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[openocd.git] / src / jtag / drivers / bitbang.c
1 /***************************************************************************
2 * Copyright (C) 2005 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
4 * *
5 * Copyright (C) 2007,2008 Øyvind Harboe *
6 * oyvind.harboe@zylin.com *
7 * *
8 * This program is free software; you can redistribute it and/or modify *
9 * it under the terms of the GNU General Public License as published by *
10 * the Free Software Foundation; either version 2 of the License, or *
11 * (at your option) any later version. *
12 * *
13 * This program is distributed in the hope that it will be useful, *
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16 * GNU General Public License for more details. *
17 * *
18 * You should have received a copy of the GNU General Public License *
19 * along with this program. If not, see <http://www.gnu.org/licenses/>. *
20 ***************************************************************************/
21
22 /* 2014-12: Addition of the SWD protocol support is based on the initial work
23 * by Paul Fertser and modifications by Jean-Christian de Rivaz. */
24
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28
29 #include "bitbang.h"
30 #include <jtag/interface.h>
31 #include <jtag/commands.h>
32
33 /* YUK! - but this is currently a global.... */
34 extern struct jtag_interface *jtag_interface;
35
36 /**
37 * Function bitbang_stableclocks
38 * issues a number of clock cycles while staying in a stable state.
39 * Because the TMS value required to stay in the RESET state is a 1, whereas
40 * the TMS value required to stay in any of the other stable states is a 0,
41 * this function checks the current stable state to decide on the value of TMS
42 * to use.
43 */
44 static int bitbang_stableclocks(int num_cycles);
45
46 static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk);
47
48 struct bitbang_interface *bitbang_interface;
49
50 /* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
51 *
52 * Set this to 1 and str912 reset halt will fail.
53 *
54 * If someone can submit a patch with an explanation it will be greatly
55 * appreciated, but as far as I can tell (ØH) DCLK is generated upon
56 * clk = 0 in TAP_IDLE. Good luck deducing that from the ARM documentation!
57 * The ARM documentation uses the term "DCLK is asserted while in the TAP_IDLE
58 * state". With hardware there is no such thing as *while* in a state. There
59 * are only edges. So clk => 0 is in fact a very subtle state transition that
60 * happens *while* in the TAP_IDLE state. "#&¤"#¤&"#&"#&
61 *
62 * For "reset halt" the last thing that happens before srst is asserted
63 * is that the breakpoint is set up. If DCLK is not wiggled one last
64 * time before the reset, then the breakpoint is not set up and
65 * "reset halt" will fail to halt.
66 *
67 */
68 #define CLOCK_IDLE() 0
69
70 /* The bitbang driver leaves the TCK 0 when in idle */
71 static void bitbang_end_state(tap_state_t state)
72 {
73 assert(tap_is_state_stable(state));
74 tap_set_end_state(state);
75 }
76
77 static int bitbang_state_move(int skip)
78 {
79 int i = 0, tms = 0;
80 uint8_t tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
81 int tms_count = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
82
83 for (i = skip; i < tms_count; i++) {
84 tms = (tms_scan >> i) & 1;
85 if (bitbang_interface->write(0, tms, 0) != ERROR_OK)
86 return ERROR_FAIL;
87 if (bitbang_interface->write(1, tms, 0) != ERROR_OK)
88 return ERROR_FAIL;
89 }
90 if (bitbang_interface->write(CLOCK_IDLE(), tms, 0) != ERROR_OK)
91 return ERROR_FAIL;
92
93 tap_set_state(tap_get_end_state());
94 return ERROR_OK;
95 }
96
97 /**
98 * Clock a bunch of TMS (or SWDIO) transitions, to change the JTAG
99 * (or SWD) state machine.
100 */
101 static int bitbang_execute_tms(struct jtag_command *cmd)
102 {
103 unsigned num_bits = cmd->cmd.tms->num_bits;
104 const uint8_t *bits = cmd->cmd.tms->bits;
105
106 DEBUG_JTAG_IO("TMS: %d bits", num_bits);
107
108 int tms = 0;
109 for (unsigned i = 0; i < num_bits; i++) {
110 tms = ((bits[i/8] >> (i % 8)) & 1);
111 if (bitbang_interface->write(0, tms, 0) != ERROR_OK)
112 return ERROR_FAIL;
113 if (bitbang_interface->write(1, tms, 0) != ERROR_OK)
114 return ERROR_FAIL;
115 }
116 if (bitbang_interface->write(CLOCK_IDLE(), tms, 0) != ERROR_OK)
117 return ERROR_FAIL;
118
119 return ERROR_OK;
120 }
121
122 static int bitbang_path_move(struct pathmove_command *cmd)
123 {
124 int num_states = cmd->num_states;
125 int state_count;
126 int tms = 0;
127
128 state_count = 0;
129 while (num_states) {
130 if (tap_state_transition(tap_get_state(), false) == cmd->path[state_count])
131 tms = 0;
132 else if (tap_state_transition(tap_get_state(), true) == cmd->path[state_count])
133 tms = 1;
134 else {
135 LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition",
136 tap_state_name(tap_get_state()),
137 tap_state_name(cmd->path[state_count]));
138 exit(-1);
139 }
140
141 if (bitbang_interface->write(0, tms, 0) != ERROR_OK)
142 return ERROR_FAIL;
143 if (bitbang_interface->write(1, tms, 0) != ERROR_OK)
144 return ERROR_FAIL;
145
146 tap_set_state(cmd->path[state_count]);
147 state_count++;
148 num_states--;
149 }
150
151 if (bitbang_interface->write(CLOCK_IDLE(), tms, 0) != ERROR_OK)
152 return ERROR_FAIL;
153
154 tap_set_end_state(tap_get_state());
155 return ERROR_OK;
156 }
157
158 static int bitbang_runtest(int num_cycles)
159 {
160 int i;
161
162 tap_state_t saved_end_state = tap_get_end_state();
163
164 /* only do a state_move when we're not already in IDLE */
165 if (tap_get_state() != TAP_IDLE) {
166 bitbang_end_state(TAP_IDLE);
167 if (bitbang_state_move(0) != ERROR_OK)
168 return ERROR_FAIL;
169 }
170
171 /* execute num_cycles */
172 for (i = 0; i < num_cycles; i++) {
173 if (bitbang_interface->write(0, 0, 0) != ERROR_OK)
174 return ERROR_FAIL;
175 if (bitbang_interface->write(1, 0, 0) != ERROR_OK)
176 return ERROR_FAIL;
177 }
178 if (bitbang_interface->write(CLOCK_IDLE(), 0, 0) != ERROR_OK)
179 return ERROR_FAIL;
180
181 /* finish in end_state */
182 bitbang_end_state(saved_end_state);
183 if (tap_get_state() != tap_get_end_state())
184 if (bitbang_state_move(0) != ERROR_OK)
185 return ERROR_FAIL;
186
187 return ERROR_OK;
188 }
189
190 static int bitbang_stableclocks(int num_cycles)
191 {
192 int tms = (tap_get_state() == TAP_RESET ? 1 : 0);
