cregit-Linux how code gets into the kernel

Release 4.10 drivers/watchdog/acquirewdt.c

Directory: drivers/watchdog
/*
 *      Acquire Single Board Computer Watchdog Timer driver
 *
 *      Based on wdt.c. Original copyright messages:
 *
 *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
 *                                              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.
 *
 *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
 *      warranty for any of this software. This material is provided
 *      "AS-IS" and at no charge.
 *
 *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 *          Can't add timeout - driver doesn't allow changing value
 */

/*
 *      Theory of Operation:
 *              The Watch-Dog Timer is provided to ensure that standalone
 *              Systems can always recover from catastrophic conditions that
 *              caused the CPU to crash. This condition may have occurred by
 *              external EMI or a software bug. When the CPU stops working
 *              correctly, hardware on the board will either perform a hardware
 *              reset (cold boot) or a non-maskable interrupt (NMI) to bring the
 *              system back to a known state.
 *
 *              The Watch-Dog Timer is controlled by two I/O Ports.
 *                443 hex       - Read  - Enable or refresh the Watch-Dog Timer
 *                043 hex       - Read  - Disable the Watch-Dog Timer
 *
 *              To enable the Watch-Dog Timer, a read from I/O port 443h must
 *              be performed. This will enable and activate the countdown timer
 *              which will eventually time out and either reset the CPU or cause
 *              an NMI depending on the setting of a jumper. To ensure that this
 *              reset condition does not occur, the Watch-Dog Timer must be
 *              periodically refreshed by reading the same I/O port 443h.
 *              The Watch-Dog Timer is disabled by reading I/O port 043h.
 *
 *              The Watch-Dog Timer Time-Out Period is set via jumpers.
 *              It can be 1, 2, 10, 20, 110 or 220 seconds.
 */

/*
 *      Includes, defines, variables, module parameters, ...
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

/* Includes */
#include <linux/module.h>		/* For module specific items */
#include <linux/moduleparam.h>		/* For new moduleparam's */
#include <linux/types.h>		/* For standard types (like size_t) */
#include <linux/errno.h>		/* For the -ENODEV/... values */
#include <linux/kernel.h>		/* For printk/panic/... */
#include <linux/miscdevice.h>		/* For struct miscdevice */
#include <linux/watchdog.h>		/* For the watchdog specific items */
#include <linux/fs.h>			/* For file operations */
#include <linux/ioport.h>		/* For io-port access */
#include <linux/platform_device.h>	/* For platform_driver framework */
#include <linux/init.h>			/* For __init/__exit/... */
#include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
#include <linux/io.h>			/* For inb/outb/... */

/* Module information */

#define DRV_NAME "acquirewdt"

#define WATCHDOG_NAME "Acquire WDT"
/* There is no way to see what the correct time-out period is */

#define WATCHDOG_HEARTBEAT 0

/* internal variables */
/* the watchdog platform device */

static struct platform_device *acq_platform_device;

static unsigned long acq_is_open;

static char expect_close;

/* module parameters */
/* You must set this - there is no sane way to probe for this board. */

static int wdt_stop = 0x43;
module_param(wdt_stop, int, 0);
MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");

/* You must set this - there is no sane way to probe for this board. */

static int wdt_start = 0x443;
module_param(wdt_start, int, 0);
MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");


static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/*
 *      Watchdog Operations
 */


static void acq_keepalive(void) { /* Write a watchdog value */ inb_p(wdt_start); }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git1285.71%133.33%
wim van sebroeckwim van sebroeck214.29%266.67%
Total14100.00%3100.00%


static void acq_stop(void) { /* Turn the card off */ inb_p(wdt_stop); }

Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck14100.00%1100.00%
Total14100.00%1100.00%

/* * /dev/watchdog handling */
static ssize_t acq_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 i; /* note: just in case someone wrote the magic character five months ago... */ expect_close = 0; /* scan to see whether or not we got the magic character */ for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } /* Well, anyhow someone wrote to us, we should return that favour */ acq_keepalive(); } return count; }

Contributors

PersonTokensPropCommitsCommitProp
dave jonesdave jones5657.73%112.50%
pre-gitpre-git3334.02%225.00%
wim van sebroeckwim van sebroeck55.15%337.50%
alan coxalan cox22.06%112.50%
al viroal viro11.03%112.50%
Total97100.00%8100.00%


static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int options, retval = -EINVAL; void __user *argp = (void __user *)arg; int __user *p = argp; static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = WATCHDOG_NAME, }; switch (cmd) { 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_SETOPTIONS: { if (get_user(options, p)) return -EFAULT; if (options & WDIOS_DISABLECARD) { acq_stop(); retval = 0; } if (options & WDIOS_ENABLECARD) { acq_keepalive(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: acq_keepalive(); return 0; case WDIOC_GETTIMEOUT: return put_user(WATCHDOG_HEARTBEAT, p); default: return -ENOTTY; } }

Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck8645.50%545.45%
pre-gitpre-git6835.98%19.09%
al viroal viro2211.64%19.09%
dave jonesdave jones115.82%218.18%
samuel tardieusamuel tardieu10.53%19.09%
alan coxalan cox10.53%19.09%
Total189100.00%11100.00%


static int acq_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &acq_is_open)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); /* Activate */ acq_keepalive(); return nonseekable_open(inode, file); }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git2752.94%225.00%
alan coxalan cox917.65%225.00%
wim van sebroeckwim van sebroeck611.76%225.00%
linus torvaldslinus torvalds611.76%112.50%
dave jonesdave jones35.88%112.50%
Total51100.00%8100.00%


static int acq_close(struct inode *inode, struct file *file) { if (expect_close == 42) { acq_stop(); } else { pr_crit("Unexpected close, not stopping watchdog!\n"); acq_keepalive(); } clear_bit(0, &acq_is_open); expect_close = 0; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git2954.72%233.33%
wim van sebroeckwim van sebroeck1833.96%233.33%
dave jonesdave jones47.55%116.67%
joe perchesjoe perches23.77%116.67%
Total53100.00%6100.00%

/* * Kernel Interfaces */ static const struct file_operations acq_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = acq_write, .unlocked_ioctl = acq_ioctl, .open = acq_open, .release = acq_close, }; static struct miscdevice acq_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &acq_fops, }; /* * Init & exit routines */
static int __init acq_probe(struct platform_device *dev) { int ret; if (wdt_stop != wdt_start) { if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { pr_err("I/O address 0x%04x already in use\n", wdt_stop); ret = -EIO; goto out; } } if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { pr_err("I/O address 0x%04x already in use\n", wdt_start); ret = -EIO; goto unreg_stop; } ret = misc_register(&acq_miscdev); if (ret != 0) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto unreg_regions; } pr_info("initialized. (nowayout=%d)\n", nowayout); return 0; unreg_regions: release_region(wdt_start, 1); unreg_stop: if (wdt_stop != wdt_start) release_region(wdt_stop, 1); out: return ret; }

Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck8758.78%436.36%
dave jonesdave jones2516.89%19.09%
pre-gitpre-git1912.84%327.27%
joe perchesjoe perches138.78%19.09%
rusty russellrusty russell32.03%19.09%
jean delvarejean delvare10.68%19.09%
Total148100.00%11100.00%


static int acq_remove(struct platform_device *dev) { misc_deregister(&acq_miscdev); release_region(wdt_start, 1); if (wdt_stop != wdt_start) release_region(wdt_stop, 1); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck2460.00%375.00%
pre-gitpre-git1640.00%125.00%
Total40100.00%4100.00%


static void acq_shutdown(struct platform_device *dev) { /* Turn the WDT off if we have a soft shutdown */ acq_stop(); }

Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck15100.00%1100.00%
Total15100.00%1100.00%

static struct platform_driver acquirewdt_driver = { .remove = acq_remove, .shutdown = acq_shutdown, .driver = { .name = DRV_NAME, }, };
static int __init acq_init(void) { int err; pr_info("WDT driver for Acquire single board computer initialising\n"); acq_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0); if (IS_ERR(acq_platform_device)) return PTR_ERR(acq_platform_device); err = platform_driver_probe(&acquirewdt_driver, acq_probe); if (err) goto unreg_platform_device; return 0; unreg_platform_device: platform_device_unregister(acq_platform_device); return err; }

Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck5371.62%133.33%
jean delvarejean delvare1925.68%133.33%
joe perchesjoe perches22.70%133.33%
Total74100.00%3100.00%


static void __exit acq_exit(void) { platform_device_unregister(acq_platform_device); platform_driver_unregister(&acquirewdt_driver); pr_info("Watchdog Module Unloaded\n"); }

Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck2184.00%133.33%
joe perchesjoe perches312.00%133.33%
pre-gitpre-git14.00%133.33%
Total25100.00%3100.00%

module_init(acq_init); module_exit(acq_exit); MODULE_AUTHOR("David Woodhouse"); MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver"); MODULE_LICENSE("GPL");

Overall Contributors

PersonTokensPropCommitsCommitProp
wim van sebroeckwim van sebroeck47647.36%1024.39%
pre-gitpre-git27727.56%921.95%
dave jonesdave jones12912.84%614.63%
joe perchesjoe perches272.69%12.44%
al viroal viro232.29%12.44%
jean delvarejean delvare212.09%24.88%
alan coxalan cox201.99%37.32%
art haasart haas101.00%12.44%
linus torvaldslinus torvalds90.90%24.88%
andrew mortonandrew morton60.60%12.44%
rusty russellrusty russell30.30%12.44%
arjan van de venarjan van de ven10.10%12.44%
andrey paninandrey panin10.10%12.44%
lucas de marchilucas de marchi10.10%12.44%
samuel tardieusamuel tardieu10.10%12.44%
Total1005100.00%41100.00%
Directory: drivers/watchdog
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.