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/*
* Copyright (C) 2011-2013 Freescale Semiconductor, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*!
* @file busfreq-imx6.c
*
* @brief A common API for the Freescale Semiconductor iMX6 Busfreq API
*
* The APIs are for setting bus frequency to different values based on the
* highest freqeuncy requested.
*
* @ingroup PM
*/
#include <asm/cacheflush.h>
#include <asm/io.h>
#include <asm/mach/map.h>
#include <asm/mach-types.h>
#include <asm/tlb.h>
#include <linux/busfreq-imx6.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/proc_fs.h>
#include <linux/regulator/consumer.h>
#include <linux/sched.h>
#include <linux/suspend.h>
#include "hardware.h"
#define LPAPM_CLK 24000000
#define DDR_AUDIO_CLK 50000000
int high_bus_freq_mode;
int med_bus_freq_mode;
int audio_bus_freq_mode;
int low_bus_freq_mode;
static int bus_freq_scaling_initialized;
static struct device *busfreq_dev;
static int busfreq_suspended;
static int bus_freq_scaling_is_active;
static int high_bus_count, med_bus_count, audio_bus_count;
static unsigned int ddr_low_rate;
unsigned int ddr_med_rate;
unsigned int ddr_normal_rate;
extern int init_mmdc_settings(struct platform_device *dev);
extern int update_ddr_freq(int ddr_rate);
DEFINE_MUTEX(bus_freq_mutex);
static struct clk *pll2_400;
static struct clk *periph_clk;
static struct clk *periph_pre_clk;
static struct clk *periph_clk2_sel;
static struct clk *periph_clk2;
static struct clk *osc_clk;
static struct clk *cpu_clk;
static struct clk *pll3;
static struct clk *pll2;
static struct clk *pll2_200;
static struct delayed_work low_bus_freq_handler;
static struct delayed_work bus_freq_daemon;
int low_bus_freq;
int reduce_bus_freq(void)
{
int ret = 0;
clk_prepare_enable(pll3);
if (low_bus_freq) {
/* Need to ensure that PLL2_PFD_400M is kept ON. */
clk_prepare_enable(pll2_400);
update_ddr_freq(DDR_AUDIO_CLK);
/* Make sure periph clk's parent also got updated */
ret = clk_set_parent(periph_clk2_sel, pll3);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
ret = clk_set_parent(periph_pre_clk, pll2_200);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
ret = clk_set_parent(periph_clk, periph_pre_clk);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
audio_bus_freq_mode = 1;
low_bus_freq_mode = 0;
} else {
update_ddr_freq(LPAPM_CLK);
/* Make sure periph clk's parent also got updated */
ret = clk_set_parent(periph_clk2_sel, osc_clk);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
ret = clk_set_parent(periph_clk, periph_clk2);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
if (audio_bus_freq_mode)
clk_disable_unprepare(pll2_400);
low_bus_freq_mode = 1;
audio_bus_freq_mode = 0;
}
if (high_bus_freq_mode && cpu_is_imx6dl())
clk_disable_unprepare(pll2_400);
clk_disable_unprepare(pll3);
med_bus_freq_mode = 0;
high_bus_freq_mode = 0;
if (audio_bus_freq_mode)
dev_dbg(busfreq_dev, "Bus freq set to audio mode. Count:\
high %d, med %d, audio %d\n",
high_bus_count, med_bus_count, audio_bus_count);
if (low_bus_freq_mode)
dev_dbg(busfreq_dev, "Bus freq set to low mode. Count:\
high %d, med %d, audio %d\n",
high_bus_count, med_bus_count, audio_bus_count);
return ret;
}
static void reduce_bus_freq_handler(struct work_struct *work)
{
mutex_lock(&bus_freq_mutex);
reduce_bus_freq();
mutex_unlock(&bus_freq_mutex);
}
/*
* Set the DDR, AHB to 24MHz.
* This mode will be activated only when none of the modules that
* need a higher DDR or AHB frequency are active.
*/
int set_low_bus_freq(int low_bus_mode)
{
if (busfreq_suspended)
return 0;
if (!bus_freq_scaling_initialized || !bus_freq_scaling_is_active)
return 0;
/*
* Don't lower the frequency immediately. Instead
* scheduled a delayed work and drop the freq if
* the conditions still remain the same.
