2 * cpufreq driver for the cell processor
4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
6 * Author: Christian Krafft <krafft@de.ibm.com>
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)
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.
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.
23 #include <linux/cpufreq.h>
24 #include <linux/module.h>
25 #include <linux/of_platform.h>
27 #include <asm/machdep.h>
29 #include <asm/cell-regs.h>
31 #include "ppc_cbe_cpufreq.h"
33 static DEFINE_MUTEX(cbe_switch_mutex
);
36 /* the CBE supports an 8 step frequency scaling */
37 static struct cpufreq_frequency_table cbe_freqs
[] = {
46 {0, CPUFREQ_TABLE_END
},
50 * hardware specific functions
53 static int set_pmode(unsigned int cpu
, unsigned int slow_mode
)
57 if (cbe_cpufreq_has_pmi
)
58 rc
= cbe_cpufreq_set_pmode_pmi(cpu
, slow_mode
);
60 rc
= cbe_cpufreq_set_pmode(cpu
, slow_mode
);
62 pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu
));
71 static int cbe_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
76 struct device_node
*cpu
;
78 cpu
= of_get_cpu_node(policy
->cpu
, NULL
);
83 pr_debug("init cpufreq on CPU %d\n", policy
->cpu
);
86 * Let's check we can actually get to the CELL regs
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");
94 max_freqp
= of_get_property(cpu
, "clock-frequency", NULL
);
101 /* we need the freq in kHz */
102 max_freq
= *max_freqp
/ 1000;
104 pr_debug("max clock-frequency is at %u kHz\n", max_freq
);
105 pr_debug("initializing frequency table\n");
107 /* initialize frequency table */
108 for (i
=0; cbe_freqs
[i
].frequency
!=CPUFREQ_TABLE_END
; i
++) {
109 cbe_freqs
[i
].frequency
= max_freq
/ cbe_freqs
[i
].driver_data
;
110 pr_debug("%d: %d\n", i
, cbe_freqs
[i
].frequency
);
113 /* if DEBUG is enabled set_pmode() measures the latency
115 policy
->cpuinfo
.transition_latency
= 25000;
117 cur_pmode
= cbe_cpufreq_get_pmode(policy
->cpu
);
118 pr_debug("current pmode is at %d\n",cur_pmode
);
120 policy
->cur
= cbe_freqs
[cur_pmode
].frequency
;
123 cpumask_copy(policy
->cpus
, cpu_sibling_mask(policy
->cpu
));
126 cpufreq_frequency_table_get_attr(cbe_freqs
, policy
->cpu
);
128 /* this ensures that policy->cpuinfo_min
129 * and policy->cpuinfo_max are set correctly */
130 return cpufreq_frequency_table_cpuinfo(policy
, cbe_freqs
);
133 static int cbe_cpufreq_cpu_exit(struct cpufreq_policy
*policy
)
135 cpufreq_frequency_table_put_attr(policy
->cpu
);
139 static int cbe_cpufreq_verify(struct cpufreq_policy
*policy
)
141 return cpufreq_frequency_table_verify(policy
, cbe_freqs
);
144 static int cbe_cpufreq_target(struct cpufreq_policy
*policy
,
145 unsigned int target_freq
,
146 unsigned int relation
)
149 struct cpufreq_freqs freqs
;
150 unsigned int cbe_pmode_new
;
152 cpufreq_frequency_table_target(policy
,
158 freqs
.old
= policy
->cur
;
159 freqs
.new = cbe_freqs
[cbe_pmode_new
].frequency
;
161 mutex_lock(&cbe_switch_mutex
);
162 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_PRECHANGE
);
164 pr_debug("setting frequency for cpu %d to %d kHz, " \
165 "1/%d of max frequency\n",
167 cbe_freqs
[cbe_pmode_new
].frequency
,
168 cbe_freqs
[cbe_pmode_new
].driver_data
);
170 rc
= set_pmode(policy
->cpu
, cbe_pmode_new
);
172 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_POSTCHANGE
);
173 mutex_unlock(&cbe_switch_mutex
);
178 static 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 .flags
= CPUFREQ_CONST_LOOPS
,
188 * module init and destoy
191 static int __init
cbe_cpufreq_init(void)
193 if (!machine_is(cell
))
196 return cpufreq_register_driver(&cbe_cpufreq_driver
);
199 static void __exit
cbe_cpufreq_exit(void)
201 cpufreq_unregister_driver(&cbe_cpufreq_driver
);
204 module_init(cbe_cpufreq_init
);
205 module_exit(cbe_cpufreq_exit
);
207 MODULE_LICENSE("GPL");
208 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");