diff options
Diffstat (limited to 'drivers/watchdog/sbc_fitpc2_wdt.c')
| -rw-r--r-- | drivers/watchdog/sbc_fitpc2_wdt.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/watchdog/sbc_fitpc2_wdt.c b/drivers/watchdog/sbc_fitpc2_wdt.c new file mode 100644 index 0000000000..b8eb8d5ca1 --- /dev/null +++ b/drivers/watchdog/sbc_fitpc2_wdt.c @@ -0,0 +1,264 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Watchdog driver for SBC-FITPC2 board + * + * Author: Denis Turischev <denis@compulab.co.il> + * + * Adapted from the IXP2000 watchdog driver by Deepak Saxena. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/ioport.h> +#include <linux/delay.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/moduleparam.h> +#include <linux/dmi.h> +#include <linux/io.h> +#include <linux/uaccess.h> + + +static bool nowayout = WATCHDOG_NOWAYOUT; +static unsigned int margin = 60; /* (secs) Default is 1 minute */ +static unsigned long wdt_status; +static DEFINE_MUTEX(wdt_lock); + +#define WDT_IN_USE 0 +#define WDT_OK_TO_CLOSE 1 + +#define COMMAND_PORT 0x4c +#define DATA_PORT 0x48 + +#define IFACE_ON_COMMAND 1 +#define REBOOT_COMMAND 2 + +#define WATCHDOG_NAME "SBC-FITPC2 Watchdog" + +static void wdt_send_data(unsigned char command, unsigned char data) +{ + outb(data, DATA_PORT); + msleep(200); + outb(command, COMMAND_PORT); + msleep(100); +} + +static void wdt_enable(void) +{ + mutex_lock(&wdt_lock); + wdt_send_data(IFACE_ON_COMMAND, 1); + wdt_send_data(REBOOT_COMMAND, margin); + mutex_unlock(&wdt_lock); +} + +static void wdt_disable(void) +{ + mutex_lock(&wdt_lock); + wdt_send_data(IFACE_ON_COMMAND, 0); + wdt_send_data(REBOOT_COMMAND, 0); + mutex_unlock(&wdt_lock); +} + +static int fitpc2_wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(WDT_IN_USE, &wdt_status)) + return -EBUSY; + + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + wdt_enable(); + + return stream_open(inode, file); +} + +static ssize_t fitpc2_wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + size_t i; + + if (!len) + return 0; + + if (nowayout) { + len = 0; + goto out; + } + + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, data + i)) + return -EFAULT; + + if (c == 'V') + set_bit(WDT_OK_TO_CLOSE, &wdt_status); + } + +out: + wdt_enable(); + + return len; +} + + +static const struct watchdog_info ident = { + .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING, + .identity = WATCHDOG_NAME, +}; + + +static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int ret = -ENOTTY; + int time; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user((struct watchdog_info __user *)arg, &ident, + sizeof(ident)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + ret = put_user(0, (int __user *)arg); + break; + + case WDIOC_GETBOOTSTATUS: + ret = put_user(0, (int __user *)arg); + break; + + case WDIOC_KEEPALIVE: + wdt_enable(); + ret = 0; + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(time, (int __user *)arg); + if (ret) + break; + + if (time < 31 || time > 255) { + ret = -EINVAL; + break; + } + + margin = time; + wdt_enable(); + fallthrough; + + case WDIOC_GETTIMEOUT: + ret = put_user(margin, (int __user *)arg); + break; + } + + return ret; +} + +static int fitpc2_wdt_release(struct inode *inode, struct file *file) +{ + if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { + wdt_disable(); + pr_info("Device disabled\n"); + } else { + pr_warn("Device closed unexpectedly - timer will not stop\n"); + wdt_enable(); + } + + clear_bit(WDT_IN_USE, &wdt_status); + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + return 0; +} + + +static const struct file_operations fitpc2_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = fitpc2_wdt_write, + .unlocked_ioctl = fitpc2_wdt_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = fitpc2_wdt_open, + .release = fitpc2_wdt_release, +}; + +static struct miscdevice fitpc2_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &fitpc2_wdt_fops, +}; + +static int __init fitpc2_wdt_init(void) +{ + int err; + const char *brd_name; + + brd_name = dmi_get_system_info(DMI_BOARD_NAME); + + if (!brd_name || !strstr(brd_name, "SBC-FITPC2")) + return -ENODEV; + + pr_info("%s found\n", brd_name); + + if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) { + pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT); + return -EIO; + } + + if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) { + pr_err("I/O address 0x%04x already in use\n", DATA_PORT); + err = -EIO; + goto err_data_port; + } + + if (margin < 31 || margin > 255) { + pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n", + margin); + err = -EINVAL; + goto err_margin; + } + + err = misc_register(&fitpc2_wdt_miscdev); + if (err) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, err); + goto err_margin; + } + + return 0; + +err_margin: + release_region(DATA_PORT, 1); +err_data_port: + release_region(COMMAND_PORT, 1); + + return err; +} + +static void __exit fitpc2_wdt_exit(void) +{ + misc_deregister(&fitpc2_wdt_miscdev); + release_region(DATA_PORT, 1); + release_region(COMMAND_PORT, 1); +} + +module_init(fitpc2_wdt_init); +module_exit(fitpc2_wdt_exit); + +MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>"); +MODULE_DESCRIPTION("SBC-FITPC2 Watchdog"); + +module_param(margin, int, 0); +MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); + +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); + +MODULE_LICENSE("GPL"); |