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/init.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 
40 static u8 pmi_slow_mode_limit[MAX_CBE];
41 
42 bool cbe_cpufreq_has_pmi = false;
43 EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi);
44 
45 /*
46  * hardware specific functions
47  */
48 
49 int 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 }
76 EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi);
77 
78 
79 static 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 
93 static 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 = policy->freq_table;
98 	u8 node;
99 
100 	/* Should this really be called for CPUFREQ_ADJUST and CPUFREQ_NOTIFY
101 	 * policy events?)
102 	 */
103 	node = cbe_cpu_to_node(policy->cpu);
104 
105 	pr_debug("got notified, event=%lu, node=%u\n", event, node);
106 
107 	if (pmi_slow_mode_limit[node] != 0) {
108 		pr_debug("limiting node %d to slow mode %d\n",
109 			 node, pmi_slow_mode_limit[node]);
110 
111 		cpufreq_verify_within_limits(policy, 0,
112 
113 			cbe_freqs[pmi_slow_mode_limit[node]].frequency);
114 	}
115 
116 	return 0;
117 }
118 
119 static struct notifier_block pmi_notifier_block = {
120 	.notifier_call = pmi_notifier,
121 };
122 
123 static struct pmi_handler cbe_pmi_handler = {
124 	.type			= PMI_TYPE_FREQ_CHANGE,
125 	.handle_pmi_message	= cbe_cpufreq_handle_pmi,
126 };
127 
128 
129 
130 static int __init cbe_cpufreq_pmi_init(void)
131 {
132 	cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0;
133 
134 	if (!cbe_cpufreq_has_pmi)
135 		return -ENODEV;
136 
137 	cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
138 
139 	return 0;
140 }
141 device_initcall(cbe_cpufreq_pmi_init);
142