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
logic_channel_unitsize(GSList * channels)29 SR_PRIV int logic_channel_unitsize(GSList *channels)
30 {
31 int number = 0;
32 struct sr_channel *channel;
33 GSList *l;
34
35 for (l = channels; l; l = l->next) {
36 channel = l->data;
37 if (channel->type == SR_CHANNEL_LOGIC)
38 number++;
39 }
40
41 return (number + 7) / 8;
42 }
43
soft_trigger_logic_new(const struct sr_dev_inst * sdi,struct sr_trigger * trigger,int pre_trigger_samples)44 SR_PRIV struct soft_trigger_logic *soft_trigger_logic_new(
45 const struct sr_dev_inst *sdi, struct sr_trigger *trigger,
46 int pre_trigger_samples)
47 {
48 struct soft_trigger_logic *stl;
49
50 stl = g_malloc0(sizeof(struct soft_trigger_logic));
51 stl->sdi = sdi;
52 stl->trigger = trigger;
53 stl->unitsize = logic_channel_unitsize(sdi->channels);
54 stl->prev_sample = g_malloc0(stl->unitsize);
55 stl->pre_trigger_size = stl->unitsize * pre_trigger_samples;
56 stl->pre_trigger_buffer = g_try_malloc(stl->pre_trigger_size);
57 if (pre_trigger_samples > 0 && !stl->pre_trigger_buffer) {
58 /*
59 * Error out if g_try_malloc() failed (or was invoked as
60 * g_try_malloc(0)) *and* more than 0 pretrigger samples
61 * were requested.
62 */
63 soft_trigger_logic_free(stl);
64 return NULL;
65 }
66 stl->pre_trigger_head = stl->pre_trigger_buffer;
67
68 if (stl->pre_trigger_size > 0 && !stl->pre_trigger_buffer) {
69 soft_trigger_logic_free(stl);
70 return NULL;
71 }
72
73 return stl;
74 }
75
soft_trigger_logic_free(struct soft_trigger_logic * stl)76 SR_PRIV void soft_trigger_logic_free(struct soft_trigger_logic *stl)
77 {
78 g_free(stl->pre_trigger_buffer);
79 g_free(stl->prev_sample);
80 g_free(stl);
81 }
82
pre_trigger_append(struct soft_trigger_logic * stl,uint8_t * buf,int len)83 static void pre_trigger_append(struct soft_trigger_logic *stl,
84 uint8_t *buf, int len)
85 {
86 /* Avoid uselessly copying more than the pre-trigger size. */
87 if (len > stl->pre_trigger_size) {
88 buf += len - stl->pre_trigger_size;
89 len = stl->pre_trigger_size;
90 }
91
92 /* Update the filling level of the pre-trigger circular buffer. */
93 stl->pre_trigger_fill = MIN(stl->pre_trigger_fill + len,
94 stl->pre_trigger_size);
95
96 /* Actually copy data to the pre-trigger circular buffer. */
97 while (len > 0) {
98 size_t size = MIN(stl->pre_trigger_buffer + stl->pre_trigger_size
99 - stl->pre_trigger_head, len);
100 memcpy(stl->pre_trigger_head, buf, size);
101 stl->pre_trigger_head += size;
102 if (stl->pre_trigger_head >= stl->pre_trigger_buffer
103 + stl->pre_trigger_size)
104 stl->pre_trigger_head = stl->pre_trigger_buffer;
105 buf += size;
106 len -= size;
107 }
108 }
109
pre_trigger_send(struct soft_trigger_logic * stl,int * pre_trigger_samples)110 static void pre_trigger_send(struct soft_trigger_logic *stl,
111 int *pre_trigger_samples)
112 {
113 struct sr_datafeed_packet packet;
114 struct sr_datafeed_logic logic;
115
116 packet.type = SR_DF_LOGIC;
117 packet.payload = &logic;
118 logic.unitsize = stl->unitsize;
119
120 if (pre_trigger_samples)
121 *pre_trigger_samples = 0;
122
123 /* If pre-trigger buffer not full, rewind head to the first valid sample. */
124 if (stl->pre_trigger_fill < stl->pre_trigger_size)
125 stl->pre_trigger_head = stl->pre_trigger_buffer;
126
127 /* Send logic packets for the pre-trigger circular buffer content. */
128 while (stl->pre_trigger_fill > 0) {
129 size_t size = MIN(stl->pre_trigger_buffer + stl->pre_trigger_size
130 - stl->pre_trigger_head, stl->pre_trigger_fill);
131 logic.length = size;
132 logic.data = stl->pre_trigger_head;
