openocd doc: update the comments about Jim Tcl a bit
[openocd/ellerodev.git] / src / jtag / transport.c
blob503b57b6b19771029e7a117396059ad02e481640
1 /*
2 * Copyright (c) 2010 by David Brownell
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.
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.
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
19 #ifdef HAVE_CONFIG_H
20 #include "config.h"
21 #endif
23 /** @file
24 * Infrastructure for specifying and managing the transport protocol
25 * used in a given debug or programming session.
27 * Examples of "debug-capable" transports are JTAG or SWD.
28 * Additionally, JTAG supports boundary scan testing.
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.
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.
45 #include <helper/log.h>
47 #include "transport.h"
49 extern struct command_context *global_cmd_ctx;
52 /*-----------------------------------------------------------------------*/
55 * Infrastructure internals
58 /** List of transports known to OpenOCD. */
59 static struct transport *transport_list;
61 /**
62 * NULL-terminated Vector of names of transports which the
63 * currently selected debug adapter supports. This is declared
64 * by the time that adapter is fully set up.
66 static const char **allowed_transports;
68 /** * The transport being used for the current OpenOCD session. */
69 static struct transport *session;
71 static int transport_select(struct command_context *ctx, const char *name)
73 /* name may only identify a known transport;
74 * caller guarantees session's transport isn't yet set.*/
75 for (struct transport *t = transport_list; t; t = t->next) {
76 if (strcmp(t->name, name) == 0) {
77 int retval = t->select(ctx);
78 /* select() registers commands specific to this
79 * transport, and may also reset the link, e.g.
80 * forcing it to JTAG or SWD mode.
82 if (retval == ERROR_OK)
83 session = t;
84 else
85 LOG_ERROR("Error %d selecting '%s' as "
86 "transport", retval, t->name);
87 return retval;
91 LOG_ERROR("No transport named '%s' is available.", name);
92 return ERROR_FAIL;
95 /**
96 * Called by debug adapter drivers, or affiliated Tcl config scripts,
97 * to declare the set of transports supported by an adapter. When
98 * there is only one member of that set, it is automatically selected.
100 int allow_transports(struct command_context *ctx, const char **vector)
102 /* NOTE: caller is required to provide only a list
103 * of *valid* transport names
105 * REVISIT should we validate that? and insist there's
106 * at least one non-NULL element in that list?
108 * ... allow removals, e.g. external strapping prevents use
109 * of one transport; C code should be definitive about what
110 * can be used when all goes well.
112 if (allowed_transports != NULL || session) {
113 LOG_ERROR("Can't modify the set of allowed transports.");
114 return ERROR_FAIL;
118 allowed_transports = vector;
120 /* autoselect if there's no choice ... */
121 if (!vector[1]) {
122 LOG_INFO("only one transport option; autoselect '%s'",
123 vector[0]);
124 return transport_select(ctx, vector [0]);
125 } else {
126 /* guard against user config errors */
127 LOG_WARNING("must select a transport.");
128 while (*vector)
129 LOG_DEBUG("allow transport '%s'", *vector++);
130 return ERROR_OK;
136 * Used to verify corrrect adapter driver initialization.
138 * @returns true iff the adapter declared one or more transports.
140 bool transports_are_declared(void)
142 return allowed_transports != NULL;
146 * Registers a transport. There are general purpose transports
147 * (such as JTAG), as well as relatively proprietary ones which are
148 * specific to a given chip (or chip family).
150 * Code implementing a transport needs to register it before it can
151 * be selected and then activated. This is a dynamic process, so
152 * that chips (and families) can define transports as needed (without
153 * nneeding error-prone static tables).
155 * @param new_transport the transport being registered. On a
156 * successful return, this memory is owned by the transport framework.
158 * @returns ERROR_OK on success, else a fault code.
160 int transport_register(struct transport *new_transport)
162 struct transport *t;
164 for (t = transport_list; t; t = t->next) {
165 if (strcmp(t->name, new_transport->name) == 0) {
166 LOG_ERROR("transport name already used");
167 return ERROR_FAIL;
171 if (!new_transport->select || !new_transport->init) {
172 LOG_ERROR("invalid transport %s", new_transport->name);
175 /* splice this into the list */
176 new_transport->next = transport_list;
177 transport_list = new_transport;
178 LOG_DEBUG("register '%s'", new_transport->name);
180 return ERROR_OK;
184 * Returns the transport currently being used by this debug or
185 * programming session.
187 * @returns handle to the read-only transport entity.
189 struct transport *get_current_transport(void)
192 /* REVISIT -- constify */
193 return session;
197 /*-----------------------------------------------------------------------*/
200 * Infrastructure for Tcl interface to transports.
