build: cleanup src/target directory
[openocd.git] / src / target / adi_v5_swd.c
1 /***************************************************************************
2 *
3 * Copyright (C) 2010 by David Brownell
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 ***************************************************************************/
20
21 /**
22 * @file
23 * Utilities to support ARM "Serial Wire Debug" (SWD), a low pin-count debug
24 * link protocol used in cases where JTAG is not wanted. This is coupled to
25 * recent versions of ARM's "CoreSight" debug framework. This specific code
26 * is a transport level interface, with "target/arm_adi_v5.[hc]" code
27 * understanding operation semantics, shared with the JTAG transport.
28 *
29 * Single-DAP support only.
30 *
31 * for details, see "ARM IHI 0031A"
32 * ARM Debug Interface v5 Architecture Specification
33 * especially section 5.3 for SWD protocol
34 *
35 * On many chips (most current Cortex-M3 parts) SWD is a run-time alternative
36 * to JTAG. Boards may support one or both. There are also SWD-only chips,
37 * (using SW-DP not SWJ-DP).
38 *
39 * Even boards that also support JTAG can benefit from SWD support, because
40 * usually there's no way to access the SWO trace view mechanism in JTAG mode.
41 * That is, trace access may require SWD support.
42 *
43 */
44
45 #ifdef HAVE_CONFIG_H
46 #include "config.h"
47 #endif
48
49 #include "arm.h"
50 #include "arm_adi_v5.h"
51 #include <helper/time_support.h>
52
53 #include <transport/transport.h>
54 #include <jtag/interface.h>
55
56 #include <jtag/swd.h>
57
58 static int swd_queue_dp_read(struct adiv5_dap *dap, unsigned reg,
59 uint32_t *data)
60 {
61 /* REVISIT status return vs ack ... */
62 return swd->read_reg(swd_cmd(true, false, reg), data);
63 }
64
65 static int swd_queue_idcode_read(struct adiv5_dap *dap,
66 uint8_t *ack, uint32_t *data)
67 {
68 int status = swd_queue_dp_read(dap, DP_IDCODE, data);
69 if (status < 0)
70 return status;
71 *ack = status;
72 /* ?? */
73 return ERROR_OK;
74 }
75
76 static int (swd_queue_dp_write)(struct adiv5_dap *dap, unsigned reg,
77 uint32_t data)
78 {
79 /* REVISIT status return vs ack ... */
80 return swd->write_reg(swd_cmd(false, false, reg), data);
81 }
82
83
84 static int (swd_queue_ap_read)(struct adiv5_dap *dap, unsigned reg,
85 uint32_t *data)
86 {
87 /* REVISIT APSEL ... */
88 /* REVISIT status return ... */
89 return swd->read_reg(swd_cmd(true, true, reg), data);
90 }
91
92 static int (swd_queue_ap_write)(struct adiv5_dap *dap, unsigned reg,
93 uint32_t data)
94 {
95 /* REVISIT APSEL ... */
96 /* REVISIT status return ... */
97 return swd->write_reg(swd_cmd(false, true, reg), data);
98 }
99
100 static int (swd_queue_ap_abort)(struct adiv5_dap *dap, uint8_t *ack)
101 {
102 return ERROR_FAIL;
103 }
104
105 /** Executes all queued DAP operations. */
106 static int swd_run(struct adiv5_dap *dap)
107 {
108 /* for now the SWD interface hard-wires a zero-size queue. */
109
110 /* FIXME but we still need to check and scrub
111 * any hardware errors ...
112 */
113 return ERROR_OK;
114 }
115
116 const struct dap_ops swd_dap_ops = {
117 .is_swd = true,
118
119 .queue_idcode_read = swd_queue_idcode_read,
120 .queue_dp_read = swd_queue_dp_read,
121 .queue_dp_write = swd_queue_dp_write,
122 .queue_ap_read = swd_queue_ap_read,
123 .queue_ap_write = swd_queue_ap_write,
124 .queue_ap_abort = swd_queue_ap_abort,
125 .run = swd_run,
126 };
127
128 /*
129 * This represents the bits which must be sent out on TMS/SWDIO to
130 * switch a DAP implemented using an SWJ-DP module into SWD mode.
131 * These bits are stored (and transmitted) LSB-first.
132 *
133 * See the DAP-Lite specification, section 2.2.5 for information
134 * about making the debug link select SWD or JTAG. (Similar info
135 * is in a few other ARM documents.)
136 */
137 static const uint8_t jtag2swd_bitseq[] = {
138 /* More than 50 TCK/SWCLK cycles with TMS/SWDIO high,
139 * putting both JTAG and SWD logic into reset state.
140 */
141 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
142 /* Switching sequence enables SWD and disables JTAG
143 * NOTE: bits in the DP's IDCODE may expose the need for
144 * an old/obsolete/deprecated sequence (0xb6 0xed).
145 */
146 0x9e, 0xe7,
147 /* More than 50 TCK/SWCLK cycles with TMS/SWDIO high,
148 * putting both JTAG and SWD logic into reset state.
149 */
150 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
151 };
152
153 /**
154 * Put the debug link into SWD mode, if the target supports it.
155 * The link's initial mode may be either JTAG (for example,
156 * with SWJ-DP after reset) or SWD.
157 *
158 * @param target Enters SWD mode (if possible).
159 *
160 * Note that targets using the JTAG-DP do not support SWD, and that
161 * some targets which could otherwise support it may have have been
162 * configured to disable SWD signaling
163 *
164 * @return ERROR_OK or else a fault code.
165 */
166 int dap_to_swd(struct target *target)
167 {
168 struct arm *arm = target_to_arm(target);
169 int retval;
170
171 LOG_DEBUG("Enter SWD mode");
172
173 /* REVISIT it's ugly to need to make calls to a "jtag"
174 * subsystem if the link may not be in JTAG mode...
