// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IDT Interprise 79RC32434 watchdog driver
*
* Copyright (C) 2006, Ondrej Zajicek <[email protected]>
* Copyright (C) 2008, Florian Fainelli <[email protected]>
*
* based on
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <[email protected]>,
* All Rights Reserved.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h> /* For module specific items */
#include <linux/moduleparam.h> /* For new moduleparam's */
#include <linux/types.h> /* For standard types (like size_t) */
#include <linux/errno.h> /* For the -ENODEV/... values */
#include <linux/kernel.h> /* For printk/panic/... */
#include <linux/fs.h> /* For file operations */
#include <linux/miscdevice.h> /* For struct miscdevice */
#include <linux/watchdog.h> /* For the watchdog specific items */
#include <linux/init.h> /* For __init/__exit/... */
#include <linux/platform_device.h> /* For platform_driver framework */
#include <linux/spinlock.h> /* For spin_lock/spin_unlock/... */
#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
#include <linux/io.h> /* For devm_ioremap */
#include <asm/mach-rc32434/integ.h> /* For the Watchdog registers */
#define VERSION "1.0"
static struct {
unsigned long inuse;
spinlock_t io_lock;
} rc32434_wdt_device;
static struct integ __iomem *wdt_reg;
static int expect_close;
/* Board internal clock speed in Hz,
* the watchdog timer ticks at. */
extern unsigned int idt_cpu_freq;
/* translate wtcompare value to seconds and vice versa */
#define WTCOMP2SEC(x) (x / idt_cpu_freq)
#define SEC2WTCOMP(x) (x * idt_cpu_freq)
/* Use a default timeout of 20s. This should be
* safe for CPU clock speeds up to 400MHz, as
* ((2 ^ 32) - 1) / (400MHz / 2) = 21s. */
#define WATCHDOG_TIMEOUT 20
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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) ")");
/* apply or and nand masks to data read from addr and write back */
#define SET_BITS(addr, or, nand) \
writel((readl(&addr) | or) & ~nand, &addr)
static int rc32434_wdt_set(int new_timeout)
{
int max_to = WTCOMP2SEC((u32)-1);
if (new_timeout < 0 || new_timeout > max_to) {
pr_err("timeout value must be between 0 and %d\n", max_to);
return -EINVAL;
}
timeout = new_timeout;
spin_lock(&rc32434_wdt_device.io_lock);
writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
spin_unlock(&rc32434_wdt_device.io_lock);
return 0;
}
static void rc32434_wdt_start(void)
{
u32 or, nand;
spin_lock(&rc32434_wdt_device.io_lock);
/* zero the counter before enabling */
writel(0, &wdt_reg->wtcount);
/* don't generate a non-maskable interrupt,
* do a warm reset instead */
nand = 1 << RC32434_ERR_WNE;
or = 1 << RC32434_ERR_WRE;
/* reset the ERRCS timeout bit in case it's set */
nand |= 1 << RC32434_ERR_WTO;
SET_BITS(wdt_reg->errcs, or, nand);
/* set the timeout (either default or based on module param) */
rc32434_wdt_set(timeout);
/* reset WTC timeout bit and enable WDT */
nand = 1 << RC32434_WTC_TO;
or = 1 << RC32434_WTC_EN;
SET_BITS(wdt_reg->wtc, or, nand);
spin_unlock(&rc32434_wdt_device.io_lock);
pr_info("Started watchdog timer\n");
}
static void rc32434_wdt_stop(void)
{
spin_lock(&rc32434_wdt_device.io_lock);
/* Disable WDT */
SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
spin_unlock(&rc32434_wdt_device.io_lock);
pr_info("Stopped watchdog timer\n");
}
static void rc32434_wdt_ping(void)
{
spin_lock(&rc32434_wdt_device.io_lock);
writel(0, &wdt_reg->wtcount);
spin_unlock(&rc32434_wdt_device.io_lock);
}
static int rc32434_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
rc32434_wdt_start();
rc32434_wdt_ping();
return stream_open(inode, file);
}
static int rc32434_wdt_release(struct inode *inode, struct file *file)
{
if (expect_close == 42) {
rc32434_wdt_stop();
module_put(THIS_MODULE);
} else {
pr_crit("device closed unexpectedly. WDT will not stop!\n");
rc32434_wdt_ping();
}
clear_bit(0, &rc32434_wdt_device.inuse);
return 0;
}
static ssize_t rc32434_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
rc32434_wdt_ping();
return len;
}
return 0;
}
static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int new_timeout;
unsigned int value;
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.identity = "RC32434_WDT Watchdog",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
value = 0;
if (copy_to_user(argp, &value, sizeof(int)))
return -EFAULT;
break;
case WDIOC_SETOPTIONS:
if (copy_from_user(&value, argp, sizeof(int)))
return -EFAULT;
switch (value) {
case WDIOS_ENABLECARD:
rc32434_wdt_start();
break;
case WDIOS_DISABLECARD:
rc32434_wdt_stop();
break;
default:
return -EINVAL;
}
break;
case WDIOC_KEEPALIVE:
rc32434_wdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (copy_from_user(&new_timeout, argp, sizeof(int)))
return -EFAULT;
if (rc32434_wdt_set(new_timeout))
return -EINVAL;
fallthrough;
case WDIOC_GETTIMEOUT:
return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0;
default:
return -ENOTTY;
}
return 0;
}
static const struct file_operations rc32434_wdt_fops = {
.owner = THIS_MODULE,
.write = rc32434_wdt_write,
.unlocked_ioctl = rc32434_wdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = rc32434_wdt_open,
.release = rc32434_wdt_release,
};
static struct miscdevice rc32434_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &rc32434_wdt_fops,
};
static int rc32434_wdt_probe(struct platform_device *pdev)
{
int ret;
struct resource *r;
r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
if (!r) {
pr_err("failed to retrieve resources\n");
return -ENODEV;
}
wdt_reg = devm_ioremap(&pdev->dev, r->start, resource_size(r));
if (!wdt_reg) {
pr_err("failed to remap I/O resources\n");
return -ENXIO;
}
spin_lock_init(&rc32434_wdt_device.io_lock);
/* Make sure the watchdog is not running */
rc32434_wdt_stop();
/* Check that the heartbeat value is within it's range;
* if not reset to the default */
if (rc32434_wdt_set(timeout)) {
rc32434_wdt_set(WATCHDOG_TIMEOUT);
pr_info("timeout value must be between 0 and %d\n",
WTCOMP2SEC((u32)-1));
}
ret = misc_register(&rc32434_wdt_miscdev);
if (ret < 0) {
pr_err("failed to register watchdog device\n");
return ret;
}
pr_info("Watchdog Timer version " VERSION ", timer margin: %d sec\n",
timeout);
return 0;
}
static void rc32434_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&rc32434_wdt_miscdev);
}
static void rc32434_wdt_shutdown(struct platform_device *pdev)
{
rc32434_wdt_stop();
}
static struct platform_driver rc32434_wdt_driver = {
.probe = rc32434_wdt_probe,
.remove_new = rc32434_wdt_remove,
.shutdown = rc32434_wdt_shutdown,
.driver = {
.name = "rc32434_wdt",
}
};
module_platform_driver(rc32434_wdt_driver);
MODULE_AUTHOR("Ondrej Zajicek <[email protected]>,"
"Florian Fainelli <[email protected]>");
MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
MODULE_LICENSE("GPL");
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