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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/watchdog/w83877f_wdt.c | |
download | op-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip op-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/char/watchdog/w83877f_wdt.c')
-rw-r--r-- | drivers/char/watchdog/w83877f_wdt.c | 426 |
1 files changed, 426 insertions, 0 deletions
diff --git a/drivers/char/watchdog/w83877f_wdt.c b/drivers/char/watchdog/w83877f_wdt.c new file mode 100644 index 0000000..bccbd4d --- /dev/null +++ b/drivers/char/watchdog/w83877f_wdt.c @@ -0,0 +1,426 @@ +/* + * W83877F Computer Watchdog Timer driver + * + * Based on acquirewdt.c by Alan Cox, + * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net> + * + * 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. + * + * The authors do NOT admit liability nor provide warranty for + * any of this software. This material is provided "AS-IS" in + * the hope that it may be useful for others. + * + * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net> + * + * 4/19 - 2001 [Initial revision] + * 9/27 - 2001 Added spinlocking + * 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments + * Eliminate fop_read + * Eliminate extra spin_unlock + * Added KERN_* tags to printks + * add CONFIG_WATCHDOG_NOWAYOUT support + * fix possible wdt_is_open race + * changed watchdog_info to correctly reflect what the driver offers + * added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, WDIOC_SETTIMEOUT, + * WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls + * 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces + * added extra printk's for startup problems + * use module_param + * made timeout (the emulated heartbeat) a module_param + * made the keepalive ping an internal subroutine + * + * This WDT driver is different from most other Linux WDT + * drivers in that the driver will ping the watchdog by itself, + * because this particular WDT has a very short timeout (1.6 + * seconds) and it would be insane to count on any userspace + * daemon always getting scheduled within that time frame. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/timer.h> +#include <linux/jiffies.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/fs.h> +#include <linux/ioport.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <asm/io.h> +#include <asm/uaccess.h> +#include <asm/system.h> + +#define OUR_NAME "w83877f_wdt" +#define PFX OUR_NAME ": " + +#define ENABLE_W83877F_PORT 0x3F0 +#define ENABLE_W83877F 0x87 +#define DISABLE_W83877F 0xAA +#define WDT_PING 0x443 +#define WDT_REGISTER 0x14 +#define WDT_ENABLE 0x9C +#define WDT_DISABLE 0x8C + +/* + * The W83877F seems to be fixed at 1.6s timeout (at least on the + * EMACS PC-104 board I'm using). If we reset the watchdog every + * ~250ms we should be safe. */ + +#define WDT_INTERVAL (HZ/4+1) + +/* + * We must not require too good response from the userspace daemon. + * Here we require the userspace daemon to send us a heartbeat + * char to /dev/watchdog every 30 seconds. + */ + +#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ +static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); + + +#ifdef CONFIG_WATCHDOG_NOWAYOUT +static int nowayout = 1; +#else +static int nowayout = 0; +#endif + +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); + +static void wdt_timer_ping(unsigned long); +static struct timer_list timer; +static unsigned long next_heartbeat; +static unsigned long wdt_is_open; +static char wdt_expect_close; +static spinlock_t wdt_spinlock; + +/* + * Whack the dog + */ + +static void wdt_timer_ping(unsigned long data) +{ + /* If we got a heartbeat pulse within the WDT_US_INTERVAL + * we agree to ping the WDT + */ + if(time_before(jiffies, next_heartbeat)) + { + /* Ping the WDT */ + spin_lock(&wdt_spinlock); + + /* Ping the WDT by reading from WDT_PING */ + inb_p(WDT_PING); + + /* Re-set the timer interval */ + timer.expires = jiffies + WDT_INTERVAL; + add_timer(&timer); + + spin_unlock(&wdt_spinlock); + + } else { + printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); + } +} + +/* + * Utility routines + */ + +static void wdt_change(int writeval) +{ + unsigned long flags; + spin_lock_irqsave(&wdt_spinlock, flags); + + /* buy some time */ + inb_p(WDT_PING); + + /* make W83877F available */ + outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); + outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); + + /* enable watchdog */ + outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); + outb_p(writeval, ENABLE_W83877F_PORT+1); + + /* lock the W8387FF away */ + outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); + + spin_unlock_irqrestore(&wdt_spinlock, flags); +} + +static void wdt_startup(void) +{ + next_heartbeat = jiffies + (timeout * HZ); + + /* Start the