Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : /*  linux/include/linux/clockchips.h
       3             :  *
       4             :  *  This file contains the structure definitions for clockchips.
       5             :  *
       6             :  *  If you are not a clockchip, or the time of day code, you should
       7             :  *  not be including this file!
       8             :  */
       9             : #ifndef _LINUX_CLOCKCHIPS_H
      10             : #define _LINUX_CLOCKCHIPS_H
      11             : 
      12             : #ifdef CONFIG_GENERIC_CLOCKEVENTS
      13             : 
      14             : # include <linux/clocksource.h>
      15             : # include <linux/cpumask.h>
      16             : # include <linux/ktime.h>
      17             : # include <linux/notifier.h>
      18             : 
      19             : struct clock_event_device;
      20             : struct module;
      21             : 
      22             : /*
      23             :  * Possible states of a clock event device.
      24             :  *
      25             :  * DETACHED:    Device is not used by clockevents core. Initial state or can be
      26             :  *              reached from SHUTDOWN.
      27             :  * SHUTDOWN:    Device is powered-off. Can be reached from PERIODIC or ONESHOT.
      28             :  * PERIODIC:    Device is programmed to generate events periodically. Can be
      29             :  *              reached from DETACHED or SHUTDOWN.
      30             :  * ONESHOT:     Device is programmed to generate event only once. Can be reached
      31             :  *              from DETACHED or SHUTDOWN.
      32             :  * ONESHOT_STOPPED: Device was programmed in ONESHOT mode and is temporarily
      33             :  *                  stopped.
      34             :  */
      35             : enum clock_event_state {
      36             :         CLOCK_EVT_STATE_DETACHED,
      37             :         CLOCK_EVT_STATE_SHUTDOWN,
      38             :         CLOCK_EVT_STATE_PERIODIC,
      39             :         CLOCK_EVT_STATE_ONESHOT,
      40             :         CLOCK_EVT_STATE_ONESHOT_STOPPED,
      41             : };
      42             : 
      43             : /*
      44             :  * Clock event features
      45             :  */
      46             : # define CLOCK_EVT_FEAT_PERIODIC        0x000001
      47             : # define CLOCK_EVT_FEAT_ONESHOT         0x000002
      48             : # define CLOCK_EVT_FEAT_KTIME           0x000004
      49             : 
      50             : /*
      51             :  * x86(64) specific (mis)features:
      52             :  *
      53             :  * - Clockevent source stops in C3 State and needs broadcast support.
      54             :  * - Local APIC timer is used as a dummy device.
      55             :  */
      56             : # define CLOCK_EVT_FEAT_C3STOP          0x000008
      57             : # define CLOCK_EVT_FEAT_DUMMY           0x000010
      58             : 
      59             : /*
      60             :  * Core shall set the interrupt affinity dynamically in broadcast mode
      61             :  */
      62             : # define CLOCK_EVT_FEAT_DYNIRQ          0x000020
      63             : # define CLOCK_EVT_FEAT_PERCPU          0x000040
      64             : 
      65             : /*
      66             :  * Clockevent device is based on a hrtimer for broadcast
      67             :  */
      68             : # define CLOCK_EVT_FEAT_HRTIMER         0x000080
      69             : 
      70             : /**
      71             :  * struct clock_event_device - clock event device descriptor
      72             :  * @event_handler:      Assigned by the framework to be called by the low
      73             :  *                      level handler of the event source
      74             :  * @set_next_event:     set next event function using a clocksource delta
      75             :  * @set_next_ktime:     set next event function using a direct ktime value
      76             :  * @next_event:         local storage for the next event in oneshot mode
      77             :  * @max_delta_ns:       maximum delta value in ns
      78             :  * @min_delta_ns:       minimum delta value in ns
      79             :  * @mult:               nanosecond to cycles multiplier
      80             :  * @shift:              nanoseconds to cycles divisor (power of two)
      81             :  * @state_use_accessors:current state of the device, assigned by the core code
      82             :  * @features:           features
      83             :  * @retries:            number of forced programming retries
      84             :  * @set_state_periodic: switch state to periodic
      85             :  * @set_state_oneshot:  switch state to oneshot
      86             :  * @set_state_oneshot_stopped: switch state to oneshot_stopped
      87             :  * @set_state_shutdown: switch state to shutdown
      88             :  * @tick_resume:        resume clkevt device
      89             :  * @broadcast:          function to broadcast events
      90             :  * @min_delta_ticks:    minimum delta value in ticks stored for reconfiguration
      91             :  * @max_delta_ticks:    maximum delta value in ticks stored for reconfiguration
      92             :  * @name:               ptr to clock event name
      93             :  * @rating:             variable to rate clock event devices
      94             :  * @irq:                IRQ number (only for non CPU local devices)
      95             :  * @bound_on:           Bound on CPU
      96             :  * @cpumask:            cpumask to indicate for which CPUs this device works
      97             :  * @list:               list head for the management code
      98             :  * @owner:              module reference
      99             :  */
     100             : struct clock_event_device {
     101             :         void                    (*event_handler)(struct clock_event_device *);
     102             :         int                     (*set_next_event)(unsigned long evt, struct clock_event_device *);
     103             :         int                     (*set_next_ktime)(ktime_t expires, struct clock_event_device *);
     104             :         ktime_t                 next_event;
     105             :         u64                     max_delta_ns;
     106             :         u64                     min_delta_ns;
     107             :         u32                     mult;
     108             :         u32                     shift;
     109             :         enum clock_event_state  state_use_accessors;
