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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #ifdef HAVE_CONFIG_H
  19 #include "config.h"
  20 #endif
  21
  22 /** @file
  23  * Infrastructure for specifying and managing the transport protocol
  24  * used in a given debug or programming session.
  25  *
  26  * Examples of "debug-capable" transports are JTAG or SWD.
  27  * Additionally, JTAG supports boundary scan testing.
  28  *
  29  * Examples of "programming-capable" transports include SPI or UART;
  30  * those are used (often mediated by a ROM bootloader) for ISP style
  31  * programming, to perform an initial load of code into flash, or
  32  * sometimes into SRAM.  Target code could use "variant" options to
  33  * decide how to use such protocols.  For example, Cortex-M3 cores
  34  * from TI/Luminary and from NXP use different protocols for for
  35  * UART or SPI based firmware loading.
  36  *
  37  * As a rule, there are protocols layered on top of the transport.
  38  * For example, different chip families use JTAG in different ways
  39  * for debugging.  Also, each family that supports programming over
  40  * a UART link for initial firmware loading tends to define its own
  41  * messaging and error handling.
  42  */
  43
  44 #include <helper/log.h>
  45 #include <helper/replacements.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 * const *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 * const *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         }
 121
 122         return ERROR_OK;
 123 }
 124
 125 /**
 126  * Registers a transport.  There are general purpose transports
 127  * (such as JTAG), as well as relatively proprietary ones which are
 128  * specific to a given chip (or chip family).
 129  *
 130  * Code implementing a transport needs to register it before it can
 131  * be selected and then activated.  This is a dynamic process, so
 132  * that chips (and families) can define transports as needed (without
 133  * needing error-prone static tables).
 134  *
 135  * @param new_transport the transport being registered.  On a
 136  * successful return, this memory is owned by the transport framework.
 137  *
 138  * @returns ERROR_OK on success, else a fault code.
 139  */
 140 int transport_register(struct transport *new_transport)
 141 {
 142         struct transport *t;
 143
 144         for (t = transport_list; t; t = t->next) {
 145                 if (strcmp(t->name, new_transport->name) == 0) {
 146                         LOG_ERROR("transport name already used");
 147                         return ERROR_FAIL;
 148                 }
 149         }
 150
 151         if (!new_transport->select || !new_transport->init)
 152                 LOG_ERROR("invalid transport %s", new_transport->name);
 153
 154         /* splice this into the list */
 155         new_transport->next = transport_list;
 156         transport_list = new_transport;
 157         LOG_DEBUG("register '%s'", new_transport->name);
 158
 159         return ERROR_OK;
 160 }
 161
 162 /**
 163  * Returns the transport currently being used by this debug or
 164  * programming session.
 165  *
 166  * @returns handle to the read-only transport entity.
 167  */
 168 struct transport *get_current_transport(void)
 169 {
 170         /* REVISIT -- constify */
 171         return session;
 172 }
 173
 174 /*-----------------------------------------------------------------------*/
 175
 176 /*
 177  * Infrastructure for Tcl interface to transports.
 178  */
 179
 180 /**
 181  * Makes and stores a copy of a set of transports passed as
 182  * parameters to a command.
 183  *
 184  * @param vector where the resulting copy is stored, as an argv-style
 185  *      NULL-terminated vector.
 186  */
 187 COMMAND_HELPER(transport_list_parse, char ***vector)
 188 {
 189         char **argv;
 190         unsigned n = CMD_ARGC;
 191         unsigned j = 0;
 192
 193         *vector = NULL;
 194
 195         if (n < 1)
 196                 return ERROR_COMMAND_SYNTAX_ERROR;
 197
 198         /* our return vector must be NULL terminated */
 199         argv = calloc(n + 1, sizeof(char *));
 200         if (argv == NULL)
 201                 return ERROR_FAIL;
 202
 203         for (unsigned i = 0; i < n; i++) {
 204                 struct transport *t;
 205
 206                 for (t = transport_list; t; t = t->next) {
 207                         if (strcmp(t->name, CMD_ARGV[i]) != 0)
 208                                 continue;
 209                         argv[j++] = strdup(CMD_ARGV[i]);
 210                         break;
 211                 }
 212                 if (!t) {
 213                         LOG_ERROR("no such transport '%s'", CMD_ARGV[i]);
 214                         goto fail;
 215                 }
 216         }
 217
 218         *vector = argv;
 219         return ERROR_OK;
 220
 221 fail:
 222         for (unsigned i = 0; i < n; i++)
 223                 free(argv[i]);
 224         free(argv);
 225         return ERROR_FAIL;
 226 }
 227
 228 COMMAND_HANDLER(handle_transport_init)
 229 {
 230         LOG_DEBUG("%s", __func__);
 231         if (!session) {
 232                 LOG_ERROR("session transport was not selected. Use 'transport select <transport>'");
 233
 234                 /* no session transport configured, print transports then fail */
 235                 LOG_ERROR("Transports available:");
 236                 const char * const *vector = allowed_transports;
 237                 while (*vector) {
 238                         LOG_ERROR("%s", *vector);
 239                         vector++;
 240                 }
 241                 return ERROR_FAIL;
 242         }
 243
 244         return session->init(CMD_CTX);
 245 }
 246
 247 COMMAND_HANDLER(handle_transport_list)
 248 {
 249         if (CMD_ARGC != 0)
 250                 return ERROR_COMMAND_SYNTAX_ERROR;
 251
 252         command_print(CMD, "The following transports are available:");
 253
 254         for (struct transport *t = transport_list; t; t = t->next)
 255                 command_print(CMD, "\t%s", t->name);
 256
 257         return ERROR_OK;
 258 }
 259
 260 /**
 261  * Implements the Tcl "transport select" command, choosing the
 262  * transport to be used in this debug session from among the
 263  * set supported by the debug adapter being used.  Return value
 264  * is scriptable (allowing "if swd then..." etc).
