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			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(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}
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(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);