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451 lines
11 KiB
451 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* ALi M7101 PMU Computer Watchdog Timer driver |
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* |
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* Based on w83877f_wdt.c by Scott Jennings <[email protected]> |
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* and the Cobalt kernel WDT timer driver by Tim Hockin |
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* <[email protected]> |
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* |
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* (c)2002 Steve Hill <[email protected]> |
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* |
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* This WDT driver is different from most other Linux WDT |
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* drivers in that the driver will ping the watchdog by itself, |
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* because this particular WDT has a very short timeout (1.6 |
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* seconds) and it would be insane to count on any userspace |
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* daemon always getting scheduled within that time frame. |
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* |
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* Additions: |
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* Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs |
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* found on very old cobalt hardware. |
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* -- Mike Waychison <[email protected]> |
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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/moduleparam.h> |
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#include <linux/types.h> |
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#include <linux/timer.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/notifier.h> |
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#include <linux/reboot.h> |
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#include <linux/init.h> |
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#include <linux/fs.h> |
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#include <linux/pci.h> |
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#include <linux/io.h> |
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#include <linux/uaccess.h> |
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#define WDT_ENABLE 0x9C |
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#define WDT_DISABLE 0x8C |
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#define ALI_7101_WDT 0x92 |
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#define ALI_7101_GPIO 0x7D |
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#define ALI_7101_GPIO_O 0x7E |
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#define ALI_WDT_ARM 0x01 |
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/* |
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* We're going to use a 1 second timeout. |
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* If we reset the watchdog every ~250ms we should be safe. */ |
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#define WDT_INTERVAL (HZ/4+1) |
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/* |
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* We must not require too good response from the userspace daemon. |
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* Here we require the userspace daemon to send us a heartbeat |
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* char to /dev/watchdog every 30 seconds. |
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*/ |
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#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ |
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/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
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static int timeout = WATCHDOG_TIMEOUT; |
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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. (1<=timeout<=3600, default=" |
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__MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
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static int use_gpio; /* Use the pic (for a1d revision alim7101) */ |
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module_param(use_gpio, int, 0); |
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MODULE_PARM_DESC(use_gpio, |
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"Use the gpio watchdog (required by old cobalt boards)."); |
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static void wdt_timer_ping(struct timer_list *); |
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static DEFINE_TIMER(timer, wdt_timer_ping); |
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static unsigned long next_heartbeat; |
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static unsigned long wdt_is_open; |
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static char wdt_expect_close; |
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static struct pci_dev *alim7101_pmu; |
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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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* Whack the dog |
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*/ |
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static void wdt_timer_ping(struct timer_list *unused) |
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{ |
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/* If we got a heartbeat pulse within the WDT_US_INTERVAL |
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* we agree to ping the WDT |
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*/ |
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char tmp; |
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if (time_before(jiffies, next_heartbeat)) { |
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/* Ping the WDT (this is actually a disarm/arm sequence) */ |
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pci_read_config_byte(alim7101_pmu, 0x92, &tmp); |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_WDT, (tmp | ALI_WDT_ARM)); |
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if (use_gpio) { |
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pci_read_config_byte(alim7101_pmu, |
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ALI_7101_GPIO_O, &tmp); |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_GPIO_O, tmp | 0x20); |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_GPIO_O, tmp & ~0x20); |
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} |
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} else { |
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pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
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} |
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/* Re-set the timer interval */ |
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mod_timer(&timer, jiffies + WDT_INTERVAL); |
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} |
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/* |
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* Utility routines |
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*/ |
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static void wdt_change(int writeval) |
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{ |
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char tmp; |
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pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp); |
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if (writeval == WDT_ENABLE) { |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_WDT, (tmp | ALI_WDT_ARM)); |
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if (use_gpio) { |
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pci_read_config_byte(alim7101_pmu, |
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ALI_7101_GPIO_O, &tmp); |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_GPIO_O, tmp & ~0x20); |
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} |
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} else { |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); |
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if (use_gpio) { |
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pci_read_config_byte(alim7101_pmu, |
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ALI_7101_GPIO_O, &tmp); |
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pci_write_config_byte(alim7101_pmu, |
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ALI_7101_GPIO_O, tmp | 0x20); |
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} |
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} |
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} |
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static void wdt_startup(void) |
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{ |
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next_heartbeat = jiffies + (timeout * HZ); |
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/* We must enable before we kick off the timer in case the timer |
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occurs as we ping it */ |
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wdt_change(WDT_ENABLE); |
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/* Start the timer */ |
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mod_timer(&timer, jiffies + WDT_INTERVAL); |
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pr_info("Watchdog timer is now enabled\n"); |
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} |
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static void wdt_turnoff(void) |
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{ |
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/* Stop the timer */ |
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del_timer_sync(&timer); |
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wdt_change(WDT_DISABLE); |
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pr_info("Watchdog timer is now disabled...\n"); |
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} |
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static void wdt_keepalive(void) |
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{ |
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/* user land ping */ |
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next_heartbeat = jiffies + (timeout * HZ); |
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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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/* See if we got the magic character 'V' and reload the timer */ |
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if (count) { |
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if (!nowayout) { |
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size_t ofs; |
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/* note: just in case someone wrote the magic character |
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* five months ago... */ |
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wdt_expect_close = 0; |
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/* now scan */ |
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for (ofs = 0; ofs != count; ofs++) { |
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char c; |
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if (get_user(c, buf + ofs)) |
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return -EFAULT; |
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if (c == 'V') |
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wdt_expect_close = 42; |
