Mastering Linux Kernel Development

Tick and interrupt handling

To provide the programming interface, the clock device generating the ticks is abstracted through the structure struct clock_event_device, defined in include/linux/clockchips.h:

struct clock_event_device {
        void                    (*event_handler)(struct clock_event_device *);
        int                     (*set_next_event)(unsigned long evt, struct clock_event_device *);
        int                     (*set_next_ktime)(ktime_t expires, struct clock_event_device *);
        ktime_t                  next_event;
        u64                      max_delta_ns;
        u64                      min_delta_ns;
        u32                      mult;
        u32                      shift;
        enum clock_event_state    state_use_accessors;
        unsigned int            features;
        unsigned long           retries;

        int                     (*set_state_periodic)(struct  clock_event_device *);
        int                     (*set_state_oneshot)(struct clock_event_device *);
        int                     (*set_state_oneshot_stopped)(struct clock_event_device ...