diff options
Diffstat (limited to 'drivers/watchdog/sbc7240_wdt.c')
| -rw-r--r-- | drivers/watchdog/sbc7240_wdt.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/drivers/watchdog/sbc7240_wdt.c b/drivers/watchdog/sbc7240_wdt.c new file mode 100644 index 000000000..d640b26e1 --- /dev/null +++ b/drivers/watchdog/sbc7240_wdt.c @@ -0,0 +1,302 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * NANO7240 SBC Watchdog device driver + * + * Based on w83877f.c by Scott Jennings, + * + * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/ioport.h> +#include <linux/jiffies.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/miscdevice.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/types.h> +#include <linux/watchdog.h> +#include <linux/io.h> +#include <linux/uaccess.h> +#include <linux/atomic.h> + +#define SBC7240_ENABLE_PORT 0x443 +#define SBC7240_DISABLE_PORT 0x043 +#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT +#define SBC7240_MAGIC_CHAR 'V' + +#define SBC7240_TIMEOUT 30 +#define SBC7240_MAX_TIMEOUT 255 +static int timeout = SBC7240_TIMEOUT; /* in seconds */ +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=" + __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default=" + __MODULE_STRING(SBC7240_TIMEOUT) ")"); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file"); + +#define SBC7240_OPEN_STATUS_BIT 0 +#define SBC7240_ENABLED_STATUS_BIT 1 +#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2 +static unsigned long wdt_status; + +/* + * Utility routines + */ + +static void wdt_disable(void) +{ + /* disable the watchdog */ + if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { + inb_p(SBC7240_DISABLE_PORT); + pr_info("Watchdog timer is now disabled\n"); + } +} + +static void wdt_enable(void) +{ + /* enable the watchdog */ + if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { + inb_p(SBC7240_ENABLE_PORT); + pr_info("Watchdog timer is now enabled\n"); + } +} + +static int wdt_set_timeout(int t) +{ + if (t < 1 || t > SBC7240_MAX_TIMEOUT) { + pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT); + return -1; + } + /* set the timeout */ + outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT); + timeout = t; + pr_info("timeout set to %d seconds\n", t); + return 0; +} + +/* Whack the dog */ +static inline void wdt_keepalive(void) +{ + if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) + inb_p(SBC7240_ENABLE_PORT); +} + +/* + * /dev/watchdog handling + */ +static ssize_t fop_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + size_t i; + char c; + + if (count) { + if (!nowayout) { + clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, + &wdt_status); + + /* is there a magic char ? */ + for (i = 0; i != count; i++) { + if (get_user(c, buf + i)) + return -EFAULT; + if (c == SBC7240_MAGIC_CHAR) { + set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, + &wdt_status); + break; + } + } + } + + wdt_keepalive(); + } + + return count; +} + +static int fop_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status)) + return -EBUSY; + + wdt_enable(); + + return stream_open(inode, file); +} + +static int fop_close(struct inode *inode, struct file *file) +{ + if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status) + || !nowayout) { + wdt_disable(); + } else { + pr_crit("Unexpected close, not stopping watchdog!\n"); + wdt_keepalive(); + } + + clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status); + return 0; +} + +static const struct watchdog_info ident = { + .options = WDIOF_KEEPALIVEPING| + WDIOF_SETTIMEOUT| + WDIOF_MAGICCLOSE, + .firmware_version = 1, + .identity = "SBC7240", +}; + + +static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user((void __user *)arg, &ident, sizeof(ident)) + ? -EFAULT : 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, (int __user *)arg); + case WDIOC_SETOPTIONS: + { + int options; + int retval = -EINVAL; + + if (get_user(options, (int __user *)arg)) + return -EFAULT; + + if (options & WDIOS_DISABLECARD) { + wdt_disable(); + retval = 0; + } + + if (options & WDIOS_ENABLECARD) { + wdt_enable(); + retval = 0; + } + + return retval; + } + case WDIOC_KEEPALIVE: + wdt_keepalive(); + return 0; + case WDIOC_SETTIMEOUT: + { + int new_timeout; + + if (get_user(new_timeout, (int __user *)arg)) + return -EFAULT; + + if (wdt_set_timeout(new_timeout)) + return -EINVAL; + } + fallthrough; + case WDIOC_GETTIMEOUT: + return put_user(timeout, (int __user *)arg); + default: + return -ENOTTY; + } +} + +static const struct file_operations wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = fop_write, + .open = fop_open, + .release = fop_close, + .unlocked_ioctl = fop_ioctl, + .compat_ioctl = compat_ptr_ioctl, +}; + +static struct miscdevice wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &wdt_fops, +}; + +/* + * Notifier for system down + */ + +static int wdt_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + wdt_disable(); + return NOTIFY_DONE; +} + +static struct notifier_block wdt_notifier = { + .notifier_call = wdt_notify_sys, +}; + +static void __exit sbc7240_wdt_unload(void) +{ + pr_info("Removing watchdog\n"); + misc_deregister(&wdt_miscdev); + + unregister_reboot_notifier(&wdt_notifier); + release_region(SBC7240_ENABLE_PORT, 1); +} + +static int __init sbc7240_wdt_init(void) +{ + int rc = -EBUSY; + + if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) { + pr_err("I/O address 0x%04x already in use\n", + SBC7240_ENABLE_PORT); + rc = -EIO; + goto err_out; + } + + /* The IO port 0x043 used to disable the watchdog + * is already claimed by the system timer, so we + * can't request_region() it ...*/ + + if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) { + timeout = SBC7240_TIMEOUT; + pr_info("timeout value must be 1<=x<=%d, using %d\n", + SBC7240_MAX_TIMEOUT, timeout); + } + wdt_set_timeout(timeout); + wdt_disable(); + + rc = register_reboot_notifier(&wdt_notifier); + if (rc) { + pr_err("cannot register reboot notifier (err=%d)\n", rc); + goto err_out_region; + } + + rc = misc_register(&wdt_miscdev); + if (rc) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + wdt_miscdev.minor, rc); + goto err_out_reboot_notifier; + } + + pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n", + nowayout); + + return 0; + +err_out_reboot_notifier: + unregister_reboot_notifier(&wdt_notifier); +err_out_region: + release_region(SBC7240_ENABLE_PORT, 1); +err_out: + return rc; +} + +module_init(sbc7240_wdt_init); +module_exit(sbc7240_wdt_unload); + +MODULE_AUTHOR("Gilles Gigan"); +MODULE_DESCRIPTION("Watchdog device driver for single board" + " computers EPIC Nano 7240 from iEi"); +MODULE_LICENSE("GPL"); |