mirror of https://gitee.com/openkylin/linux.git
254 lines
6.5 KiB
C
254 lines
6.5 KiB
C
/*
|
|
* Watchdog driver for Atmel AT91SAM9x processors.
|
|
*
|
|
* Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* The Watchdog Timer Mode Register can be only written to once. If the
|
|
* timeout need to be set from Linux, be sure that the bootstrap or the
|
|
* bootloader doesn't write to this register.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/init.h>
|
|
#include <linux/io.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/types.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/of.h>
|
|
|
|
#include "at91sam9_wdt.h"
|
|
|
|
#define DRV_NAME "AT91SAM9 Watchdog"
|
|
|
|
#define wdt_read(field) \
|
|
__raw_readl(at91wdt_private.base + field)
|
|
#define wdt_write(field, val) \
|
|
__raw_writel((val), at91wdt_private.base + field)
|
|
|
|
/* AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
|
|
* use this to convert a watchdog
|
|
* value from/to milliseconds.
|
|
*/
|
|
#define ms_to_ticks(t) (((t << 8) / 1000) - 1)
|
|
#define ticks_to_ms(t) (((t + 1) * 1000) >> 8)
|
|
|
|
/* Hardware timeout in seconds */
|
|
#define WDT_HW_TIMEOUT 2
|
|
|
|
/* Timer heartbeat (500ms) */
|
|
#define WDT_TIMEOUT (HZ/2)
|
|
|
|
/* User land timeout */
|
|
#define WDT_HEARTBEAT 15
|
|
static int heartbeat;
|
|
module_param(heartbeat, int, 0);
|
|
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
|
|
"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
|
|
|
|
static bool nowayout = WATCHDOG_NOWAYOUT;
|
|
module_param(nowayout, bool, 0);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
|
|
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
|
|
|
|
static struct watchdog_device at91_wdt_dev;
|
|
static void at91_ping(unsigned long data);
|
|
|
|
static struct {
|
|
void __iomem *base;
|
|
unsigned long next_heartbeat; /* the next_heartbeat for the timer */
|
|
struct timer_list timer; /* The timer that pings the watchdog */
|
|
} at91wdt_private;
|
|
|
|
/* ......................................................................... */
|
|
|
|
/*
|
|
* Reload the watchdog timer. (ie, pat the watchdog)
|
|
*/
|
|
static inline void at91_wdt_reset(void)
|
|
{
|
|
wdt_write(AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
|
|
}
|
|
|
|
/*
|
|
* Timer tick
|
|
*/
|
|
static void at91_ping(unsigned long data)
|
|
{
|
|
if (time_before(jiffies, at91wdt_private.next_heartbeat) ||
|
|
(!watchdog_active(&at91_wdt_dev))) {
|
|
at91_wdt_reset();
|
|
mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT);
|
|
} else
|
|
pr_crit("I will reset your machine !\n");
|
|
}
|
|
|
|
static int at91_wdt_ping(struct watchdog_device *wdd)
|
|
{
|
|
/* calculate when the next userspace timeout will be */
|
|
at91wdt_private.next_heartbeat = jiffies + wdd->timeout * HZ;
|
|
return 0;
|
|
}
|
|
|
|
static int at91_wdt_start(struct watchdog_device *wdd)
|
|
{
|
|
/* calculate the next userspace timeout and modify the timer */
|
|
at91_wdt_ping(wdd);
|
|
mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT);
|
|
return 0;
|
|
}
|
|
|
|
static int at91_wdt_stop(struct watchdog_device *wdd)
|
|
{
|
|
/* The watchdog timer hardware can not be stopped... */
|
|
return 0;
|
|
}
|
|
|
|
static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout)
|
|
{
|
|
wdd->timeout = new_timeout;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Set the watchdog time interval in 1/256Hz (write-once)
|
|
* Counter is 12 bit.