133 sr_session_send(stl->sdi, &packet);
134 stl->pre_trigger_head = stl->pre_trigger_buffer;
135 stl->pre_trigger_fill -= size;
136 if (pre_trigger_samples)
137 *pre_trigger_samples += size / stl->unitsize;
138 }
139 }
140
logic_check_match(struct soft_trigger_logic * stl,uint8_t * sample,struct sr_trigger_match * match)141 static gboolean logic_check_match(struct soft_trigger_logic *stl,
142 uint8_t *sample, struct sr_trigger_match *match)
143 {
144 int bit, prev_bit;
145 gboolean result;
146
147 stl->count++;
148 result = FALSE;
149 bit = *(sample + match->channel->index / 8)
150 & (1 << (match->channel->index % 8));
151 if (match->match == SR_TRIGGER_ZERO)
152 result = bit == 0;
153 else if (match->match == SR_TRIGGER_ONE)
154 result = bit != 0;
155 else {
156 /* Edge matches. */
157 if (stl->count == 1)
158 /* First sample, don't have enough for an edge match yet. */
159 return FALSE;
160 prev_bit = *(stl->prev_sample + match->channel->index / 8)
161 & (1 << (match->channel->index % 8));
162 if (match->match == SR_TRIGGER_RISING)
163 result = prev_bit == 0 && bit != 0;
164 else if (match->match == SR_TRIGGER_FALLING)
165 result = prev_bit != 0 && bit == 0;
166 else if (match->match == SR_TRIGGER_EDGE)
167 result = prev_bit != bit;
168 }
169
170 return result;
171 }
172
173 /* Returns the offset (in samples) within buf of where the trigger
174 * occurred, or -1 if not triggered. */
soft_trigger_logic_check(struct soft_trigger_logic * stl,uint8_t * buf,int len,int * pre_trigger_samples)175 SR_PRIV int soft_trigger_logic_check(struct soft_trigger_logic *stl,
176 uint8_t *buf, int len, int *pre_trigger_samples)
177 {
178 struct sr_datafeed_packet packet;
179 struct sr_trigger_stage *stage;
180 struct sr_trigger_match *match;
181 GSList *l, *l_stage;
182 int offset;
183 int i;
184 gboolean match_found;
185
186 offset = -1;
187 for (i = 0; i < len; i += stl->unitsize) {
188 l_stage = g_slist_nth(stl->trigger->stages, stl->cur_stage);
189 stage = l_stage->data;
190 if (!stage->matches)
191 /* No matches supplied, client error. */
192 return SR_ERR_ARG;
193
194 match_found = TRUE;
195 for (l = stage->matches; l; l = l->next) {
196 match = l->data;
197 if (!match->channel->enabled)
198 /* Ignore disabled channels with a trigger. */
199 continue;
200 if (!logic_check_match(stl, buf + i, match)) {
201 match_found = FALSE;
202 break;
203 }
204 }
205 memcpy(stl->prev_sample, buf + i, stl->unitsize);
206 if (match_found) {
207 /* Matched on the current stage. */
208 if (l_stage->next) {
209 /* Advance to next stage. */
210 stl->cur_stage++;
211 } else {
212 /* Matched on last stage, send pre-trigger data. */
213 pre_trigger_append(stl, buf, i);
214 pre_trigger_send(stl, pre_trigger_samples);
215
216 /* Fire trigger. */
217 offset = i / stl->unitsize;
218
219 packet.type = SR_DF_TRIGGER;
220 packet.payload = NULL;
221 sr_session_send(stl->sdi, &packet);
222 break;
223 }
224 } else if (stl->cur_stage > 0) {
225 /*
226 * We had a match at an earlier stage, but failed on the
227 * current stage. However, we may have a match on this
228 * stage in the next bit -- trigger on 0001 will fail on
229 * seeing 00001, so we need to go back to stage 0 -- but
230 * at the next sample from the one that matched originally,
231 * which the counter increment at the end of the loop
232 * takes care of.
233 */
234 i -= stl->cur_stage * stl->unitsize;
235 if (i < -1)
236 i = -1; /* Oops, went back past this buffer. */
237 /* Reset trigger stage. */
238 stl->cur_stage = 0;
239 }
240 }
241
242 if (offset == -1)
243 pre_trigger_append(stl, buf, len);
244
245 return offset;
246 }
247