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
28bool cbe_cpufreq_has_pmi = false;
29EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
30
31/*
32 * hardware specific functions
33 */
34
35int 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}
62EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
63
64
65static 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
99static struct pmi_handler cbe_pmi_handler = {
100	.type			= PMI_TYPE_FREQ_CHANGE,
101	.handle_pmi_message	= cbe_cpufreq_handle_pmi,
102};
103
104void 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}
126EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_init);
127
128void 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}
137EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_policy_exit);
138
139void cbe_cpufreq_pmi_init(void)
140{
141	if (!pmi_register_handler(&cbe_pmi_handler))
142		cbe_cpufreq_has_pmi = true;
143}
144EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_init);
145
146void cbe_cpufreq_pmi_exit(void)
147{
148	pmi_unregister_handler(&cbe_pmi_handler);
149	cbe_cpufreq_has_pmi = false;
150}
151EXPORT_SYMBOL_GPL(cbe_cpufreq_pmi_exit);
152