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
31static DEFINE_PER_CPU(struct clk, sh_cpuclk);
32
33struct cpufreq_target {
34	struct cpufreq_policy	*policy;
35	unsigned int		freq;
36};
37
38static unsigned int sh_cpufreq_get(unsigned int cpu)
39{
40	return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
41}
42
43static 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 */
81static 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
90static 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
108static 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
139static 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
149static 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
159static 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
171static 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
177static void __exit sh_cpufreq_module_exit(void)
178{
179	cpufreq_unregister_driver(&sh_cpufreq_driver);
180}
181
182module_init(sh_cpufreq_module_init);
183module_exit(sh_cpufreq_module_exit);
184
185MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
186MODULE_DESCRIPTION("cpufreq driver for SuperH");
187MODULE_LICENSE("GPL");
188