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);
153