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       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                 :          3 :         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                 :          3 :         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                 :          0 :         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                 :          3 :         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                 :          3 :         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                 :          3 :         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 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 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 */