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Linux/include/linux/clockchips.h

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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         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         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 */
228 

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