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55a1b87e07
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. [1] https://www.kernel.org/doc/html/v5.7-rc7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200717164059.GA26947@embeddedor Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
264 lines
6.2 KiB
C
264 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* drivers/char/watchdog/scx200_wdt.c
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National Semiconductor SCx200 Watchdog support
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Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
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Some code taken from:
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National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
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(c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
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The author(s) of this software shall not be held liable for damages
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of any nature resulting due to the use of this software. This
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software is provided AS-IS with no warranties. */
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/init.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/fs.h>
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#include <linux/ioport.h>
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#include <linux/scx200.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#define DEBUG
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MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
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MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
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MODULE_LICENSE("GPL");
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static int margin = 60; /* in seconds */
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module_param(margin, int, 0);
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MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
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static u16 wdto_restart;
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static char expect_close;
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static unsigned long open_lock;
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static DEFINE_SPINLOCK(scx_lock);
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/* Bits of the WDCNFG register */
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#define W_ENABLE 0x00fa /* Enable watchdog */
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#define W_DISABLE 0x0000 /* Disable watchdog */
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/* The scaling factor for the timer, this depends on the value of W_ENABLE */
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#define W_SCALE (32768/1024)
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static void scx200_wdt_ping(void)
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{
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spin_lock(&scx_lock);
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outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
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spin_unlock(&scx_lock);
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}
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static void scx200_wdt_update_margin(void)
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{
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pr_info("timer margin %d seconds\n", margin);
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wdto_restart = margin * W_SCALE;
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}
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static void scx200_wdt_enable(void)
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{
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pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart);
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spin_lock(&scx_lock);
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outw(0, scx200_cb_base + SCx200_WDT_WDTO);
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outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
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outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
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spin_unlock(&scx_lock);
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scx200_wdt_ping();
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}
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static void scx200_wdt_disable(void)
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{
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pr_debug("disabling watchdog timer\n");
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spin_lock(&scx_lock);
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outw(0, scx200_cb_base + SCx200_WDT_WDTO);
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outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
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outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
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spin_unlock(&scx_lock);
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}
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static int scx200_wdt_open(struct inode *inode, struct file *file)
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{
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/* only allow one at a time */
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if (test_and_set_bit(0, &open_lock))
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return -EBUSY;
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scx200_wdt_enable();
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return stream_open(inode, file);
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}
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static int scx200_wdt_release(struct inode *inode, struct file *file)
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{
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if (expect_close != 42)
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pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
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else if (!nowayout)
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scx200_wdt_disable();
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expect_close = 0;
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clear_bit(0, &open_lock);
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return 0;
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}
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static int scx200_wdt_notify_sys(struct notifier_block *this,
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unsigned long code, void *unused)
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{
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if (code == SYS_HALT || code == SYS_POWER_OFF)
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if (!nowayout)
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scx200_wdt_disable();
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return NOTIFY_DONE;
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}
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static struct notifier_block scx200_wdt_notifier = {
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.notifier_call = scx200_wdt_notify_sys,
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};
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static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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{
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/* check for a magic close character */
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if (len) {
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size_t i;
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scx200_wdt_ping();
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expect_close = 0;
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for (i = 0; i < len; ++i) {
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char c;
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if (get_user(c, data + i))
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return -EFAULT;
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if (c == 'V')
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expect_close = 42;
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}
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return len;
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}
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return 0;
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}
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static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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static const struct watchdog_info ident = {
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.identity = "NatSemi SCx200 Watchdog",
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.firmware_version = 1,
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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int new_margin;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &ident, sizeof(ident)))
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return -EFAULT;
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return 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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if (put_user(0, p))
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return -EFAULT;
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return 0;
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case WDIOC_KEEPALIVE:
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scx200_wdt_ping();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_margin, p))
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return -EFAULT;
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if (new_margin < 1)
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return -EINVAL;
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margin = new_margin;
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scx200_wdt_update_margin();
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scx200_wdt_ping();
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fallthrough;
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case WDIOC_GETTIMEOUT:
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if (put_user(margin, p))
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return -EFAULT;
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return 0;
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default:
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return -ENOTTY;
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}
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}
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static const struct file_operations scx200_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = scx200_wdt_write,
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.unlocked_ioctl = scx200_wdt_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.open = scx200_wdt_open,
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.release = scx200_wdt_release,
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};
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static struct miscdevice scx200_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &scx200_wdt_fops,
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};
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static int __init scx200_wdt_init(void)
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{
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int r;
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pr_debug("NatSemi SCx200 Watchdog Driver\n");
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/* check that we have found the configuration block */
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if (!scx200_cb_present())
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return -ENODEV;
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if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
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SCx200_WDT_SIZE,
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"NatSemi SCx200 Watchdog")) {
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pr_warn("watchdog I/O region busy\n");
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return -EBUSY;
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}
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scx200_wdt_update_margin();
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scx200_wdt_disable();
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r = register_reboot_notifier(&scx200_wdt_notifier);
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if (r) {
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pr_err("unable to register reboot notifier\n");
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release_region(scx200_cb_base + SCx200_WDT_OFFSET,
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SCx200_WDT_SIZE);
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return r;
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}
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r = misc_register(&scx200_wdt_miscdev);
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if (r) {
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unregister_reboot_notifier(&scx200_wdt_notifier);
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release_region(scx200_cb_base + SCx200_WDT_OFFSET,
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SCx200_WDT_SIZE);
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return r;
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}
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return 0;
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}
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static void __exit scx200_wdt_cleanup(void)
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{
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misc_deregister(&scx200_wdt_miscdev);
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unregister_reboot_notifier(&scx200_wdt_notifier);
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release_region(scx200_cb_base + SCx200_WDT_OFFSET,
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SCx200_WDT_SIZE);
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}
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module_init(scx200_wdt_init);
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module_exit(scx200_wdt_cleanup);
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