ssb: remove the ssb DMA API
[linux-2.6.git] / include / linux / ring_buffer.h
1 #ifndef _LINUX_RING_BUFFER_H
2 #define _LINUX_RING_BUFFER_H
3
4 #include <linux/kmemcheck.h>
5 #include <linux/mm.h>
6 #include <linux/seq_file.h>
7
8 struct ring_buffer;
9 struct ring_buffer_iter;
10
11 /*
12  * Don't refer to this struct directly, use functions below.
13  */
14 struct ring_buffer_event {
15         kmemcheck_bitfield_begin(bitfield);
16         u32             type_len:5, time_delta:27;
17         kmemcheck_bitfield_end(bitfield);
18
19         u32             array[];
20 };
21
22 /**
23  * enum ring_buffer_type - internal ring buffer types
24  *
25  * @RINGBUF_TYPE_PADDING:       Left over page padding or discarded event
26  *                               If time_delta is 0:
27  *                                array is ignored
28  *                                size is variable depending on how much
29  *                                padding is needed
30  *                               If time_delta is non zero:
31  *                                array[0] holds the actual length
32  *                                size = 4 + length (bytes)
33  *
34  * @RINGBUF_TYPE_TIME_EXTEND:   Extend the time delta
35  *                               array[0] = time delta (28 .. 59)
36  *                               size = 8 bytes
37  *
38  * @RINGBUF_TYPE_TIME_STAMP:    Sync time stamp with external clock
39  *                               array[0]    = tv_nsec
40  *                               array[1..2] = tv_sec
41  *                               size = 16 bytes
42  *
43  * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
44  *                              Data record
45  *                               If type_len is zero:
46  *                                array[0] holds the actual length
47  *                                array[1..(length+3)/4] holds data
48  *                                size = 4 + length (bytes)
49  *                               else
50  *                                length = type_len << 2
51  *                                array[0..(length+3)/4-1] holds data
52  *                                size = 4 + length (bytes)
53  */
54 enum ring_buffer_type {
55         RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
56         RINGBUF_TYPE_PADDING,
57         RINGBUF_TYPE_TIME_EXTEND,
58         /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
59         RINGBUF_TYPE_TIME_STAMP,
60 };
61
62 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
63 void *ring_buffer_event_data(struct ring_buffer_event *event);
64
65 /**
66  * ring_buffer_event_time_delta - return the delta timestamp of the event
67  * @event: the event to get the delta timestamp of
68  *
69  * The delta timestamp is the 27 bit timestamp since the last event.
70  */
71 static inline unsigned
72 ring_buffer_event_time_delta(struct ring_buffer_event *event)
73 {
74         return event->time_delta;
75 }
76
77 /*
78  * ring_buffer_discard_commit will remove an event that has not
79  *   ben committed yet. If this is used, then ring_buffer_unlock_commit
80  *   must not be called on the discarded event. This function
81  *   will try to remove the event from the ring buffer completely
82  *   if another event has not been written after it.
83  *
84  * Example use:
85  *
86  *  if (some_condition)
87  *    ring_buffer_discard_commit(buffer, event);
88  *  else
89  *    ring_buffer_unlock_commit(buffer, event);
90  */
91 void ring_buffer_discard_commit(struct ring_buffer *buffer,
92                                 struct ring_buffer_event *event);
93
94 /*
95  * size is in bytes for each per CPU buffer.
96  */
97 struct ring_buffer *
98 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
99
100 /*
101  * Because the ring buffer is generic, if other users of the ring buffer get
102  * traced by ftrace, it can produce lockdep warnings. We need to keep each
103  * ring buffer's lock class separate.
104  */
105 #define ring_buffer_alloc(size, flags)                  \
106 ({                                                      \
107         static struct lock_class_key __key;             \
108         __ring_buffer_alloc((size), (flags), &__key);   \
109 })
110
111 void ring_buffer_free(struct ring_buffer *buffer);
112
113 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
114
115 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
116                                                    unsigned long length);
117 int ring_buffer_unlock_commit(struct ring_buffer *buffer,
118                               struct ring_buffer_event *event);
119 int ring_buffer_write(struct ring_buffer *buffer,
120                       unsigned long length, void *data);
121
122 struct ring_buffer_event *
123 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
124                  unsigned long *lost_events);
125 struct ring_buffer_event *
126 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
127                     unsigned long *lost_events);
128
129 struct ring_buffer_iter *
130 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
131 void ring_buffer_read_prepare_sync(void);
132 void ring_buffer_read_start(struct ring_buffer_iter *iter);
133 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
134
135 struct ring_buffer_event *
136 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
137 struct ring_buffer_event *
138 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
139 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
140 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
141
142 unsigned long ring_buffer_size(struct ring_buffer *buffer);
143
144 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
145 void ring_buffer_reset(struct ring_buffer *buffer);
146
147 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
148 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
149                          struct ring_buffer *buffer_b, int cpu);
150 #else
151 static inline int
152 ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
153                      struct ring_buffer *buffer_b, int cpu)
154 {
155         return -ENODEV;
156 }
157 #endif
158
159 int ring_buffer_empty(struct ring_buffer *buffer);
160 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
161
162 void ring_buffer_record_disable(struct ring_buffer *buffer);
163 void ring_buffer_record_enable(struct ring_buffer *buffer);
164 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
165 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
166
167 unsigned long ring_buffer_entries(struct ring_buffer *buffer);
168 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
169 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
170 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
171 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
172
173 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
174 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
175                                       int cpu, u64 *ts);
176 void ring_buffer_set_clock(struct ring_buffer *buffer,
177                            u64 (*clock)(void));
178
179 size_t ring_buffer_page_len(void *page);
180
181
182 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
183 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
184 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
185                           size_t len, int cpu, int full);
186
187 struct trace_seq;
188
189 int ring_buffer_print_entry_header(struct trace_seq *s);
190 int ring_buffer_print_page_header(struct trace_seq *s);
191
192 enum ring_buffer_flags {
193         RB_FL_OVERWRITE         = 1 << 0,
194 };
195
196 #endif /* _LINUX_RING_BUFFER_H */