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https://github.com/torvalds/linux
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017189b51e
Many common initializations of struct policy are moved to core now and hence this driver doesn't need to do it. This patch removes such code. Most recent of those changes is to call ->get() in the core after calling ->init(). Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
152 lines
3.7 KiB
C
152 lines
3.7 KiB
C
/*
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* Copyright (C) 2004-2007 Atmel Corporation
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*
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* Based on MIPS implementation arch/mips/kernel/time.c
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* Copyright 2001 MontaVista Software Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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/*#define DEBUG*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/cpufreq.h>
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#include <linux/io.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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static struct clk *cpuclk;
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static struct cpufreq_frequency_table *freq_table;
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static unsigned int at32_get_speed(unsigned int cpu)
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{
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/* No SMP support */
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if (cpu)
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return 0;
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return (unsigned int)((clk_get_rate(cpuclk) + 500) / 1000);
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}
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static unsigned int ref_freq;
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static unsigned long loops_per_jiffy_ref;
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static int at32_set_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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struct cpufreq_freqs freqs;
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long freq;
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/* Convert target_freq from kHz to Hz */
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freq = clk_round_rate(cpuclk, target_freq * 1000);
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/* Check if policy->min <= new_freq <= policy->max */
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if(freq < (policy->min * 1000) || freq > (policy->max * 1000))
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return -EINVAL;
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pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
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freqs.old = at32_get_speed(0);
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freqs.new = (freq + 500) / 1000;
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freqs.flags = 0;
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if (!ref_freq) {
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ref_freq = freqs.old;
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loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
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}
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
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if (freqs.old < freqs.new)
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boot_cpu_data.loops_per_jiffy = cpufreq_scale(
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loops_per_jiffy_ref, ref_freq, freqs.new);
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clk_set_rate(cpuclk, freq);
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if (freqs.new < freqs.old)
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boot_cpu_data.loops_per_jiffy = cpufreq_scale(
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loops_per_jiffy_ref, ref_freq, freqs.new);
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
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pr_debug("cpufreq: set frequency %lu Hz\n", freq);
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return 0;
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}
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static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
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{
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unsigned int frequency, rate, min_freq;
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int retval, steps, i;
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if (policy->cpu != 0)
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return -EINVAL;
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cpuclk = clk_get(NULL, "cpu");
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if (IS_ERR(cpuclk)) {
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pr_debug("cpufreq: could not get CPU clk\n");
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retval = PTR_ERR(cpuclk);
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goto out_err;
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}
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min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
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frequency = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
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policy->cpuinfo.transition_latency = 0;
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/*
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* AVR32 CPU frequency rate scales in power of two between maximum and
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* minimum, also add space for the table end marker.
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*
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* Further validate that the frequency is usable, and append it to the
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* frequency table.
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*/
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steps = fls(frequency / min_freq) + 1;
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freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
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GFP_KERNEL);
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if (!freq_table) {
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retval = -ENOMEM;
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goto out_err_put_clk;
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}
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for (i = 0; i < (steps - 1); i++) {
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rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
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if (rate != frequency)
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freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
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else
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freq_table[i].frequency = frequency;
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frequency /= 2;
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}
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freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
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retval = cpufreq_table_validate_and_show(policy, freq_table);
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if (!retval) {
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printk("cpufreq: AT32AP CPU frequency driver\n");
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return 0;
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}
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kfree(freq_table);
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out_err_put_clk:
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clk_put(cpuclk);
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out_err:
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return retval;
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}
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static struct cpufreq_driver at32_driver = {
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.name = "at32ap",
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.init = at32_cpufreq_driver_init,
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.verify = cpufreq_generic_frequency_table_verify,
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.target = at32_set_target,
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.get = at32_get_speed,
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.flags = CPUFREQ_STICKY,
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};
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static int __init at32_cpufreq_init(void)
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{
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return cpufreq_register_driver(&at32_driver);
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}
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late_initcall(at32_cpufreq_init);
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