/*
* Copyright (C) 2012 Freescale Semiconductor, Inc.
*
* The OPP code in function cpu0_set_target() is reused from
* drivers/cpufreq/omap-cpufreq.c
*
* 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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/opp.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
static unsigned int transition_latency;
static unsigned int voltage_tolerance; /* in percentage */
static struct device *cpu_dev;
static struct clk *cpu_clk;
static struct regulator *cpu_reg;
static struct cpufreq_frequency_table *freq_table;
static int cpu0_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, freq_table);
}
static unsigned int cpu0_get_speed(unsigned int cpu)
{
return clk_get_rate(cpu_clk) / 1000;
}
static int cpu0_set_target(struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
struct cpufreq_freqs freqs;
struct opp *opp;
unsigned long freq_Hz, volt = 0, volt_old = 0, tol = 0;
unsigned int index, cpu;
int ret;
ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
relation, &index);
if (ret) {
pr_err("failed to match target freqency %d: %d\n",
target_freq, ret);
return ret;
}
freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
if (freq_Hz < 0)
freq_Hz = freq_table[index].frequency * 1000;
freqs.new = freq_Hz / 1000;
freqs.old = clk_get_rate(cpu_clk) / 1000;
if (freqs.old == freqs.new)
return 0;
for_each_online_cpu(cpu) {
freqs.cpu = cpu;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
if (cpu_reg) {
opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);
if (IS_ERR(opp)) {
pr_err("failed to find OPP for %ld\n", freq_Hz);
return PTR_ERR(opp);
}
volt = opp_get_voltage(opp);
tol = volt * voltage_tolerance / 100;
volt_old = regulator_get_voltage(cpu_reg);
}
pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
freqs.new / 1000, volt ? volt / 1000 : -1);
/* scaling up? scale voltage before frequency */
if (cpu_reg && freqs.new > freqs.old) {
ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
if (ret) {
pr_err("failed to scale voltage up: %d\n", ret);
freqs.new = freqs.old;
return ret;
}
}
ret = clk_set_rate(cpu_clk, freqs.new * 1000);
if (ret) {
pr_err("failed to set clock rate: %d\n", ret);
if (cpu_reg)
regulator_set_voltage_tol(cpu_reg, volt_old, tol);
return ret;
}
/* scaling down? scale voltage after frequency */
if (cpu_reg && freqs.new < freqs.old) {
ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
if (ret) {
pr_err("failed to scale voltage down: %d\n", ret);
clk_set_rate(cpu_clk, freqs.old * 1000);
freqs.new = freqs.old;
return ret;
}
}
for_each_online_cpu(cpu) {
freqs.cpu = cpu;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
return 0;
}
static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
{
int ret;
if (policy->cpu != 0)
return -EINVAL;
ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (ret) {
pr_err("invalid frequency table: %d\n", ret);
return ret;
}
policy->cpuinfo.transition_latency = transition_latency;
policy->cur = clk_get_rate(cpu_clk) / 1000;
/*
* The driver only supports the SMP configuartion where all processors
* share the clock and voltage and clock. Use cpufreq affected_cpus
* interface to have all CPUs scaled together.
*/
policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
cpumask_setall(policy->cpus);
cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
return 0;
}
static int cpu0_cpufreq_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_put_attr(policy->cpu);
return 0;
}
static struct freq_attr *cpu0_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver cpu0_cpufreq_driver = {
.flags = CPUFREQ_STICKY,
.verify = cpu0_verify_speed,
.target = cpu0_set_target,
.get = cpu0_get_speed,
.init = cpu0_cpufreq_init,
.exit = cpu0_cpufreq_exit,
.name = "generic_cpu0",
.attr = cpu0_cpufreq_attr,
};
static int cpu0_cpufreq_driver_init(void)
{
struct device_node *np;
int ret;
np = of_find_node_by_path("/cpus/cpu@0");
if (!np) {
pr_err("failed to find cpu0 node\n");
return -ENOENT;
}
cpu_dev = get_cpu_device(0);
if (!cpu_dev) {
pr_err("failed to get cpu0 device\n");
ret = -ENODEV;
goto out_put_node;
}
cpu_dev->of_node = np;
cpu_clk = clk_get(cpu_dev, NULL);
if (IS_ERR(cpu_clk)) {
ret = PTR_ERR(cpu_clk);
pr_err("failed to get cpu0 clock: %d\n", ret);
goto out_put_node;
}
cpu_reg = regulator_get(cpu_dev, "cpu0");
if (IS_ERR(cpu_reg)) {
pr_warn("failed to get cpu0 regulator\n");
cpu_reg = NULL;
}
ret = of_init_opp_table(cpu_dev);
if (ret) {
pr_err("failed to init OPP table: %d\n", ret);
goto out_put_node;
}
ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
if (ret) {
pr_err("failed to init cpufreq table: %d\n", ret);
goto out_put_node;
}
of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);
if (of_property_read_u32(np, "clock-latency", &transition_latency))
transition_latency = CPUFREQ_ETERNAL;
if (cpu_reg) {
struct opp *opp;
unsigned long min_uV, max_uV;
int i;
/*
* OPP is maintained in order of increasing frequency, and
* freq_table initialised from OPP is therefore sorted in the
* same order.
*/
for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
;
opp = opp_find_freq_exact(cpu_dev,
freq_table[0].frequency * 1000, true);
min_uV = opp_get_voltage(opp);
opp = opp_find_freq_exact(cpu_dev,
freq_table[i-1].frequency * 1000, true);
max_uV = opp_get_voltage(opp);
ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
if (ret > 0)
transition_latency += ret * 1000;
}
ret = cpufreq_register_driver(&cpu0_cpufreq_driver);
if (ret) {
pr_err("failed register driver: %d\n", ret);
goto out_free_table;
}
of_node_put(np);
return 0;
out_free_table:
opp_free_cpufreq_table(cpu_dev, &freq_table);
out_put_node:
of_node_put(np);
return ret;
}
late_initcall(cpu0_cpufreq_driver_init);
MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
MODULE_LICENSE("GPL");
