1/*
  2 * arch/sh/kernel/cpufreq.c
  3 *
  4 * cpufreq driver for the SuperH processors.
  5 *
  6 * Copyright (C) 2002 - 2012 Paul Mundt
  7 * Copyright (C) 2002 M. R. Brown
  8 *
  9 * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
 10 *
 11 *   Copyright (C) 2004-2007 Atmel Corporation
 12 *
 13 * This file is subject to the terms and conditions of the GNU General Public
 14 * License.  See the file "COPYING" in the main directory of this archive
 15 * for more details.
 16 */
 17#define pr_fmt(fmt) "cpufreq: " fmt
 18
 19#include <linux/types.h>
 20#include <linux/cpufreq.h>
 21#include <linux/kernel.h>
 22#include <linux/module.h>
 23#include <linux/init.h>
 24#include <linux/err.h>
 25#include <linux/cpumask.h>
 26#include <linux/cpu.h>
 27#include <linux/smp.h>
 28#include <linux/sched.h>	/* set_cpus_allowed() */
 29#include <linux/clk.h>
 30#include <linux/percpu.h>
 31#include <linux/sh_clk.h>
 32
 33static DEFINE_PER_CPU(struct clk, sh_cpuclk);
 34
 35static unsigned int sh_cpufreq_get(unsigned int cpu)
 36{
 37	return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
 38}
 39
 40/*
 41 * Here we notify other drivers of the proposed change and the final change.
 42 */
 43static int sh_cpufreq_target(struct cpufreq_policy *policy,
 44			     unsigned int target_freq,
 45			     unsigned int relation)
 46{
 47	unsigned int cpu = policy->cpu;
 48	struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
 49	cpumask_t cpus_allowed;
 50	struct cpufreq_freqs freqs;
 51	struct device *dev;
 52	long freq;
 53
 54	if (!cpu_online(cpu))
 55		return -ENODEV;
 56
 57	cpus_allowed = current->cpus_allowed;
 58	set_cpus_allowed_ptr(current, cpumask_of(cpu));
 59
 60	BUG_ON(smp_processor_id() != cpu);
 61
 62	dev = get_cpu_device(cpu);
 63
 64	/* Convert target_freq from kHz to Hz */
 65	freq = clk_round_rate(cpuclk, target_freq * 1000);
 66
 67	if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
 68		return -EINVAL;
 69
 70	dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000);
 71
 72	freqs.cpu	= cpu;
 73	freqs.old	= sh_cpufreq_get(cpu);
 74	freqs.new	= (freq + 500) / 1000;
 75	freqs.flags	= 0;
 76
 77	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 78	set_cpus_allowed_ptr(current, &cpus_allowed);
 79	clk_set_rate(cpuclk, freq);
 80	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 81
 82	dev_dbg(dev, "set frequency %lu Hz\n", freq);
 83
 84	return 0;
 85}
 86
 87static int sh_cpufreq_verify(struct cpufreq_policy *policy)
 88{
 89	struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
 90	struct cpufreq_frequency_table *freq_table;
 91
 92	freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
 93	if (freq_table)
 94		return cpufreq_frequency_table_verify(policy, freq_table);
 95
 96	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 97				     policy->cpuinfo.max_freq);
 98
 99	policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
100	policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
101
102	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
103				     policy->cpuinfo.max_freq);
104
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	if (!cpu_online(cpu))
116		return -ENODEV;
117
118	dev = get_cpu_device(cpu);
119
120	cpuclk = clk_get(dev, "cpu_clk");
121	if (IS_ERR(cpuclk)) {
122		dev_err(dev, "couldn't get CPU clk\n");
123		return PTR_ERR(cpuclk);
124	}
125
126	policy->cur = policy->min = policy->max = sh_cpufreq_get(cpu);
127
128	freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
129	if (freq_table) {
130		int result;
131
132		result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
133		if (!result)
134			cpufreq_frequency_table_get_attr(freq_table, cpu);
135	} else {
136		dev_notice(dev, "no frequency table found, falling back "
137			   "to rate rounding.\n");
138
139		policy->cpuinfo.min_freq =
140			(clk_round_rate(cpuclk, 1) + 500) / 1000;
141		policy->cpuinfo.max_freq =
142			(clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
143	}
144
145	policy->min = policy->cpuinfo.min_freq;
146	policy->max = policy->cpuinfo.max_freq;
147
148	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
149
150	dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, "
151	       "Maximum %u.%03u MHz.\n",
152	       policy->min / 1000, policy->min % 1000,
153	       policy->max / 1000, policy->max % 1000);
154
155	return 0;
156}
157
158static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
159{
160	unsigned int cpu = policy->cpu;
161	struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
162
163	cpufreq_frequency_table_put_attr(cpu);
164	clk_put(cpuclk);
165
166	return 0;
167}
168
169static struct freq_attr *sh_freq_attr[] = {
170	&cpufreq_freq_attr_scaling_available_freqs,
171	NULL,
172};
173
174static struct cpufreq_driver sh_cpufreq_driver = {
175	.owner		= THIS_MODULE,
176	.name		= "sh",
177	.get		= sh_cpufreq_get,
178	.target		= sh_cpufreq_target,
179	.verify		= sh_cpufreq_verify,
180	.init		= sh_cpufreq_cpu_init,
181	.exit		= sh_cpufreq_cpu_exit,
182	.attr		= sh_freq_attr,
183};
184
185static int __init sh_cpufreq_module_init(void)
186{
187	pr_notice("SuperH CPU frequency driver.\n");
188	return cpufreq_register_driver(&sh_cpufreq_driver);
189}
190
191static void __exit sh_cpufreq_module_exit(void)
192{
193	cpufreq_unregister_driver(&sh_cpufreq_driver);
194}
195
196module_init(sh_cpufreq_module_init);
197module_exit(sh_cpufreq_module_exit);
198
199MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
200MODULE_DESCRIPTION("cpufreq driver for SuperH");
201MODULE_LICENSE("GPL");