     110             :         unsigned int            features;
     111             :         unsigned long           retries;
     112             : 
     113             :         int                     (*set_state_periodic)(struct clock_event_device *);
     114             :         int                     (*set_state_oneshot)(struct clock_event_device *);
     115             :         int                     (*set_state_oneshot_stopped)(struct clock_event_device *);
     116             :         int                     (*set_state_shutdown)(struct clock_event_device *);
     117             :         int                     (*tick_resume)(struct clock_event_device *);
     118             : 
     119             :         void                    (*broadcast)(const struct cpumask *mask);
     120             :         void                    (*suspend)(struct clock_event_device *);
     121             :         void                    (*resume)(struct clock_event_device *);
     122             :         unsigned long           min_delta_ticks;
     123             :         unsigned long           max_delta_ticks;
     124             : 
     125             :         const char              *name;
     126             :         int                     rating;
     127             :         int                     irq;
     128             :         int                     bound_on;
     129             :         const struct cpumask    *cpumask;
     130             :         struct list_head        list;
     131             :         struct module           *owner;
     132             : } ____cacheline_aligned;
     133             : 
     134             : /* Helpers to verify state of a clockevent device */
     135             : static inline bool clockevent_state_detached(struct clock_event_device *dev)
     136             : {
     137             :         return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
     138             : }
     139             : 
     140             : static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
     141             : {
     142             :         return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
     143             : }
     144             : 
     145             : static inline bool clockevent_state_periodic(struct clock_event_device *dev)
     146             : {
     147             :         return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
     148             : }
     149             : 
     150             : static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
     151             : {
     152             :         return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
     153             : }
     154             : 
     155             : static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev)
     156             : {
     157             :         return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT_STOPPED;
     158             : }
     159             : 
     160             : /*
     161             :  * Calculate a multiplication factor for scaled math, which is used to convert
     162             :  * nanoseconds based values to clock ticks:
     163             :  *
     164             :  * clock_ticks = (nanoseconds * factor) >> shift.
     165             :  *
     166             :  * div_sc is the rearranged equation to calculate a factor from a given clock
     167             :  * ticks / nanoseconds ratio:
     168             :  *
     169             :  * factor = (clock_ticks << shift) / nanoseconds
     170             :  */
     171             : static inline unsigned long
     172             : div_sc(unsigned long ticks, unsigned long nsec, int shift)
     173             : {
     174             :         u64 tmp = ((u64)ticks) << shift;
     175             : 
     176             :         do_div(tmp, nsec);
     177             : 
     178             :         return (unsigned long) tmp;
     179             : }
     180             : 
     181             : /* Clock event layer functions */
     182             : extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
     183             : extern void clockevents_register_device(struct clock_event_device *dev);
     184             : extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
     185             : 
     186             : extern void clockevents_config_and_register(struct clock_event_device *dev,
     187             :                                             u32 freq, unsigned long min_delta,
     188             :                                             unsigned long max_delta);
     189             : 
     190             : extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
     191             : 
     192             : static inline void
     193             : clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 maxsec)
     194             : {
     195           0 :         return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, maxsec);
     196             : }
     197             : 
     198             : extern void clockevents_suspend(void);
     199             : extern void clockevents_resume(void);
     200             : 
     201             : # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
     202             : #  ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
     203             : extern void tick_broadcast(const struct cpumask *mask);
     204             : #  else
     205             : #   define tick_broadcast       NULL
     206             : #  endif
     207             : extern int tick_receive_broadcast(void);
     208             : # endif
     209             : 
     210             : # if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
     211             : extern void tick_setup_hrtimer_broadcast(void);
     212             : extern int tick_check_broadcast_expired(void);
     213             : # else
     214             : static __always_inline int tick_check_broadcast_expired(void) { return 0; }
     215             : static inline void tick_setup_hrtimer_broadcast(void) { }
     216             : # endif
     217             : 
     218             : #else /* !CONFIG_GENERIC_CLOCKEVENTS: */
     219             : 
     220             : static inline void clockevents_suspend(void) { }
     221             : static inline void clockevents_resume(void) { }
     222             : static __always_inline int tick_check_broadcast_expired(void) { return 0; }
     223             : static inline void tick_setup_hrtimer_broadcast(void) { }
     224             : 
     225             : #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
     226             : 
     227             : #endif /* _LINUX_CLOCKCHIPS_H */