Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * arch/sh/kernel/cpufreq.c | |
3 | * | |
4 | * cpufreq driver for the SuperH processors. | |
5 | * | |
cb5ec75b | 6 | * Copyright (C) 2002 - 2007 Paul Mundt |
1da177e4 LT |
7 | * Copyright (C) 2002 M. R. Brown |
8 | * | |
cb5ec75b PM |
9 | * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c |
10 | * | |
11 | * Copyright (C) 2004-2007 Atmel Corporation | |
12 | * | |
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 | |
15 | * for more details. | |
1da177e4 LT |
16 | */ |
17 | #include <linux/types.h> | |
18 | #include <linux/cpufreq.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/module.h> | |
1da177e4 | 21 | #include <linux/init.h> |
cb5ec75b | 22 | #include <linux/err.h> |
1da177e4 LT |
23 | #include <linux/cpumask.h> |
24 | #include <linux/smp.h> | |
4e57b681 | 25 | #include <linux/sched.h> /* set_cpus_allowed() */ |
cb5ec75b | 26 | #include <linux/clk.h> |
1da177e4 | 27 | |
cb5ec75b | 28 | static struct clk *cpuclk; |
1da177e4 | 29 | |
cb5ec75b | 30 | static unsigned int sh_cpufreq_get(unsigned int cpu) |
1da177e4 | 31 | { |
cb5ec75b | 32 | return (clk_get_rate(cpuclk) + 500) / 1000; |
1da177e4 LT |
33 | } |
34 | ||
1da177e4 LT |
35 | /* |
36 | * Here we notify other drivers of the proposed change and the final change. | |
37 | */ | |
cb5ec75b PM |
38 | static int sh_cpufreq_target(struct cpufreq_policy *policy, |
39 | unsigned int target_freq, | |
40 | unsigned int relation) | |
1da177e4 | 41 | { |
cb5ec75b | 42 | unsigned int cpu = policy->cpu; |
1da177e4 LT |
43 | cpumask_t cpus_allowed; |
44 | struct cpufreq_freqs freqs; | |
cb5ec75b | 45 | long freq; |
1da177e4 LT |
46 | |
47 | if (!cpu_online(cpu)) | |
48 | return -ENODEV; | |
49 | ||
50 | cpus_allowed = current->cpus_allowed; | |
51 | set_cpus_allowed(current, cpumask_of_cpu(cpu)); | |
52 | ||
53 | BUG_ON(smp_processor_id() != cpu); | |
54 | ||
cb5ec75b PM |
55 | /* Convert target_freq from kHz to Hz */ |
56 | freq = clk_round_rate(cpuclk, target_freq * 1000); | |
1da177e4 | 57 | |
cb5ec75b PM |
58 | if (freq < (policy->min * 1000) || freq > (policy->max * 1000)) |
59 | return -EINVAL; | |
60 | ||
61 | pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000); | |
1da177e4 | 62 | |
cb5ec75b PM |
63 | freqs.cpu = cpu; |
64 | freqs.old = sh_cpufreq_get(cpu); | |
65 | freqs.new = (freq + 500) / 1000; | |
66 | freqs.flags = 0; | |
67 | ||
68 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
1da177e4 | 69 | set_cpus_allowed(current, cpus_allowed); |
cb5ec75b | 70 | clk_set_rate(cpuclk, freq); |
1da177e4 LT |
71 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
72 | ||
cb5ec75b PM |
73 | pr_debug("cpufreq: set frequency %lu Hz\n", freq); |
74 | ||
1da177e4 LT |
75 | return 0; |
76 | } | |
77 | ||
78 | static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
79 | { | |
1da177e4 LT |
80 | if (!cpu_online(policy->cpu)) |
81 | return -ENODEV; | |
82 | ||
cb5ec75b PM |
83 | cpuclk = clk_get(NULL, "cpu_clk"); |
84 | if (IS_ERR(cpuclk)) { | |
85 | printk(KERN_ERR "cpufreq: couldn't get CPU clk\n"); | |
86 | return PTR_ERR(cpuclk); | |
87 | } | |
1da177e4 LT |
88 | |
89 | /* cpuinfo and default policy values */ | |
cb5ec75b PM |
90 | policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000; |
91 | policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000; | |
1da177e4 | 92 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
1da177e4 | 93 | |
cb5ec75b PM |
94 | policy->cur = sh_cpufreq_get(policy->cpu); |
95 | policy->min = policy->cpuinfo.min_freq; | |
96 | policy->max = policy->cpuinfo.max_freq; | |
1da177e4 | 97 | |
1da177e4 | 98 | |
cb5ec75b PM |
99 | /* |
100 | * Catch the cases where the clock framework hasn't been wired up | |
101 | * properly to support scaling. | |
102 | */ | |
103 | if (unlikely(policy->min == policy->max)) { | |
104 | printk(KERN_ERR "cpufreq: clock framework rate rounding " | |
105 | "not supported on this CPU.\n"); | |
1da177e4 | 106 | |
cb5ec75b | 107 | clk_put(cpuclk); |
1da177e4 | 108 | return -EINVAL; |
cb5ec75b | 109 | } |
1da177e4 | 110 | |
cb5ec75b PM |
111 | printk(KERN_INFO "cpufreq: Frequencies - Minimum %u.%03u MHz, " |
112 | "Maximum %u.%03u MHz.\n", | |
113 | policy->min / 1000, policy->min % 1000, | |
114 | policy->max / 1000, policy->max % 1000); | |
1da177e4 | 115 | |
cb5ec75b PM |
116 | return 0; |
117 | } | |
1da177e4 | 118 | |
cb5ec75b PM |
119 | static int sh_cpufreq_verify(struct cpufreq_policy *policy) |
120 | { | |
121 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
122 | policy->cpuinfo.max_freq); | |
123 | return 0; | |
124 | } | |
125 | ||
126 | static int sh_cpufreq_exit(struct cpufreq_policy *policy) | |
127 | { | |
128 | clk_put(cpuclk); | |
1da177e4 LT |
129 | return 0; |
130 | } | |
131 | ||
132 | static struct cpufreq_driver sh_cpufreq_driver = { | |
133 | .owner = THIS_MODULE, | |
cb5ec75b | 134 | .name = "sh", |
1da177e4 LT |
135 | .init = sh_cpufreq_cpu_init, |
136 | .verify = sh_cpufreq_verify, | |
137 | .target = sh_cpufreq_target, | |
cb5ec75b PM |
138 | .get = sh_cpufreq_get, |
139 | .exit = sh_cpufreq_exit, | |
1da177e4 LT |
140 | }; |
141 | ||
cb5ec75b | 142 | static int __init sh_cpufreq_module_init(void) |
1da177e4 | 143 | { |
00765c81 | 144 | printk(KERN_INFO "cpufreq: SuperH CPU frequency driver.\n"); |
cb5ec75b | 145 | return cpufreq_register_driver(&sh_cpufreq_driver); |
1da177e4 LT |
146 | } |
147 | ||
cb5ec75b | 148 | static void __exit sh_cpufreq_module_exit(void) |
1da177e4 LT |
149 | { |
150 | cpufreq_unregister_driver(&sh_cpufreq_driver); | |
151 | } | |
152 | ||
cb5ec75b PM |
153 | module_init(sh_cpufreq_module_init); |
154 | module_exit(sh_cpufreq_module_exit); | |
1da177e4 LT |
155 | |
156 | MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); | |
157 | MODULE_DESCRIPTION("cpufreq driver for SuperH"); | |
158 | MODULE_LICENSE("GPL"); |