204 * Makes and stores a copy of a set of transports passed as
205 * parameters to a command.
207 * @param vector where the resulting copy is stored, as an argv-style
208 * NULL-terminated vector.
210 COMMAND_HELPER(transport_list_parse, char ***vector)
212 char **argv;
213 unsigned n = CMD_ARGC;
214 unsigned j = 0;
216 *vector = NULL;
218 if (n < 1)
219 return ERROR_COMMAND_SYNTAX_ERROR;
221 /* our return vector must be NULL terminated */
222 argv = (char **) calloc(n + 1, sizeof(char *));
223 if (argv == NULL)
224 return ERROR_FAIL;
226 for (unsigned i = 0; i < n; i++) {
227 struct transport *t;
229 for (t = transport_list; t; t = t->next) {
230 if (strcmp(t->name, CMD_ARGV[i]) != 0)
231 continue;
232 argv[j++] = strdup(CMD_ARGV[i]);
233 break;
235 if (!t) {
236 LOG_ERROR("no such transport '%s'", CMD_ARGV[i]);
237 goto fail;
241 *vector = argv;
242 return ERROR_OK;
244 fail:
245 for (unsigned i = 0; i < n; i++)
246 free(argv[i]);
247 free(argv);
248 return ERROR_FAIL;
251 COMMAND_HANDLER(handle_transport_init)
253 LOG_DEBUG("%s", __func__);
254 if (!session) {
255 LOG_ERROR("session's transport is not selected.");
256 return ERROR_FAIL;
259 return session->init(CMD_CTX);
262 COMMAND_HANDLER(handle_transport_list)
264 if (CMD_ARGC != 0)
265 return ERROR_COMMAND_SYNTAX_ERROR;
267 command_print(CMD_CTX, "The following transports are available:");
269 for (struct transport *t = transport_list; t; t = t->next)
270 command_print(CMD_CTX, "\t%s", t->name);
272 return ERROR_OK;
276 * Implements the Tcl "transport select" command, choosing the
277 * transport to be used in this debug session from among the
278 * set supported by the debug adapter being used. Return value
279 * is scriptable (allowing "if swd then..." etc).
281 static int jim_transport_select(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
283 switch (argc) {
284 case 1: /* return/display */
285 if (!session) {
286 LOG_ERROR("session's transport is not selected.");
287 return JIM_ERR;
288 } else {
289 Jim_SetResultString(interp, session->name, -1);
290 return JIM_OK;
292 break;
293 case 2: /* assign */
294 if (session) {
295 /* can't change session's transport after-the-fact */
296 LOG_ERROR("session's transport is already selected.");
297 return JIM_ERR;
300 /* Is this transport supported by our debug adapter?
301 * Example, "JTAG-only" means SWD is not supported.
303 * NOTE: requires adapter to have been set up, with
304 * transports declared via C.
306 if (!allowed_transports) {
307 LOG_ERROR("Debug adapter doesn't support any transports?");
308 return JIM_ERR;
311 for (unsigned i = 0; allowed_transports[i]; i++) {
313 if (strcmp(allowed_transports[i], argv[0]->bytes) == 0)
314 return transport_select(global_cmd_ctx, argv[0]->bytes);
317 LOG_ERROR("Debug adapter doesn't support '%s' "
318 "transport", argv[0]->bytes);
319 return JIM_ERR;
320 break;
321 default:
322 Jim_WrongNumArgs(interp, 1, argv, "[too many parameters]");
323 return JIM_ERR;
327 static const struct command_registration transport_commands[] = {
329 .name = "init",
330 .handler = handle_transport_init,
331 /* this would be COMMAND_CONFIG ... except that
332 * it needs to trigger event handlers that may
333 * require COMMAND_EXEC ...
335 .mode = COMMAND_ANY,
336 .help = "Initialize this session's transport",
339 .name = "list",
340 .handler = handle_transport_list,
341 .mode = COMMAND_ANY,
342 .help = "list all built-in transports",
345 .name = "select",
346 .jim_handler = jim_transport_select,
347 .mode = COMMAND_ANY,
348 .help = "Select this session's transport",
349 .usage = "[transport_name]",
351 COMMAND_REGISTRATION_DONE
354 static const struct command_registration transport_group[] = {
356 .name = "transport",
357 .mode = COMMAND_ANY,
358 .help = "Transport command group",
359 .chain = transport_commands,
361 COMMAND_REGISTRATION_DONE
365 int transport_register_commands(struct command_context *ctx)
367 return register_commands(ctx, NULL, transport_group);