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linux/drivers/cpufreq/exynos5440-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

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/*
* Copyright (c) 2013 Samsung Electronics Co., Ltd.
* http://www.samsung.com
*
* Amit Daniel Kachhap <amit.daniel@samsung.com>
*
* EXYNOS5440 - CPU frequency scaling support
*
* 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/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
/* Register definitions */
#define XMU_DVFS_CTRL 0x0060
#define XMU_PMU_P0_7 0x0064
#define XMU_C0_3_PSTATE 0x0090
#define XMU_P_LIMIT 0x00a0
#define XMU_P_STATUS 0x00a4
#define XMU_PMUEVTEN 0x00d0
#define XMU_PMUIRQEN 0x00d4
#define XMU_PMUIRQ 0x00d8
/* PMU mask and shift definations */
#define P_VALUE_MASK 0x7
#define XMU_DVFS_CTRL_EN_SHIFT 0
#define P0_7_CPUCLKDEV_SHIFT 21
#define P0_7_CPUCLKDEV_MASK 0x7
#define P0_7_ATBCLKDEV_SHIFT 18
#define P0_7_ATBCLKDEV_MASK 0x7
#define P0_7_CSCLKDEV_SHIFT 15
#define P0_7_CSCLKDEV_MASK 0x7
#define P0_7_CPUEMA_SHIFT 28
#define P0_7_CPUEMA_MASK 0xf
#define P0_7_L2EMA_SHIFT 24
#define P0_7_L2EMA_MASK 0xf
#define P0_7_VDD_SHIFT 8
#define P0_7_VDD_MASK 0x7f
#define P0_7_FREQ_SHIFT 0
#define P0_7_FREQ_MASK 0xff
#define C0_3_PSTATE_VALID_SHIFT 8
#define C0_3_PSTATE_CURR_SHIFT 4
#define C0_3_PSTATE_NEW_SHIFT 0
#define PSTATE_CHANGED_EVTEN_SHIFT 0
#define PSTATE_CHANGED_IRQEN_SHIFT 0
#define PSTATE_CHANGED_SHIFT 0
/* some constant values for clock divider calculation */
#define CPU_DIV_FREQ_MAX 500
#define CPU_DBG_FREQ_MAX 375
#define CPU_ATB_FREQ_MAX 500
#define PMIC_LOW_VOLT 0x30
#define PMIC_HIGH_VOLT 0x28
#define CPUEMA_HIGH 0x2
#define CPUEMA_MID 0x4
#define CPUEMA_LOW 0x7
#define L2EMA_HIGH 0x1
#define L2EMA_MID 0x3
#define L2EMA_LOW 0x4
#define DIV_TAB_MAX 2
/* frequency unit is 20MHZ */
#define FREQ_UNIT 20
#define MAX_VOLTAGE 1550000 /* In microvolt */
#define VOLTAGE_STEP 12500 /* In microvolt */
#define CPUFREQ_NAME "exynos5440_dvfs"
#define DEF_TRANS_LATENCY 100000
enum cpufreq_level_index {
L0, L1, L2, L3, L4,
L5, L6, L7, L8, L9,
};
#define CPUFREQ_LEVEL_END (L7 + 1)
struct exynos_dvfs_data {
void __iomem *base;
struct resource *mem;
int irq;
struct clk *cpu_clk;
unsigned int cur_frequency;
unsigned int latency;
struct cpufreq_frequency_table *freq_table;
unsigned int freq_count;
struct device *dev;
bool dvfs_enabled;
struct work_struct irq_work;
};
static struct exynos_dvfs_data *dvfs_info;
static DEFINE_MUTEX(cpufreq_lock);
static struct cpufreq_freqs freqs;
static int init_div_table(void)
{
struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
unsigned int tmp, clk_div, ema_div, freq, volt_id;
int i = 0;
struct dev_pm_opp *opp;
rcu_read_lock();
for (i = 0; freq_tbl[i].frequency != CPUFREQ_TABLE_END; i++) {
opp = dev_pm_opp_find_freq_exact(dvfs_info->dev,
freq_tbl[i].frequency * 1000, true);
if (IS_ERR(opp)) {
rcu_read_unlock();
dev_err(dvfs_info->dev,
"failed to find valid OPP for %u KHZ\n",
freq_tbl[i].frequency);
return PTR_ERR(opp);
}
freq = freq_tbl[i].frequency / 1000; /* In MHZ */
clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
<< P0_7_CPUCLKDEV_SHIFT;
clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
<< P0_7_ATBCLKDEV_SHIFT;
clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
<< P0_7_CSCLKDEV_SHIFT;
/* Calculate EMA */
volt_id = dev_pm_opp_get_voltage(opp);
volt_id = (MAX_VOLTAGE - volt_id) / VOLTAGE_STEP;
if (volt_id < PMIC_HIGH_VOLT) {
ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
(L2EMA_HIGH << P0_7_L2EMA_SHIFT);
} else if (volt_id > PMIC_LOW_VOLT) {
ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
