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/*
* CPU frequency scaling for OMAP
*
* Copyright (C) 2005 Nokia Corporation
* Written by Tony Lindgren <tony@atomide.com>
*
* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
*
* Copyright (C) 2007-2011 Texas Instruments, Inc.
* - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
*
* 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/kernel.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/opp.h>
#include <linux/cpu.h>
#include <asm/system.h>
#include <asm/smp_plat.h>
#include <asm/cpu.h>
#include <plat/clock.h>
#include <plat/omap-pm.h>
#include <plat/common.h>
#include <mach/hardware.h>
#define VERY_HI_RATE 900000000
#ifdef CONFIG_SMP
struct lpj_info {
unsigned long ref;
unsigned int freq;
};
static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
static struct lpj_info global_lpj_ref;
#endif
static struct cpufreq_frequency_table *freq_table;
static struct clk *mpu_clk;
static char *mpu_clk_name;
static struct device *mpu_dev;
static int omap_verify_speed(struct cpufreq_policy *policy)
{
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(mpu_clk, policy->min * 1000) / 1000;
policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
return 0;
}
static unsigned int omap_getspeed(unsigned int cpu)
{
unsigned long rate;
if (cpu >= NR_CPUS)
return 0;
rate = clk_get_rate(mpu_clk) / 1000;
return rate;
}
static int omap_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
int i, ret = 0;
struct cpufreq_freqs freqs;
/* Ensure desired rate is within allowed range. Some govenors
* (ondemand) will just pass target_freq=0 to get the minimum. */
if (target_freq < policy->min)
target_freq = policy->min;
if (target_freq > policy->max)
target_freq = policy->max;
freqs.old = omap_getspeed(policy->cpu);
freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
freqs.cpu = policy->cpu;
if (freqs.old == freqs.new && policy->cur == freqs.new)
return ret;
/* notifiers */
for_each_cpu(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
#ifdef CONFIG_CPU_FREQ_DEBUG
pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
#endif
ret = clk_set_rate(mpu_clk, freqs.new * 1000);
freqs.new = omap_getspeed(policy->cpu);
#ifdef CONFIG_SMP
/*
* Note that loops_per_jiffy is not updated on SMP systems in
* cpufreq driver. So, update the per-CPU loops_per_jiffy value
* on frequency transition. We need to update all dependent CPUs.
*/
for_each_cpu(i, policy->cpus) {
struct lpj_info *lpj = &per_cpu(lpj_ref, i);
if (!lpj->freq) {
lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
lpj->freq = freqs.old;
}
per_cpu(cpu_data, i).loops_per_jiffy =
cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
}
/* And don't forget to adjust the global one */
if (!global_lpj_ref.freq) {
global_lpj_ref.ref = loops_per_jiffy;
global_lpj_ref.freq = freqs.old;
}
loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
freqs.new);
#endif
/* notifiers */
for_each_cpu(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
return ret;
}
static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
{
int result = 0;
mpu_clk = clk_get(NULL, mpu_clk_name);
if (IS_ERR(mpu_clk))
return PTR_ERR(mpu_clk);
if (policy->cpu >= NR_CPUS)
return -EINVAL;
policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
opp_init_cpufreq_table(mpu_dev, &freq_table);
if (freq_table) {
result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (!result)
cpufreq_frequency_table_get_attr(freq_table,
policy->cpu);
} else {
policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
VERY_HI_RATE) / 1000;
}
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = omap_getspeed(policy->cpu);
/*
* On OMAP SMP configuartion, both processors share the voltage
* and clock. So both CPUs needs to be scaled together and hence
* needs software co-ordination. Use cpufreq affected_cpus
* interface to handle this scenario. Additional is_smp() check
* is to keep SMP_ON_UP build working.
*/
if (is_smp()) {
policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
cpumask_setall(policy->cpus);
}
/* FIXME: what's the actual transition time? */
policy->cpuinfo.transition_latency = 300 * 1000;
return 0;
}
static int omap_cpu_exit(struct cpufreq_policy *policy)
{
clk_exit_cpufreq_table(&freq_table);
clk_put(mpu_clk);
return 0;
}
static struct freq_attr *omap_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver omap_driver = {
.flags = CPUFREQ_STICKY,
.verify = omap_verify_speed,
.target = omap_target,
.get = omap_getspeed,
.init = omap_cpu_init,
.exit = omap_cpu_exit,
.name = "omap",
.attr = omap_cpufreq_attr,
};
static int __init omap_cpufreq_init(void)
{
if (cpu_is_omap24xx())
mpu_clk_name = "virt_prcm_set";
else if (cpu_is_omap34xx())
mpu_clk_name = "dpll1_ck";
else if (cpu_is_omap44xx())
mpu_clk_name = "dpll_mpu_ck";
if (!mpu_clk_name) {
pr_err("%s: unsupported Silicon?\n", __func__);
return -EINVAL;
}
mpu_dev = omap2_get_mpuss_device();
if (!mpu_dev) {
pr_warning("%s: unable to get the mpu device\n", __func__);
return -EINVAL;
}
return cpufreq_register_driver(&omap_driver);
}
static void __exit omap_cpufreq_exit(void)
{
cpufreq_unregister_driver(&omap_driver);
}
MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
MODULE_LICENSE("GPL");
module_init(omap_cpufreq_init);
module_exit(omap_cpufreq_exit);
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