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/sched.h> /* set_cpus_allowed() */
27 #include <linux/clk.h>
28 #include <linux/percpu.h>
29 #include <linux/sh_clk.h>
30
31 static DEFINE_PER_CPU(struct clk, sh_cpuclk);
32
33 struct cpufreq_target {
34 struct cpufreq_policy *policy;
35 unsigned int freq;
36 };
37
sh_cpufreq_get(unsigned int cpu)38 static unsigned int sh_cpufreq_get(unsigned int cpu)
39 {
40 return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
41 }
42
__sh_cpufreq_target(void * arg)43 static long __sh_cpufreq_target(void *arg)
44 {
45 struct cpufreq_target *target = arg;
46 struct cpufreq_policy *policy = target->policy;
47 int cpu = policy->cpu;
48 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
49 struct cpufreq_freqs freqs;
50 struct device *dev;
51 long freq;
52
53 if (smp_processor_id() != cpu)
54 return -ENODEV;
55
56 dev = get_cpu_device(cpu);
57
58 /* Convert target_freq from kHz to Hz */
59 freq = clk_round_rate(cpuclk, target->freq * 1000);
60
61 if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
62 return -EINVAL;
63
64 dev_dbg(dev, "requested frequency %u Hz\n", target->freq * 1000);
65
66 freqs.old = sh_cpufreq_get(cpu);
67 freqs.new = (freq + 500) / 1000;
68 freqs.flags = 0;
69
70 cpufreq_freq_transition_begin(target->policy, &freqs);
71 clk_set_rate(cpuclk, freq);
72 cpufreq_freq_transition_end(target->policy, &freqs, 0);
73
74 dev_dbg(dev, "set frequency %lu Hz\n", freq);
75 return 0;
76 }
77
78 /*
79 * Here we notify other drivers of the proposed change and the final change.
80 */
sh_cpufreq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)81 static int sh_cpufreq_target(struct cpufreq_policy *policy,
82 unsigned int target_freq,
83 unsigned int relation)
84 {
85 struct cpufreq_target data = { .policy = policy, .freq = target_freq };
86
87 return work_on_cpu(policy->cpu, __sh_cpufreq_target, &data);
88 }
89
sh_cpufreq_verify(struct cpufreq_policy_data * policy)90 static int sh_cpufreq_verify(struct cpufreq_policy_data *policy)
91 {
92 struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
93 struct cpufreq_frequency_table *freq_table;
94
95 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
96 if (freq_table)
97 return cpufreq_frequency_table_verify(policy, freq_table);
98
99 cpufreq_verify_within_cpu_limits(policy);
100
101 policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
102 policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
103
104 cpufreq_verify_within_cpu_limits(policy);
105 return 0;
106 }
107
sh_cpufreq_cpu_init(struct cpufreq_policy * policy)108 static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
109 {
110 unsigned int cpu = policy->cpu;
111 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
112 struct cpufreq_frequency_table *freq_table;
113 struct device *dev;
114
115 dev = get_cpu_device(cpu);
116
117 cpuclk = clk_get(dev, "cpu_clk");
118 if (IS_ERR(cpuclk)) {
119 dev_err(dev, "couldn't get CPU clk\n");
120 return PTR_ERR(cpuclk);
121 }
122
123 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
124 if (freq_table) {
125 policy->freq_table = freq_table;
126 } else {
127 dev_notice(dev, "no frequency table found, falling back "
128 "to rate rounding.\n");
129
130 policy->min = policy->cpuinfo.min_freq =
131 (clk_round_rate(cpuclk, 1) + 500) / 1000;
132 policy->max = policy->cpuinfo.max_freq =
133 (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
134 }
135
136 return 0;
137 }
138
sh_cpufreq_cpu_exit(struct cpufreq_policy * policy)139 static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
140 {
141 unsigned int cpu = policy->cpu;
142 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
143
144 clk_put(cpuclk);
145
146 return 0;
147 }
148
sh_cpufreq_cpu_ready(struct cpufreq_policy * policy)149 static void sh_cpufreq_cpu_ready(struct cpufreq_policy *policy)
150 {
151 struct device *dev = get_cpu_device(policy->cpu);
152
153 dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, "
154 "Maximum %u.%03u MHz.\n",
155 policy->min / 1000, policy->min % 1000,
156 policy->max / 1000, policy->max % 1000);
157 }
158
159 static struct cpufreq_driver sh_cpufreq_driver = {
160 .name = "sh",
161 .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
162 .get = sh_cpufreq_get,
163 .target = sh_cpufreq_target,
164 .verify = sh_cpufreq_verify,
165 .init = sh_cpufreq_cpu_init,
166 .exit = sh_cpufreq_cpu_exit,
167 .ready = sh_cpufreq_cpu_ready,
168 .attr = cpufreq_generic_attr,
169 };
170
sh_cpufreq_module_init(void)171 static int __init sh_cpufreq_module_init(void)
172 {
173 pr_notice("SuperH CPU frequency driver.\n");
174 return cpufreq_register_driver(&sh_cpufreq_driver);
175 }
176
sh_cpufreq_module_exit(void)177 static void __exit sh_cpufreq_module_exit(void)
178 {
179 cpufreq_unregister_driver(&sh_cpufreq_driver);
180 }
181
182 module_init(sh_cpufreq_module_init);
183 module_exit(sh_cpufreq_module_exit);
184
185 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
186 MODULE_DESCRIPTION("cpufreq driver for SuperH");
187 MODULE_LICENSE("GPL");
188