timer */ + timer.expires = jiffies + WDT_INTERVAL; + add_timer(&timer); + + wdt_change(WDT_ENABLE); + + printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); +} + +static void wdt_turnoff(void) +{ + /* Stop the timer */ + del_timer(&timer); + + wdt_change(WDT_DISABLE); + + printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); +} + +static void wdt_keepalive(void) +{ + /* user land ping */ + next_heartbeat = jiffies + (timeout * HZ); +} + +/* + * /dev/watchdog handling + */ + +static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) +{ + /* See if we got the magic character 'V' and reload the timer */ + if(count) + { + if (!nowayout) + { + size_t ofs; + + /* note: just in case someone wrote the magic character + * five months ago... */ + wdt_expect_close = 0; + + /* scan to see whether or not we got the magic character */ + for(ofs = 0; ofs != count; ofs++) + { + char c; + if (get_user(c, buf + ofs)) + return -EFAULT; + if (c == 'V') + wdt_expect_close = 42; + } + } + + /* someone wrote to us, we should restart timer */ + wdt_keepalive(); + } + return count; +} + +static int fop_open(struct inode * inode, struct file * file) +{ + /* Just in case we're already talking to someone... */ + if(test_and_set_bit(0, &wdt_is_open)) + return -EBUSY; + + /* Good, fire up the show */ + wdt_startup(); + return nonseekable_open(inode, file); +} + +static int fop_close(struct inode * inode, struct file * file) +{ + if(wdt_expect_close == 42) + wdt_turnoff(); + else { + del_timer(&timer); + printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n"); + } + clear_bit(0, &wdt_is_open); + wdt_expect_close = 0; + return 0; +} + +static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + static struct watchdog_info ident= + { + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, + .firmware_version = 1, + .identity = "W83877F", + }; + + switch(cmd) + { + default: + return -ENOIOCTLCMD; + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + case WDIOC_KEEPALIVE: + wdt_keepalive(); + return 0; + case WDIOC_SETOPTIONS: + { + int new_options, retval = -EINVAL; + + if(get_user(new_options, p)) + return -EFAULT; + + if(new_options & WDIOS_DISABLECARD) { + wdt_turnoff(); + retval = 0; + } + + if(new_options & WDIOS_ENABLECARD) { + wdt_startup(); + retval = 0; + } + + return retval; + } + case WDIOC_SETTIMEOUT: + { + int new_timeout; + + if(get_user(new_timeout, p)) + return -EFAULT; + + if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */ + return -EINVAL; + + timeout = new_timeout; + wdt_keepalive(); + /* Fall through */ + } + case WDIOC_GETTIMEOUT: + return put_user(timeout, p); + } +} + +static struct file_operations wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = fop_write, + .open = fop_open, + .release = fop_close, + .ioctl = fop_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_turnoff(); + return NOTIFY_DONE; +} + +/* + * The WDT needs to learn about soft shutdowns in order to + * turn the timebomb registers off. + */ + +static struct notifier_block wdt_notifier= +{ + .notifier_call = wdt_notify_sys, +}; + +static void __exit w83877f_wdt_unload(void) +{ + wdt_turnoff(); + + /* Deregister */ + misc_deregister(&wdt_miscdev); + + unregister_reboot_notifier(&wdt_notifier); + release_region(WDT_PING,1); + release_region(ENABLE_W83877F_PORT,2); +} + +static int __init w83877f_wdt_init(void) +{ + int rc = -EBUSY; + + spin_lock_init(&wdt_spinlock); + + if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */ + { + timeout = WATCHDOG_TIMEOUT; + printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n", + timeout); + } + + if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) + { + printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", + ENABLE_W83877F_PORT); + rc = -EIO; + goto err_out; + } + + if (!request_region(WDT_PING, 1, "W8387FF WDT")) + { + printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", + WDT_PING); + rc = -EIO; + goto err_out_region1; + } + + init_timer(&timer); + timer.function = wdt_timer_ping; + timer.data = 0; + + rc = misc_register(&wdt_miscdev); + if (rc) + { + printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", + wdt_miscdev.minor, rc); + goto err_out_region2; + } + + rc = register_reboot_notifier(&wdt_notifier); + if (rc) + { + printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", + rc); + goto err_out_miscdev; + } + + printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", + timeout, nowayout); + + return 0; + +err_out_miscdev: + misc_deregister(&wdt_miscdev); +err_out_region2: + release_region(WDT_PING,1); +err_out_region1: + release_region(ENABLE_W83877F_PORT,2); +err_out: + return rc; +} + +module_init(w83877f_wdt_init); +module_exit(w83877f_wdt_unload); + +MODULE_AUTHOR("Scott and Bill Jennings"); +MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |