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379 lines
8.1 KiB
379 lines
8.1 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* IB700 Single Board Computer WDT driver |
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* |
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* (c) Copyright 2001 Charles Howes <[email protected]> |
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* |
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* Based on advantechwdt.c which is based on acquirewdt.c which |
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* is based on wdt.c. |
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* |
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* (c) Copyright 2000-2001 Marek Michalkiewicz <[email protected]> |
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* |
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* Based on acquirewdt.c which is based on wdt.c. |
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* Original copyright messages: |
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* |
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* (c) Copyright 1996 Alan Cox <[email protected]>, |
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* All Rights Reserved. |
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* |
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* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
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* warranty for any of this software. This material is provided |
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* "AS-IS" and at no charge. |
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* |
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* (c) Copyright 1995 Alan Cox <[email protected]> |
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* |
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* 14-Dec-2001 Matt Domsch <[email protected]> |
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* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT |
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* Added timeout module option to override default |
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* |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/types.h> |
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#include <linux/miscdevice.h> |
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#include <linux/watchdog.h> |
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#include <linux/ioport.h> |
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#include <linux/fs.h> |
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#include <linux/init.h> |
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#include <linux/spinlock.h> |
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#include <linux/moduleparam.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <linux/uaccess.h> |
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static struct platform_device *ibwdt_platform_device; |
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static unsigned long ibwdt_is_open; |
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static DEFINE_SPINLOCK(ibwdt_lock); |
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static char expect_close; |
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/* Module information */ |
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#define DRV_NAME "ib700wdt" |
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/* |
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* |
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* Watchdog Timer Configuration |
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* |
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* The function of the watchdog timer is to reset the system |
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* automatically and is defined at I/O port 0443H. To enable the |
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* watchdog timer and allow the system to reset, write I/O port 0443H. |
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* To disable the timer, write I/O port 0441H for the system to stop the |
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* watchdog function. The timer has a tolerance of 20% for its |
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* intervals. |
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* |
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* The following describes how the timer should be programmed. |
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* |
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* Enabling Watchdog: |
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* MOV AX,000FH (Choose the values from 0 to F) |
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* MOV DX,0443H |
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* OUT DX,AX |
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* |
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* Disabling Watchdog: |
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* MOV AX,000FH (Any value is fine.) |
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* MOV DX,0441H |
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* OUT DX,AX |
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* |
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* Watchdog timer control table: |
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* Level Value Time/sec | Level Value Time/sec |
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* 1 F 0 | 9 7 16 |
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* 2 E 2 | 10 6 18 |
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* 3 D 4 | 11 5 20 |
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* 4 C 6 | 12 4 22 |
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* 5 B 8 | 13 3 24 |
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* 6 A 10 | 14 2 26 |
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* 7 9 12 | 15 1 28 |
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* 8 8 14 | 16 0 30 |
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* |
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*/ |
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#define WDT_STOP 0x441 |
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#define WDT_START 0x443 |
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/* Default timeout */ |
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#define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */ |
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static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, |
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"Watchdog timeout in seconds. 0<= timeout <=30, default=" |
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__MODULE_STRING(WATCHDOG_TIMEOUT) "."); |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, |
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"Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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/* |
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* Watchdog Operations |
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*/ |
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static void ibwdt_ping(void) |
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{ |
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int wd_margin = 15 - ((timeout + 1) / 2); |
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spin_lock(&ibwdt_lock); |
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/* Write a watchdog value */ |
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outb_p(wd_margin, WDT_START); |
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spin_unlock(&ibwdt_lock); |
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} |
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static void ibwdt_disable(void) |
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{ |
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spin_lock(&ibwdt_lock); |
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outb_p(0, WDT_STOP); |
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spin_unlock(&ibwdt_lock); |
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} |
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static int ibwdt_set_heartbeat(int t) |
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{ |
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if (t < 0 || t > 30) |
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return -EINVAL; |
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timeout = t; |
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return 0; |
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} |
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/* |
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* /dev/watchdog handling |
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*/ |
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static ssize_t ibwdt_write(struct file *file, const char __user *buf, |
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size_t count, loff_t *ppos) |
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{ |
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if (count) { |
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if (!nowayout) { |
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size_t i; |
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/* In case it was set long ago */ |
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expect_close = 0; |
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for (i = 0; i != count; i++) { |
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char c; |
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if (get_user(c, buf + i)) |
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return -EFAULT; |
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if (c == 'V') |
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expect_close = 42; |
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} |
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} |
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ibwdt_ping(); |
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} |
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return count; |
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} |
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static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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int new_margin; |
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void __user *argp = (void __user *)arg; |
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int __user *p = argp; |
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static const struct watchdog_info ident = { |
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.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
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| WDIOF_MAGICCLOSE, |
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.firmware_version = 1, |
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.identity = "IB700 WDT", |
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}; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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if (copy_to_user(argp, &ident, sizeof(ident))) |
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return -EFAULT; |
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break; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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return put_user(0, p); |
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case WDIOC_SETOPTIONS: |
