| 1 | /* $NetBSD: timetc.h,v 1.6 2009/01/11 02:45:56 christos Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * ---------------------------------------------------------------------------- |
| 5 | * "THE BEER-WARE LICENSE" (Revision 42): |
| 6 | * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you |
| 7 | * can do whatever you want with this stuff. If we meet some day, and you think |
| 8 | * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp |
| 9 | * ---------------------------------------------------------------------------- |
| 10 | * |
| 11 | * $FreeBSD: src/sys/sys/timetc.h,v 1.58 2003/08/16 08:23:52 phk Exp $ |
| 12 | */ |
| 13 | |
| 14 | #ifndef _SYS_TIMETC_H_ |
| 15 | #define _SYS_TIMETC_H_ |
| 16 | |
| 17 | #ifndef _KERNEL |
| 18 | #error "no user-serviceable parts inside" |
| 19 | #endif |
| 20 | |
| 21 | /* |
| 22 | * max recommended timecounter name length |
| 23 | * |
| 24 | * it is not a functional limit but names longer |
| 25 | * then that will not be controllable via |
| 26 | * sysctl. see kern/kern_tc.c for the sysctl |
| 27 | * implementation. |
| 28 | */ |
| 29 | #define MAX_TCNAMELEN 64 |
| 30 | |
| 31 | /*- |
| 32 | * `struct timecounter' is the interface between the hardware which implements |
| 33 | * a timecounter and the MI code which uses this to keep track of time. |
| 34 | * |
| 35 | * A timecounter is a binary counter which has two properties: |
| 36 | * * it runs at a fixed, known frequency. |
| 37 | * * it has sufficient bits to not roll over in less than approximately |
| 38 | * max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta, |
| 39 | * for some indeterminate value of delta.) |
| 40 | */ |
| 41 | |
| 42 | struct timecounter; |
| 43 | typedef u_int timecounter_get_t(struct timecounter *); |
| 44 | typedef void timecounter_pps_t(struct timecounter *); |
| 45 | |
| 46 | struct timecounter { |
| 47 | timecounter_get_t *tc_get_timecount; |
| 48 | /* |
| 49 | * This function reads the counter. It is not required to |
| 50 | * mask any unimplemented bits out, as long as they are |
| 51 | * constant. |
| 52 | */ |
| 53 | timecounter_pps_t *tc_poll_pps; |
| 54 | /* |
| 55 | * This function is optional. It will be called whenever the |
| 56 | * timecounter is rewound, and is intended to check for PPS |
| 57 | * events. Normal hardware does not need it but timecounters |
| 58 | * which latch PPS in hardware (like sys/pci/xrpu.c) do. |
| 59 | */ |
| 60 | u_int tc_counter_mask; |
| 61 | /* This mask should mask off any unimplemented bits. */ |
| 62 | u_int64_t tc_frequency; |
| 63 | /* Frequency of the counter in Hz. */ |
| 64 | const char *tc_name; |
| 65 | /* Name of the timecounter. */ |
| 66 | int tc_quality; |
| 67 | /* |
| 68 | * Used to determine if this timecounter is better than |
| 69 | * another timecounter higher means better. Negative |
| 70 | * means "only use at explicit request". |
| 71 | */ |
| 72 | |
| 73 | void *tc_priv; |
| 74 | /* Pointer to the timecounter's private parts. */ |
| 75 | struct timecounter *tc_next; |
| 76 | /* Pointer to the next timecounter. */ |
| 77 | }; |
| 78 | |
| 79 | extern struct timecounter *timecounter; |
| 80 | |
| 81 | u_int64_t tc_getfrequency(void); |
| 82 | void tc_init(struct timecounter *tc); |
| 83 | int tc_detach(struct timecounter *); |
| 84 | void tc_setclock(const struct timespec *ts); |
| 85 | void tc_ticktock(void); |
| 86 | void tc_gonebad(struct timecounter *); |
| 87 | |
| 88 | #ifdef SYSCTL_DECL |
| 89 | SYSCTL_DECL(_kern_timecounter); |
| 90 | #endif |
| 91 | |
| 92 | #endif /* !_SYS_TIMETC_H_ */ |
| 93 | |