 cbe_cpufreq_has_pmi = true;
 144 }
 145 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_init);
 146
 147 void cbe_cpufreq_pmi_exit(void)
 148 {
 149         pmi_unregister_handler(&cbe_pmi_handler);
 150         cbe_cpufreq_has_pmi = false;
 151 }
 152 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_exit);