193 int i;
194
195 /* send num_cycles clocks onto the cable */
196 for (i = 0; i < num_cycles; i++) {
197 if (bitbang_interface->write(1, tms, 0) != ERROR_OK)
198 return ERROR_FAIL;
199 if (bitbang_interface->write(0, tms, 0) != ERROR_OK)
200 return ERROR_FAIL;
201 }
202
203 return ERROR_OK;
204 }
205
206 static int bitbang_scan(bool ir_scan, enum scan_type type, uint8_t *buffer,
207 unsigned scan_size)
208 {
209 tap_state_t saved_end_state = tap_get_end_state();
210 unsigned bit_cnt;
211
212 if (!((!ir_scan &&
213 (tap_get_state() == TAP_DRSHIFT)) ||
214 (ir_scan && (tap_get_state() == TAP_IRSHIFT)))) {
215 if (ir_scan)
216 bitbang_end_state(TAP_IRSHIFT);
217 else
218 bitbang_end_state(TAP_DRSHIFT);
219
220 if (bitbang_state_move(0) != ERROR_OK)
221 return ERROR_FAIL;
222 bitbang_end_state(saved_end_state);
223 }
224
225 size_t buffered = 0;
226 for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++) {
227 int tms = (bit_cnt == scan_size-1) ? 1 : 0;
228 int tdi;
229 int bytec = bit_cnt/8;
230 int bcval = 1 << (bit_cnt % 8);
231
232 /* if we're just reading the scan, but don't care about the output
233 * default to outputting 'low', this also makes valgrind traces more readable,
234 * as it removes the dependency on an uninitialised value
235 */
236 tdi = 0;
237 if ((type != SCAN_IN) && (buffer[bytec] & bcval))
238 tdi = 1;
239
240 if (bitbang_interface->write(0, tms, tdi) != ERROR_OK)
241 return ERROR_FAIL;
242
243 if (type != SCAN_OUT) {
244 if (bitbang_interface->buf_size) {
245 if (bitbang_interface->sample() != ERROR_OK)
246 return ERROR_FAIL;
247 buffered++;
248 } else {
249 switch (bitbang_interface->read()) {
250 case BB_LOW:
251 buffer[bytec] &= ~bcval;
252 break;
253 case BB_HIGH:
254 buffer[bytec] |= bcval;
255 break;
256 default:
257 return ERROR_FAIL;
258 }
259 }
260 }
261
262 if (bitbang_interface->write(1, tms, tdi) != ERROR_OK)
263 return ERROR_FAIL;
264
265 if (type != SCAN_OUT && bitbang_interface->buf_size &&
266 (buffered == bitbang_interface->buf_size ||
267 bit_cnt == scan_size - 1)) {
268 for (unsigned i = bit_cnt + 1 - buffered; i <= bit_cnt; i++) {
269 switch (bitbang_interface->read_sample()) {
270 case BB_LOW:
271 buffer[i/8] &= ~(1 << (i % 8));
272 break;
273 case BB_HIGH:
274 buffer[i/8] |= 1 << (i % 8);
275 break;
276 default:
277 return ERROR_FAIL;
278 }
279 }
280 buffered = 0;
281 }
282 }
283
284 if (tap_get_state() != tap_get_end_state()) {
285 /* we *KNOW* the above loop transitioned out of
286 * the shift state, so we skip the first state
287 * and move directly to the end state.