 265  */
 266 static int jim_transport_select(Jim_Interp *interp, int argc, Jim_Obj * const *argv)
 267 {
 268         int res;
 269         switch (argc) {
 270                 case 1: /* autoselect if necessary, then return/display current config */
 271                         if (!session) {
 272                                 if (!allowed_transports) {
 273                                         LOG_ERROR("Debug adapter does not support any transports? Check config file order.");
 274                                         return JIM_ERR;
 275                                 }
 276                                 LOG_INFO("auto-selecting first available session transport \"%s\". "
 277                                          "To override use 'transport select <transport>'.", allowed_transports[0]);
 278                                 res = transport_select(global_cmd_ctx, allowed_transports[0]);
 279                                 if (res != JIM_OK)
 280                                         return res;
 281                         }
 282                         Jim_SetResultString(interp, session->name, -1);
 283                         return JIM_OK;
 284                 case 2: /* assign */
 285                         if (session) {
 286                                 if (!strcmp(session->name, argv[1]->bytes)) {
 287                                         LOG_WARNING("Transport \"%s\" was already selected", session->name);
 288                                         Jim_SetResultString(interp, session->name, -1);
 289                                         return JIM_OK;
 290                                 } else {
 291                                         LOG_ERROR("Can't change session's transport after the initial selection was made");
 292                                         return JIM_ERR;
 293                                 }
 294                         }
 295
 296                         /* Is this transport supported by our debug adapter?
 297                          * Example, "JTAG-only" means SWD is not supported.
 298                          *
 299                          * NOTE:  requires adapter to have been set up, with
 300                          * transports declared via C.
 301                          */
 302                         if (!allowed_transports) {
 303                                 LOG_ERROR("Debug adapter doesn't support any transports?");
 304                                 return JIM_ERR;
 305                         }
 306
 307                         for (unsigned i = 0; allowed_transports[i]; i++) {
 308
 309                                 if (strcmp(allowed_transports[i], argv[1]->bytes) == 0) {
 310                                         if (transport_select(global_cmd_ctx, argv[1]->bytes) == ERROR_OK) {
 311                                                 Jim_SetResultString(interp, session->name, -1);
 312                                                 return JIM_OK;
 313                                         }
 314                                         return JIM_ERR;
 315                                 }
 316                         }
 317
 318                         LOG_ERROR("Debug adapter doesn't support '%s' transport", argv[1]->bytes);
 319                         return JIM_ERR;
 320                 default:
 321                         Jim_WrongNumArgs(interp, 1, argv, "[too many parameters]");
 322                         return JIM_ERR;
 323         }
 324 }
 325
 326 static const struct command_registration transport_commands[] = {
 327         {
 328                 .name = "init",
 329                 .handler = handle_transport_init,
 330                 /* this would be COMMAND_CONFIG ... except that
 331                  * it needs to trigger event handlers that may
 332                  * require COMMAND_EXEC ...
 333                  */
 334                 .mode = COMMAND_ANY,
 335                 .help = "Initialize this session's transport",
 336                 .usage = ""
 337         },
 338         {
 339                 .name = "list",
 340                 .handler = handle_transport_list,
 341                 .mode = COMMAND_ANY,
 342                 .help = "list all built-in transports",
 343                 .usage = ""
 344         },
 345         {
 346                 .name = "select",
 347                 .jim_handler = jim_transport_select,
 348                 .mode = COMMAND_ANY,
 349                 .help = "Select this session's transport",
 350                 .usage = "[transport_name]",
 351         },
 352         COMMAND_REGISTRATION_DONE
 353 };
 354
 355 static const struct command_registration transport_group[] = {
 356         {
 357                 .name = "transport",
 358                 .mode = COMMAND_ANY,
 359                 .help = "Transport command group",
 360                 .chain = transport_commands,
 361                 .usage = ""
 362         },
 363         COMMAND_REGISTRATION_DONE
 364 };
 365
 366 int transport_register_commands(struct command_context *ctx)
 367 {
 368         return register_commands(ctx, NULL, transport_group);
 369 }