*/
low_bus_freq = low_bus_mode;
schedule_delayed_work(&low_bus_freq_handler,
usecs_to_jiffies(3000000));
return 0;
}
/*
* Set the DDR to either 528MHz or 400MHz for iMX6qd
* or 400MHz for iMX6dl.
*/
int set_high_bus_freq(int high_bus_freq)
{
int ret = 0;
if (bus_freq_scaling_initialized && bus_freq_scaling_is_active)
cancel_delayed_work_sync(&low_bus_freq_handler);
if (busfreq_suspended)
return 0;
/* for high setpoint, i.MX6Q is 528MHz, i.MX6DL is 400MHz */
if (cpu_is_imx6q())
high_bus_freq = 1;
else
high_bus_freq = 0;
if (!bus_freq_scaling_initialized || !bus_freq_scaling_is_active)
return 0;
if (high_bus_freq_mode)
return 0;
/* medium bus freq is only supported for MX6DQ */
if (med_bus_freq_mode && !high_bus_freq)
return 0;
clk_prepare_enable(pll3);
if (high_bus_freq) {
update_ddr_freq(ddr_normal_rate);
/* Make sure periph clk's parent also got updated */
ret = clk_set_parent(periph_clk2_sel, pll3);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
ret = clk_set_parent(periph_pre_clk, pll2);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
ret = clk_set_parent(periph_clk, periph_pre_clk);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
if (med_bus_freq_mode)
clk_disable_unprepare(pll2_400);
} else {
clk_prepare_enable(pll2_400);
update_ddr_freq(ddr_med_rate);
/* Make sure periph clk's parent also got updated */
ret = clk_set_parent(periph_clk2_sel, pll3);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
ret = clk_set_parent(periph_pre_clk, pll2_400);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
ret = clk_set_parent(periph_clk, periph_pre_clk);
if (ret)
dev_WARN(busfreq_dev, "%s: %d: clk set parent fail!\n",
__func__, __LINE__);
}
if (audio_bus_freq_mode)
clk_disable_unprepare(pll2_400);
high_bus_freq_mode = 1;
med_bus_freq_mode = 0;
low_bus_freq_mode = 0;
audio_bus_freq_mode = 0;
clk_disable_unprepare(pll3);
if (high_bus_freq_mode)
dev_dbg(busfreq_dev, "Bus freq set to high mode. Count:\
high %d, med %d, audio %d\n",
high_bus_count, med_bus_count, audio_bus_count);
if (med_bus_freq_mode)
dev_dbg(busfreq_dev, "Bus freq set to med mode. Count:\
high %d, med %d, audio %d\n",
high_bus_count, med_bus_count, audio_bus_count);
return 0;
}
void request_bus_freq(enum bus_freq_mode mode)
{
mutex_lock(&bus_freq_mutex);
if (mode == BUS_FREQ_HIGH)
high_bus_count++;
else if (mode == BUS_FREQ_MED)
med_bus_count++;
else if (mode == BUS_FREQ_AUDIO)
audio_bus_count++;
if (busfreq_suspended || !bus_freq_scaling_initialized ||
!bus_freq_scaling_is_active) {
mutex_unlock(&bus_freq_mutex);
return;
}
cancel_delayed_work_sync(&low_bus_freq_handler);
if ((mode == BUS_FREQ_HIGH) && (!high_bus_freq_mode)) {
set_high_bus_freq(1);
mutex_unlock(&bus_freq_mutex);
return;
}
if ((mode == BUS_FREQ_MED) && (!high_bus_freq_mode) &&
(!med_bus_freq_mode)) {
set_high_bus_freq(0);
mutex_unlock(&bus_freq_mutex);
return;
}
if ((mode == BUS_FREQ_AUDIO) && (!high_bus_freq_mode) &&
(!med_bus_freq_mode) && (!audio_bus_freq_mode)) {
set_low_bus_freq(1);
