diff options
Diffstat (limited to 'drivers/char/watchdog/sbc_epx_c3.c')
| -rw-r--r-- | drivers/char/watchdog/sbc_epx_c3.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/char/watchdog/sbc_epx_c3.c b/drivers/char/watchdog/sbc_epx_c3.c new file mode 100644 index 0000000000000..951764614ebf6 --- /dev/null +++ b/drivers/char/watchdog/sbc_epx_c3.c @@ -0,0 +1,216 @@ +/* + * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3 + * single board computer + * + * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights + * Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * based on softdog.c by Alan Cox <alan@redhat.com> + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/config.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <asm/uaccess.h> +#include <asm/io.h> + +#define PFX "epx_c3: " +static int epx_c3_alive; + +#define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */ + +static int nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); + +#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */ +#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */ + +static void epx_c3_start(void) +{ + outb(1, EPXC3_WATCHDOG_CTL_REG); +} + +static void epx_c3_stop(void) +{ + + outb(0, EPXC3_WATCHDOG_CTL_REG); + + printk(KERN_INFO PFX "Stopped watchdog timer.\n"); +} + +static void epx_c3_pet(void) +{ + outb(1, EPXC3_WATCHDOG_PET_REG); +} + +/* + * Allow only one person to hold it open + */ +static int epx_c3_open(struct inode *inode, struct file *file) +{ + if (epx_c3_alive) + return -EBUSY; + + if (nowayout) + __module_get(THIS_MODULE); + + /* Activate timer */ + epx_c3_start(); + epx_c3_pet(); + + epx_c3_alive = 1; + printk(KERN_INFO "Started watchdog timer.\n"); + + return nonseekable_open(inode, file); +} + +static int epx_c3_release(struct inode *inode, struct file *file) +{ + /* Shut off the timer. + * Lock it in if it's a module and we defined ...NOWAYOUT */ + if (!nowayout) + epx_c3_stop(); /* Turn the WDT off */ + + epx_c3_alive = 0; + + return 0; +} + +static ssize_t epx_c3_write(struct file *file, const char *data, + size_t len, loff_t *ppos) +{ + /* Refresh the timer. */ + if (len) + epx_c3_pet(); + return len; +} + +static int epx_c3_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + int options, retval = -EINVAL; + static struct watchdog_info ident = { + .options = WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, + .firmware_version = 0, + .identity = "Winsystems EPX-C3 H/W Watchdog", + }; + + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user((struct watchdog_info *)arg, + &ident, sizeof(ident))) + return -EFAULT; + return 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0,(int *)arg); + case WDIOC_KEEPALIVE: + epx_c3_pet(); + return 0; + case WDIOC_GETTIMEOUT: + return put_user(WATCHDOG_TIMEOUT,(int *)arg); + case WDIOC_SETOPTIONS: { + if (get_user(options, (int *)arg)) + return -EFAULT; + + if (options & WDIOS_DISABLECARD) { + epx_c3_stop(); + retval = 0; + } + + if (options & WDIOS_ENABLECARD) { + epx_c3_start(); + retval = 0; + } + + return retval; + } + default: + return -ENOIOCTLCMD; + } +} + +static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + epx_c3_stop(); /* Turn the WDT off */ + + return NOTIFY_DONE; +} + +static struct file_operations epx_c3_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = epx_c3_write, + .ioctl = epx_c3_ioctl, + .open = epx_c3_open, + .release = epx_c3_release, +}; + +static struct miscdevice epx_c3_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &epx_c3_fops, +}; + +static struct notifier_block epx_c3_notifier = { + .notifier_call = epx_c3_notify_sys, +}; + +static const char banner[] __initdata = + KERN_INFO PFX "Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n"; + +static int __init watchdog_init(void) +{ + int ret; + + ret = register_reboot_notifier(&epx_c3_notifier); + if (ret) { + printk(KERN_ERR PFX "cannot register reboot notifier " + "(err=%d)\n", ret); + return ret; + } + + ret = misc_register(&epx_c3_miscdev); + if (ret) { + printk(KERN_ERR PFX "cannot register miscdev on minor=%d " + "(err=%d)\n", WATCHDOG_MINOR, ret); + unregister_reboot_notifier(&epx_c3_notifier); + return ret; + } + + printk(banner); + + return 0; +} + +static void __exit watchdog_exit(void) +{ + misc_deregister(&epx_c3_miscdev); + unregister_reboot_notifier(&epx_c3_notifier); +} + +module_init(watchdog_init); +module_exit(watchdog_exit); + +MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>"); +MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. Note that there is no way to probe for this device -- so only use it if you are *sure* you are runnning on this specific SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |