jtag: only change state if necessary
[openocd.git] / src / jtag / drivers / bitq.c
blobac58190eef85dcdc391319a9573dab1f6793136d
1 /***************************************************************************
2 * Copyright (C) 2007 by Pavel Chromy *
3 * chromy@asix.cz *
4 * *
5 * This program is free software; you can redistribute it and/or modify *
6 * it under the terms of the GNU General Public License as published by *
7 * the Free Software Foundation; either version 2 of the License, or *
8 * (at your option) any later version. *
9 * *
10 * This program is distributed in the hope that it will be useful, *
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
13 * GNU General Public License for more details. *
14 * *
15 * You should have received a copy of the GNU General Public License *
16 * along with this program; if not, write to the *
17 * Free Software Foundation, Inc., *
18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
19 ***************************************************************************/
21 #ifdef HAVE_CONFIG_H
22 #include "config.h"
23 #endif
25 #include <jtag/jtag.h>
26 #include "bitq.h"
27 #include <jtag/interface.h>
29 struct bitq_interface *bitq_interface; /* low level bit queue interface */
31 /* state of input queue */
32 struct bitq_state {
33 struct jtag_command *cmd; /* command currently processed */
34 int field_idx; /* index of field currently being processed */
35 int bit_pos; /* position of bit currently being processed */
36 int status; /* processing status */
38 static struct bitq_state bitq_in_state;
41 * input queue processing does not use jtag_read_buffer() to avoid unnecessary overhead
42 * no parameters, makes use of stored state information
44 static void bitq_in_proc(void)
46 /* loop through the queue */
47 while (bitq_in_state.cmd) {
48 /* only JTAG_SCAN command may return data */
49 if (bitq_in_state.cmd->type == JTAG_SCAN) {
50 /* loop through the fields */
51 while (bitq_in_state.field_idx < bitq_in_state.cmd->cmd.scan->num_fields) {
52 struct scan_field *field;
53 field = &bitq_in_state.cmd->cmd.scan->fields[bitq_in_state.field_idx];
54 if (field->in_value) {
55 /* field scanning */
56 while (bitq_in_state.bit_pos < field->num_bits) {
57 /* index of byte being scanned */
58 int in_idx = bitq_in_state.bit_pos / 8;
59 /* mask of next bit to be scanned */
60 uint8_t in_mask = 1 << (bitq_in_state.bit_pos % 8);
62 int tdo = bitq_interface->in();
63 if (tdo < 0) {
64 #ifdef _DEBUG_JTAG_IO_
65 LOG_DEBUG("bitq in EOF");
66 #endif
67 return;
69 if (in_mask == 0x01)
70 field->in_value[in_idx] = 0;
71 if (tdo)
72 field->in_value[in_idx] |= in_mask;
73 bitq_in_state.bit_pos++;
77 bitq_in_state.field_idx++; /* advance to next field */
78 bitq_in_state.bit_pos = 0; /* start next field from the first bit */
81 bitq_in_state.cmd = bitq_in_state.cmd->next; /* advance to next command */
82 bitq_in_state.field_idx = 0; /* preselect first field */
86 static void bitq_io(int tms, int tdi, int tdo_req)
88 bitq_interface->out(tms, tdi, tdo_req);
89 /* check and process the input queue */
90 if (bitq_interface->in_rdy())
91 bitq_in_proc();
94 static void bitq_end_state(tap_state_t state)
96 if (!tap_is_state_stable(state)) {
97 LOG_ERROR("BUG: %i is not a valid end state", state);
98 exit(-1);
100 tap_set_end_state(state);
103 static void bitq_state_move(tap_state_t new_state)
105 int i = 0;
106 uint8_t tms_scan;
108 if (!tap_is_state_stable(tap_get_state()) || !tap_is_state_stable(new_state)) {
109 LOG_ERROR("TAP move from or to unstable state");
110 exit(-1);
113 tms_scan = tap_get_tms_path(tap_get_state(), new_state);
114 int tms_count = tap_get_tms_path_len(tap_get_state(), new_state);
116 for (i = 0; i < tms_count; i++) {
117 bitq_io(tms_scan & 1, 0, 0);
118 tms_scan >>= 1;
121 tap_set_state(new_state);
124 static void bitq_path_move(struct pathmove_command *cmd)
126 int i;
128 for (i = 0; i <= cmd->num_states; i++) {
129 if (tap_state_transition(tap_get_state(), false) == cmd->path[i])
130 bitq_io(0, 0, 0);
131 else if (tap_state_transition(tap_get_state(), true) == cmd->path[i])
132 bitq_io(1, 0, 0);
133 else {
134 LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_name(
135 tap_get_state()), tap_state_name(cmd->path[i]));
136 exit(-1);
139 tap_set_state(cmd->path[i]);
142 tap_set_end_state(tap_get_state());
145 static void bitq_runtest(int num_cycles)
147 int i;
149 /* only do a state_move when we're not already in IDLE */
150 if (tap_get_state() != TAP_IDLE)
151 bitq_state_move(TAP_IDLE);
153 /* execute num_cycles */
154 for (i = 0; i < num_cycles; i++)
155 bitq_io(0, 0, 0);
157 /* finish in end_state */
158 if (tap_get_state() != tap_get_end_state())
159 bitq_state_move(tap_get_end_state());
162 static void bitq_scan_field(struct scan_field *field, int do_pause)
164 int bit_cnt;
165 int tdo_req;
167 const uint8_t *out_ptr;
168 uint8_t out_mask;
170 if (field->in_value)
171 tdo_req = 1;
172 else
173 tdo_req = 0;
175 if (field->out_value == NULL) {
176 /* just send zeros and request data from TDO */
177 for (bit_cnt = field->num_bits; bit_cnt > 1; bit_cnt--)
178 bitq_io(0, 0, tdo_req);
180 bitq_io(do_pause, 0, tdo_req);
181 } else {
182 /* send data, and optionally request TDO */
183 out_mask = 0x01;
184 out_ptr = field->out_value;
185 for (bit_cnt = field->num_bits; bit_cnt > 1; bit_cnt--) {
186 bitq_io(0, ((*out_ptr) & out_mask) != 0, tdo_req);
187 if (out_mask == 0x80) {
188 out_mask = 0x01;
189 out_ptr++;
190 } else
191 out_mask <<= 1;
194 bitq_io(do_pause, ((*out_ptr) & out_mask) != 0, tdo_req);
197 if (do_pause) {
198 bitq_io(0, 0, 0);
199 if (tap_get_state() == TAP_IRSHIFT)
200 tap_set_state(TAP_IRPAUSE);
201 else if (tap_get_state() == TAP_DRSHIFT)
202 tap_set_state(TAP_DRPAUSE);
206 static void bitq_scan(struct scan_command *cmd)
208 int i;
210 if (cmd->ir_scan)
211 bitq_state_move(TAP_IRSHIFT);
212 else
213 bitq_state_move(TAP_DRSHIFT);
215 for (i = 0; i < cmd->num_fields - 1; i++)
216 bitq_scan_field(&cmd->fields[i], 0);
218 bitq_scan_field(&cmd->fields[i], 1);
221 int bitq_execute_queue(void)
223 struct jtag_command *cmd = jtag_command_queue; /* currently processed command */
225 bitq_in_state.cmd = jtag_command_queue;
226 bitq_in_state.field_idx = 0;
227 bitq_in_state.bit_pos = 0;
228 bitq_in_state.status = ERROR_OK;
230 while (cmd) {
231 switch (cmd->type) {
232 case JTAG_RESET:
233 #ifdef _DEBUG_JTAG_IO_
234 LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
235 #endif
236 if ((cmd->cmd.reset->trst == 1) ||
237 (cmd->cmd.reset->srst &&
238 (jtag_get_reset_config() & RESET_SRST_PULLS_TRST)))
239 tap_set_state(TAP_RESET);
240 bitq_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
241 if (bitq_interface->in_rdy())
242 bitq_in_proc();
243 break;
245 case JTAG_RUNTEST:
246 #ifdef _DEBUG_JTAG_IO_
247 LOG_DEBUG("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, cmd->cmd.runtest->end_state);
248 #endif
249 bitq_end_state(cmd->cmd.runtest->end_state);
250 bitq_runtest(cmd->cmd.runtest->num_cycles);
251 break;
253 case JTAG_TLR_RESET:
254 #ifdef _DEBUG_JTAG_IO_
255 LOG_DEBUG("statemove end in %i", cmd->cmd.statemove->end_state);
256 #endif
257 bitq_end_state(cmd->cmd.statemove->end_state);
258 bitq_state_move(tap_get_end_state()); /* uncoditional TAP move */
259 break;
261 case JTAG_PATHMOVE:
262 #ifdef _DEBUG_JTAG_IO_
263 LOG_DEBUG("pathmove: %i states, end in %i", cmd->cmd.pathmove->num_states,
264 cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
265 #endif
266 bitq_path_move(cmd->cmd.pathmove);
267 break;
269 case JTAG_SCAN:
270 #ifdef _DEBUG_JTAG_IO_
271 LOG_DEBUG("scan end in %i", cmd->cmd.scan->end_state);
272 if (cmd->cmd.scan->ir_scan)
273 LOG_DEBUG("scan ir");
274 else
275 LOG_DEBUG("scan dr");
276 #endif
277 bitq_end_state(cmd->cmd.scan->end_state);
278 bitq_scan(cmd->cmd.scan);
279 if (tap_get_state() != tap_get_end_state())
280 bitq_state_move(tap_get_end_state());
281 break;
283 case JTAG_SLEEP:
284 #ifdef _DEBUG_JTAG_IO_
285 LOG_DEBUG("sleep %i", cmd->cmd.sleep->us);
286 #endif
287 bitq_interface->sleep(cmd->cmd.sleep->us);
288 if (bitq_interface->in_rdy())
289 bitq_in_proc();
290 break;
292 default:
293 LOG_ERROR("BUG: unknown JTAG command type encountered");
294 exit(-1);
297 cmd = cmd->next;
300 bitq_interface->flush();
301 bitq_in_proc();
303 if (bitq_in_state.cmd) {
304 LOG_ERROR("missing data from bitq interface");
305 return ERROR_JTAG_QUEUE_FAILED;
307 if (bitq_interface->in() >= 0) {
308 LOG_ERROR("extra data from bitq interface");
309 return ERROR_JTAG_QUEUE_FAILED;
312 return bitq_in_state.status;
315 void bitq_cleanup(void)