175 */
176
177 retval = jtag_add_tms_seq(8 * sizeof(jtag2swd_bitseq),
178 jtag2swd_bitseq, TAP_INVALID);
179 if (retval == ERROR_OK)
180 retval = jtag_execute_queue();
181
182 /* set up the DAP's ops vector for SWD mode. */
183 arm->dap->ops = &swd_dap_ops;
184
185 return retval;
186 }
187
188
189
190 COMMAND_HANDLER(handle_swd_wcr)
191 {
192 int retval;
193 struct target *target = get_current_target(CMD_CTX);
194 struct arm *arm = target_to_arm(target);
195 struct adiv5_dap *dap = arm->dap;
196 uint32_t wcr;
197 unsigned trn, scale = 0;
198
199 switch (CMD_ARGC) {
200 /* no-args: just dump state */
201 case 0:
202 /*retval = swd_queue_dp_read(dap, DP_WCR, &wcr); */
203 retval = dap_queue_dp_read(dap, DP_WCR, &wcr);
204 if (retval == ERROR_OK)
205 dap->ops->run(dap);
206 if (retval != ERROR_OK) {
207 LOG_ERROR("can't read WCR?");
208 return retval;
209 }
210
211 command_print(CMD_CTX,
212 "turnaround=%d, prescale=%d",
213 WCR_TO_TRN(wcr),
214 WCR_TO_PRESCALE(wcr));
215 return ERROR_OK;
216
217 case 2: /* TRN and prescale */
218 COMMAND_PARSE_NUMBER(uint, CMD_ARGV[1], scale);
219 if (scale > 7) {
220 LOG_ERROR("prescale %d is too big", scale);
221 return ERROR_FAIL;
222 }
223 /* FALL THROUGH */
224
225 case 1: /* TRN only */
226 COMMAND_PARSE_NUMBER(uint, CMD_ARGV[0], trn);
227 if (trn < 1 || trn > 4) {
228 LOG_ERROR("turnaround %d is invalid", trn);
229 return ERROR_FAIL;
230 }
231
232 wcr = ((trn - 1) << 8) | scale;
233 /* FIXME
234 * write WCR ...
235 * then, re-init adapter with new TRN
236 */
237 LOG_ERROR("can't yet modify WCR");
238 return ERROR_FAIL;
239
240 default: /* too many arguments */
241 return ERROR_COMMAND_SYNTAX_ERROR;
242 }
243 }
244
245 static const struct command_registration swd_commands[] = {
246 {
247 /*
248 * Set up SWD and JTAG targets identically, unless/until
249 * infrastructure improves ... meanwhile, ignore all
250 * JTAG-specific stuff like IR length for SWD.
251 *
252 * REVISIT can we verify "just one SWD DAP" here/early?
253 */
254 .name = "newdap",
255 .jim_handler = jim_jtag_newtap,
256 .mode = COMMAND_CONFIG,
257 .help = "declare a new SWD DAP"
258 },
259 {
260 .name = "wcr",
261 .handler = handle_swd_wcr,
262 .mode = COMMAND_ANY,
263 .help = "display or update DAP's WCR register",
264 .usage = "turnaround (1..4), prescale (0..7)",
265 },
266
267 /* REVISIT -- add a command for SWV trace on/off */
268 COMMAND_REGISTRATION_DONE
269 };
270
271 static const struct command_registration swd_handlers[] = {
272 {
273 .name = "swd",
274 .mode = COMMAND_ANY,
275 .help = "SWD command group",
276 .chain = swd_commands,
277 },
278 COMMAND_REGISTRATION_DONE
279 };
280
281 static int swd_select(struct command_context *ctx)
282 {
283 struct target *target = get_current_target(ctx);
284 int retval;
285
286 retval = register_commands(ctx, NULL, swd_handlers);
287
288 if (retval != ERROR_OK)
289 return retval;
290
291 /* be sure driver is in SWD mode; start
292 * with hardware default TRN (1), it can be changed later
293 */
294 if (!swd || !swd->read_reg || !swd->write_reg || !swd->init) {
295 LOG_DEBUG("no SWD driver?");
296 return ERROR_FAIL;
297 }
298
299 retval = swd->init(1);
300 if (retval != ERROR_OK) {
301 LOG_DEBUG("can't init SWD driver");
302 return retval;
303 }
304
305 /* force DAP into SWD mode (not JTAG) */
306 retval = dap_to_swd(target);
307
308 return retval;
309 }
310
311 static int swd_init(struct command_context *ctx)
312 {
313 struct target *target = get_current_target(ctx);
314 struct arm *arm = target_to_arm(target);
315 struct adiv5_dap *dap = arm->dap;
316 uint32_t idcode;
317 int status;
318
319 /* FIXME validate transport config ... is the
320 * configured DAP present (check IDCODE)?
321 * Is *only* one DAP configured?
322 *
323 * MUST READ IDCODE
324 */
325
326 /* Note, debugport_init() does setup too */
327
328 uint8_t ack;
329
330 status = swd_queue_idcode_read(dap, &ack, &idcode);
331
332 if (status == ERROR_OK)
333 LOG_INFO("SWD IDCODE %#8.8x", idcode);
334
335 return status;
336
337 }
338
339 static struct transport swd_transport = {
340 .name = "swd",
341 .select = swd_select,
342 .init = swd_init,
343 };
344
345 static void swd_constructor(void) __attribute__((constructor));
346 static void swd_constructor(void)
347 {
348 transport_register(&swd_transport);
349 }
350
351 /** Returns true if the current debug session
352 * is using SWD as its transport.
353 */
354 bool transport_is_swd(void)
355 {
356 return get_current_transport() == &swd_transport;
357 }