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302 lines
6.5 KiB
302 lines
6.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* NANO7240 SBC Watchdog device driver |
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* |
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* Based on w83877f.c by Scott Jennings, |
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* |
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* (c) Copyright 2007 Gilles GIGAN <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/fs.h> |
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#include <linux/init.h> |
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#include <linux/ioport.h> |
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#include <linux/jiffies.h> |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/miscdevice.h> |
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#include <linux/notifier.h> |
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#include <linux/reboot.h> |
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#include <linux/types.h> |
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#include <linux/watchdog.h> |
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#include <linux/io.h> |
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#include <linux/uaccess.h> |
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#include <linux/atomic.h> |
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#define SBC7240_ENABLE_PORT 0x443 |
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#define SBC7240_DISABLE_PORT 0x043 |
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#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT |
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#define SBC7240_MAGIC_CHAR 'V' |
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#define SBC7240_TIMEOUT 30 |
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#define SBC7240_MAX_TIMEOUT 255 |
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static int timeout = SBC7240_TIMEOUT; /* in seconds */ |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=" |
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__MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default=" |
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__MODULE_STRING(SBC7240_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, "Disable watchdog when closing device file"); |
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#define SBC7240_OPEN_STATUS_BIT 0 |
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#define SBC7240_ENABLED_STATUS_BIT 1 |
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#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2 |
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static unsigned long wdt_status; |
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/* |
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* Utility routines |
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*/ |
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static void wdt_disable(void) |
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{ |
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/* disable the watchdog */ |
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if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { |
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inb_p(SBC7240_DISABLE_PORT); |
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pr_info("Watchdog timer is now disabled\n"); |
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} |
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} |
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static void wdt_enable(void) |
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{ |
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/* enable the watchdog */ |
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if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { |
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inb_p(SBC7240_ENABLE_PORT); |
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pr_info("Watchdog timer is now enabled\n"); |
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} |
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} |
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static int wdt_set_timeout(int t) |
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{ |
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if (t < 1 || t > SBC7240_MAX_TIMEOUT) { |
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pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT); |
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return -1; |
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} |
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/* set the timeout */ |
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outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT); |
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timeout = t; |
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pr_info("timeout set to %d seconds\n", t); |
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return 0; |
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} |
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/* Whack the dog */ |
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static inline void wdt_keepalive(void) |
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{ |
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if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) |
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inb_p(SBC7240_ENABLE_PORT); |
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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 fop_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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size_t i; |
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char c; |
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if (count) { |
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if (!nowayout) { |
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clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, |
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&wdt_status); |
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/* is there a magic char ? */ |
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for (i = 0; i != count; i++) { |
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if (get_user(c, buf + i)) |
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return -EFAULT; |
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if (c == SBC7240_MAGIC_CHAR) { |
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set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, |
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&wdt_status); |
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break; |
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} |
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} |
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} |
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wdt_keepalive(); |
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} |
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return count; |
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} |
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static int fop_open(struct inode *inode, struct file *file) |
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{ |
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if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status)) |
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return -EBUSY; |
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wdt_enable(); |
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return stream_open(inode, file); |
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} |
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static int fop_close(struct inode *inode, struct file *file) |
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{ |
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if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status) |
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|| !nowayout) { |
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wdt_disable(); |
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} else { |
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pr_crit("Unexpected close, not stopping watchdog!\n"); |
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wdt_keepalive(); |
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} |
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clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status); |
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return 0; |
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} |
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static const struct watchdog_info ident = { |
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.options = WDIOF_KEEPALIVEPING| |
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WDIOF_SETTIMEOUT| |
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WDIOF_MAGICCLOSE, |
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.firmware_version = 1, |
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.identity = "SBC7240", |
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}; |
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static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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return copy_to_user((void __user *)arg, &ident, sizeof(ident)) |
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? -EFAULT : 0; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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return put_user(0, (int __user *)arg); |
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case WDIOC_SETOPTIONS: |
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{ |
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int options; |
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int retval = -EINVAL; |
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if (get_user(options, (int __user *)arg)) |
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return -EFAULT; |
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if (options & WDIOS_DISABLECARD) { |
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wdt_disable(); |
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retval = 0; |
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} |
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if (options & WDIOS_ENABLECARD) { |
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wdt_enable(); |
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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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wdt_keepalive(); |
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return 0; |
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case WDIOC_SETTIMEOUT: |
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{ |
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int new_timeout; |
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if (get_user(new_timeout, (int __user *)arg)) |
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return -EFAULT; |
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if (wdt_set_timeout(new_timeout)) |
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return -EINVAL; |
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} |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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return put_user(timeout, (int __user *)arg); |
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default: |
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return -ENOTTY; |
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} |
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} |
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static const struct file_operations wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = fop_write, |
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.open = fop_open, |
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.release = fop_close, |
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.unlocked_ioctl = fop_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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}; |
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static struct miscdevice wdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &wdt_fops, |
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}; |
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/* |
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* Notifier for system down |
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*/ |
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static int wdt_notify_sys(struct notifier_block *this, unsigned long code, |
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void *unused) |
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{ |
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if (code == SYS_DOWN || code == SYS_HALT) |
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wdt_disable(); |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block wdt_notifier = { |
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.notifier_call = wdt_notify_sys, |
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}; |
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static void __exit sbc7240_wdt_unload(void) |
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{ |
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pr_info("Removing watchdog\n"); |
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misc_deregister(&wdt_miscdev); |
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unregister_reboot_notifier(&wdt_notifier); |
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release_region(SBC7240_ENABLE_PORT, 1); |
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} |
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static int __init sbc7240_wdt_init(void) |
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{ |
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int rc = -EBUSY; |
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if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) { |
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pr_err("I/O address 0x%04x already in use\n", |
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SBC7240_ENABLE_PORT); |
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rc = -EIO; |
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goto err_out; |
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} |
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/* The IO port 0x043 used to disable the watchdog |
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* is already claimed by the system timer, so we |
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* can't request_region() it ...*/ |
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if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) { |
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timeout = SBC7240_TIMEOUT; |
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pr_info("timeout value must be 1<=x<=%d, using %d\n", |
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SBC7240_MAX_TIMEOUT, timeout); |
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} |
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wdt_set_timeout(timeout); |
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wdt_disable(); |
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rc = register_reboot_notifier(&wdt_notifier); |
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if (rc) { |
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pr_err("cannot register reboot notifier (err=%d)\n", rc); |
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goto err_out_region; |
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} |
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rc = misc_register(&wdt_miscdev); |
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if (rc) { |
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pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
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wdt_miscdev.minor, rc); |
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goto err_out_reboot_notifier; |
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} |
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pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n", |
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nowayout); |
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return 0; |
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err_out_reboot_notifier: |
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unregister_reboot_notifier(&wdt_notifier); |
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err_out_region: |
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release_region(SBC7240_ENABLE_PORT, 1); |
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err_out: |
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return rc; |
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} |
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module_init(sbc7240_wdt_init); |
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module_exit(sbc7240_wdt_unload); |
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MODULE_AUTHOR("Gilles Gigan"); |
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MODULE_DESCRIPTION("Watchdog device driver for single board" |
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" computers EPIC Nano 7240 from iEi"); |
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MODULE_LICENSE("GPL");
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