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 <transport/transport.h>
  46
  47 extern struct command_context *global_cmd_ctx;
  48
  49 /*-----------------------------------------------------------------------*/
  50
  51 /*
  52  * Infrastructure internals
  53  */
  54
  55 /** List of transports known to OpenOCD. */
  56 static struct transport *transport_list;
  57
  58 /**
  59  * NULL-terminated Vector of names of transports which the
  60  * currently selected debug adapter supports.  This is declared
  61  * by the time that adapter is fully set up.
  62  */
  63 static const char * const *allowed_transports;
  64
  65 /** * The transport being used for the current OpenOCD session.  */
  66 static struct transport *session;
  67
  68 static int transport_select(struct command_context *ctx, const char *name)
  69 {
  70         /* name may only identify a known transport;
  71          * caller guarantees session's transport isn't yet set.*/
  72         for (struct transport *t = transport_list; t; t = t->next) {
  73                 if (strcmp(t->name, name) == 0) {
  74                         int retval = t->select(ctx);
  75                         /* select() registers commands specific to this
  76                          * transport, and may also reset the link, e.g.
  77                          * forcing it to JTAG or SWD mode.
  78                          */
  79                         if (retval == ERROR_OK)
  80                                 session = t;
  81                         else
  82                                 LOG_ERROR("Error selecting '%s' as transport", t->name);
  83                         return retval;
  84                 }
  85         }
  86
  87         LOG_ERROR("No transport named '%s' is available.", name);
  88         return ERROR_FAIL;
  89 }
  90
  91 /**
  92  * Called by debug adapter drivers, or affiliated Tcl config scripts,
  93  * to declare the set of transports supported by an adapter.  When
  94  * there is only one member of that set, it is automatically selected.
  95  */
  96 int allow_transports(struct command_context *ctx, const char * const *vector)
  97 {
  98         /* NOTE:  caller is required to provide only a list
  99          * of *valid* transport names
 100          *
 101          * REVISIT should we validate that?  and insist there's
 102          * at least one non-NULL element in that list?
 103          *
 104          * ... allow removals, e.g. external strapping prevents use
 105          * of one transport; C code should be definitive about what
 106          * can be used when all goes well.
 107          */
 108         if (allowed_transports != NULL || session) {
 109                 LOG_ERROR("Can't modify the set of allowed transports.");
 110                 return ERROR_FAIL;
 111         }
 112
 113         allowed_transports = vector;
 114
 115         /* autoselect if there's no choice ... */
 116         if (!vector[1]) {
 117                 LOG_INFO("only one transport option; autoselect '%s'", vector[0]);
 118                 return transport_select(ctx, vector[0]);
 119         }
 120
 121         return ERROR_OK;
 122 }
 123
 124 /**
 125  * Registers a transport.  There are general purpose transports
 126  * (such as JTAG), as well as relatively proprietary ones which are
 127  * specific to a given chip (or chip family).
 128  *
 129  * Code implementing a transport needs to register it before it can
 130  * be selected and then activated.  This is a dynamic process, so
 131  * that chips (and families) can define transports as needed (without
 132  * needing error-prone static tables).
 133  *
 134  * @param new_transport the transport being registered.  On a
 135  * successful return, this memory is owned by the transport framework.
 136  *
 137  * @returns ERROR_OK on success, else a fault code.
 138  */
 139 int transport_register(struct transport *new_transport)
 140 {
 141         struct transport *t;
 142
 143         for (t = transport_list; t; t = t->next) {
 144                 if (strcmp(t->name, new_transport->name) == 0) {
 145                         LOG_ERROR("transport name already used");
 146                         return ERROR_FAIL;
 147                 }
 148         }
 149
 150         if (!new_transport->select || !new_transport->init)
 151                 LOG_ERROR("invalid transport %s", new_transport->name);
 152
 153         /* splice this into the list */
 154         new_transport->next = transport_list;
 155         transport_list = new_transport;
 156         LOG_DEBUG("register '%s'", new_transport->name);
 157
 158         return ERROR_OK;
 159 }
 160
 161 /**
 162  * Returns the transport currently being used by this debug or
 163  * programming session.
 164  *
 165  * @returns handle to the read-only transport entity.
 166  */
 167 struct transport *get_current_transport(void)
 168 {
 169         /* REVISIT -- constify */
 170         return session;
 171 }
 172
 173 /*-----------------------------------------------------------------------*/
 174
 175 /*
 176  * Infrastructure for Tcl interface to transports.
 177  */
 178
 179 /**
 180  * Makes and stores a copy of a set of transports passed as
 181  * parameters to a command.
 182  *
 183  * @param vector where the resulting copy is stored, as an argv-style
 184  *      NULL-terminated vector.