|
|
*/
|
|
static int at91_wdt_settimeout(unsigned int timeout)
|
|
{
|
|
unsigned int reg;
|
|
unsigned int mr;
|
|
|
|
/* Check if disabled */
|
|
mr = wdt_read(AT91_WDT_MR);
|
|
if (mr & AT91_WDT_WDDIS) {
|
|
pr_err("sorry, watchdog is disabled\n");
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* All counting occurs at SLOW_CLOCK / 128 = 256 Hz
|
|
*
|
|
* Since WDV is a 12-bit counter, the maximum period is
|
|
* 4096 / 256 = 16 seconds.
|
|
*/
|
|
reg = AT91_WDT_WDRSTEN /* causes watchdog reset */
|
|
/* | AT91_WDT_WDRPROC causes processor reset only */
|
|
| AT91_WDT_WDDBGHLT /* disabled in debug mode */
|
|
| AT91_WDT_WDD /* restart at any time */
|
|
| (timeout & AT91_WDT_WDV); /* timer value */
|
|
wdt_write(AT91_WDT_MR, reg);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* ......................................................................... */
|
|
|
|
static const struct watchdog_info at91_wdt_info = {
|
|
.identity = DRV_NAME,
|
|
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
|
|
WDIOF_MAGICCLOSE,
|
|
};
|
|
|
|
static const struct watchdog_ops at91_wdt_ops = {
|
|
.owner = THIS_MODULE,
|
|
.start = at91_wdt_start,
|
|
.stop = at91_wdt_stop,
|
|
.ping = at91_wdt_ping,
|
|
.set_timeout = at91_wdt_set_timeout,
|
|
};
|
|
|
|
static struct watchdog_device at91_wdt_dev = {
|
|
.info = &at91_wdt_info,
|
|
.ops = &at91_wdt_ops,
|
|
.timeout = WDT_HEARTBEAT,
|
|
.min_timeout = 1,
|
|
.max_timeout = 0xFFFF,
|
|
};
|
|
|
|
static int __init at91wdt_probe(struct platform_device *pdev)
|
|
{
|
|
struct resource *r;
|
|
int res;
|
|
|
|
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!r)
|
|
return -ENODEV;
|
|
at91wdt_private.base = ioremap(r->start, resource_size(r));
|
|
if (!at91wdt_private.base) {
|
|
dev_err(&pdev->dev, "failed to map registers, aborting.\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
at91_wdt_dev.parent = &pdev->dev;
|
|
watchdog_init_timeout(&at91_wdt_dev, heartbeat, &pdev->dev);
|
|
watchdog_set_nowayout(&at91_wdt_dev, nowayout);
|
|
|
|
/* Set watchdog */
|
|
res = at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000));
|
|
if (res)
|
|
return res;
|
|
|
|
res = watchdog_register_device(&at91_wdt_dev);
|
|
if (res)
|
|
return res;
|
|
|
|
at91wdt_private.next_heartbeat = jiffies + at91_wdt_dev.timeout * HZ;
|
|
setup_timer(&at91wdt_private.timer, at91_ping, 0);
|
|
mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT);
|
|
|
|
pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n",
|
|
at91_wdt_dev.timeout, nowayout);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __exit at91wdt_remove(struct platform_device *pdev)
|
|
{
|
|
watchdog_unregister_device(&at91_wdt_dev);
|
|
|
|
pr_warn("I quit now, hardware will probably reboot!\n");
|
|
del_timer(&at91wdt_private.timer);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#if defined(CONFIG_OF)
|
|
static const struct of_device_id at91_wdt_dt_ids[] = {
|
|
{ .compatible = "atmel,at91sam9260-wdt" },
|
|
{ /* sentinel */ }
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
|
|
#endif
|
|
|
|
static struct platform_driver at91wdt_driver = {
|
|
.remove = __exit_p(at91wdt_remove),
|
|
.driver = {
|
|
.name = "at91_wdt",
|
|
.owner = THIS_MODULE,
|
|
.of_match_table = of_match_ptr(at91_wdt_dt_ids),
|
|
},
|
|
};
|
|
|
|
module_platform_driver_probe(at91wdt_driver, at91wdt_probe);
|
|
|
|
MODULE_AUTHOR("Renaud CERRATO <r.cerrato@til-technologies.fr>");
|
|
MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
|
|
MODULE_LICENSE("GPL");
|