288 */
289 if (bitbang_state_move(1) != ERROR_OK)
290 return ERROR_FAIL;
291 }
292 return ERROR_OK;
293 }
294
295 int bitbang_execute_queue(void)
296 {
297 struct jtag_command *cmd = jtag_command_queue; /* currently processed command */
298 int scan_size;
299 enum scan_type type;
300 uint8_t *buffer;
301 int retval;
302
303 if (!bitbang_interface) {
304 LOG_ERROR("BUG: Bitbang interface called, but not yet initialized");
305 exit(-1);
306 }
307
308 /* return ERROR_OK, unless a jtag_read_buffer returns a failed check
309 * that wasn't handled by a caller-provided error handler
310 */
311 retval = ERROR_OK;
312
313 if (bitbang_interface->blink) {
314 if (bitbang_interface->blink(1) != ERROR_OK)
315 return ERROR_FAIL;
316 }
317
318 while (cmd) {
319 switch (cmd->type) {
320 case JTAG_RESET:
321 #ifdef _DEBUG_JTAG_IO_
322 LOG_DEBUG("reset trst: %i srst %i",
323 cmd->cmd.reset->trst,
324 cmd->cmd.reset->srst);
325 #endif
326 if ((cmd->cmd.reset->trst == 1) ||
327 (cmd->cmd.reset->srst && (jtag_get_reset_config() & RESET_SRST_PULLS_TRST)))
328 tap_set_state(TAP_RESET);
329 if (bitbang_interface->reset(cmd->cmd.reset->trst,
330 cmd->cmd.reset->srst) != ERROR_OK)
331 return ERROR_FAIL;
332 break;
333 case JTAG_RUNTEST:
334 #ifdef _DEBUG_JTAG_IO_
335 LOG_DEBUG("runtest %i cycles, end in %s",
336 cmd->cmd.runtest->num_cycles,
337 tap_state_name(cmd->cmd.runtest->end_state));
338 #endif
339 bitbang_end_state(cmd->cmd.runtest->end_state);
340 if (bitbang_runtest(cmd->cmd.runtest->num_cycles) != ERROR_OK)
341 return ERROR_FAIL;
342 break;
343
344 case JTAG_STABLECLOCKS:
345 /* this is only allowed while in a stable state. A check for a stable
346 * state was done in jtag_add_clocks()
347 */
348 if (bitbang_stableclocks(cmd->cmd.stableclocks->num_cycles) != ERROR_OK)
349 return ERROR_FAIL;
350 break;
351
352 case JTAG_TLR_RESET:
353 #ifdef _DEBUG_JTAG_IO_
354 LOG_DEBUG("statemove end in %s",
355 tap_state_name(cmd->cmd.statemove->end_state));
356 #endif
357 bitbang_end_state(cmd->cmd.statemove->end_state);
358 if (bitbang_state_move(0) != ERROR_OK)
359 return ERROR_FAIL;
360 break;
361 case JTAG_PATHMOVE:
362 #ifdef _DEBUG_JTAG_IO_
363 LOG_DEBUG("pathmove: %i states, end in %s",
364 cmd->cmd.pathmove->num_states,
365 tap_state_name(cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]));
366 #endif
367 if (bitbang_path_move(cmd->cmd.pathmove) != ERROR_OK)
368 return ERROR_FAIL;
369 break;
370 case JTAG_SCAN:
371 bitbang_end_state(cmd->cmd.scan->end_state);
372 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
373 #ifdef _DEBUG_JTAG_IO_
374 LOG_DEBUG("%s scan %d bits; end in %s",
375 (cmd->cmd.scan->ir_scan) ? "IR" : "DR",
376 scan_size,
377 tap_state_name(cmd->cmd.scan->end_state));
378 #endif
379 type = jtag_scan_type(cmd->cmd.scan);
380 if (bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer,
381 scan_size) != ERROR_OK)
382 return ERROR_FAIL;
383 if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
384 retval = ERROR_JTAG_QUEUE_FAILED;
385 if (buffer)
386 free(buffer);
387 break;
388 case JTAG_SLEEP:
389 #ifdef _DEBUG_JTAG_IO_
390 LOG_DEBUG("sleep %" PRIi32, cmd->cmd.sleep->us);
