1/*
  2 * pmi backend for the cbe_cpufreq driver
  3 *
  4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
  5 *
  6 * Author: Christian Krafft <krafft@de.ibm.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License as published by
 10 * the Free Software Foundation; either version 2, or (at your option)
 11 * any later version.
 12 *
 13 * This program is distributed in the hope that it will be useful,
 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 16 * GNU General Public License for more details.
 17 *
 18 * You should have received a copy of the GNU General Public License
 19 * along with this program; if not, write to the Free Software
 20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 21 */
 22
 23#include <linux/kernel.h>
 24#include <linux/types.h>
 25#include <linux/timer.h>
 26#include <linux/module.h>
 27#include <linux/of_platform.h>
 28
 29#include <asm/processor.h>
 30#include <asm/prom.h>
 31#include <asm/pmi.h>
 32#include <asm/cell-regs.h>
 33
 34#ifdef DEBUG
 35#include <asm/time.h>
 36#endif
 37
 38#include "ppc_cbe_cpufreq.h"
 39
 40static u8 pmi_slow_mode_limit[MAX_CBE];
 41
 42bool cbe_cpufreq_has_pmi = false;
 43EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
 44
 45/*
 46 * hardware specific functions
 47 */
 48
 49int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode)
 50{
 51	int ret;
 52	pmi_message_t pmi_msg;
 53#ifdef DEBUG
 54	long time;
 55#endif
 56	pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
 57	pmi_msg.data1 =	cbe_cpu_to_node(cpu);
 58	pmi_msg.data2 = pmode;
 59
 60#ifdef DEBUG
 61	time = jiffies;
 62#endif
 63	pmi_send_message(pmi_msg);
 64
 65#ifdef DEBUG
 66	time = jiffies  - time;
 67	time = jiffies_to_msecs(time);
 68	pr_debug("had to wait %lu ms for a transition using " \
 69		 "PMI\n", time);
 70#endif
 71	ret = pmi_msg.data2;
 72	pr_debug("PMI returned slow mode %d\n", ret);
 73
 74	return ret;
 75}
 76EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
 77
 78
 79static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
 80{
 81	u8 node, slow_mode;
 82
 83	BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
 84
 85	node = pmi_msg.data1;
 86	slow_mode = pmi_msg.data2;
 87
 88	pmi_slow_mode_limit[node] = slow_mode;
 89
 90	pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode);
 91}
 92
 93static int pmi_notifier(struct notifier_block *nb,
 94				       unsigned long event, void *data)
 95{
 96	struct cpufreq_policy *policy = data;
 97	struct cpufreq_frequency_table *cbe_freqs;
 98	u8 node;
 99
100	/* Should this really be called for CPUFREQ_ADJUST, CPUFREQ_INCOMPATIBLE
101	 * and CPUFREQ_NOTIFY policy events?)
102	 */
103	if (event == CPUFREQ_START)
104		return 0;
105
106	cbe_freqs = cpufreq_frequency_get_table(policy->cpu);
107	node = cbe_cpu_to_node(policy->cpu);
108
109	pr_debug("got notified, event=%lu, node=%u\n", event, node);
110
111	if (pmi_slow_mode_limit[node] != 0) {
112		pr_debug("limiting node %d to slow mode %d\n",
113			 node, pmi_slow_mode_limit[node]);
114
115		cpufreq_verify_within_limits(policy, 0,
116
117			cbe_freqs[pmi_slow_mode_limit[node]].frequency);
118	}
119
120	return 0;
121}
122
123static struct notifier_block pmi_notifier_block = {
124	.notifier_call = pmi_notifier,
125};
126
127static struct pmi_handler cbe_pmi_handler = {
128	.type			= PMI_TYPE_FREQ_CHANGE,
129	.handle_pmi_message	= cbe_cpufreq_handle_pmi,
130};
131
132
133
134static int __init cbe_cpufreq_pmi_init(void)
135{
136	cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0;
137
138	if (!cbe_cpufreq_has_pmi)
139		return -ENODEV;
140
141	cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
142
143	return 0;
144}
145
146static void __exit cbe_cpufreq_pmi_exit(void)
147{
148	cpufreq_unregister_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
149	pmi_unregister_handler(&cbe_pmi_handler);
150}
151
152module_init(cbe_cpufreq_pmi_init);
153module_exit(cbe_cpufreq_pmi_exit);
154
155MODULE_LICENSE("GPL");
156MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");