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_types.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_CLOCKSOURCE_COUPLED 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 * @set_next_coupled: set next event function for clocksource coupled mode 77 * @next_event: local storage for the next event in oneshot mode 78 * @max_delta_ns: maximum delta value in ns 79 * @min_delta_ns: minimum delta value in ns 80 * @mult: nanosecond to cycles multiplier 81 * @shift: nanoseconds to cycles divisor (power of two) 82 * @state_use_accessors:current state of the device, assigned by the core code 83 * @features: features 84 * @cs_id: Clocksource ID to denote the clocksource for coupled mode 85 * @next_event_forced: True if the last programming was a forced event 86 * @retries: number of forced programming retries 87 * @set_state_periodic: switch state to periodic 88 * @set_state_oneshot: switch state to oneshot 89 * @set_state_oneshot_stopped: switch state to oneshot_stopped 90 * @set_state_shutdown: switch state to shutdown 91 * @tick_resume: resume clkevt device 92 * @broadcast: function to broadcast events 93 * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration 94 * @max_delta_ticks: maximum delta value in ticks stored for reconfiguration 95 * @name: ptr to clock event name 96 * @rating: variable to rate clock event devices 97 * @irq: IRQ number (only for non CPU local devices) 98 * @bound_on: Bound on CPU 99 * @cpumask: cpumask to indicate for which CPUs this device works 100 * @list: list head for the management code 101 * @owner: module reference 102 */ 103 struct clock_event_device { 104 void (*event_handler)(struct clock_event_device *); 105 int (*set_next_event)(unsigned long evt, struct clock_event_device *); 106 int (*set_next_ktime)(ktime_t expires, struct clock_event_device *); 107 void (*set_next_coupled)(u64 cycles, struct clock_event_device *); 108 ktime_t next_event; 109 u64 max_delta_ns; 110 u64 min_delta_ns; 111 u32 mult; 112 u32 shift; 113 enum clock_event_state state_use_accessors; 114 unsigned int features; 115 enum clocksource_ids cs_id; 116 unsigned int next_event_forced; 117 unsigned long retries; 118 119 int (*set_state_periodic)(struct clock_event_device *); 120 int (*set_state_oneshot)(struct clock_event_device *); 121 int (*set_state_oneshot_stopped)(struct clock_event_device *); 122 int (*set_state_shutdown)(struct clock_event_device *); 123 int (*tick_resume)(struct clock_event_device *); 124 125 void (*broadcast)(const struct cpumask *mask); 126 void (*suspend)(struct clock_event_device *); 127 void (*resume)(struct clock_event_device *); 128 unsigned long min_delta_ticks; 129 unsigned long max_delta_ticks; 130 131 const char *name; 132 int rating; 133 int irq; 134 int bound_on; 135 const struct cpumask *cpumask; 136 struct list_head list; 137 struct module *owner; 138 } ____cacheline_aligned; 139 140 /* Helpers to verify state of a clockevent device */ 141 static inline bool clockevent_state_detached(struct clock_event_device *dev) 142 { 143 return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED; 144 } 145 146 static inline bool clockevent_state_shutdown(struct clock_event_device *dev) 147 { 148 return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN; 149 } 150 151 static inline bool clockevent_state_periodic(struct clock_event_device *dev) 152 { 153 return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC; 154 } 155 156 static inline bool clockevent_state_oneshot(struct clock_event_device *dev) 157 { 158 return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT; 159 } 160 161 static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev) 162 { 163 return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT_STOPPED; 164 } 165 166 /* 167 * Calculate a multiplication factor for scaled math, which is used to convert 168 * nanoseconds based values to clock ticks: 169 * 170 * clock_ticks = (nanoseconds * factor) >> shift. 171 * 172 * div_sc is the rearranged equation to calculate a factor from a given clock 173 * ticks / nanoseconds ratio: 174 * 175 * factor = (clock_ticks << shift) / nanoseconds 176 */ 177 static inline unsigned long 178 div_sc(unsigned long ticks, unsigned long nsec, int shift) 179 { 180 u64 tmp = ((u64)ticks) << shift; 181 182 do_div(tmp, nsec); 183 184 return (unsigned long) tmp; 185 } 186 187 /* Clock event layer functions */ 188 extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt); 189 extern void clockevents_register_device(struct clock_event_device *dev); 190 extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu); 191 192 extern void clockevents_config_and_register(struct clock_event_device *dev, 193 u32 freq, unsigned long min_delta, 194 unsigned long max_delta); 195 196 extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq); 197 198 static inline void 199 clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 maxsec) 200 { 201 return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, maxsec); 202 } 203 204 extern void clockevents_suspend(void); 205 extern void clockevents_resume(void); 206 207 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 208 # ifdef CONFIG_ARCH_HAS_TICK_BROADCAST 209 extern void tick_broadcast(const struct cpumask *mask); 210 # else 211 # define tick_broadcast NULL 212 # endif 213 extern int tick_receive_broadcast(void); 214 # endif 215 216 # if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT) 217 extern void tick_setup_hrtimer_broadcast(void); 218 extern int tick_check_broadcast_expired(void); 219 # else 220 static __always_inline int tick_check_broadcast_expired(void) { return 0; } 221 static inline void tick_setup_hrtimer_broadcast(void) { } 222 # endif 223 224 #else /* !CONFIG_GENERIC_CLOCKEVENTS: */ 225 226 static inline void clockevents_suspend(void) { } 227 static inline void clockevents_resume(void) { } 228 static __always_inline int tick_check_broadcast_expired(void) { return 0; } 229 static inline void tick_setup_hrtimer_broadcast(void) { } 230 231 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */ 232 233 #endif /* _LINUX_CLOCKCHIPS_H */ 234