(L2EMA_LOW << P0_7_L2EMA_SHIFT);
} else {
ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
(L2EMA_MID << P0_7_L2EMA_SHIFT);
}
tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
| ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
__raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * i);
}
rcu_read_unlock();
return 0;
}
static void exynos_enable_dvfs(void)
{
unsigned int tmp, i, cpu;
struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
/* Disable DVFS */
__raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);
/* Enable PSTATE Change Event */
tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
__raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);
/* Enable PSTATE Change IRQ */
tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);
/* Set initial performance index */
for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
if (freq_table[i].frequency == dvfs_info->cur_frequency)
break;
if (freq_table[i].frequency == CPUFREQ_TABLE_END) {
dev_crit(dvfs_info->dev, "Boot up frequency not supported\n");
/* Assign the highest frequency */
i = 0;
dvfs_info->cur_frequency = freq_table[i].frequency;
}
dev_info(dvfs_info->dev, "Setting dvfs initial frequency = %uKHZ",
dvfs_info->cur_frequency);
for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
tmp |= (i << C0_3_PSTATE_NEW_SHIFT);
__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
}
/* Enable DVFS */
__raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
dvfs_info->base + XMU_DVFS_CTRL);
}
static unsigned int exynos_getspeed(unsigned int cpu)
{
return dvfs_info->cur_frequency;
}
static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
{
unsigned int tmp;
int i;
struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
mutex_lock(&cpufreq_lock);
freqs.old = dvfs_info->cur_frequency;
freqs.new = freq_table[index].frequency;
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
/* Set the target frequency in all C0_3_PSTATE register */
for_each_cpu(i, policy->cpus) {
tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
tmp |= (index << C0_3_PSTATE_NEW_SHIFT);
__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
}
mutex_unlock(&cpufreq_lock);
return 0;
}
static void exynos_cpufreq_work(struct work_struct *work)
{
unsigned int cur_pstate, index;
struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
/* Ensure we can access cpufreq structures */
if (unlikely(dvfs_info->dvfs_enabled == false))
goto skip_work;
mutex_lock(&cpufreq_lock);
freqs.old = dvfs_info->cur_frequency;
cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
else
index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;
if (likely(index < dvfs_info->freq_count)) {
freqs.new = freq_table[index].frequency;
dvfs_info->cur_frequency = freqs.new;
} else {
dev_crit(dvfs_info->dev, "New frequency out of range\n");
freqs.new = dvfs_info->cur_frequency;
}
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
cpufreq_cpu_put(policy);
mutex_unlock(&cpufreq_lock);
skip_work:
enable_irq(dvfs_info->irq);
}
static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
{
unsigned int tmp;
tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
disable_irq_nosync(irq);
schedule_work(&dvfs_info->irq_work);
}
return IRQ_HANDLED;
}
static void exynos_sort_descend_freq_table(void)
{
struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
int i = 0, index;
unsigned int tmp_freq;
/*
* Exynos5440 clock controller state logic expects the cpufreq table to
* be in descending order. But the OPP library constructs the table in
* ascending order. So to make the table descending we just need to
* swap the i element with the N - i element.