391 #endif
392 jtag_sleep(cmd->cmd.sleep->us);
393 break;
394 case JTAG_TMS:
395 retval = bitbang_execute_tms(cmd);
396 break;
397 default:
398 LOG_ERROR("BUG: unknown JTAG command type encountered");
399 exit(-1);
400 }
401 cmd = cmd->next;
402 }
403 if (bitbang_interface->blink) {
404 if (bitbang_interface->blink(0) != ERROR_OK)
405 return ERROR_FAIL;
406 }
407
408 return retval;
409 }
410
411
412 bool swd_mode;
413 static int queued_retval;
414
415 static int bitbang_swd_init(void)
416 {
417 LOG_DEBUG("bitbang_swd_init");
418 swd_mode = true;
419 return ERROR_OK;
420 }
421
422 static void bitbang_exchange(bool rnw, uint8_t buf[], unsigned int offset, unsigned int bit_cnt)
423 {
424 LOG_DEBUG("bitbang_exchange");
425 int tdi;
426
427 for (unsigned int i = offset; i < bit_cnt + offset; i++) {
428 int bytec = i/8;
429 int bcval = 1 << (i % 8);
430 tdi = !rnw && (buf[bytec] & bcval);
431
432 bitbang_interface->write(0, 0, tdi);
433
434 if (rnw && buf) {
435 if (bitbang_interface->swdio_read())
436 buf[bytec] |= bcval;
437 else
438 buf[bytec] &= ~bcval;
439 }
440
441 bitbang_interface->write(1, 0, tdi);
442 }
443 }
444
445 int bitbang_swd_switch_seq(enum swd_special_seq seq)
446 {
447 LOG_DEBUG("bitbang_swd_switch_seq");
448
449 switch (seq) {
450 case LINE_RESET:
451 LOG_DEBUG("SWD line reset");
452 bitbang_exchange(false, (uint8_t *)swd_seq_line_reset, 0, swd_seq_line_reset_len);
453 break;
454 case JTAG_TO_SWD:
455 LOG_DEBUG("JTAG-to-SWD");
456 bitbang_exchange(false, (uint8_t *)swd_seq_jtag_to_swd, 0, swd_seq_jtag_to_swd_len);
457 break;
458 case SWD_TO_JTAG:
459 LOG_DEBUG("SWD-to-JTAG");
460 bitbang_exchange(false, (uint8_t *)swd_seq_swd_to_jtag, 0, swd_seq_swd_to_jtag_len);
461 break;
462 default:
463 LOG_ERROR("Sequence %d not supported", seq);
464 return ERROR_FAIL;
465 }
466
467 return ERROR_OK;
468 }
469
470 void bitbang_switch_to_swd(void)
471 {
472 LOG_DEBUG("bitbang_switch_to_swd");
473 bitbang_exchange(false, (uint8_t *)swd_seq_jtag_to_swd, 0, swd_seq_jtag_to_swd_len);
474 }
475
476 static void swd_clear_sticky_errors(void)
477 {
478 bitbang_swd_write_reg(swd_cmd(false, false, DP_ABORT),
479 STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
480 }
481
482 static void bitbang_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay_clk)
483 {
484 LOG_DEBUG("bitbang_swd_read_reg");
485 assert(cmd & SWD_CMD_RnW);
486
487 if (queued_retval != ERROR_OK) {
488 LOG_DEBUG("Skip bitbang_swd_read_reg because queued_retval=%d", queued_retval);
489 return;
490 }
491
492 for (;;) {
493 uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)];
494
495 cmd |= SWD_CMD_START | (1 << 7);
496 bitbang_exchange(false, &cmd, 0, 8);
497
498 bitbang_interface->swdio_drive(false);
499 bitbang_exchange(true, trn_ack_data_parity_trn, 0, 1 + 3 + 32 + 1 + 1);
500 bitbang_interface->swdio_drive(true);
501
502 int ack = buf_get_u32(trn_ack_data_parity_trn, 1, 3);
503 uint32_t data = buf_get_u32(trn_ack_data_parity_trn, 1 + 3, 32);
504 int parity = buf_get_u32(trn_ack_data_parity_trn, 1 + 3 + 32, 1);
505
506 LOG_DEBUG("%s %s %s reg %X = %08"PRIx32,
