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 }