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);
151