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} |
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} |
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/* someone wrote to us, we should restart timer */ |
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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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/* Just in case we're already talking to someone... */ |
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if (test_and_set_bit(0, &wdt_is_open)) |
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return -EBUSY; |
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/* Good, fire up the show */ |
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wdt_startup(); |
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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 (wdt_expect_close == 42) |
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wdt_turnoff(); |
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else { |
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/* wim: shouldn't there be a: del_timer(&timer); */ |
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pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
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} |
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clear_bit(0, &wdt_is_open); |
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wdt_expect_close = 0; |
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return 0; |
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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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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 = "ALiM7101", |
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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(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
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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 new_options, retval = -EINVAL; |
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if (get_user(new_options, p)) |
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return -EFAULT; |
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if (new_options & WDIOS_DISABLECARD) { |
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wdt_turnoff(); |
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retval = 0; |
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} |
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if (new_options & WDIOS_ENABLECARD) { |
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wdt_startup(); |
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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, p)) |
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return -EFAULT; |
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/* arbitrary upper limit */ |
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if (new_timeout < 1 || new_timeout > 3600) |
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return -EINVAL; |
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timeout = new_timeout; |
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wdt_keepalive(); |
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} |
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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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} |
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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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static int wdt_restart_handle(struct notifier_block *this, unsigned long mode, |
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void *cmd) |
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{ |
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/* |
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* Cobalt devices have no way of rebooting themselves other |
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* than getting the watchdog to pull reset, so we restart the |
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* watchdog on reboot with no heartbeat. |
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*/ |
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wdt_change(WDT_ENABLE); |
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/* loop until the watchdog fires */ |
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while (true) |
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; |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block wdt_restart_handler = { |
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.notifier_call = wdt_restart_handle, |
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.priority = 128, |
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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, |
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unsigned long code, void *unused) |
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{ |
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if (code == SYS_DOWN || code == SYS_HALT) |
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wdt_turnoff(); |
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return NOTIFY_DONE; |
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} |
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/* |
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* The WDT needs to learn about soft shutdowns in order to |
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* turn the timebomb registers off. |
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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 alim7101_wdt_unload(void) |
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{ |
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wdt_turnoff(); |
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/* Deregister */ |
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misc_deregister(&wdt_miscdev); |
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unregister_reboot_notifier(&wdt_notifier); |
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unregister_restart_handler(&wdt_restart_handler); |
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pci_dev_put(alim7101_pmu); |
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} |
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static int __init alim7101_wdt_init(void) |
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{ |
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int rc = -EBUSY; |
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struct pci_dev *ali1543_south; |
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char tmp; |
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pr_info("Steve Hill <[email protected]>\n"); |
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alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101, |
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NULL); |
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if (!alim7101_pmu) { |
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pr_info("ALi M7101 PMU not present - WDT not set\n"); |
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return -EBUSY; |
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} |
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/* Set the WDT in the PMU to 1 second */ |
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pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02); |
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ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, |
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NULL); |
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if (!ali1543_south) { |
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pr_info("ALi 1543 South-Bridge not present - WDT not set\n"); |
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goto err_out; |
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} |
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pci_read_config_byte(ali1543_south, 0x5e, &tmp); |
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pci_dev_put(ali1543_south); |
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if ((tmp & 0x1e) == 0x00) { |
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if (!use_gpio) { |
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pr_info("Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n"); |
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goto err_out; |
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} |
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nowayout = 1; |
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} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) { |
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pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n"); |
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goto err_out; |
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} |
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if (timeout < 1 || timeout > 3600) { |
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/* arbitrary upper limit */ |
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timeout = WATCHDOG_TIMEOUT; |
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pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
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timeout); |
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} |
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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; |
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} |
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rc = register_restart_handler(&wdt_restart_handler); |
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if (rc) { |
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pr_err("cannot register restart handler (err=%d)\n", rc); |
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goto err_out_reboot; |
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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_restart; |
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} |
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if (nowayout) |
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__module_get(THIS_MODULE); |
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pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n", |
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timeout, nowayout); |
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return 0; |
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err_out_restart: |
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unregister_restart_handler(&wdt_restart_handler); |
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err_out_reboot: |
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unregister_reboot_notifier(&wdt_notifier); |
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err_out: |
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pci_dev_put(alim7101_pmu); |
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return rc; |
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} |
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module_init(alim7101_wdt_init); |
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module_exit(alim7101_wdt_unload); |
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static const struct pci_device_id alim7101_pci_tbl[] __used = { |
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{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) }, |
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{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl); |
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MODULE_AUTHOR("Steve Hill"); |
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MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver"); |
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MODULE_LICENSE("GPL");
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