Watchdog data structures and APIs

In this section, we will walk through the watchdog framework and learn how it works under the hood. The watchdog subsystem has a few data structures. The main one is struct watchdog_device, which is the Linux kernel representation of a watchdog device, containing all the information about it. It is defined in include/linux/watchdog.h, as follows:

struct watchdog_device {
    int id;
    struct device *parent;
    const struct watchdog_info *info;
    const struct watchdog_ops *ops;
    const struct watchdog_governor *gov;
    unsigned int bootstatus;
    unsigned int timeout;
    unsigned int pretimeout;
    unsigned int min_timeout;
    struct watchdog_core_data *wd_data;
    unsigned long status;
    [...]
...