linux/drivers/cpufreq/at32ap-cpufreq.c

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/*
* Copyright (C) 2004-2007 Atmel Corporation
*
* Based on MIPS implementation arch/mips/kernel/time.c
* Copyright 2001 MontaVista Software Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/*#define DEBUG*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/slab.h>
static struct cpufreq_frequency_table *freq_table;
static unsigned int ref_freq;
static unsigned long loops_per_jiffy_ref;
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 16:15:48 +02:00
static int at32_set_target(struct cpufreq_policy *policy, unsigned int index)
{
unsigned int old_freq, new_freq;
old_freq = policy->cur;
new_freq = freq_table[index].frequency;
if (!ref_freq) {
ref_freq = old_freq;
loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
}
if (old_freq < new_freq)
boot_cpu_data.loops_per_jiffy = cpufreq_scale(
loops_per_jiffy_ref, ref_freq, new_freq);
clk_set_rate(policy->clk, new_freq * 1000);
if (new_freq < old_freq)
boot_cpu_data.loops_per_jiffy = cpufreq_scale(
loops_per_jiffy_ref, ref_freq, new_freq);
return 0;
}
static int at32_cpufreq_driver_init(struct cpufreq_policy *policy)
{
unsigned int frequency, rate, min_freq;
struct clk *cpuclk;
int retval, steps, i;
if (policy->cpu != 0)
return -EINVAL;
cpuclk = clk_get(NULL, "cpu");
if (IS_ERR(cpuclk)) {
pr_debug("cpufreq: could not get CPU clk\n");
retval = PTR_ERR(cpuclk);
goto out_err;
}
min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
frequency = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
policy->cpuinfo.transition_latency = 0;
/*
* AVR32 CPU frequency rate scales in power of two between maximum and
* minimum, also add space for the table end marker.
*
* Further validate that the frequency is usable, and append it to the
* frequency table.
*/
steps = fls(frequency / min_freq) + 1;
freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
GFP_KERNEL);
if (!freq_table) {
retval = -ENOMEM;
goto out_err_put_clk;
}
for (i = 0; i < (steps - 1); i++) {
rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
if (rate != frequency)
freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
else
freq_table[i].frequency = frequency;
frequency /= 2;
}
policy->clk = cpuclk;
freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
retval = cpufreq_table_validate_and_show(policy, freq_table);
if (!retval) {
printk("cpufreq: AT32AP CPU frequency driver\n");
return 0;
}
kfree(freq_table);
out_err_put_clk:
clk_put(cpuclk);
out_err:
return retval;
}
static struct cpufreq_driver at32_driver = {
.name = "at32ap",
.init = at32_cpufreq_driver_init,
.verify = cpufreq_generic_frequency_table_verify,
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 16:15:48 +02:00
.target_index = at32_set_target,
.get = cpufreq_generic_get,
.flags = CPUFREQ_STICKY,
};
static int __init at32_cpufreq_init(void)
{
return cpufreq_register_driver(&at32_driver);
}
late_initcall(at32_cpufreq_init);