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{ |
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int options, retval = -EINVAL; |
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if (get_user(options, p)) |
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return -EFAULT; |
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if (options & WDIOS_DISABLECARD) { |
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ibwdt_disable(); |
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retval = 0; |
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} |
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if (options & WDIOS_ENABLECARD) { |
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ibwdt_ping(); |
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retval = 0; |
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} |
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return retval; |
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} |
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case WDIOC_KEEPALIVE: |
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ibwdt_ping(); |
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break; |
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case WDIOC_SETTIMEOUT: |
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if (get_user(new_margin, p)) |
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return -EFAULT; |
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if (ibwdt_set_heartbeat(new_margin)) |
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return -EINVAL; |
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ibwdt_ping(); |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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return put_user(timeout, p); |
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default: |
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return -ENOTTY; |
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} |
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return 0; |
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} |
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static int ibwdt_open(struct inode *inode, struct file *file) |
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{ |
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if (test_and_set_bit(0, &ibwdt_is_open)) |
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return -EBUSY; |
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if (nowayout) |
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__module_get(THIS_MODULE); |
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/* Activate */ |
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ibwdt_ping(); |
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return stream_open(inode, file); |
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} |
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static int ibwdt_close(struct inode *inode, struct file *file) |
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{ |
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if (expect_close == 42) { |
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ibwdt_disable(); |
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} else { |
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pr_crit("WDT device closed unexpectedly. WDT will not stop!\n"); |
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ibwdt_ping(); |
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} |
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clear_bit(0, &ibwdt_is_open); |
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expect_close = 0; |
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return 0; |
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} |
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/* |
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* Kernel Interfaces |
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*/ |
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static const struct file_operations ibwdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = ibwdt_write, |
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.unlocked_ioctl = ibwdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = ibwdt_open, |
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.release = ibwdt_close, |
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}; |
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static struct miscdevice ibwdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &ibwdt_fops, |
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}; |
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/* |
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* Init & exit routines |
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*/ |
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static int __init ibwdt_probe(struct platform_device *dev) |
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{ |
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int res; |
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#if WDT_START != WDT_STOP |
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if (!request_region(WDT_STOP, 1, "IB700 WDT")) { |
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pr_err("STOP method I/O %X is not available\n", WDT_STOP); |
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res = -EIO; |
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goto out_nostopreg; |
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} |
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#endif |
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if (!request_region(WDT_START, 1, "IB700 WDT")) { |
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pr_err("START method I/O %X is not available\n", WDT_START); |
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res = -EIO; |
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goto out_nostartreg; |
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} |
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/* Check that the heartbeat value is within it's range ; |
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* if not reset to the default */ |
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if (ibwdt_set_heartbeat(timeout)) { |
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ibwdt_set_heartbeat(WATCHDOG_TIMEOUT); |
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pr_info("timeout value must be 0<=x<=30, using %d\n", timeout); |
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} |
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res = misc_register(&ibwdt_miscdev); |
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if (res) { |
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pr_err("failed to register misc device\n"); |
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goto out_nomisc; |
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} |
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return 0; |
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out_nomisc: |
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release_region(WDT_START, 1); |
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out_nostartreg: |
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#if WDT_START != WDT_STOP |
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release_region(WDT_STOP, 1); |
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#endif |
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out_nostopreg: |
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return res; |
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} |
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static int ibwdt_remove(struct platform_device *dev) |
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{ |
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misc_deregister(&ibwdt_miscdev); |
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release_region(WDT_START, 1); |
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#if WDT_START != WDT_STOP |
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release_region(WDT_STOP, 1); |
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#endif |
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return 0; |
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} |
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static void ibwdt_shutdown(struct platform_device *dev) |
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{ |
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/* Turn the WDT off if we have a soft shutdown */ |
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ibwdt_disable(); |
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} |
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static struct platform_driver ibwdt_driver = { |
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.remove = ibwdt_remove, |
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.shutdown = ibwdt_shutdown, |
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.driver = { |
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.name = DRV_NAME, |
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}, |
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}; |
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static int __init ibwdt_init(void) |
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{ |
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int err; |
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pr_info("WDT driver for IB700 single board computer initialising\n"); |
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ibwdt_platform_device = platform_device_register_simple(DRV_NAME, |
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-1, NULL, 0); |
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if (IS_ERR(ibwdt_platform_device)) |
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return PTR_ERR(ibwdt_platform_device); |
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err = platform_driver_probe(&ibwdt_driver, ibwdt_probe); |
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if (err) |
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goto unreg_platform_device; |
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return 0; |
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unreg_platform_device: |
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platform_device_unregister(ibwdt_platform_device); |
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return err; |
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} |
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static void __exit ibwdt_exit(void) |
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{ |
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platform_device_unregister(ibwdt_platform_device); |
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platform_driver_unregister(&ibwdt_driver); |
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pr_info("Watchdog Module Unloaded\n"); |
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} |
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module_init(ibwdt_init); |
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module_exit(ibwdt_exit); |
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MODULE_AUTHOR("Charles Howes <[email protected]>"); |
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MODULE_DESCRIPTION("IB700 SBC watchdog driver"); |
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MODULE_LICENSE("GPL"); |
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/* end of ib700wdt.c */
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