2 * arch/sh/kernel/cpufreq.c
4 * cpufreq driver for the SuperH processors.
6 * Copyright (C) 2002 - 2007 Paul Mundt
7 * Copyright (C) 2002 M. R. Brown
9 * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
11 * Copyright (C) 2004-2007 Atmel Corporation
13 * This file is subject to the terms and conditions of the GNU General Public
14 * License. See the file "COPYING" in the main directory of this archive
17 #include <linux/types.h>
18 #include <linux/cpufreq.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/cpumask.h>
24 #include <linux/smp.h>
25 #include <linux/sched.h> /* set_cpus_allowed() */
27 #include <linux/clk.h>
28 #include <asm/processor.h>
29 #include <asm/watchdog.h>
31 #include <asm/clock.h>
33 static struct clk
*cpuclk
;
35 static unsigned int sh_cpufreq_get(unsigned int cpu
)
37 return (clk_get_rate(cpuclk
) + 500) / 1000;
41 * Here we notify other drivers of the proposed change and the final change.
43 static int sh_cpufreq_target(struct cpufreq_policy
*policy
,
44 unsigned int target_freq
,
45 unsigned int relation
)
47 unsigned int cpu
= policy
->cpu
;
48 cpumask_t cpus_allowed
;
49 struct cpufreq_freqs freqs
;
55 cpus_allowed
= current
->cpus_allowed
;
56 set_cpus_allowed(current
, cpumask_of_cpu(cpu
));
58 BUG_ON(smp_processor_id() != cpu
);
60 /* Convert target_freq from kHz to Hz */
61 freq
= clk_round_rate(cpuclk
, target_freq
* 1000);
63 if (freq
< (policy
->min
* 1000) || freq
> (policy
->max
* 1000))
66 pr_debug("cpufreq: requested frequency %u Hz\n", target_freq
* 1000);
69 freqs
.old
= sh_cpufreq_get(cpu
);
70 freqs
.new = (freq
+ 500) / 1000;
73 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
74 set_cpus_allowed(current
, cpus_allowed
);
75 clk_set_rate(cpuclk
, freq
);
76 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
78 pr_debug("cpufreq: set frequency %lu Hz\n", freq
);
83 static int sh_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
85 printk(KERN_INFO
"cpufreq: SuperH CPU frequency driver.\n");
87 if (!cpu_online(policy
->cpu
))
90 cpuclk
= clk_get(NULL
, "cpu_clk");
92 printk(KERN_ERR
"cpufreq: couldn't get CPU clk\n");
93 return PTR_ERR(cpuclk
);
96 /* cpuinfo and default policy values */
97 policy
->cpuinfo
.min_freq
= (clk_round_rate(cpuclk
, 1) + 500) / 1000;
98 policy
->cpuinfo
.max_freq
= (clk_round_rate(cpuclk
, ~0UL) + 500) / 1000;
99 policy
->cpuinfo
.transition_latency
= CPUFREQ_ETERNAL
;
101 policy
->governor
= CPUFREQ_DEFAULT_GOVERNOR
;
102 policy
->cur
= sh_cpufreq_get(policy
->cpu
);
103 policy
->min
= policy
->cpuinfo
.min_freq
;
104 policy
->max
= policy
->cpuinfo
.max_freq
;
108 * Catch the cases where the clock framework hasn't been wired up
109 * properly to support scaling.
111 if (unlikely(policy
->min
== policy
->max
)) {
112 printk(KERN_ERR
"cpufreq: clock framework rate rounding "
113 "not supported on this CPU.\n");
119 printk(KERN_INFO
"cpufreq: Frequencies - Minimum %u.%03u MHz, "
120 "Maximum %u.%03u MHz.\n",
121 policy
->min
/ 1000, policy
->min
% 1000,
122 policy
->max
/ 1000, policy
->max
% 1000);
127 static int sh_cpufreq_verify(struct cpufreq_policy
*policy
)
129 cpufreq_verify_within_limits(policy
, policy
->cpuinfo
.min_freq
,
130 policy
->cpuinfo
.max_freq
);
134 static int sh_cpufreq_exit(struct cpufreq_policy
*policy
)
140 static struct cpufreq_driver sh_cpufreq_driver
= {
141 .owner
= THIS_MODULE
,
143 .init
= sh_cpufreq_cpu_init
,
144 .verify
= sh_cpufreq_verify
,
145 .target
= sh_cpufreq_target
,
146 .get
= sh_cpufreq_get
,
147 .exit
= sh_cpufreq_exit
,
150 static int __init
sh_cpufreq_module_init(void)
152 return cpufreq_register_driver(&sh_cpufreq_driver
);
155 static void __exit
sh_cpufreq_module_exit(void)
157 cpufreq_unregister_driver(&sh_cpufreq_driver
);
160 module_init(sh_cpufreq_module_init
);
161 module_exit(sh_cpufreq_module_exit
);
163 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
164 MODULE_DESCRIPTION("cpufreq driver for SuperH");
165 MODULE_LICENSE("GPL");