mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Viresh Kumar](/assets/img/avatar_default.png)
PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e either both should be called or both shouldn't be. In case we have started PRECHANGE notifier and found an error, we must call POSTCHANGE notifier with freqs.new = freqs.old to guarantee that sequence of calling notifiers is complete. Davinci driver was taking care of it but frequency isn't restored to freqs.old. This patch fixes it. Acked-by: Sekhar Nori <nsekhar@ti.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
234 lines
5.7 KiB
C
234 lines
5.7 KiB
C
/*
|
|
* CPU frequency scaling for DaVinci
|
|
*
|
|
* Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
|
|
*
|
|
* Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows:
|
|
*
|
|
* Copyright (C) 2005 Nokia Corporation
|
|
* Written by Tony Lindgren <tony@atomide.com>
|
|
*
|
|
* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
|
|
*
|
|
* Copyright (C) 2007-2008 Texas Instruments, Inc.
|
|
* Updated to support OMAP3
|
|
* Rajendra Nayak <rnayak@ti.com>
|
|
*
|
|
* 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.
|
|
*/
|
|
#include <linux/types.h>
|
|
#include <linux/cpufreq.h>
|
|
#include <linux/init.h>
|
|
#include <linux/err.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/export.h>
|
|
|
|
#include <mach/hardware.h>
|
|
#include <mach/cpufreq.h>
|
|
#include <mach/common.h>
|
|
|
|
struct davinci_cpufreq {
|
|
struct device *dev;
|
|
struct clk *armclk;
|
|
struct clk *asyncclk;
|
|
unsigned long asyncrate;
|
|
};
|
|
static struct davinci_cpufreq cpufreq;
|
|
|
|
static int davinci_verify_speed(struct cpufreq_policy *policy)
|
|
{
|
|
struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
|
|
struct cpufreq_frequency_table *freq_table = pdata->freq_table;
|
|
struct clk *armclk = cpufreq.armclk;
|
|
|
|
if (freq_table)
|
|
return cpufreq_frequency_table_verify(policy, freq_table);
|
|
|
|
if (policy->cpu)
|
|
return -EINVAL;
|
|
|
|
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
|
|
policy->cpuinfo.max_freq);
|
|
|
|
policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000;
|
|
policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000;
|
|
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
|
|
policy->cpuinfo.max_freq);
|
|
return 0;
|
|
}
|
|
|
|
static unsigned int davinci_getspeed(unsigned int cpu)
|
|
{
|
|
if (cpu)
|
|
return 0;
|
|
|
|
return clk_get_rate(cpufreq.armclk) / 1000;
|
|
}
|
|
|
|
static int davinci_target(struct cpufreq_policy *policy,
|
|
unsigned int target_freq, unsigned int relation)
|
|
{
|
|
int ret = 0;
|
|
unsigned int idx;
|
|
struct cpufreq_freqs freqs;
|
|
struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
|
|
struct clk *armclk = cpufreq.armclk;
|
|
|
|
freqs.old = davinci_getspeed(0);
|
|
freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000;
|
|
|
|
if (freqs.old == freqs.new)
|
|
return ret;
|
|
|
|
dev_dbg(cpufreq.dev, "transition: %u --> %u\n", freqs.old, freqs.new);
|
|
|
|
ret = cpufreq_frequency_table_target(policy, pdata->freq_table,
|
|
freqs.new, relation, &idx);
|
|
if (ret)
|
|
return -EINVAL;
|
|
|
|
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
|
|
|
|
/* if moving to higher frequency, up the voltage beforehand */
|
|
if (pdata->set_voltage && freqs.new > freqs.old) {
|
|
ret = pdata->set_voltage(idx);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
ret = clk_set_rate(armclk, idx);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (cpufreq.asyncclk) {
|
|
ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
/* if moving to lower freq, lower the voltage after lowering freq */
|
|
if (pdata->set_voltage && freqs.new < freqs.old)
|
|
pdata->set_voltage(idx);
|
|
|
|
out:
|
|
if (ret)
|
|
freqs.new = freqs.old;
|
|
|
|
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int davinci_cpu_init(struct cpufreq_policy *policy)
|
|
{
|
|
int result = 0;
|
|
struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
|
|
struct cpufreq_frequency_table *freq_table = pdata->freq_table;
|
|
|
|
if (policy->cpu != 0)
|
|
return -EINVAL;
|
|
|
|
/* Finish platform specific initialization */
|
|
if (pdata->init) {
|
|
result = pdata->init();
|
|
if (result)
|
|
return result;
|
|
}
|
|
|
|
policy->cur = davinci_getspeed(0);
|
|
|
|
result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
|
|
if (result) {
|
|
pr_err("%s: cpufreq_frequency_table_cpuinfo() failed",
|
|
__func__);
|
|
return result;
|
|
}
|
|
|
|
cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
|
|
|
|
/*
|
|
* Time measurement across the target() function yields ~1500-1800us
|
|
* time taken with no drivers on notification list.
