build: cleanup src/transport directory
[openocd.git] / src / transport / transport.c
1 /*
2 * Copyright (c) 2010 by David Brownell
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software Foundation,
16 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
19 #ifdef HAVE_CONFIG_H
20 #include "config.h"
21 #endif
22
23 /** @file
24 * Infrastructure for specifying and managing the transport protocol
25 * used in a given debug or programming session.
26 *
27 * Examples of "debug-capable" transports are JTAG or SWD.
28 * Additionally, JTAG supports boundary scan testing.
29 *
30 * Examples of "programming-capable" transports include SPI or UART;
31 * those are used (often mediated by a ROM bootloader) for ISP style
32 * programming, to perform an initial load of code into flash, or
33 * sometimes into SRAM. Target code could use "variant" options to
34 * decide how to use such protocols. For example, Cortex-M3 cores
35 * from TI/Luminary and from NXP use different protocols for for
36 * UART or SPI based firmware loading.
37 *
38 * As a rule, there are protocols layered on top of the transport.
39 * For example, different chip families use JTAG in different ways
40 * for debugging. Also, each family that supports programming over
41 * a UART link for initial firmware loading tends to define its own
42 * messaging and error handling.
43 */
44
45 #include <helper/log.h>
46 #include <transport/transport.h>
47
48 extern struct command_context *global_cmd_ctx;
49
50 /*-----------------------------------------------------------------------*/
51
52 /*
53 * Infrastructure internals
54 */
55
56 /** List of transports known to OpenOCD. */
57 static struct transport *transport_list;
58
59 /**
60 * NULL-terminated Vector of names of transports which the
61 * currently selected debug adapter supports. This is declared
62 * by the time that adapter is fully set up.
63 */
64 static const char **allowed_transports;
65
66 /** * The transport being used for the current OpenOCD session. */
67 static struct transport *session;
68
69 static int transport_select(struct command_context *ctx, const char *name)
70 {
71 /* name may only identify a known transport;
72 * caller guarantees session's transport isn't yet set.*/
73 for (struct transport *t = transport_list; t; t = t->next) {
74 if (strcmp(t->name, name) == 0) {
75 int retval = t->select(ctx);
76 /* select() registers commands specific to this
77 * transport, and may also reset the link, e.g.
78 * forcing it to JTAG or SWD mode.
79 */
80 if (retval == ERROR_OK)
81 session = t;
82 else
83 LOG_ERROR("Error selecting '%s' as transport", t->name);
84 return retval;
85 }
86 }
87
88 LOG_ERROR("No transport named '%s' is available.", name);
89 return ERROR_FAIL;
90 }
91
92 /**
93 * Called by debug adapter drivers, or affiliated Tcl config scripts,
94 * to declare the set of transports supported by an adapter. When
95 * there is only one member of that set, it is automatically selected.
96 */
97 int allow_transports(struct command_context *ctx, const char **vector)
98 {
99 /* NOTE: caller is required to provide only a list
100 * of *valid* transport names
101 *
102 * REVISIT should we validate that? and insist there's
103 * at least one non-NULL element in that list?
104 *
105 * ... allow removals, e.g. external strapping prevents use
106 * of one transport; C code should be definitive about what
107 * can be used when all goes well.
108 */
109 if (allowed_transports != NULL || session) {
110 LOG_ERROR("Can't modify the set of allowed transports.");
111 return ERROR_FAIL;
112 }
113
114 allowed_transports = vector;
115
116 /* autoselect if there's no choice ... */
117 if (!vector[1]) {
118 LOG_INFO("only one transport option; autoselect '%s'", vector[0]);
119 return transport_select(ctx, vector[0]);
120 } else {
121 /* guard against user config errors */
122 LOG_WARNING("must select a transport.");
123 while (*vector) {
124 LOG_DEBUG("allow transport '%s'", *vector);
125 vector++;
126 }
127 return ERROR_OK;
128 }
129 }
130
131 /**
132 * Used to verify corrrect adapter driver initialization.
133 *
134 * @returns true iff the adapter declared one or more transports.
135 */
136 bool transports_are_declared(void)
137 {
138 return allowed_transports != NULL;
139 }
140
141 /**
142 * Registers a transport. There are general purpose transports
143 * (such as JTAG), as well as relatively proprietary ones which are
144 * specific to a given chip (or chip family).
145 *
146 * Code implementing a transport needs to register it before it can
147 * be selected and then activated. This is a dynamic process, so
148 * that chips (and families) can define transports as needed (without
149 * nneeding error-prone static tables).
150 *
151 * @param new_transport the transport being registered. On a
152 * successful return, this memory is owned by the transport framework.
153 *
154 * @returns ERROR_OK on success, else a fault code.
155 */
156 int transport_register(struct transport *new_transport)
157 {
158 struct transport *t;
159
160 for (t = transport_list; t; t = t->next) {
161 if (strcmp(t->name, new_transport->name) == 0) {
162 LOG_ERROR("transport name already used");
163 return ERROR_FAIL;
164 }
165 }
166
167 if (!new_transport->select || !new_transport->init)
168 LOG_ERROR("invalid transport %s", new_transport->name);
169
170 /* splice this into the list */
171 new_transport->next = transport_list;
172 transport_list = new_transport;
173 LOG_DEBUG("register '%s'", new_transport->name);
174
175 return ERROR_OK;
176 }
177
178 /**
179 * Returns the transport currently being used by this debug or
180 * programming session.
