1 /***************************************************************************
3 * Copyright (C) 2010 by David Brownell
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.
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.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 ***************************************************************************/
21 * Utilities to support ARM "Serial Wire Debug" (SWD), a low pin-count debug
22 * link protocol used in cases where JTAG is not wanted. This is coupled to
23 * recent versions of ARM's "CoreSight" debug framework. This specific code
24 * is a transport level interface, with "target/arm_adi_v5.[hc]" code
25 * understanding operation semantics, shared with the JTAG transport.
27 * Single-DAP support only.
29 * for details, see "ARM IHI 0031A"
30 * ARM Debug Interface v5 Architecture Specification
31 * especially section 5.3 for SWD protocol
33 * On many chips (most current Cortex-M3 parts) SWD is a run-time alternative
34 * to JTAG. Boards may support one or both. There are also SWD-only chips,
35 * (using SW-DP not SWJ-DP).
37 * Even boards that also support JTAG can benefit from SWD support, because
38 * usually there's no way to access the SWO trace view mechanism in JTAG mode.
39 * That is, trace access may require SWD support.
48 #include "arm_adi_v5.h"
49 #include <helper/time_support.h>
51 #include <transport/transport.h>
52 #include <jtag/interface.h>
56 /* for debug, set do_sync to true to force synchronous transfers */
59 static struct adiv5_dap *swd_multidrop_selected_dap;
62 static int swd_queue_dp_write_inner(struct adiv5_dap *dap, unsigned int reg,
66 static int swd_send_sequence(struct adiv5_dap *dap, enum swd_special_seq seq)
68 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
71 return swd->switch_seq(seq);
74 static void swd_finish_read(struct adiv5_dap *dap)
76 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
78 swd->read_reg(swd_cmd(true, false, DP_RDBUFF), dap->last_read, 0);
79 dap->last_read = NULL;
83 static void swd_clear_sticky_errors(struct adiv5_dap *dap)
85 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
88 swd->write_reg(swd_cmd(false, false, DP_ABORT),
89 STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
92 static int swd_run_inner(struct adiv5_dap *dap)
94 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
99 if (retval != ERROR_OK) {
101 dap->do_reconnect = true;
107 static inline int check_sync(struct adiv5_dap *dap)
109 return do_sync ? swd_run_inner(dap) : ERROR_OK;
112 /** Select the DP register bank matching bits 7:4 of reg. */
113 static int swd_queue_dp_bankselect(struct adiv5_dap *dap, unsigned int reg)
115 /* Only register address 4 is banked. */
116 if ((reg & 0xf) != 4)
119 uint32_t select_dp_bank = (reg & 0x000000F0) >> 4;
120 uint32_t sel = select_dp_bank
121 | (dap->select & (DP_SELECT_APSEL | DP_SELECT_APBANK));
123 if (sel == dap->select)
128 int retval = swd_queue_dp_write_inner(dap, DP_SELECT, sel);
129 if (retval != ERROR_OK)
130 dap->select = DP_SELECT_INVALID;
135 static int swd_queue_dp_read_inner(struct adiv5_dap *dap, unsigned int reg,
138 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
141 int retval = swd_queue_dp_bankselect(dap, reg);
142 if (retval != ERROR_OK)
145 swd->read_reg(swd_cmd(true, false, reg), data, 0);
147 return check_sync(dap);
150 static int swd_queue_dp_write_inner(struct adiv5_dap *dap, unsigned int reg,
154 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
157 swd_finish_read(dap);
159 if (reg == DP_SELECT) {
160 dap->select = data & (DP_SELECT_APSEL | DP_SELECT_APBANK | DP_SELECT_DPBANK);
162 swd->write_reg(swd_cmd(false, false, reg), data, 0);
164 retval = check_sync(dap);
165 if (retval != ERROR_OK)
166 dap->select = DP_SELECT_INVALID;
171 retval = swd_queue_dp_bankselect(dap, reg);
172 if (retval != ERROR_OK)
175 swd->write_reg(swd_cmd(false, false, reg), data, 0);