*/
for (i = 0; i < dvfs_info->freq_count / 2; i++) {
index = dvfs_info->freq_count - i - 1;
tmp_freq = freq_tbl[i].frequency;
freq_tbl[i].frequency = freq_tbl[index].frequency;
freq_tbl[index].frequency = tmp_freq;
}
}
static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
return cpufreq_generic_init(policy, dvfs_info->freq_table,
dvfs_info->latency);
}
static struct cpufreq_driver exynos_driver = {
.flags = CPUFREQ_STICKY | CPUFREQ_ASYNC_NOTIFICATION |
CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = exynos_target,
.get = exynos_getspeed,
.init = exynos_cpufreq_cpu_init,
.exit = cpufreq_generic_exit,
.name = CPUFREQ_NAME,
.attr = cpufreq_generic_attr,
};
static const struct of_device_id exynos_cpufreq_match[] = {
{
.compatible = "samsung,exynos5440-cpufreq",
},
{},
};
MODULE_DEVICE_TABLE(of, exynos_cpufreq_match);
static int exynos_cpufreq_probe(struct platform_device *pdev)
{
int ret = -EINVAL;
struct device_node *np;
struct resource res;
np = pdev->dev.of_node;
if (!np)
return -ENODEV;
dvfs_info = devm_kzalloc(&pdev->dev, sizeof(*dvfs_info), GFP_KERNEL);
if (!dvfs_info) {
ret = -ENOMEM;
goto err_put_node;
}
dvfs_info->dev = &pdev->dev;
ret = of_address_to_resource(np, 0, &res);
if (ret)
goto err_put_node;
dvfs_info->base = devm_ioremap_resource(dvfs_info->dev, &res);
if (IS_ERR(dvfs_info->base)) {
ret = PTR_ERR(dvfs_info->base);
goto err_put_node;
}
dvfs_info->irq = irq_of_parse_and_map(np, 0);
if (!dvfs_info->irq) {
dev_err(dvfs_info->dev, "No cpufreq irq found\n");
ret = -ENODEV;
goto err_put_node;
}
ret = of_init_opp_table(dvfs_info->dev);
if (ret) {
dev_err(dvfs_info->dev, "failed to init OPP table: %d\n", ret);
goto err_put_node;
}
ret = dev_pm_opp_init_cpufreq_table(dvfs_info->dev,
&dvfs_info->freq_table);
if (ret) {
dev_err(dvfs_info->dev,
"failed to init cpufreq table: %d\n", ret);
goto err_put_node;
}
dvfs_info->freq_count = dev_pm_opp_get_opp_count(dvfs_info->dev);
exynos_sort_descend_freq_table();
if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
dvfs_info->latency = DEF_TRANS_LATENCY;
dvfs_info->cpu_clk = devm_clk_get(dvfs_info->dev, "armclk");
if (IS_ERR(dvfs_info->cpu_clk)) {
dev_err(dvfs_info->dev, "Failed to get cpu clock\n");
ret = PTR_ERR(dvfs_info->cpu_clk);
goto err_free_table;
}
dvfs_info->cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
if (!dvfs_info->cur_frequency) {
dev_err(dvfs_info->dev, "Failed to get clock rate\n");
ret = -EINVAL;
goto err_free_table;
}
dvfs_info->cur_frequency /= 1000;
INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
ret = devm_request_irq(dvfs_info->dev, dvfs_info->irq,
exynos_cpufreq_irq, IRQF_TRIGGER_NONE,
CPUFREQ_NAME, dvfs_info);
if (ret) {
dev_err(dvfs_info->dev, "Failed to register IRQ\n");
goto err_free_table;
}
ret = init_div_table();
if (ret) {
dev_err(dvfs_info->dev, "Failed to initialise div table\n");
goto err_free_table;
}
exynos_enable_dvfs();
ret = cpufreq_register_driver(&exynos_driver);
if (ret) {
dev_err(dvfs_info->dev,
"%s: failed to register cpufreq driver\n", __func__);
goto err_free_table;
}
of_node_put(np);
dvfs_info->dvfs_enabled = true;
return 0;
err_free_table:
dev_pm_opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
err_put_node:
of_node_put(np);
dev_err(&pdev->dev, "%s: failed initialization\n", __func__);
return ret;
}
static int exynos_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&exynos_driver);
dev_pm_opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
return 0;
}
static struct platform_driver exynos_cpufreq_platdrv = {
.driver = {
.name = "exynos5440-cpufreq",
.owner = THIS_MODULE,
.of_match_table = exynos_cpufreq_match,
},
.probe = exynos_cpufreq_probe,
.remove = exynos_cpufreq_remove,
};
module_platform_driver(exynos_cpufreq_platdrv);
MODULE_AUTHOR("Amit Daniel Kachhap <amit.daniel@samsung.com>");
MODULE_DESCRIPTION("Exynos5440 cpufreq driver");
MODULE_LICENSE("GPL");
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