linux/drivers/cpufreq/integrator-cpufreq.c
Viresh Kumar ae6b427132 cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag
Sometimes boot loaders set CPU frequency to a value outside of frequency table
present with cpufreq core. In such cases CPU might be unstable if it has to run
on that frequency for long duration of time and so its better to set it to a
frequency which is specified in frequency table.

On some systems we can't really say what frequency we're running at the moment
and so for these we shouldn't check if we are running at a frequency present in
frequency table. And so we really can't force this for all the cpufreq drivers.

Hence we are created another flag here: CPUFREQ_NEED_INITIAL_FREQ_CHECK that
will be marked by platforms which want to go for this check at boot time.

Initially this is done for all ARM platforms but others may follow if required.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-06 14:17:25 +01:00

241 lines
5.7 KiB
C

/*
* Copyright (C) 2001-2002 Deep Blue Solutions Ltd.
*
* 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.
*
* CPU support functions
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <asm/mach-types.h>
#include <asm/hardware/icst.h>
static void __iomem *cm_base;
/* The cpufreq driver only use the OSC register */
#define INTEGRATOR_HDR_OSC_OFFSET 0x08
#define INTEGRATOR_HDR_LOCK_OFFSET 0x14
static struct cpufreq_driver integrator_driver;
static const struct icst_params lclk_params = {
.ref = 24000000,
.vco_max = ICST525_VCO_MAX_5V,
.vco_min = ICST525_VCO_MIN,
.vd_min = 8,
.vd_max = 132,
.rd_min = 24,
.rd_max = 24,
.s2div = icst525_s2div,
.idx2s = icst525_idx2s,
};
static const struct icst_params cclk_params = {
.ref = 24000000,
.vco_max = ICST525_VCO_MAX_5V,
.vco_min = ICST525_VCO_MIN,
.vd_min = 12,
.vd_max = 160,
.rd_min = 24,
.rd_max = 24,
.s2div = icst525_s2div,
.idx2s = icst525_idx2s,
};
/*
* Validate the speed policy.
*/
static int integrator_verify_policy(struct cpufreq_policy *policy)
{
struct icst_vco vco;
cpufreq_verify_within_cpu_limits(policy);
vco = icst_hz_to_vco(&cclk_params, policy->max * 1000);
policy->max = icst_hz(&cclk_params, vco) / 1000;
vco = icst_hz_to_vco(&cclk_params, policy->min * 1000);
policy->min = icst_hz(&cclk_params, vco) / 1000;
cpufreq_verify_within_cpu_limits(policy);
return 0;
}
static int integrator_set_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
cpumask_t cpus_allowed;
int cpu = policy->cpu;
struct icst_vco vco;
struct cpufreq_freqs freqs;
u_int cm_osc;
/*
* Save this threads cpus_allowed mask.
*/
cpus_allowed = current->cpus_allowed;
/*
* Bind to the specified CPU. When this call returns,
* we should be running on the right CPU.
*/
set_cpus_allowed(current, cpumask_of_cpu(cpu));
BUG_ON(cpu != smp_processor_id());
/* get current setting */
cm_osc = __raw_readl(cm_base + INTEGRATOR_HDR_OSC_OFFSET);
if (machine_is_integrator()) {
vco.s = (cm_osc >> 8) & 7;
} else if (machine_is_cintegrator()) {
vco.s = 1;
}
vco.v = cm_osc & 255;
vco.r = 22;
freqs.old = icst_hz(&cclk_params, vco) / 1000;
/* icst_hz_to_vco rounds down -- so we need the next
* larger freq in case of CPUFREQ_RELATION_L.
*/
if (relation == CPUFREQ_RELATION_L)
target_freq += 999;
if (target_freq > policy->max)
target_freq = policy->max;
vco = icst_hz_to_vco(&cclk_params, target_freq * 1000);
freqs.new = icst_hz(&cclk_params, vco) / 1000;
if (freqs.old == freqs.new) {
set_cpus_allowed(current, cpus_allowed);
return 0;
}
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
cm_osc = __raw_readl(cm_base + INTEGRATOR_HDR_OSC_OFFSET);
if (machine_is_integrator()) {
cm_osc &= 0xfffff800;
cm_osc |= vco.s << 8;
} else if (machine_is_cintegrator()) {
cm_osc &= 0xffffff00;
}
cm_osc |= vco.v;
__raw_writel(0xa05f, cm_base + INTEGRATOR_HDR_LOCK_OFFSET);
__raw_writel(cm_osc, cm_base + INTEGRATOR_HDR_OSC_OFFSET);
__raw_writel(0, cm_base + INTEGRATOR_HDR_LOCK_OFFSET);
/*
* Restore the CPUs allowed mask.
*/
set_cpus_allowed(current, cpus_allowed);
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
return 0;
}
static unsigned int integrator_get(unsigned int cpu)
{
cpumask_t cpus_allowed;
unsigned int current_freq;
u_int cm_osc;
struct icst_vco vco;
cpus_allowed = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(cpu));
BUG_ON(cpu != smp_processor_id());
/* detect memory etc. */
cm_osc = __raw_readl(cm_base + INTEGRATOR_HDR_OSC_OFFSET);
if (machine_is_integrator()) {
vco.s = (cm_osc >> 8) & 7;
} else {
vco.s = 1;
}
vco.v = cm_osc & 255;
vco.r = 22;
current_freq = icst_hz(&cclk_params, vco) / 1000; /* current freq */
set_cpus_allowed(current, cpus_allowed);
return current_freq;
}
static int integrator_cpufreq_init(struct cpufreq_policy *policy)
{
/* set default policy and cpuinfo */
policy->max = policy->cpuinfo.max_freq = 160000;
policy->min = policy->cpuinfo.min_freq = 12000;
policy->cpuinfo.transition_latency = 1000000; /* 1 ms, assumed */
return 0;
}
static struct cpufreq_driver integrator_driver = {
.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = integrator_verify_policy,
.target = integrator_set_target,
.get = integrator_get,
.init = integrator_cpufreq_init,
.name = "integrator",
};
static int __init integrator_cpufreq_probe(struct platform_device *pdev)
{
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
cm_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!cm_base)
return -ENODEV;
return cpufreq_register_driver(&integrator_driver);
}
static void __exit integrator_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&integrator_driver);
}
static const struct of_device_id integrator_cpufreq_match[] = {
{ .compatible = "arm,core-module-integrator"},
{ },
};
static struct platform_driver integrator_cpufreq_driver = {
.driver = {
.name = "integrator-cpufreq",
.owner = THIS_MODULE,
.of_match_table = integrator_cpufreq_match,
},
.remove = __exit_p(integrator_cpufreq_remove),
};
module_platform_driver_probe(integrator_cpufreq_driver,
integrator_cpufreq_probe);
MODULE_AUTHOR ("Russell M. King");
MODULE_DESCRIPTION ("cpufreq driver for ARM Integrator CPUs");
MODULE_LICENSE ("GPL");