drivers/watchdog/watchdog_core.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  *      watchdog_core.h
   4  *
   5  *      (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>,
   6  *                                              All Rights Reserved.
   7  *
   8  *      (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>.
   9  *
  10  *      (c) Copyright 2021 Hewlett Packard Enterprise Development LP.
  11  *
  12  *      This source code is part of the generic code that can be used
  13  *      by all the watchdog timer drivers.
  14  *
  15  *      Based on source code of the following authors:
  16  *        Matt Domsch <Matt_Domsch@dell.com>,
  17  *        Rob Radez <rob@osinvestor.com>,
  18  *        Rusty Lynch <rusty@linux.co.intel.com>
  19  *        Satyam Sharma <satyam@infradead.org>
  20  *        Randy Dunlap <randy.dunlap@oracle.com>
  21  *
  22  *      Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw.
  23  *      admit liability nor provide warranty for any of this software.
  24  *      This material is provided "AS-IS" and at no charge.
  25  */
  26
  27 #include <linux/hrtimer.h>
  28 #include <linux/kthread.h>
  29
  30 #define MAX_DOGS        32      /* Maximum number of watchdog devices */
  31
  32 /*
  33  * struct watchdog_core_data - watchdog core internal data
  34  * @dev:        The watchdog's internal device
  35  * @cdev:       The watchdog's Character device.
  36  * @wdd:        Pointer to watchdog device.
  37  * @lock:       Lock for watchdog core.
  38  * @status:     Watchdog core internal status bits.
  39  */
  40 struct watchdog_core_data {
  41         struct device dev;
  42         struct cdev cdev;
  43         struct watchdog_device *wdd;
  44         struct mutex lock;
  45         ktime_t last_keepalive;
  46         ktime_t last_hw_keepalive;
  47         ktime_t open_deadline;
  48         struct hrtimer timer;
  49         struct kthread_work work;
  50 #if IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT)
  51         struct hrtimer pretimeout_timer;
  52 #endif
  53         unsigned long status;           /* Internal status bits */
  54 #define _WDOG_DEV_OPEN          0       /* Opened ? */
  55 #define _WDOG_ALLOW_RELEASE     1       /* Did we receive the magic char ? */
  56 #define _WDOG_KEEPALIVE         2       /* Did we receive a keepalive ? */
  57 };
  58
  59 /*
  60  *      Functions/procedures to be called by the core
  61  */
  62 extern int watchdog_dev_register(struct watchdog_device *);
  63 extern void watchdog_dev_unregister(struct watchdog_device *);
  64 extern int __init watchdog_dev_init(void);
  65 extern void __exit watchdog_dev_exit(void);
  66
  67 static inline bool watchdog_have_pretimeout(struct watchdog_device *wdd)
  68 {
  69         return wdd->info->options & WDIOF_PRETIMEOUT ||
  70                IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT);
  71 }
  72
  73 #if IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT)
  74 void watchdog_hrtimer_pretimeout_init(struct watchdog_device *wdd);
  75 void watchdog_hrtimer_pretimeout_start(struct watchdog_device *wdd);
  76 void watchdog_hrtimer_pretimeout_stop(struct watchdog_device *wdd);
  77 #else
  78 static inline void watchdog_hrtimer_pretimeout_init(struct watchdog_device *wdd) {}
  79 static inline void watchdog_hrtimer_pretimeout_start(struct watchdog_device *wdd) {}
  80 static inline void watchdog_hrtimer_pretimeout_stop(struct watchdog_device *wdd) {}
  81 #endif