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