181 *
182 * @returns handle to the read-only transport entity.
183 */
184 struct transport *get_current_transport(void)
185 {
186 /* REVISIT -- constify */
187 return session;
188 }
189
190 /*-----------------------------------------------------------------------*/
191
192 /*
193 * Infrastructure for Tcl interface to transports.
194 */
195
196 /**
197 * Makes and stores a copy of a set of transports passed as
198 * parameters to a command.
199 *
200 * @param vector where the resulting copy is stored, as an argv-style
201 * NULL-terminated vector.
202 */
203 COMMAND_HELPER(transport_list_parse, char ***vector)
204 {
205 char **argv;
206 unsigned n = CMD_ARGC;
207 unsigned j = 0;
208
209 *vector = NULL;
210
211 if (n < 1)
212 return ERROR_COMMAND_SYNTAX_ERROR;
213
214 /* our return vector must be NULL terminated */
215 argv = (char **) calloc(n + 1, sizeof(char *));
216 if (argv == NULL)
217 return ERROR_FAIL;
218
219 for (unsigned i = 0; i < n; i++) {
220 struct transport *t;
221
222 for (t = transport_list; t; t = t->next) {
223 if (strcmp(t->name, CMD_ARGV[i]) != 0)
224 continue;
225 argv[j++] = strdup(CMD_ARGV[i]);
226 break;
227 }
228 if (!t) {
229 LOG_ERROR("no such transport '%s'", CMD_ARGV[i]);
230 goto fail;
231 }
232 }
233
234 *vector = argv;
235 return ERROR_OK;
236
237 fail:
238 for (unsigned i = 0; i < n; i++)
239 free(argv[i]);
240 free(argv);
241 return ERROR_FAIL;
242 }
243
244 COMMAND_HANDLER(handle_transport_init)
245 {
246 LOG_DEBUG("%s", __func__);
247 if (!session) {
248 LOG_ERROR("session's transport is not selected.");
249 return ERROR_FAIL;
250 }
251
252 return session->init(CMD_CTX);
253 }
254
255 COMMAND_HANDLER(handle_transport_list)
256 {
257 if (CMD_ARGC != 0)
258 return ERROR_COMMAND_SYNTAX_ERROR;
259
260 command_print(CMD_CTX, "The following transports are available:");
261
262 for (struct transport *t = transport_list; t; t = t->next)
263 command_print(CMD_CTX, "\t%s", t->name);
264
265 return ERROR_OK;
266 }
267
268 /**
269 * Implements the Tcl "transport select" command, choosing the
270 * transport to be used in this debug session from among the
271 * set supported by the debug adapter being used. Return value
272 * is scriptable (allowing "if swd then..." etc).
273 */
274 static int jim_transport_select(Jim_Interp *interp, int argc, Jim_Obj * const *argv)
275 {
276 switch (argc) {
277 case 1: /* return/display */
278 if (!session) {
279 LOG_ERROR("session's transport is not selected.");
280 return JIM_ERR;
281 } else {
282 Jim_SetResultString(interp, session->name, -1);
283 return JIM_OK;
284 }
285 break;
286 case 2: /* assign */
287 if (session) {
288 /* can't change session's transport after-the-fact */
289 LOG_ERROR("session's transport is already selected.");
290 return JIM_ERR;
291 }
292
293 /* Is this transport supported by our debug adapter?
294 * Example, "JTAG-only" means SWD is not supported.
295 *
296 * NOTE: requires adapter to have been set up, with
297 * transports declared via C.
298 */
299 if (!allowed_transports) {
300 LOG_ERROR("Debug adapter doesn't support any transports?");
301 return JIM_ERR;
302 }
303
304 for (unsigned i = 0; allowed_transports[i]; i++) {
305
306 if (strcmp(allowed_transports[i], argv[1]->bytes) == 0)
307 return transport_select(global_cmd_ctx, argv[1]->bytes);
308 }
309
310 LOG_ERROR("Debug adapter doesn't support '%s' transport", argv[1]->bytes);
311 return JIM_ERR;
312 break;
313 default:
314 Jim_WrongNumArgs(interp, 1, argv, "[too many parameters]");
315 return JIM_ERR;
316 }
317 }
318
319 static const struct command_registration transport_commands[] = {
320 {
321 .name = "init",
322 .handler = handle_transport_init,
323 /* this would be COMMAND_CONFIG ... except that
324 * it needs to trigger event handlers that may
325 * require COMMAND_EXEC ...
326 */
327 .mode = COMMAND_ANY,
328 .help = "Initialize this session's transport",
329 .usage = ""
330 },
331 {
332 .name = "list",
333 .handler = handle_transport_list,
334 .mode = COMMAND_ANY,
335 .help = "list all built-in transports",
336 .usage = ""
337 },
338 {
339 .name = "select",
340 .jim_handler = jim_transport_select,
341 .mode = COMMAND_ANY,
342 .help = "Select this session's transport",
343 .usage = "[transport_name]",
344 },
345 COMMAND_REGISTRATION_DONE
346 };
347
348 static const struct command_registration transport_group[] = {
349 {
350 .name = "transport",
351 .mode = COMMAND_ANY,
352 .help = "Transport command group",
353 .chain = transport_commands,
354 .usage = ""
355 },
356 COMMAND_REGISTRATION_DONE
357 };
358
359 int transport_register_commands(struct command_context *ctx)
360 {
361 return register_commands(ctx, NULL, transport_group);
362 }