1 /*- 2 * ---------------------------------------------------------------------------- 3 * "THE BEER-WARE LICENSE" (Revision 42): 4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you 5 * can do whatever you want with this stuff. If we meet some day, and you think 6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 7 * ---------------------------------------------------------------------------- 8 * 9 * $FreeBSD: stable/9/sys/sys/timetc.h 280973 2015-04-02 01:02:42Z jhb $ 10 */ 11 12 #ifndef _SYS_TIMETC_H_ 13 #define _SYS_TIMETC_H_ 14 15 #ifndef _KERNEL 16 #error "no user-serviceable parts inside" 17 #endif 18 19 /*- 20 * `struct timecounter' is the interface between the hardware which implements 21 * a timecounter and the MI code which uses this to keep track of time. 22 * 23 * A timecounter is a binary counter which has two properties: 24 * * it runs at a fixed, known frequency. 25 * * it has sufficient bits to not roll over in less than approximately 26 * max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta, 27 * for some indeterminate value of delta.) 28 */ 29 30 struct timecounter; 31 typedef u_int timecounter_get_t(struct timecounter *); 32 typedef void timecounter_pps_t(struct timecounter *); 33 34 struct timecounter { 35 timecounter_get_t *tc_get_timecount; 36 /* 37 * This function reads the counter. It is not required to 38 * mask any unimplemented bits out, as long as they are 39 * constant. 40 */ 41 timecounter_pps_t *tc_poll_pps; 42 /* 43 * This function is optional. It will be called whenever the 44 * timecounter is rewound, and is intended to check for PPS 45 * events. Normal hardware does not need it but timecounters 46 * which latch PPS in hardware (like sys/pci/xrpu.c) do. 47 */ 48 u_int tc_counter_mask; 49 /* This mask should mask off any unimplemented bits. */ 50 uint64_t tc_frequency; 51 /* Frequency of the counter in Hz. */ 52 char *tc_name; 53 /* Name of the timecounter. */ 54 int tc_quality; 55 /* 56 * Used to determine if this timecounter is better than 57 * another timecounter higher means better. Negative 58 * means "only use at explicit request". 59 */ 60 u_int tc_flags; 61 #define TC_FLAGS_C2STOP 1 /* Timer dies in C2+. */ 62 63 void *tc_priv; 64 /* Pointer to the timecounter's private parts. */ 65 struct timecounter *tc_next; 66 /* Pointer to the next timecounter. */ 67 }; 68 69 extern struct timecounter *timecounter; 70 extern int tc_min_ticktock_freq; /* 71 * Minimal tc_ticktock() call frequency, 72 * required to handle counter wraps. 73 */ 74 75 u_int64_t tc_getfrequency(void); 76 void tc_init(struct timecounter *tc); 77 void tc_setclock(struct timespec *ts); 78 void tc_ticktock(int cnt); 79 void cpu_tick_calibration(void); 80 81 #ifdef SYSCTL_DECL 82 SYSCTL_DECL(_kern_timecounter); 83 #endif 84 85 #endif /* !_SYS_TIMETC_H_ */ 86