1 | /* |
2 | * cpufreq driver for the SuperH processors. |
3 | * |
4 | * Copyright (C) 2002 - 2012 Paul Mundt |
5 | * Copyright (C) 2002 M. R. Brown |
6 | * |
7 | * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c |
8 | * |
9 | * Copyright (C) 2004-2007 Atmel Corporation |
10 | * |
11 | * This file is subject to the terms and conditions of the GNU General Public |
12 | * License. See the file "COPYING" in the main directory of this archive |
13 | * for more details. |
14 | */ |
15 | #define pr_fmt(fmt) "cpufreq: " fmt |
16 | |
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/cpu.h> |
25 | #include <linux/smp.h> |
26 | #include <linux/clk.h> |
27 | #include <linux/percpu.h> |
28 | #include <linux/sh_clk.h> |
29 | |
30 | static DEFINE_PER_CPU(struct clk, sh_cpuclk); |
31 | |
32 | struct cpufreq_target { |
33 | struct cpufreq_policy *policy; |
34 | unsigned int freq; |
35 | }; |
36 | |
37 | static unsigned int sh_cpufreq_get(unsigned int cpu) |
38 | { |
39 | return (clk_get_rate(clk: &per_cpu(sh_cpuclk, cpu)) + 500) / 1000; |
40 | } |
41 | |
42 | static long __sh_cpufreq_target(void *arg) |
43 | { |
44 | struct cpufreq_target *target = arg; |
45 | struct cpufreq_policy *policy = target->policy; |
46 | int cpu = policy->cpu; |
47 | struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); |
48 | struct cpufreq_freqs freqs; |
49 | struct device *dev; |
50 | long freq; |
51 | |
52 | if (smp_processor_id() != cpu) |
53 | return -ENODEV; |
54 | |
55 | dev = get_cpu_device(cpu); |
56 | |
57 | /* Convert target_freq from kHz to Hz */ |
58 | freq = clk_round_rate(clk: cpuclk, rate: target->freq * 1000); |
59 | |
60 | if (freq < (policy->min * 1000) || freq > (policy->max * 1000)) |
61 | return -EINVAL; |
62 | |
63 | dev_dbg(dev, "requested frequency %u Hz\n" , target->freq * 1000); |
64 | |
65 | freqs.old = sh_cpufreq_get(cpu); |
66 | freqs.new = (freq + 500) / 1000; |
67 | freqs.flags = 0; |
68 | |
69 | cpufreq_freq_transition_begin(policy: target->policy, freqs: &freqs); |
70 | clk_set_rate(clk: cpuclk, rate: freq); |
71 | cpufreq_freq_transition_end(policy: target->policy, freqs: &freqs, transition_failed: 0); |
72 | |
73 | dev_dbg(dev, "set frequency %lu Hz\n" , freq); |
74 | return 0; |
75 | } |
76 | |
77 | /* |
78 | * Here we notify other drivers of the proposed change and the final change. |
79 | */ |
80 | static int sh_cpufreq_target(struct cpufreq_policy *policy, |
81 | unsigned int target_freq, |
82 | unsigned int relation) |
83 | { |
84 | struct cpufreq_target data = { .policy = policy, .freq = target_freq }; |
85 | |
86 | return work_on_cpu(policy->cpu, __sh_cpufreq_target, &data); |
87 | } |
88 | |
89 | static int sh_cpufreq_verify(struct cpufreq_policy_data *policy) |
90 | { |
91 | struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu); |
92 | struct cpufreq_frequency_table *freq_table; |
93 | |
94 | freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL; |
95 | if (freq_table) |
96 | return cpufreq_frequency_table_verify(policy, table: freq_table); |
97 | |
98 | cpufreq_verify_within_cpu_limits(policy); |
99 | |
100 | policy->min = (clk_round_rate(clk: cpuclk, rate: 1) + 500) / 1000; |
101 | policy->max = (clk_round_rate(clk: cpuclk, rate: ~0UL) + 500) / 1000; |
102 | |
103 | cpufreq_verify_within_cpu_limits(policy); |
104 | return 0; |
105 | } |
106 | |
107 | static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy) |
108 | { |
109 | unsigned int cpu = policy->cpu; |
110 | struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); |
111 | struct cpufreq_frequency_table *freq_table; |
112 | struct device *dev; |
113 | |
114 | dev = get_cpu_device(cpu); |
115 | |
116 | cpuclk = clk_get(dev, id: "cpu_clk" ); |
117 | if (IS_ERR(ptr: cpuclk)) { |
118 | dev_err(dev, "couldn't get CPU clk\n" ); |
119 | return PTR_ERR(ptr: cpuclk); |
120 | } |
121 | |
122 | freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL; |
123 | if (freq_table) { |
124 | policy->freq_table = freq_table; |
125 | } else { |
126 | dev_notice(dev, "no frequency table found, falling back " |
127 | "to rate rounding.\n" ); |
128 | |
129 | policy->min = policy->cpuinfo.min_freq = |
130 | (clk_round_rate(clk: cpuclk, rate: 1) + 500) / 1000; |
131 | policy->max = policy->cpuinfo.max_freq = |
132 | (clk_round_rate(clk: cpuclk, rate: ~0UL) + 500) / 1000; |
133 | } |
134 | |
135 | return 0; |
136 | } |
137 | |
138 | static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy) |
139 | { |
140 | unsigned int cpu = policy->cpu; |
141 | struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); |
142 | |
143 | clk_put(clk: cpuclk); |
144 | |
145 | return 0; |
146 | } |
147 | |
148 | static struct cpufreq_driver sh_cpufreq_driver = { |
149 | .name = "sh" , |
150 | .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, |
151 | .get = sh_cpufreq_get, |
152 | .target = sh_cpufreq_target, |
153 | .verify = sh_cpufreq_verify, |
154 | .init = sh_cpufreq_cpu_init, |
155 | .exit = sh_cpufreq_cpu_exit, |
156 | .attr = cpufreq_generic_attr, |
157 | }; |
158 | |
159 | static int __init sh_cpufreq_module_init(void) |
160 | { |
161 | pr_notice("SuperH CPU frequency driver.\n" ); |
162 | return cpufreq_register_driver(driver_data: &sh_cpufreq_driver); |
163 | } |
164 | |
165 | static void __exit sh_cpufreq_module_exit(void) |
166 | { |
167 | cpufreq_unregister_driver(driver_data: &sh_cpufreq_driver); |
168 | } |
169 | |
170 | module_init(sh_cpufreq_module_init); |
171 | module_exit(sh_cpufreq_module_exit); |
172 | |
173 | MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>" ); |
174 | MODULE_DESCRIPTION("cpufreq driver for SuperH" ); |
175 | MODULE_LICENSE("GPL" ); |
176 | |