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