177 return check_sync(dap);
181 static int swd_multidrop_select_inner(struct adiv5_dap *dap, uint32_t *dpidr_ptr,
182 uint32_t *dlpidr_ptr, bool clear_sticky)
185 uint32_t dpidr, dlpidr;
187 assert(dap_is_multidrop(dap));
189 swd_send_sequence(dap, LINE_RESET);
191 retval = swd_queue_dp_write_inner(dap, DP_TARGETSEL, dap->multidrop_targetsel);
192 if (retval != ERROR_OK)
195 retval = swd_queue_dp_read_inner(dap, DP_DPIDR, &dpidr);
196 if (retval != ERROR_OK)
200 /* Clear all sticky errors (including ORUN) */
201 swd_clear_sticky_errors(dap);
203 /* Ideally just clear ORUN flag which is set by reset */
204 retval = swd_queue_dp_write_inner(dap, DP_ABORT, ORUNERRCLR);
205 if (retval != ERROR_OK)
209 retval = swd_queue_dp_read_inner(dap, DP_DLPIDR, &dlpidr);
210 if (retval != ERROR_OK)
213 retval = swd_run_inner(dap);
214 if (retval != ERROR_OK)
217 if ((dpidr & DP_DPIDR_VERSION_MASK) < (2UL << DP_DPIDR_VERSION_SHIFT)) {
218 LOG_INFO("Read DPIDR 0x%08" PRIx32
219 " has version < 2. A non multidrop capable device connected?",
224 /* TODO: check TARGETID if DLIPDR is same for more than one DP */
225 uint32_t expected_dlpidr = DP_DLPIDR_PROTVSN |
226 (dap->multidrop_targetsel & DP_TARGETSEL_INSTANCEID_MASK);
227 if (dlpidr != expected_dlpidr) {
228 LOG_INFO("Read incorrect DLPIDR 0x%08" PRIx32
229 " (possibly CTRL/STAT value)",
234 LOG_DEBUG_IO("Selected DP_TARGETSEL 0x%08" PRIx32, dap->multidrop_targetsel);
235 swd_multidrop_selected_dap = dap;
241 *dlpidr_ptr = dlpidr;
246 static int swd_multidrop_select(struct adiv5_dap *dap)
248 if (!dap_is_multidrop(dap))
251 if (swd_multidrop_selected_dap == dap)
254 int retval = ERROR_OK;
255 for (unsigned int retry = 0; ; retry++) {
256 bool clear_sticky = retry > 0;
258 retval = swd_multidrop_select_inner(dap, NULL, NULL, clear_sticky);
259 if (retval == ERROR_OK)
262 swd_multidrop_selected_dap = NULL;
264 LOG_ERROR("Failed to select multidrop %s", adiv5_dap_name(dap));
268 LOG_DEBUG("Failed to select multidrop %s, retrying...",
269 adiv5_dap_name(dap));
275 static int swd_connect_multidrop(struct adiv5_dap *dap)
278 uint32_t dpidr = 0xdeadbeef;
279 uint32_t dlpidr = 0xdeadbeef;
280 int64_t timeout = timeval_ms() + 500;
283 swd_send_sequence(dap, JTAG_TO_DORMANT);
284 swd_send_sequence(dap, DORMANT_TO_SWD);
286 /* Clear link state, including the SELECT cache. */
287 dap->do_reconnect = false;
288 dap_invalidate_cache(dap);
289 swd_multidrop_selected_dap = NULL;
291 retval = swd_multidrop_select_inner(dap, &dpidr, &dlpidr, true);
292 if (retval == ERROR_OK)
297 } while (timeval_ms() < timeout);
299 if (retval != ERROR_OK) {
300 swd_multidrop_selected_dap = NULL;
301 LOG_ERROR("Failed to connect multidrop %s", adiv5_dap_name(dap));
305 LOG_INFO("SWD DPIDR 0x%08" PRIx32 ", DLPIDR 0x%08" PRIx32,
311 static int swd_connect_single(struct adiv5_dap *dap)
314 uint32_t dpidr = 0xdeadbeef;
315 int64_t timeout = timeval_ms() + 500;
318 if (dap->switch_through_dormant) {
319 swd_send_sequence(dap, JTAG_TO_DORMANT);
320 swd_send_sequence(dap, DORMANT_TO_SWD);
322 swd_send_sequence(dap, JTAG_TO_SWD);
325 /* Clear link state, including the SELECT cache. */
326 dap->do_reconnect = false;
327 dap_invalidate_cache(dap);
329 retval = swd_queue_dp_read_inner(dap, DP_DPIDR, &dpidr);
330 if (retval == ERROR_OK) {
331 retval = swd_run_inner(dap);
332 if (retval == ERROR_OK)
338 dap->switch_through_dormant = !dap->switch_through_dormant;
339 } while (timeval_ms() < timeout);
341 if (retval != ERROR_OK) {
342 LOG_ERROR("Error connecting DP: cannot read IDR");
346 LOG_INFO("SWD DPIDR 0x%08" PRIx32, dpidr);
349 dap->do_reconnect = false;
351 /* force clear all sticky faults */
352 swd_clear_sticky_errors(dap);
354 retval = swd_run_inner(dap);
355 if (retval != ERROR_WAIT)
360 } while (timeval_ms() < timeout);
365 static int swd_connect(struct adiv5_dap *dap)
369 /* FIXME validate transport config ... is the
370 * configured DAP present (check IDCODE)?
