Aaron Durbin | a421791 | 2013-04-29 22:31:51 -0500 | [diff] [blame^] | 1 | /* |
| 2 | * This file is part of the coreboot project. |
| 3 | * |
| 4 | * Copyright (C) 2013 Google, Inc. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; version 2 of the License. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | #ifndef TIMER_H |
| 20 | #define TIMER_H |
| 21 | |
| 22 | #define USECS_PER_SEC 1000000 |
| 23 | #define MSECS_PER_SEC 1000 |
| 24 | #define USECS_PER_MSEC (USECS_PER_SEC / MSECS_PER_SEC) |
| 25 | |
| 26 | /* The time structures are defined to be a representation of the time since |
| 27 | * coreboot started executing one of its stages. The reason for using structures |
| 28 | * is to allow for changes in the future. The structures' details are exposed |
| 29 | * so that the compiler can allocate space on the stack and use in other |
| 30 | * structures. In other words, accessing any field within this structure |
| 31 | * outside of the core timer code is not supported. */ |
| 32 | |
| 33 | struct mono_time { |
| 34 | long microseconds; |
| 35 | }; |
| 36 | |
| 37 | struct rela_time { |
| 38 | long microseconds; |
| 39 | }; |
| 40 | |
| 41 | /* Obtain the current monotonic time. The assumption is that the time counts |
| 42 | * up from the value 0 with value 0 being the point when the timer was |
| 43 | * initialized. Additionally, the timer is assumed to only be valid for the |
| 44 | * duration of the boot. |
| 45 | * |
| 46 | * Note that any implementations of timer_monotonic_get() |
| 47 | * need to ensure its timesource does not roll over within 10 secs. The reason |
| 48 | * is that the time between calls to timer_monotonic_get() may be on order |
| 49 | * of 10 seconds. */ |
| 50 | void timer_monotonic_get(struct mono_time *mt); |
| 51 | |
| 52 | /* Add microseconds to an absoute time. */ |
| 53 | static inline void mono_time_add_usecs(struct mono_time *mt, long us) |
| 54 | { |
| 55 | mt->microseconds += us; |
| 56 | } |
| 57 | |
| 58 | /* Add milliseconds to an absoute time. */ |
| 59 | static inline void mono_time_add_msecs(struct mono_time *mt, long ms) |
| 60 | { |
| 61 | mono_time_add_usecs(mt, ms * USECS_PER_MSEC); |
| 62 | } |
| 63 | |
| 64 | static inline void mono_time_add_rela_time(struct mono_time *mt, |
| 65 | const struct rela_time *t) |
| 66 | { |
| 67 | mono_time_add_usecs(mt, t->microseconds); |
| 68 | } |
| 69 | |
| 70 | /* Compare two absoluted times: Return -1, 0, or 1 if t1 is <, =, or > t2, |
| 71 | * respectively. */ |
| 72 | static inline int mono_time_cmp(const struct mono_time *t1, |
| 73 | const struct mono_time *t2) |
| 74 | { |
| 75 | if (t1->microseconds == t2->microseconds) |
| 76 | return 0; |
| 77 | |
| 78 | if (t1->microseconds < t2->microseconds) |
| 79 | return -1; |
| 80 | |
| 81 | return 1; |
| 82 | } |
| 83 | |
| 84 | static inline int rela_time_cmp(const struct rela_time *t1, |
| 85 | const struct rela_time *t2) |
| 86 | { |
| 87 | if (t1->microseconds == t2->microseconds) |
| 88 | return 0; |
| 89 | |
| 90 | if (t1->microseconds < t2->microseconds) |
| 91 | return -1; |
| 92 | |
| 93 | return 1; |
| 94 | } |
| 95 | |
| 96 | /* Iniitalize a rela_time structure. */ |
| 97 | static inline struct rela_time rela_time_init_usecs(long us) |
| 98 | { |
| 99 | struct rela_time t; |
| 100 | t.microseconds = us; |
| 101 | return t; |
| 102 | } |
| 103 | |
| 104 | /* Return time difference between t1 and t2. i.e. t2 - t1. */ |
| 105 | static struct rela_time mono_time_diff(const struct mono_time *t1, |
| 106 | const struct mono_time *t2) |
| 107 | { |
| 108 | return rela_time_init_usecs(t2->microseconds - t1->microseconds); |
| 109 | } |
| 110 | |
| 111 | /* Return true if t1 after t2 */ |
| 112 | static inline int mono_time_after(const struct mono_time *t1, |
| 113 | const struct mono_time *t2) |
| 114 | { |
| 115 | return mono_time_cmp(t1, t2) > 0; |
| 116 | } |
| 117 | |
| 118 | /* Return true if t1 before t2. */ |
| 119 | static inline int mono_time_before(const struct mono_time *t1, |
| 120 | const struct mono_time *t2) |
| 121 | { |
| 122 | return mono_time_cmp(t1, t2) < 0; |
| 123 | } |
| 124 | |
| 125 | /* Return the difference between now and t. */ |
| 126 | static inline struct rela_time current_time_from(const struct mono_time *t) |
| 127 | { |
| 128 | struct mono_time now; |
| 129 | |
| 130 | timer_monotonic_get(&now); |
| 131 | return mono_time_diff(t, &now); |
| 132 | |
| 133 | } |
| 134 | |
| 135 | static inline long rela_time_in_microseconds(const struct rela_time *rt) |
| 136 | { |
| 137 | return rt->microseconds; |
| 138 | } |
| 139 | |
| 140 | #endif /* TIMER_H */ |