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
27bool cbe_cpufreq_has_pmi = false;
28EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
29
30/*
31 * hardware specific functions
32 */
33
34int 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}
61EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
62
63
64static 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 new_value: 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
98static struct pmi_handler cbe_pmi_handler = {
99 .type = PMI_TYPE_FREQ_CHANGE,
100 .handle_pmi_message = cbe_cpufreq_handle_pmi,
101};
102
103void 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(size: sizeof(*req), GFP_KERNEL);
112 if (!req)
113 return;
114
115 ret = freq_qos_add_request(qos: &policy->constraints, req, type: FREQ_QOS_MAX,
116 value: policy->freq_table[0].frequency);
117 if (ret < 0) {
118 pr_err("Failed to add freq constraint (%d)\n", ret);
119 kfree(objp: req);
120 return;
121 }
122
123 policy->driver_data = req;
124}
125EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_init);
126
127void 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(objp: req);
134 }
135}
136EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_exit);
137
138void cbe_cpufreq_pmi_init(void)
139{
140 if (!pmi_register_handler(&cbe_pmi_handler))
141 cbe_cpufreq_has_pmi = true;
142}
143EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_init);
144
145void cbe_cpufreq_pmi_exit(void)
146{
147 pmi_unregister_handler(&cbe_pmi_handler);
148 cbe_cpufreq_has_pmi = false;
149}
150EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_exit);
151

source code of linux/drivers/cpufreq/ppc_cbe_cpufreq_pmi.c