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
cbe_cpufreq_set_pmode_pmi(int cpu,unsigned int pmode)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
cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)65 static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
66 {
67 struct cpufreq_policy *policy;
68 struct freq_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 = freq_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
cbe_cpufreq_pmi_policy_init(struct cpufreq_policy * policy)104 void cbe_cpufreq_pmi_policy_init(struct cpufreq_policy *policy)
105 {
106 struct freq_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 = freq_qos_add_request(&policy->constraints, req, FREQ_QOS_MAX,
117 policy->freq_table[0].frequency);
118 if (ret < 0) {
119 pr_err("Failed to add freq constraint (%d)\n", ret);
120 kfree(req);
121 return;
122 }
123
124 policy->driver_data = req;
125 }
126 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_init);
127
cbe_cpufreq_pmi_policy_exit(struct cpufreq_policy * policy)128 void cbe_cpufreq_pmi_policy_exit(struct cpufreq_policy *policy)
129 {
130 struct freq_qos_request *req = policy->driver_data;
131
132 if (cbe_cpufreq_has_pmi) {
133 freq_qos_remove_request(req);
134 kfree(req);
135 }
136 }
137 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_exit);
138
cbe_cpufreq_pmi_init(void)139 void cbe_cpufreq_pmi_init(void)
140 {
141 if (!pmi_register_handler(&cbe_pmi_handler))
142 cbe_cpufreq_has_pmi = true;
143 }
144 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_init);
145
cbe_cpufreq_pmi_exit(void)146 void cbe_cpufreq_pmi_exit(void)
147 {
148 pmi_unregister_handler(&cbe_pmi_handler);
149 cbe_cpufreq_has_pmi = false;
150 }
151 EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_exit);
152