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
30static DEFINE_PER_CPU(struct clk, sh_cpuclk);
31
32struct cpufreq_target {
33	struct cpufreq_policy	*policy;
34	unsigned int		freq;
35};
36
37static unsigned int sh_cpufreq_get(unsigned int cpu)
38{
39	return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
40}
41
42static 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(cpuclk, 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(target->policy, &freqs);
70	clk_set_rate(cpuclk, freq);
71	cpufreq_freq_transition_end(target->policy, &freqs, 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 */
80static 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
89static 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, freq_table);
97
98	cpufreq_verify_within_cpu_limits(policy);
99
100	policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
101	policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
102
103	cpufreq_verify_within_cpu_limits(policy);
104	return 0;
105}
106
107static 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, "cpu_clk");
117	if (IS_ERR(cpuclk)) {
118		dev_err(dev, "couldn't get CPU clk\n");
119		return PTR_ERR(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(cpuclk, 1) + 500) / 1000;
131		policy->max = policy->cpuinfo.max_freq =
132			(clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
133	}
134
135	return 0;
136}
137
138static 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(cpuclk);
144
145	return 0;
146}
147
148static 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
159static int __init sh_cpufreq_module_init(void)
160{
161	pr_notice("SuperH CPU frequency driver.\n");
162	return cpufreq_register_driver(&sh_cpufreq_driver);
163}
164
165static void __exit sh_cpufreq_module_exit(void)
166{
167	cpufreq_unregister_driver(&sh_cpufreq_driver);
168}
169
170module_init(sh_cpufreq_module_init);
171module_exit(sh_cpufreq_module_exit);
172
173MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
174MODULE_DESCRIPTION("cpufreq driver for SuperH");
175MODULE_LICENSE("GPL");
176