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Christian Krafft36ca4ba2006-10-24 18:39:45 +02001/*
2 * cpufreq driver for the cell processor
3 *
Christian Krafft74889e42007-07-20 21:39:22 +02004 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
Christian Krafft36ca4ba2006-10-24 18:39:45 +02005 *
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/cpufreq.h>
Paul Gortmaker7dfe2932011-05-27 13:23:32 -040024#include <linux/module.h>
Jon Loeligerd8caf742007-11-13 11:10:58 -060025#include <linux/of_platform.h>
26
Olof Johansson4bd4aa12007-04-28 12:49:03 +100027#include <asm/machdep.h>
Christian Krafft74889e42007-07-20 21:39:22 +020028#include <asm/prom.h>
Benjamin Herrenschmidteef686a02007-10-04 15:40:42 +100029#include <asm/cell-regs.h>
Viresh Kumar6eb1c372013-03-25 11:20:23 +053030
31#include "ppc_cbe_cpufreq.h"
Christian Krafft36ca4ba2006-10-24 18:39:45 +020032
33static DEFINE_MUTEX(cbe_switch_mutex);
34
35
36/* the CBE supports an 8 step frequency scaling */
37static struct cpufreq_frequency_table cbe_freqs[] = {
38 {1, 0},
39 {2, 0},
40 {3, 0},
41 {4, 0},
42 {5, 0},
43 {6, 0},
44 {8, 0},
45 {10, 0},
46 {0, CPUFREQ_TABLE_END},
47};
48
Christian Krafft36ca4ba2006-10-24 18:39:45 +020049/*
50 * hardware specific functions
51 */
52
Christian Krafft74889e42007-07-20 21:39:22 +020053static int set_pmode(unsigned int cpu, unsigned int slow_mode)
Christian Krafft813f9072007-07-20 21:39:18 +020054{
Christian Krafft1e21fd52007-07-20 21:39:21 +020055 int rc;
Christian Krafft1e21fd52007-07-20 21:39:21 +020056
Christian Krafft74889e42007-07-20 21:39:22 +020057 if (cbe_cpufreq_has_pmi)
58 rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode);
59 else
60 rc = cbe_cpufreq_set_pmode(cpu, slow_mode);
61
62 pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu));
Christian Krafft1e21fd52007-07-20 21:39:21 +020063
64 return rc;
Christian Krafft50500632007-04-23 21:35:42 +020065}
66
Christian Krafft36ca4ba2006-10-24 18:39:45 +020067/*
68 * cpufreq functions
69 */
70
Olof Johansson4bd4aa12007-04-28 12:49:03 +100071static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
Christian Krafft36ca4ba2006-10-24 18:39:45 +020072{
Stephen Rothwell9c1a2ba2007-04-03 22:50:59 +100073 const u32 *max_freqp;
74 u32 max_freq;
Christian Krafft36ca4ba2006-10-24 18:39:45 +020075 int i, cur_pmode;
76 struct device_node *cpu;
77
78 cpu = of_get_cpu_node(policy->cpu, NULL);
79
Olof Johansson4bd4aa12007-04-28 12:49:03 +100080 if (!cpu)
Christian Krafft36ca4ba2006-10-24 18:39:45 +020081 return -ENODEV;
82
83 pr_debug("init cpufreq on CPU %d\n", policy->cpu);
84
Jean-Christophe DUBOIS64bafa92007-07-20 21:39:23 +020085 /*
86 * Let's check we can actually get to the CELL regs
87 */
88 if (!cbe_get_cpu_pmd_regs(policy->cpu) ||
89 !cbe_get_cpu_mic_tm_regs(policy->cpu)) {
90 pr_info("invalid CBE regs pointers for cpufreq\n");
91 return -EINVAL;
92 }
93
Stephen Rothwell9c1a2ba2007-04-03 22:50:59 +100094 max_freqp = of_get_property(cpu, "clock-frequency", NULL);
Christian Krafft36ca4ba2006-10-24 18:39:45 +020095
Christian Krafft1e21fd52007-07-20 21:39:21 +020096 of_node_put(cpu);
97
Stephen Rothwell9c1a2ba2007-04-03 22:50:59 +100098 if (!max_freqp)
Christian Krafft36ca4ba2006-10-24 18:39:45 +020099 return -EINVAL;
100
Olof Johansson4bd4aa12007-04-28 12:49:03 +1000101 /* we need the freq in kHz */
Stephen Rothwell9c1a2ba2007-04-03 22:50:59 +1000102 max_freq = *max_freqp / 1000;
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200103
Stephen Rothwell9c1a2ba2007-04-03 22:50:59 +1000104 pr_debug("max clock-frequency is at %u kHz\n", max_freq);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200105 pr_debug("initializing frequency table\n");
106
Olof Johansson4bd4aa12007-04-28 12:49:03 +1000107 /* initialize frequency table */
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200108 for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
Viresh Kumar50701582013-03-30 16:25:15 +0530109 cbe_freqs[i].frequency = max_freq / cbe_freqs[i].driver_data;
