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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PNX833x Hardware Watchdog Driver
* Copyright 2008 NXP Semiconductors
* Daniel Laird <daniel.j.laird@nxp.com>
* Andre McCurdy <andre.mccurdy@nxp.com>
*
* Heavily based upon - IndyDog 0.3
* A Hardware Watchdog Device for SGI IP22
*
* (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
*
* based on softdog.c by Alan Cox <alan@redhat.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <asm/mach-pnx833x/pnx833x.h>
#define WATCHDOG_TIMEOUT 30 /* 30 sec Maximum timeout */
#define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */
#define PNX_WATCHDOG_TIMEOUT (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY)
#define PNX_TIMEOUT_VALUE 2040000000U
/** CONFIG block */
#define PNX833X_CONFIG (0x07000U)
#define PNX833X_CONFIG_CPU_WATCHDOG (0x54)
#define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58)
#define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c)
/** RESET block */
#define PNX833X_RESET (0x08000U)
#define PNX833X_RESET_CONFIG (0x08)
static int pnx833x_wdt_alive;
/* Set default timeout in MHZ.*/
static int pnx833x_wdt_timeout = PNX_WATCHDOG_TIMEOUT;
module_param(pnx833x_wdt_timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default="
__MODULE_STRING(PNX_TIMEOUT_VALUE) "(30 seconds).");
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) ")");
#define START_DEFAULT 1
static int start_enabled = START_DEFAULT;
module_param(start_enabled, int, 0);
MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion "
"(default=" __MODULE_STRING(START_DEFAULT) ")");
static void pnx833x_wdt_start(void)
{
/* Enable watchdog causing reset. */
PNX833X_REG(PNX833X_RESET + PNX833X_RESET_CONFIG) |= 0x1;
/* Set timeout.*/
PNX833X_REG(PNX833X_CONFIG +
PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
/* Enable watchdog. */
PNX833X_REG(PNX833X_CONFIG +
PNX833X_CONFIG_CPU_COUNTERS_CONTROL) |= 0x1;
pr_info("Started watchdog timer\n");
}
static void pnx833x_wdt_stop(void)
{
/* Disable watchdog causing reset. */
PNX833X_REG(PNX833X_RESET + PNX833X_CONFIG) &= 0xFFFFFFFE;
/* Disable watchdog.*/
PNX833X_REG(PNX833X_CONFIG +
PNX833X_CONFIG_CPU_COUNTERS_CONTROL) &= 0xFFFFFFFE;
pr_info("Stopped watchdog timer\n");
}
static void pnx833x_wdt_ping(void)
{
PNX833X_REG(PNX833X_CONFIG +
PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
}
/*
* Allow only one person to hold it open
*/
static int pnx833x_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &pnx833x_wdt_alive))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Activate timer */
if (!start_enabled)
pnx833x_wdt_start();
pnx833x_wdt_ping();
pr_info("Started watchdog timer\n");
return stream_open(inode, file);
}
static int pnx833x_wdt_release(struct inode *inode, struct file *file)
{
/* Shut off the timer.
* Lock it in if it's a module and we defined ...NOWAYOUT */
if (!nowayout)
pnx833x_wdt_stop(); /* Turn the WDT off */
clear_bit(0, &pnx833x_wdt_alive);
return 0;
}
static ssize_t pnx833x_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
/* Refresh the timer. */
if (len)
pnx833x_wdt_ping();
return len;
}
static long pnx833x_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int options, new_timeout = 0;
uint32_t timeout, timeout_left = 0;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
.firmware_version = 0,
.identity = "Hardware Watchdog for PNX833x",
};
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if (copy_to_user((struct watchdog_info *)arg,
&ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, (int *)arg);
case WDIOC_SETOPTIONS:
if (get_user(options, (int *)arg))
return -EFAULT;
if (options & WDIOS_DISABLECARD)
pnx833x_wdt_stop();
if (options & WDIOS_ENABLECARD)
pnx833x_wdt_start();
return 0;
case WDIOC_KEEPALIVE:
pnx833x_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
{
if (get_user(new_timeout, (int *)arg))
return -EFAULT;
pnx833x_wdt_timeout = new_timeout;
PNX833X_REG(PNX833X_CONFIG +
PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = new_timeout;
return put_user(new_timeout, (int *)arg);
}
case WDIOC_GETTIMEOUT:
timeout = PNX833X_REG(PNX833X_CONFIG +
PNX833X_CONFIG_CPU_WATCHDOG_COMPARE);
return put_user(timeout, (int *)arg);
case WDIOC_GETTIMELEFT:
timeout_left = PNX833X_REG(PNX833X_CONFIG +
PNX833X_CONFIG_CPU_WATCHDOG);
return put_user(timeout_left, (int *)arg);
}
}
static int pnx833x_wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
pnx833x_wdt_stop(); /* Turn the WDT off */
return NOTIFY_DONE;
}
static const struct file_operations pnx833x_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = pnx833x_wdt_write,
.unlocked_ioctl = pnx833x_wdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = pnx833x_wdt_open,
.release = pnx833x_wdt_release,
};
static struct miscdevice pnx833x_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &pnx833x_wdt_fops,
};
static struct notifier_block pnx833x_wdt_notifier = {
.notifier_call = pnx833x_wdt_notify_sys,
};
static int __init watchdog_init(void)
{
int ret, cause;
/* Lets check the reason for the reset.*/
cause = PNX833X_REG(PNX833X_RESET);
/*If bit 31 is set then watchdog was cause of reset.*/
if (cause & 0x80000000) {
pr_info("The system was previously reset due to the watchdog firing - please investigate...\n");
}
ret = register_reboot_notifier(&pnx833x_wdt_notifier);
if (ret) {
pr_err("cannot register reboot notifier (err=%d)\n", ret);
return ret;
}
ret = misc_register(&pnx833x_wdt_miscdev);
if (ret) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
unregister_reboot_notifier(&pnx833x_wdt_notifier);
return ret;
}
pr_info("Hardware Watchdog Timer for PNX833x: Version 0.1\n");
if (start_enabled)
pnx833x_wdt_start();
return 0;
}
static void __exit watchdog_exit(void)
{
misc_deregister(&pnx833x_wdt_miscdev);
unregister_reboot_notifier(&pnx833x_wdt_notifier);
}
module_init(watchdog_init);
module_exit(watchdog_exit);
MODULE_AUTHOR("Daniel Laird/Andre McCurdy");
MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x");
MODULE_LICENSE("GPL");
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