mutex_unlock(&bus_freq_mutex);
return;
}
mutex_unlock(&bus_freq_mutex);
return;
}
EXPORT_SYMBOL(request_bus_freq);
void release_bus_freq(enum bus_freq_mode mode)
{
mutex_lock(&bus_freq_mutex);
if (mode == BUS_FREQ_HIGH) {
if (high_bus_count == 0) {
dev_err(busfreq_dev, "high bus count mismatch!\n");
dump_stack();
mutex_unlock(&bus_freq_mutex);
return;
}
high_bus_count--;
} else if (mode == BUS_FREQ_MED) {
if (med_bus_count == 0) {
dev_err(busfreq_dev, "med bus count mismatch!\n");
dump_stack();
mutex_unlock(&bus_freq_mutex);
return;
}
med_bus_count--;
} else if (mode == BUS_FREQ_AUDIO) {
if (audio_bus_count == 0) {
dev_err(busfreq_dev, "audio bus count mismatch!\n");
dump_stack();
mutex_unlock(&bus_freq_mutex);
return;
}
audio_bus_count--;
}
if (busfreq_suspended || !bus_freq_scaling_initialized ||
!bus_freq_scaling_is_active) {
mutex_unlock(&bus_freq_mutex);
return;
}
if ((!audio_bus_freq_mode) && (high_bus_count == 0) &&
(med_bus_count == 0) && (audio_bus_count != 0)) {
set_low_bus_freq(1);
mutex_unlock(&bus_freq_mutex);
return;
}
if ((!low_bus_freq_mode) && (high_bus_count == 0) &&
(med_bus_count == 0) && (audio_bus_count == 0))
set_low_bus_freq(0);
mutex_unlock(&bus_freq_mutex);
return;
}
EXPORT_SYMBOL(release_bus_freq);
static void bus_freq_daemon_handler(struct work_struct *work)
{
mutex_lock(&bus_freq_mutex);
if ((!low_bus_freq_mode) && (high_bus_count == 0) &&
(med_bus_count == 0) && (audio_bus_count == 0))
set_low_bus_freq(0);
mutex_unlock(&bus_freq_mutex);
}
static ssize_t bus_freq_scaling_enable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
if (bus_freq_scaling_is_active)
return sprintf(buf, "Bus frequency scaling is enabled\n");
else
return sprintf(buf, "Bus frequency scaling is disabled\n");
}
static ssize_t bus_freq_scaling_enable_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
if (strncmp(buf, "1", 1) == 0) {
bus_freq_scaling_is_active = 1;
set_high_bus_freq(1);
/*
* We set bus freq to highest at the beginning,
* so we use this daemon thread to make sure system
* can enter low bus mode if
* there is no high bus request pending
*/
schedule_delayed_work(&bus_freq_daemon,
usecs_to_jiffies(5000000));
} else if (strncmp(buf, "0", 1) == 0) {
if (bus_freq_scaling_is_active)
set_high_bus_freq(1);
bus_freq_scaling_is_active = 0;
}
return size;
}
static int bus_freq_pm_notify(struct notifier_block *nb, unsigned long event,
void *dummy)
{
mutex_lock(&bus_freq_mutex);
if (event == PM_SUSPEND_PREPARE) {
high_bus_count++;
set_high_bus_freq(1);
busfreq_suspended = 1;
} else if (event == PM_POST_SUSPEND) {
busfreq_suspended = 0;
high_bus_count--;
schedule_delayed_work(&bus_freq_daemon,
usecs_to_jiffies(5000000));
}
mutex_unlock(&bus_freq_mutex);
return NOTIFY_OK;
}
static struct notifier_block imx_bus_freq_pm_notifier = {
.notifier_call = bus_freq_pm_notify,
};
static DEVICE_ATTR(enable, 0644, bus_freq_scaling_enable_show,
bus_freq_scaling_enable_store);
/*!
* This is the probe routine for the bus frequency driver.
