cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sh-cpufreq.c (4479B)

      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");