1 #ifndef _LINUX_RING_BUFFER_H 2 #define _LINUX_RING_BUFFER_H 3 4 #include <linux/mm.h> 5 #include <linux/seq_file.h> 6 7 struct ring_buffer; 8 struct ring_buffer_iter; 9 10 /* 11 * Don't refer to this struct directly, use functions below. 12 */ 13 struct ring_buffer_event { 14 u32 type:2, len:3, time_delta:27; 15 u32 array[]; 16 }; 17 18 /** 19 * enum ring_buffer_type - internal ring buffer types 20 * 21 * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event 22 * If time_delta is 0: 23 * array is ignored 24 * size is variable depending on how much 25 * padding is needed 26 * If time_delta is non zero: 27 * everything else same as RINGBUF_TYPE_DATA 28 * 29 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta 30 * array[0] = time delta (28 .. 59) 31 * size = 8 bytes 32 * 33 * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock 34 * array[0] = tv_nsec 35 * array[1..2] = tv_sec 36 * size = 16 bytes 37 * 38 * @RINGBUF_TYPE_DATA: Data record 39 * If len is zero: 40 * array[0] holds the actual length 41 * array[1..(length+3)/4] holds data 42 * size = 4 + 4 + length (bytes) 43 * else 44 * length = len << 2 45 * array[0..(length+3)/4-1] holds data 46 * size = 4 + length (bytes) 47 */ 48 enum ring_buffer_type { 49 RINGBUF_TYPE_PADDING, 50 RINGBUF_TYPE_TIME_EXTEND, 51 /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */ 52 RINGBUF_TYPE_TIME_STAMP, 53 RINGBUF_TYPE_DATA, 54 }; 55 56 unsigned ring_buffer_event_length(struct ring_buffer_event *event); 57 void *ring_buffer_event_data(struct ring_buffer_event *event); 58 59 /** 60 * ring_buffer_event_time_delta - return the delta timestamp of the event 61 * @event: the event to get the delta timestamp of 62 * 63 * The delta timestamp is the 27 bit timestamp since the last event. 64 */ 65 static inline unsigned 66 ring_buffer_event_time_delta(struct ring_buffer_event *event) 67 { 68 return event->time_delta; 69 } 70 71 void ring_buffer_event_discard(struct ring_buffer_event *event); 72 73 /* 74 * size is in bytes for each per CPU buffer. 75 */ 76 struct ring_buffer * 77 ring_buffer_alloc(unsigned long size, unsigned flags); 78 void ring_buffer_free(struct ring_buffer *buffer); 79 80 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size); 81 82 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, 83 unsigned long length); 84 int ring_buffer_unlock_commit(struct ring_buffer *buffer, 85 struct ring_buffer_event *event); 86 int ring_buffer_write(struct ring_buffer *buffer, 87 unsigned long length, void *data); 88 89 struct ring_buffer_event * 90 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts); 91 struct ring_buffer_event * 92 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts); 93 94 struct ring_buffer_iter * 95 ring_buffer_read_start(struct ring_buffer *buffer, int cpu); 96 void ring_buffer_read_finish(struct ring_buffer_iter *iter); 97 98 struct ring_buffer_event * 99 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 100 struct ring_buffer_event * 101 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); 102 void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 103 int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 104 105 unsigned long ring_buffer_size(struct ring_buffer *buffer); 106 107 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); 108 void ring_buffer_reset(struct ring_buffer *buffer); 109 110 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 111 struct ring_buffer *buffer_b, int cpu); 112 113 int ring_buffer_empty(struct ring_buffer *buffer); 114 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); 115 116 void ring_buffer_record_disable(struct ring_buffer *buffer); 117 void ring_buffer_record_enable(struct ring_buffer *buffer); 118 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); 119 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); 120 121 unsigned long ring_buffer_entries(struct ring_buffer *buffer); 122 unsigned long ring_buffer_overruns(struct ring_buffer *buffer); 123 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); 124 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); 125 126 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); 127 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, 128 int cpu, u64 *ts); 129 void ring_buffer_set_clock(struct ring_buffer *buffer, 130 u64 (*clock)(void)); 131 132 size_t ring_buffer_page_len(void *page); 133 134 135 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer); 136 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); 137 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, 138 size_t len, int cpu, int full); 139 140 enum ring_buffer_flags { 141 RB_FL_OVERWRITE = 1 << 0, 142 }; 143 144 #endif /* _LINUX_RING_BUFFER_H */ 145