linux/drivers/watchdog/rc32434_wdt.c
Al Viro cb787f4ac0 [tree-wide] finally take no_llseek out
no_llseek had been defined to NULL two years ago, in commit 868941b144
("fs: remove no_llseek")

To quote that commit,

  At -rc1 we'll need do a mechanical removal of no_llseek -

  git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\<no_llseek\>/d' $i
  done

  would do it.

Unfortunately, that hadn't been done.  Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
	.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-27 08:18:43 -07:00

325 lines
7.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IDT Interprise 79RC32434 watchdog driver
*
* Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
* Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
*
* based on
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
* 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 <santiago@crfreenet.org>,"
"Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
MODULE_LICENSE("GPL");