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1 | /* | |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2014 Bert Vermeulen <bert@biot.com> | |
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, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <config.h> | |
21 | #include <string.h> | |
22 | #include <libsigrok/libsigrok.h> | |
23 | #include "libsigrok-internal.h" | |
24 | ||
25 | /* @cond PRIVATE */ | |
26 | #define LOG_PREFIX "soft-trigger" | |
27 | /* @endcond */ | |
28 | ||
29 | SR_PRIV struct soft_trigger_logic *soft_trigger_logic_new( | |
30 | const struct sr_dev_inst *sdi, struct sr_trigger *trigger, | |
31 | int pre_trigger_samples) | |
32 | { | |
33 | struct soft_trigger_logic *stl; | |
34 | ||
35 | stl = g_malloc0(sizeof(struct soft_trigger_logic)); | |
36 | stl->sdi = sdi; | |
37 | stl->trigger = trigger; | |
38 | stl->unitsize = (g_slist_length(sdi->channels) + 7) / 8; | |
39 | stl->prev_sample = g_malloc0(stl->unitsize); | |
40 | stl->pre_trigger_size = stl->unitsize * pre_trigger_samples; | |
41 | stl->pre_trigger_buffer = g_try_malloc(stl->pre_trigger_size); | |
42 | if (!stl->pre_trigger_buffer) { | |
43 | soft_trigger_logic_free(stl); | |
44 | return NULL; | |
45 | } | |
46 | stl->pre_trigger_head = stl->pre_trigger_buffer; | |
47 | ||
48 | if (stl->pre_trigger_size > 0 && !stl->pre_trigger_buffer) { | |
49 | soft_trigger_logic_free(stl); | |
50 | return NULL; | |
51 | } | |
52 | ||
53 | return stl; | |
54 | } | |
55 | ||
56 | SR_PRIV void soft_trigger_logic_free(struct soft_trigger_logic *stl) | |
57 | { | |
58 | g_free(stl->pre_trigger_buffer); | |
59 | g_free(stl->prev_sample); | |
60 | g_free(stl); | |
61 | } | |
62 | ||
63 | static void pre_trigger_append(struct soft_trigger_logic *stl, | |
64 | uint8_t *buf, int len) | |
65 | { | |
66 | /* Avoid uselessly copying more than the pre-trigger size. */ | |
67 | if (len > stl->pre_trigger_size) { | |
68 | buf += len - stl->pre_trigger_size; | |
69 | len = stl->pre_trigger_size; | |
70 | } | |
71 | ||
72 | /* Update the filling level of the pre-trigger circular buffer. */ | |
73 | stl->pre_trigger_fill = MIN(stl->pre_trigger_fill + len, | |
74 | stl->pre_trigger_size); | |
75 | ||
76 | /* Actually copy data to the pre-trigger circular buffer. */ | |
77 | while (len > 0) { | |
78 | size_t size = MIN(stl->pre_trigger_buffer + stl->pre_trigger_size | |
79 | - stl->pre_trigger_head, len); | |
80 | memcpy(stl->pre_trigger_head, buf, size); | |
81 | stl->pre_trigger_head += size; | |
82 | if (stl->pre_trigger_head >= stl->pre_trigger_buffer | |
83 | + stl->pre_trigger_size) | |
84 | stl->pre_trigger_head = stl->pre_trigger_buffer; | |
85 | buf += size; | |
86 | len -= size; | |
87 | } | |
88 | } | |
89 | ||
90 | static void pre_trigger_send(struct soft_trigger_logic *stl, | |
91 | int *pre_trigger_samples) | |
92 | { | |
93 | struct sr_datafeed_packet packet; | |
94 | struct sr_datafeed_logic logic; | |
95 | ||
96 | packet.type = SR_DF_LOGIC; | |
97 | packet.payload = &logic; | |
98 | logic.unitsize = stl->unitsize; | |
99 | ||
100 | if (pre_trigger_samples) | |
101 | *pre_trigger_samples = 0; | |
102 | ||
103 | /* If pre-trigger buffer not full, rewind head to the first valid sample. */ | |
104 | if (stl->pre_trigger_fill < stl->pre_trigger_size) | |
105 | stl->pre_trigger_head = stl->pre_trigger_buffer; | |
106 | ||
107 | /* Send logic packets for the pre-trigger circular buffer content. */ | |
108 | while (stl->pre_trigger_fill > 0) { | |
109 | size_t size = MIN(stl->pre_trigger_buffer + stl->pre_trigger_size | |
110 | - stl->pre_trigger_head, stl->pre_trigger_fill); | |
111 | logic.length = size; | |
112 | logic.data = stl->pre_trigger_head; | |
113 | sr_session_send(stl->sdi, &packet); | |
114 | stl->pre_trigger_head = stl->pre_trigger_buffer; | |
115 | stl->pre_trigger_fill -= size; | |
116 | if (pre_trigger_samples) | |
117 | *pre_trigger_samples += size / stl->unitsize; | |
118 | } | |
119 | } | |
120 | ||
121 | static gboolean logic_check_match(struct soft_trigger_logic *stl, | |
122 | uint8_t *sample, struct sr_trigger_match *match) | |
123 | { | |
124 | int bit, prev_bit; | |
125 | gboolean result; | |
126 | ||
127 | stl->count++; | |
128 | result = FALSE; | |
129 | bit = *(sample + match->channel->index / 8) | |
130 | & (1 << (match->channel->index % 8)); | |
131 | if (match->match == SR_TRIGGER_ZERO) | |
132 | result = bit == 0; | |
133 | else if (match->match == SR_TRIGGER_ONE) | |
134 | result = bit != 0; | |
135 | else { | |
136 | /* Edge matches. */ | |
137 | if (stl->count == 1) | |
138 | /* First sample, don't have enough for an edge match yet. */ | |
139 | return FALSE; | |
140 | prev_bit = *(stl->prev_sample + match->channel->index / 8) | |
141 | & (1 << (match->channel->index % 8)); | |
142 | if (match->match == SR_TRIGGER_RISING) | |
143 | result = prev_bit == 0 && bit != 0; | |
144 | else if (match->match == SR_TRIGGER_FALLING) | |
145 | result = prev_bit != 0 && bit == 0; | |
146 | else if (match->match == SR_TRIGGER_EDGE) | |
147 | result = prev_bit != bit; | |
148 | } | |
149 | ||
150 | return result; | |
151 | } | |
152 | ||
153 | /* Returns the offset (in samples) within buf of where the trigger | |
154 | * occurred, or -1 if not triggered. */ | |
155 | SR_PRIV int soft_trigger_logic_check(struct soft_trigger_logic *stl, | |
156 | uint8_t *buf, int len, int *pre_trigger_samples) | |
157 | { | |
158 | struct sr_datafeed_packet packet; | |
159 | struct sr_trigger_stage *stage; | |
160 | struct sr_trigger_match *match; | |
161 | GSList *l, *l_stage; | |
162 | int offset; | |
163 | int i; | |
164 | gboolean match_found; | |
165 | ||
166 | offset = -1; | |
167 | for (i = 0; i < len; i += stl->unitsize) { | |
168 | l_stage = g_slist_nth(stl->trigger->stages, stl->cur_stage); | |
169 | stage = l_stage->data; | |
170 | if (!stage->matches) | |
171 | /* No matches supplied, client error. */ | |
172 | return SR_ERR_ARG; | |
173 | ||
174 | match_found = TRUE; | |
175 | for (l = stage->matches; l; l = l->next) { | |
176 | match = l->data; | |
177 | if (!match->channel->enabled) | |
178 | /* Ignore disabled channels with a trigger. */ | |
179 | continue; | |
180 | if (!logic_check_match(stl, buf + i, match)) { | |
181 | match_found = FALSE; | |
182 | break; | |
183 | } | |
184 | } | |
185 | memcpy(stl->prev_sample, buf + i, stl->unitsize); | |
186 | if (match_found) { | |
187 | /* Matched on the current stage. */ | |
188 | if (l_stage->next) { | |
189 | /* Advance to next stage. */ | |
190 | stl->cur_stage++; | |
191 | } else { | |
192 | /* Matched on last stage, send pre-trigger data. */ | |
193 | pre_trigger_append(stl, buf, i); | |
194 | pre_trigger_send(stl, pre_trigger_samples); | |
195 | ||
196 | /* Fire trigger. */ | |
197 | offset = i / stl->unitsize; | |
198 | ||
199 | packet.type = SR_DF_TRIGGER; | |
200 | packet.payload = NULL; | |
201 | sr_session_send(stl->sdi, &packet); | |
202 | break; | |
203 | } | |
204 | } else if (stl->cur_stage > 0) { | |
205 | /* | |
206 | * We had a match at an earlier stage, but failed on the | |
207 | * current stage. However, we may have a match on this | |
208 | * stage in the next bit -- trigger on 0001 will fail on | |
209 | * seeing 00001, so we need to go back to stage 0 -- but | |
210 | * at the next sample from the one that matched originally, | |
211 | * which the counter increment at the end of the loop | |
212 | * takes care of. | |
213 | */ | |
214 | i -= stl->cur_stage * stl->unitsize; | |
215 | if (i < -1) | |
216 | i = -1; /* Oops, went back past this buffer. */ | |
217 | /* Reset trigger stage. */ | |
218 | stl->cur_stage = 0; | |
219 | } | |
220 | } | |
221 | ||
222 | if (offset == -1) | |
223 | pre_trigger_append(stl, buf, len); | |
224 | ||
225 | return offset; | |
226 | } |