373 /* Check if we should reset srst already when connecting, but not if reconnecting. */
374 if (!dap->do_reconnect) {
375 enum reset_types jtag_reset_config = jtag_get_reset_config();
377 if (jtag_reset_config & RESET_CNCT_UNDER_SRST) {
378 if (jtag_reset_config & RESET_SRST_NO_GATING)
379 adapter_assert_reset();
381 LOG_WARNING("\'srst_nogate\' reset_config option is required");
385 if (dap_is_multidrop(dap))
386 status = swd_connect_multidrop(dap);
388 status = swd_connect_single(dap);
391 * "A WAIT response must not be issued to the ...
392 * ... writes to the ABORT register"
393 * swd_clear_sticky_errors() writes to the ABORT register only.
395 * Unfortunately at least Microchip SAMD51/E53/E54 returns WAIT
396 * in a corner case. Just try if ABORT resolves the problem.
398 if (status == ERROR_WAIT) {
399 LOG_WARNING("Connecting DP: stalled AP operation, issuing ABORT");
401 dap->do_reconnect = false;
403 status = swd_queue_dp_write_inner(dap, DP_ABORT,
404 DAPABORT | STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR);
406 if (status == ERROR_OK)
407 status = swd_run_inner(dap);
410 if (status == ERROR_OK)
411 status = dap_dp_init(dap);
416 static int swd_check_reconnect(struct adiv5_dap *dap)
418 if (dap->do_reconnect)
419 return swd_connect(dap);
424 static int swd_queue_ap_abort(struct adiv5_dap *dap, uint8_t *ack)
426 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
429 /* TODO: Send DAPABORT in swd_multidrop_select_inner()
430 * in the case the multidrop dap is not selected?
431 * swd_queue_ap_abort() is not currently used anyway...
433 int retval = swd_multidrop_select(dap);
434 if (retval != ERROR_OK)
437 swd->write_reg(swd_cmd(false, false, DP_ABORT),
438 DAPABORT | STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
439 return check_sync(dap);
442 static int swd_queue_dp_read(struct adiv5_dap *dap, unsigned reg,
445 int retval = swd_check_reconnect(dap);
446 if (retval != ERROR_OK)
449 retval = swd_multidrop_select(dap);
450 if (retval != ERROR_OK)
453 return swd_queue_dp_read_inner(dap, reg, data);
456 static int swd_queue_dp_write(struct adiv5_dap *dap, unsigned reg,
459 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
462 int retval = swd_check_reconnect(dap);
463 if (retval != ERROR_OK)
466 retval = swd_multidrop_select(dap);
467 if (retval != ERROR_OK)
470 return swd_queue_dp_write_inner(dap, reg, data);
473 /** Select the AP register bank matching bits 7:4 of reg. */
474 static int swd_queue_ap_bankselect(struct adiv5_ap *ap, unsigned reg)
476 struct adiv5_dap *dap = ap->dap;
477 uint32_t sel = ((uint32_t)ap->ap_num << 24)
479 | (dap->select & DP_SELECT_DPBANK);
481 if (sel == dap->select)
486 int retval = swd_queue_dp_write_inner(dap, DP_SELECT, sel);
487 if (retval != ERROR_OK)
488 dap->select = DP_SELECT_INVALID;
493 static int swd_queue_ap_read(struct adiv5_ap *ap, unsigned reg,
496 struct adiv5_dap *dap = ap->dap;
497 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
500 int retval = swd_check_reconnect(dap);
501 if (retval != ERROR_OK)
504 retval = swd_multidrop_select(dap);
505 if (retval != ERROR_OK)
508 retval = swd_queue_ap_bankselect(ap, reg);
509 if (retval != ERROR_OK)
512 swd->read_reg(swd_cmd(true, true, reg), dap->last_read, ap->memaccess_tck);
513 dap->last_read = data;
515 return check_sync(dap);
518 static int swd_queue_ap_write(struct adiv5_ap *ap, unsigned reg,
521 struct adiv5_dap *dap = ap->dap;