 185  */
 186 COMMAND_HELPER(transport_list_parse, char ***vector)
 187 {
 188         char **argv;
 189         unsigned n = CMD_ARGC;
 190         unsigned j = 0;
 191
 192         *vector = NULL;
 193
 194         if (n < 1)
 195                 return ERROR_COMMAND_SYNTAX_ERROR;
 196
 197         /* our return vector must be NULL terminated */
 198         argv = calloc(n + 1, sizeof(char *));
 199         if (argv == NULL)
 200                 return ERROR_FAIL;
 201
 202         for (unsigned i = 0; i < n; i++) {
 203                 struct transport *t;
 204
 205                 for (t = transport_list; t; t = t->next) {
 206                         if (strcmp(t->name, CMD_ARGV[i]) != 0)
 207                                 continue;
 208                         argv[j++] = strdup(CMD_ARGV[i]);
 209                         break;
 210                 }
 211                 if (!t) {
 212                         LOG_ERROR("no such transport '%s'", CMD_ARGV[i]);
 213                         goto fail;
 214                 }
 215         }
 216
 217         *vector = argv;
 218         return ERROR_OK;
 219
 220 fail:
 221         for (unsigned i = 0; i < n; i++)
 222                 free(argv[i]);
 223         free(argv);
 224         return ERROR_FAIL;
 225 }
 226
 227 COMMAND_HANDLER(handle_transport_init)
 228 {
 229         LOG_DEBUG("%s", __func__);
 230         if (!session) {
 231                 LOG_ERROR("session transport was not selected. Use 'transport select <transport>'");
 232
 233                 /* no session transport configured, print transports then fail */
 234                 LOG_ERROR("Transports available:");
 235                 const char * const *vector = allowed_transports;
 236                 while (*vector) {
 237                         LOG_ERROR("%s", *vector);
 238                         vector++;
 239                 }
 240                 return ERROR_FAIL;
 241         }
 242
 243         return session->init(CMD_CTX);
 244 }
 245
 246 COMMAND_HANDLER(handle_transport_list)
 247 {
 248         if (CMD_ARGC != 0)
 249                 return ERROR_COMMAND_SYNTAX_ERROR;
 250
 251         command_print(CMD, "The following transports are available:");
 252
 253         for (struct transport *t = transport_list; t; t = t->next)
 254                 command_print(CMD, "\t%s", t->name);
 255
 256         return ERROR_OK;
 257 }
 258
 259 /**
 260  * Implements the Tcl "transport select" command, choosing the
 261  * transport to be used in this debug session from among the
 262  * set supported by the debug adapter being used.  Return value
 263  * is scriptable (allowing "if swd then..." etc).
 264  */
 265 static int jim_transport_select(Jim_Interp *interp, int argc, Jim_Obj * const *argv)
 266 {
 267         int res;
 268         switch (argc) {
 269                 case 1: /* autoselect if necessary, then return/display current config */
 270                         if (!session) {
 271                                 if (!allowed_transports) {
 272                                         LOG_ERROR("Debug adapter does not support any transports? Check config file order.");
 273                                         return JIM_ERR;
 274                                 }
 275                                 LOG_INFO("auto-selecting first available session transport \"%s\". "
 276                                          "To override use 'transport select <transport>'.", allowed_transports[0]);
 277                                 res = transport_select(global_cmd_ctx, allowed_transports[0]);
 278                                 if (res != JIM_OK)
 279                                         return res;
 280                         }
 281                         Jim_SetResultString(interp, session->name, -1);
 282                         return JIM_OK;
 283                 case 2: /* assign */
 284                         if (session) {
 285                                 if (!strcmp(session->name, argv[1]->bytes)) {
 286                                         LOG_WARNING("Transport \"%s\" was already selected", session->name);
 287                                         Jim_SetResultString(interp, session->name, -1);
 288                                         return JIM_OK;
 289                                 } else {
 290                                         LOG_ERROR("Can't change session's transport after the initial selection was made");
 291                                         return JIM_ERR;
 292                                 }
 293                         }
 294
 295                         /* Is this transport supported by our debug adapter?
 296                          * Example, "JTAG-only" means SWD is not supported.
 297                          *
 298                          * NOTE:  requires adapter to have been set up, with
 299                          * transports declared via C.
 300                          */
 301                         if (!allowed_transports) {
 302                                 LOG_ERROR("Debug adapter doesn't support any transports?");
 303                                 return JIM_ERR;
 304                         }
 305
 306                         for (unsigned i = 0; allowed_transports[i]; i++) {
 307
 308                                 if (strcmp(allowed_transports[i], argv[1]->bytes) == 0) {
 309                                         if (transport_select(global_cmd_ctx, argv[1]->bytes) == ERROR_OK) {
 310                                                 Jim_SetResultString(interp, session->name, -1);
 311                                                 return JIM_OK;
 312                                         }
 313                                         return JIM_ERR;
 314                                 }
 315                         }
 316
 317                         LOG_ERROR("Debug adapter doesn't support '%s' transport", argv[1]->bytes);
 318                         return JIM_ERR;
 319                 default:
 320                         Jim_WrongNumArgs(interp, 1, argv, "[too many parameters]");
 321                         return JIM_ERR;
 322         }
 323 }
 324
 325 static const struct command_registration transport_commands[] = {
 326         {
 327                 .name = "init",
 328                 .handler = handle_transport_init,
 329                 /* this would be COMMAND_CONFIG ... except that
 330                  * it needs to trigger event handlers that may
 331                  * require COMMAND_EXEC ...
 332                  */
 333                 .mode = COMMAND_ANY,
 334                 .help = "Initialize this session's transport",
 335                 .usage = ""
 336         },
 337         {
 338                 .name = "list",
 339                 .handler = handle_transport_list,
 340                 .mode = COMMAND_ANY,
 341                 .help = "list all built-in transports",
 342                 .usage = ""
 343         },
 344         {
 345                 .name = "select",
 346                 .jim_handler = jim_transport_select,
 347                 .mode = COMMAND_ANY,
 348                 .help = "Select this session's transport",
 349                 .usage = "[transport_name]",
 350         },
 351         COMMAND_REGISTRATION_DONE
 352 };
 353
 354 static const struct command_registration transport_group[] = {
 355         {
 356                 .name = "transport",
 357                 .mode = COMMAND_ANY,
 358                 .help = "Transport command group",
 359                 .chain = transport_commands,
 360                 .usage = ""
 361         },
 362         COMMAND_REGISTRATION_DONE
 363 };
 364
 365 int transport_register_commands(struct command_context *ctx)
 366 {
 367         return register_commands(ctx, NULL, transport_group);
 368 }