*
* @param pdev The platform device structure
*
* @return The function returns 0 on success
*
*/
static int busfreq_probe(struct platform_device *pdev)
{
u32 err;
busfreq_dev = &pdev->dev;
pll2_400 = devm_clk_get(&pdev->dev, "pll2_pfd2_396m");
if (IS_ERR(pll2_400)) {
dev_err(busfreq_dev, "%s: failed to get pll2_pfd2_396m\n",
__func__);
return PTR_ERR(pll2_400);
}
pll2_200 = devm_clk_get(&pdev->dev, "pll2_198m");
if (IS_ERR(pll2_200)) {
dev_err(busfreq_dev, "%s: failed to get pll2_198m\n",
__func__);
return PTR_ERR(pll2_200);
}
pll2 = devm_clk_get(&pdev->dev, "pll2_bus");
if (IS_ERR(pll2)) {
dev_err(busfreq_dev, "%s: failed to get pll2_bus\n",
__func__);
return PTR_ERR(pll2);
}
cpu_clk = devm_clk_get(&pdev->dev, "arm");
if (IS_ERR(cpu_clk)) {
dev_err(busfreq_dev, "%s: failed to get cpu_clk\n",
__func__);
return PTR_ERR(cpu_clk);
}
pll3 = devm_clk_get(&pdev->dev, "pll3_usb_otg");
if (IS_ERR(pll3)) {
dev_err(busfreq_dev, "%s: failed to get pll3_usb_otg\n",
__func__);
return PTR_ERR(pll3);
}
periph_clk = devm_clk_get(&pdev->dev, "periph");
if (IS_ERR(periph_clk)) {
dev_err(busfreq_dev, "%s: failed to get periph\n",
__func__);
return PTR_ERR(periph_clk);
}
periph_pre_clk = devm_clk_get(&pdev->dev, "periph_pre");
if (IS_ERR(periph_pre_clk)) {
dev_err(busfreq_dev, "%s: failed to get periph_pre\n",
__func__);
return PTR_ERR(periph_pre_clk);
}
periph_clk2 = devm_clk_get(&pdev->dev, "periph_clk2");
if (IS_ERR(periph_clk2)) {
dev_err(busfreq_dev, "%s: failed to get periph_clk2\n",
__func__);
return PTR_ERR(periph_clk2);
}
periph_clk2_sel = devm_clk_get(&pdev->dev, "periph_clk2_sel");
if (IS_ERR(periph_clk2_sel)) {
dev_err(busfreq_dev, "%s: failed to get periph_clk2_sel\n",
__func__);
return PTR_ERR(periph_clk2_sel);
}
osc_clk = devm_clk_get(&pdev->dev, "osc");
if (IS_ERR(osc_clk)) {
dev_err(busfreq_dev, "%s: failed to get osc_clk\n",
__func__);
return PTR_ERR(osc_clk);
}
err = sysfs_create_file(&busfreq_dev->kobj, &dev_attr_enable.attr);
if (err) {
dev_err(busfreq_dev,
"Unable to register sysdev entry for BUSFREQ");
return err;
}
if (of_property_read_u32(pdev->dev.of_node, "fsl,max_ddr_freq",
&ddr_normal_rate)) {
dev_err(busfreq_dev, "max_ddr_freq entry missing\n");
return -EINVAL;
}
high_bus_freq_mode = 1;
med_bus_freq_mode = 0;
low_bus_freq_mode = 0;
audio_bus_freq_mode = 0;
bus_freq_scaling_is_active = 1;
bus_freq_scaling_initialized = 1;
ddr_low_rate = LPAPM_CLK;
if (cpu_is_imx6q()) {
if (of_property_read_u32(pdev->dev.of_node, "fsl,med_ddr_freq",
&ddr_med_rate)) {
dev_err(busfreq_dev,
"DDR medium rate not supported.\n");
ddr_med_rate = ddr_normal_rate;
}
}
INIT_DELAYED_WORK(&low_bus_freq_handler, reduce_bus_freq_handler);
INIT_DELAYED_WORK(&bus_freq_daemon, bus_freq_daemon_handler);
register_pm_notifier(&imx_bus_freq_pm_notifier);
err = init_mmdc_settings(pdev);
if (err) {
dev_err(busfreq_dev, "Busfreq init of MMDC failed\n");
return err;
}
return 0;
}
static const struct of_device_id imx6_busfreq_ids[] = {
{ .compatible = "fsl,imx6_busfreq", },
{ /* sentinel */ }
};
static struct platform_driver busfreq_driver = {
.driver = {
.name = "imx6_busfreq",
.owner = THIS_MODULE,
.of_match_table = imx6_busfreq_ids,
},
.probe = busfreq_probe,
};
/*!
* Initialise the busfreq_driver.
*
* @return The function always returns 0.
*/
static int __init busfreq_init(void)
{
if (platform_driver_register(&busfreq_driver) != 0)
return -ENODEV;
printk(KERN_INFO "Bus freq driver module loaded\n");
return 0;
}
static void __exit busfreq_cleanup(void)
{
sysfs_remove_file(&busfreq_dev->kobj, &dev_attr_enable.attr);
/* Unregister the device structure */
platform_driver_unregister(&busfreq_driver);
bus_freq_scaling_initialized = 0;
}
module_init(busfreq_init);
module_exit(busfreq_cleanup);
MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("BusFreq driver");
MODULE_LICENSE("GPL");
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