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200110 pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
111 }
112
Christian Krafft1e21fd52007-07-20 21:39:21 +0200113 /* if DEBUG is enabled set_pmode() measures the latency
114 * of a transition */
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200115 policy->cpuinfo.transition_latency = 25000;
116
Christian Krafft74889e42007-07-20 21:39:22 +0200117 cur_pmode = cbe_cpufreq_get_pmode(policy->cpu);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200118 pr_debug("current pmode is at %d\n",cur_pmode);
119
120 policy->cur = cbe_freqs[cur_pmode].frequency;
121
122#ifdef CONFIG_SMP
Anton Blanchardcc1ba8e2010-04-26 15:32:41 +0000123 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200124#endif
125
Olof Johansson4bd4aa12007-04-28 12:49:03 +1000126 cpufreq_frequency_table_get_attr(cbe_freqs, policy->cpu);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200127
Christian Krafft1e21fd52007-07-20 21:39:21 +0200128 /* this ensures that policy->cpuinfo_min
129 * and policy->cpuinfo_max are set correctly */
Olof Johansson4bd4aa12007-04-28 12:49:03 +1000130 return cpufreq_frequency_table_cpuinfo(policy, cbe_freqs);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200131}
132
133static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
134{
135 cpufreq_frequency_table_put_attr(policy->cpu);
136 return 0;
137}
138
139static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
140{
141 return cpufreq_frequency_table_verify(policy, cbe_freqs);
142}
143
Christian Krafft1e21fd52007-07-20 21:39:21 +0200144static int cbe_cpufreq_target(struct cpufreq_policy *policy,
145 unsigned int target_freq,
146 unsigned int relation)
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200147{
148 int rc;
149 struct cpufreq_freqs freqs;
Christian Krafft1e21fd52007-07-20 21:39:21 +0200150 unsigned int cbe_pmode_new;
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200151
152 cpufreq_frequency_table_target(policy,
153 cbe_freqs,
154 target_freq,
155 relation,
156 &cbe_pmode_new);
157
158 freqs.old = policy->cur;
159 freqs.new = cbe_freqs[cbe_pmode_new].frequency;
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200160
Olof Johansson4bd4aa12007-04-28 12:49:03 +1000161 mutex_lock(&cbe_switch_mutex);
Viresh Kumarb43a7ff2013-03-24 11:56:43 +0530162 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200163
Christian Krafft1e21fd52007-07-20 21:39:21 +0200164 pr_debug("setting frequency for cpu %d to %d kHz, " \
165 "1/%d of max frequency\n",
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200166 policy->cpu,
167 cbe_freqs[cbe_pmode_new].frequency,
Viresh Kumar50701582013-03-30 16:25:15 +0530168 cbe_freqs[cbe_pmode_new].driver_data);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200169
170 rc = set_pmode(policy->cpu, cbe_pmode_new);
Christian Krafft1e21fd52007-07-20 21:39:21 +0200171
Viresh Kumarb43a7ff2013-03-24 11:56:43 +0530172 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200173 mutex_unlock(&cbe_switch_mutex);
174
175 return rc;
176}
177
178static struct cpufreq_driver cbe_cpufreq_driver = {
179 .verify = cbe_cpufreq_verify,
180 .target = cbe_cpufreq_target,
181 .init = cbe_cpufreq_cpu_init,
182 .exit = cbe_cpufreq_cpu_exit,
183 .name = "cbe-cpufreq",
184 .owner = THIS_MODULE,
185 .flags = CPUFREQ_CONST_LOOPS,
186};
187
188/*
189 * module init and destoy
190 */
191
192static int __init cbe_cpufreq_init(void)
193{
Olof Johansson4bd4aa12007-04-28 12:49:03 +1000194 if (!machine_is(cell))
195 return -ENODEV;
Christian Krafft50500632007-04-23 21:35:42 +0200196
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200197 return cpufreq_register_driver(&cbe_cpufreq_driver);
198}
199
200static void __exit cbe_cpufreq_exit(void)
201{
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200202 cpufreq_unregister_driver(&cbe_cpufreq_driver);
Christian Krafft36ca4ba2006-10-24 18:39:45 +0200203}
204
205module_init(cbe_cpufreq_init);
206module_exit(cbe_cpufreq_exit);
207
208MODULE_LICENSE("GPL");
209MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");