|
|
* Setting the latency to 2000 us to accommodate addition of drivers
|
|
* to pre/post change notification list.
|
|
*/
|
|
policy->cpuinfo.transition_latency = 2000 * 1000;
|
|
return 0;
|
|
}
|
|
|
|
static int davinci_cpu_exit(struct cpufreq_policy *policy)
|
|
{
|
|
cpufreq_frequency_table_put_attr(policy->cpu);
|
|
return 0;
|
|
}
|
|
|
|
static struct freq_attr *davinci_cpufreq_attr[] = {
|
|
&cpufreq_freq_attr_scaling_available_freqs,
|
|
NULL,
|
|
};
|
|
|
|
static struct cpufreq_driver davinci_driver = {
|
|
.flags = CPUFREQ_STICKY,
|
|
.verify = davinci_verify_speed,
|
|
.target = davinci_target,
|
|
.get = davinci_getspeed,
|
|
.init = davinci_cpu_init,
|
|
.exit = davinci_cpu_exit,
|
|
.name = "davinci",
|
|
.attr = davinci_cpufreq_attr,
|
|
};
|
|
|
|
static int __init davinci_cpufreq_probe(struct platform_device *pdev)
|
|
{
|
|
struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
|
|
struct clk *asyncclk;
|
|
|
|
if (!pdata)
|
|
return -EINVAL;
|
|
if (!pdata->freq_table)
|
|
return -EINVAL;
|
|
|
|
cpufreq.dev = &pdev->dev;
|
|
|
|
cpufreq.armclk = clk_get(NULL, "arm");
|
|
if (IS_ERR(cpufreq.armclk)) {
|
|
dev_err(cpufreq.dev, "Unable to get ARM clock\n");
|
|
return PTR_ERR(cpufreq.armclk);
|
|
}
|
|
|
|
asyncclk = clk_get(cpufreq.dev, "async");
|
|
if (!IS_ERR(asyncclk)) {
|
|
cpufreq.asyncclk = asyncclk;
|
|
cpufreq.asyncrate = clk_get_rate(asyncclk);
|
|
}
|
|
|
|
return cpufreq_register_driver(&davinci_driver);
|
|
}
|
|
|
|
static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
|
|
{
|
|
clk_put(cpufreq.armclk);
|
|
|
|
if (cpufreq.asyncclk)
|
|
clk_put(cpufreq.asyncclk);
|
|
|
|
return cpufreq_unregister_driver(&davinci_driver);
|
|
}
|
|
|
|
static struct platform_driver davinci_cpufreq_driver = {
|
|
.driver = {
|
|
.name = "cpufreq-davinci",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.remove = __exit_p(davinci_cpufreq_remove),
|
|
};
|
|
|
|
int __init davinci_cpufreq_init(void)
|
|
{
|
|
return platform_driver_probe(&davinci_cpufreq_driver,
|
|
davinci_cpufreq_probe);
|
|
}
|
|
|