/*
* Watchdog driver for IMX2 and later processors
*
* Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de>
*
* some parts adapted by similar drivers from Darius Augulis and Vladimir
* Zapolskiy, additional improvements by Wim Van Sebroeck.
*
* 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.
*
* NOTE: MX1 has a slightly different Watchdog than MX2 and later:
*
* MX1: MX2+:
* ---- -----
* Registers: 32-bit 16-bit
* Stopable timer: Yes No
* Need to enable clk: No Yes
* Halt on suspend: Manual Can be automatic
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/clk.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <mach/hardware.h>
#define DRIVER_NAME "imx2-wdt"
#define IMX2_WDT_WCR 0x00 /* Control Register */
#define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */
#define IMX2_WDT_WCR_WRE (1 << 3) /* -> WDOG Reset Enable */
#define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */
#define IMX2_WDT_WSR 0x02 /* Service Register */
#define IMX2_WDT_SEQ1 0x5555 /* -> service sequence 1 */
#define IMX2_WDT_SEQ2 0xAAAA /* -> service sequence 2 */
#define IMX2_WDT_MAX_TIME 128
#define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */
#define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)
#define IMX2_WDT_STATUS_OPEN 0
#define IMX2_WDT_STATUS_STARTED 1
#define IMX2_WDT_EXPECT_CLOSE 2
static struct {
struct clk *clk;
void __iomem *base;
unsigned timeout;
unsigned long status;
struct timer_list timer; /* Pings the watchdog when closed */
} imx2_wdt;
static struct miscdevice imx2_wdt_miscdev;
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static unsigned timeout = IMX2_WDT_DEFAULT_TIME;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
__MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");
static const struct watchdog_info imx2_wdt_info = {
.identity = "imx2+ watchdog",
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
};
static inline void imx2_wdt_setup(void)
{
u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);
/* Strip the old watchdog Time-Out value */
val &= ~IMX2_WDT_WCR_WT;
/* Generate reset if WDOG times out */
val &= ~IMX2_WDT_WCR_WRE;
/* Keep Watchdog Disabled */
val &= ~IMX2_WDT_WCR_WDE;
/* Set the watchdog's Time-Out value */
val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout);
__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
/* enable the watchdog */
val |= IMX2_WDT_WCR_WDE;
__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
}
static inline void imx2_wdt_ping(void)
{
__raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR);
__raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR);
}
static void imx2_wdt_timer_ping(unsigned long arg)
{
/* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */
imx2_wdt_ping();
mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2);
}
static void imx2_wdt_start(void)
{
if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
/* at our first start we enable clock and do initialisations */
clk_enable(imx2_wdt.clk);
imx2_wdt_setup();
} else /* delete the timer that pings the watchdog after close */
del_timer_sync(&imx2_wdt.timer);
/* Watchdog is enabled - time to reload the timeout value */
imx2_wdt_ping();
}
static void imx2_wdt_stop(void)
{
/* we don't need a clk_disable, it cannot be disabled once started.
* We use a timer to ping the watchdog while /dev/watchdog is closed */
imx2_wdt_timer_ping(0);
}
static void imx2_wdt_set_timeout(int new_timeout)
{
u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);
/* set the new timeout value in the WSR */
val &= ~IMX2_WDT_WCR_WT;
val |= WDOG_SEC_TO_COUNT(new_timeout);
__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
}
static int imx2_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status))
return -EBUSY;
imx2_wdt_start();
return nonseekable_open(inode, file);
}
static int imx2_wdt_close(struct inode *inode, struct file *file)
{
if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout)
imx2_wdt_stop();
else {
dev_crit(imx2_wdt_miscdev.parent,
"Unexpected close: Expect reboot!\n");
imx2_wdt_ping();
}
clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status);
return 0;
}
static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_value;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &imx2_wdt_info,
sizeof(struct watchdog_info)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_KEEPALIVE:
imx2_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_value, p))
return -EFAULT;
if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME))
return -EINVAL;
imx2_wdt_set_timeout(new_value);
imx2_wdt.timeout = new_value;
imx2_wdt_ping();
/* Fallthrough to return current value */
case WDIOC_GETTIMEOUT:
return put_user(imx2_wdt.timeout, p);
default:
return -ENOTTY;
}
}
static ssize_t imx2_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
size_t i;
char c;
if (len == 0) /* Can we see this even ? */
return 0;
clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
/* scan to see whether or not we got the magic character */
for (i = 0; i != len; i++) {
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
}
imx2_wdt_ping();
return len;
}
static const struct file_operations imx2_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.unlocked_ioctl = imx2_wdt_ioctl,
.open = imx2_wdt_open,
.release = imx2_wdt_close,
.write = imx2_wdt_write,
};
static struct miscdevice imx2_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &imx2_wdt_fops,
};
static int __init imx2_wdt_probe(struct platform_device *pdev)
{
int ret;
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "can't get device resources\n");
return -ENODEV;
}
imx2_wdt.base = devm_request_and_ioremap(&pdev->dev, res);
if (!imx2_wdt.base) {
dev_err(&pdev->dev, "ioremap failed\n");
return -ENOMEM;
}
imx2_wdt.clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(imx2_wdt.clk)) {
dev_err(&pdev->dev, "can't get Watchdog clock\n");
return PTR_ERR(imx2_wdt.clk);
}
imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
if (imx2_wdt.timeout != timeout)
dev_warn(&pdev->dev, "Initial timeout out of range! "
"Clamped from %u to %u\n", timeout, imx2_wdt.timeout);
setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0);
imx2_wdt_miscdev.parent = &pdev->dev;
ret = misc_register(&imx2_wdt_miscdev);
if (ret)
goto fail;
dev_info(&pdev->dev,
"IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n",
imx2_wdt.timeout, nowayout);
return 0;
fail:
imx2_wdt_miscdev.parent = NULL;
clk_put(imx2_wdt.clk);
return ret;
}
static int __exit imx2_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&imx2_wdt_miscdev);
if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
del_timer_sync(&imx2_wdt.timer);
dev_crit(imx2_wdt_miscdev.parent,
"Device removed: Expect reboot!\n");
} else
clk_put(imx2_wdt.clk);
imx2_wdt_miscdev.parent = NULL;
return 0;
}
static void imx2_wdt_shutdown(struct platform_device *pdev)
{
if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
/* we are running, we need to delete the timer but will give
* max timeout before reboot will take place */
del_timer_sync(&imx2_wdt.timer);
imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME);
imx2_wdt_ping();
dev_crit(imx2_wdt_miscdev.parent,
"Device shutdown: Expect reboot!\n");
}
}
static const struct of_device_id imx2_wdt_dt_ids[] = {
{ .compatible = "fsl,imx21-wdt", },
{ /* sentinel */ }
};
static struct platform_driver imx2_wdt_driver = {
.remove = __exit_p(imx2_wdt_remove),
.shutdown = imx2_wdt_shutdown,
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = imx2_wdt_dt_ids,
},
};
static int __init imx2_wdt_init(void)
{
return platform_driver_probe(&imx2_wdt_driver, imx2_wdt_probe);
}
module_init(imx2_wdt_init);
static void __exit imx2_wdt_exit(void)
{
platform_driver_unregister(&imx2_wdt_driver);
}
module_exit(imx2_wdt_exit);
MODULE_AUTHOR("Wolfram Sang");
MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:" DRIVER_NAME);
