1 | /*- |
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2 | * ---------------------------------------------------------------------------- |
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3 | * "THE BEER-WARE LICENSE" (Revision 42): |
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4 | * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you |
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5 | * can do whatever you want with this stuff. If we meet some day, and you think |
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6 | * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp |
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7 | * ---------------------------------------------------------------------------- |
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8 | * |
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9 | * $FreeBSD r277406 2015-01-20T03:54:30Z$ |
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10 | */ |
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11 | |
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12 | #ifndef _SYS_TIMETC_H_ |
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13 | #define _SYS_TIMETC_H_ |
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14 | |
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15 | #ifndef _KERNEL |
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16 | #error "no user-serviceable parts inside" |
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17 | #endif |
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18 | |
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19 | /*- |
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20 | * `struct timecounter' is the interface between the hardware which implements |
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21 | * a timecounter and the MI code which uses this to keep track of time. |
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22 | * |
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23 | * A timecounter is a binary counter which has two properties: |
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24 | * * it runs at a fixed, known frequency. |
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25 | * * it has sufficient bits to not roll over in less than approximately |
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26 | * max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta, |
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27 | * for some indeterminate value of delta.) |
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28 | */ |
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29 | |
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30 | struct timecounter; |
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31 | typedef uint32_t timecounter_get_t(struct timecounter *); |
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32 | typedef void timecounter_pps_t(struct timecounter *); |
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33 | |
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34 | struct timecounter { |
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35 | timecounter_get_t *tc_get_timecount; |
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36 | /* |
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37 | * This function reads the counter. It is not required to |
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38 | * mask any unimplemented bits out, as long as they are |
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39 | * constant. |
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40 | */ |
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41 | timecounter_pps_t *tc_poll_pps; |
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42 | /* |
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43 | * This function is optional. It will be called whenever the |
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44 | * timecounter is rewound, and is intended to check for PPS |
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45 | * events. Normal hardware does not need it but timecounters |
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46 | * which latch PPS in hardware (like sys/pci/xrpu.c) do. |
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47 | */ |
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48 | uint32_t tc_counter_mask; |
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49 | /* This mask should mask off any unimplemented bits. */ |
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50 | uint64_t tc_frequency; |
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51 | /* Frequency of the counter in Hz. */ |
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52 | char *tc_name; |
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53 | /* Name of the timecounter. */ |
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54 | int tc_quality; |
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55 | /* |
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56 | * Used to determine if this timecounter is better than |
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57 | * another timecounter higher means better. Negative |
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58 | * means "only use at explicit request". |
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59 | */ |
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60 | u_int tc_flags; |
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61 | #define TC_FLAGS_C2STOP 1 /* Timer dies in C2+. */ |
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62 | #define TC_FLAGS_SUSPEND_SAFE 2 /* |
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63 | * Timer functional across |
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64 | * suspend/resume. |
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65 | */ |
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66 | |
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67 | void *tc_priv; |
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68 | /* Pointer to the timecounter's private parts. */ |
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69 | struct timecounter *tc_next; |
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70 | /* Pointer to the next timecounter. */ |
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71 | }; |
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72 | |
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73 | extern struct timecounter *timecounter; |
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74 | extern int tc_min_ticktock_freq; /* |
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75 | * Minimal tc_ticktock() call frequency, |
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76 | * required to handle counter wraps. |
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77 | */ |
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78 | |
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79 | u_int64_t tc_getfrequency(void); |
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80 | void tc_init(struct timecounter *tc); |
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81 | void tc_setclock(struct timespec *ts); |
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82 | void tc_ticktock(int cnt); |
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83 | void cpu_tick_calibration(void); |
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84 | |
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85 | #ifdef SYSCTL_DECL |
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86 | SYSCTL_DECL(_kern_timecounter); |
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87 | #endif |
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88 | |
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89 | #endif /* !_SYS_TIMETC_H_ */ |
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