507 ack == SWD_ACK_OK ? "OK" : ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK",
508 cmd & SWD_CMD_APnDP ? "AP" : "DP",
509 cmd & SWD_CMD_RnW ? "read" : "write",
510 (cmd & SWD_CMD_A32) >> 1,
511 data);
512
513 switch (ack) {
514 case SWD_ACK_OK:
515 if (parity != parity_u32(data)) {
516 LOG_DEBUG("Wrong parity detected");
517 queued_retval = ERROR_FAIL;
518 return;
519 }
520 if (value)
521 *value = data;
522 if (cmd & SWD_CMD_APnDP)
523 bitbang_exchange(true, NULL, 0, ap_delay_clk);
524 return;
525 case SWD_ACK_WAIT:
526 LOG_DEBUG("SWD_ACK_WAIT");
527 swd_clear_sticky_errors();
528 break;
529 case SWD_ACK_FAULT:
530 LOG_DEBUG("SWD_ACK_FAULT");
531 queued_retval = ack;
532 return;
533 default:
534 LOG_DEBUG("No valid acknowledge: ack=%d", ack);
535 queued_retval = ack;
536 return;
537 }
538 }
539 }
540
541 static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk)
542 {
543 LOG_DEBUG("bitbang_swd_write_reg");
544 assert(!(cmd & SWD_CMD_RnW));
545
546 if (queued_retval != ERROR_OK) {
547 LOG_DEBUG("Skip bitbang_swd_write_reg because queued_retval=%d", queued_retval);
548 return;
549 }
550
551 for (;;) {
552 uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)];
553 buf_set_u32(trn_ack_data_parity_trn, 1 + 3 + 1, 32, value);
554 buf_set_u32(trn_ack_data_parity_trn, 1 + 3 + 1 + 32, 1, parity_u32(value));
555
556 cmd |= SWD_CMD_START | (1 << 7);
557 bitbang_exchange(false, &cmd, 0, 8);
558
559 bitbang_interface->swdio_drive(false);
560 bitbang_exchange(true, trn_ack_data_parity_trn, 0, 1 + 3 + 1);
561 bitbang_interface->swdio_drive(true);
562 bitbang_exchange(false, trn_ack_data_parity_trn, 1 + 3 + 1, 32 + 1);
563
564 int ack = buf_get_u32(trn_ack_data_parity_trn, 1, 3);
565 LOG_DEBUG("%s %s %s reg %X = %08"PRIx32,
566 ack == SWD_ACK_OK ? "OK" : ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK",
567 cmd & SWD_CMD_APnDP ? "AP" : "DP",
568 cmd & SWD_CMD_RnW ? "read" : "write",
569 (cmd & SWD_CMD_A32) >> 1,
570 buf_get_u32(trn_ack_data_parity_trn, 1 + 3 + 1, 32));
571
572 switch (ack) {
573 case SWD_ACK_OK:
574 if (cmd & SWD_CMD_APnDP)
575 bitbang_exchange(true, NULL, 0, ap_delay_clk);
576 return;
577 case SWD_ACK_WAIT:
578 LOG_DEBUG("SWD_ACK_WAIT");
579 swd_clear_sticky_errors();
580 break;
581 case SWD_ACK_FAULT:
582 LOG_DEBUG("SWD_ACK_FAULT");
583 queued_retval = ack;
584 return;
585 default:
586 LOG_DEBUG("No valid acknowledge: ack=%d", ack);
587 queued_retval = ack;
588 return;
589 }
590 }
591 }
592
593 static int bitbang_swd_run_queue(void)
594 {
595 LOG_DEBUG("bitbang_swd_run_queue");
596 /* A transaction must be followed by another transaction or at least 8 idle cycles to
597 * ensure that data is clocked through the AP. */
598 bitbang_exchange(true, NULL, 0, 8);
599
600 int retval = queued_retval;
601 queued_retval = ERROR_OK;
602 LOG_DEBUG("SWD queue return value: %02x", retval);
603 return retval;
604 }
605
606 const struct swd_driver bitbang_swd = {
607 .init = bitbang_swd_init,
608 .switch_seq = bitbang_swd_switch_seq,
609 .read_reg = bitbang_swd_read_reg,
610 .write_reg = bitbang_swd_write_reg,
611 .run = bitbang_swd_run_queue,
612 };
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