522 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
525 int retval = swd_check_reconnect(dap);
526 if (retval != ERROR_OK)
529 retval = swd_multidrop_select(dap);
530 if (retval != ERROR_OK)
533 swd_finish_read(dap);
535 retval = swd_queue_ap_bankselect(ap, reg);
536 if (retval != ERROR_OK)
539 swd->write_reg(swd_cmd(false, true, reg), data, ap->memaccess_tck);
541 return check_sync(dap);
544 /** Executes all queued DAP operations. */
545 static int swd_run(struct adiv5_dap *dap)
547 int retval = swd_multidrop_select(dap);
548 if (retval != ERROR_OK)
551 swd_finish_read(dap);
553 return swd_run_inner(dap);
556 /** Put the SWJ-DP back to JTAG mode */
557 static void swd_quit(struct adiv5_dap *dap)
559 const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
562 /* There is no difference if the sequence is sent at the last
563 * or the first swd_quit() call, send it just once */
568 if (dap_is_multidrop(dap)) {
569 swd->switch_seq(SWD_TO_DORMANT);
571 * Leaving DPs in dormant state was tested and offers some safety
572 * against DPs mismatch in case of unintentional use of non-multidrop SWD.
573 * To put SWJ-DPs to power-on state issue
574 * swd->switch_seq(DORMANT_TO_JTAG);
577 if (dap->switch_through_dormant) {
578 swd->switch_seq(SWD_TO_DORMANT);
579 swd->switch_seq(DORMANT_TO_JTAG);
581 swd->switch_seq(SWD_TO_JTAG);
585 /* flush the queue to shift out the sequence before exit */
589 const struct dap_ops swd_dap_ops = {
590 .connect = swd_connect,
591 .send_sequence = swd_send_sequence,
592 .queue_dp_read = swd_queue_dp_read,
593 .queue_dp_write = swd_queue_dp_write,
594 .queue_ap_read = swd_queue_ap_read,
595 .queue_ap_write = swd_queue_ap_write,
596 .queue_ap_abort = swd_queue_ap_abort,
601 static const struct command_registration swd_commands[] = {
604 * Set up SWD and JTAG targets identically, unless/until
605 * infrastructure improves ... meanwhile, ignore all
606 * JTAG-specific stuff like IR length for SWD.
608 * REVISIT can we verify "just one SWD DAP" here/early?
611 .jim_handler = jim_jtag_newtap,
612 .mode = COMMAND_CONFIG,
613 .help = "declare a new SWD DAP"
615 COMMAND_REGISTRATION_DONE
618 static const struct command_registration swd_handlers[] = {
622 .help = "SWD command group",
623 .chain = swd_commands,
626 COMMAND_REGISTRATION_DONE
629 static int swd_select(struct command_context *ctx)
631 /* FIXME: only place where global 'adapter_driver' is still needed */
632 extern struct adapter_driver *adapter_driver;
633 const struct swd_driver *swd = adapter_driver->swd_ops;
636 retval = register_commands(ctx, NULL, swd_handlers);
637 if (retval != ERROR_OK)
640 /* be sure driver is in SWD mode; start
641 * with hardware default TRN (1), it can be changed later
643 if (!swd || !swd->read_reg || !swd->write_reg || !swd->init) {
644 LOG_DEBUG("no SWD driver?");
648 retval = swd->init();
649 if (retval != ERROR_OK) {
650 LOG_DEBUG("can't init SWD driver");
657 static int swd_init(struct command_context *ctx)
659 /* nothing done here, SWD is initialized
660 * together with the DAP */
664 static struct transport swd_transport = {
666 .select = swd_select,
670 static void swd_constructor(void) __attribute__((constructor));
671 static void swd_constructor(void)
673 transport_register(&swd_transport);
676 /** Returns true if the current debug session
677 * is using SWD as its transport.
679 bool transport_is_swd(void)
681 return get_current_transport() == &swd_transport;