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   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
   6  *   oyvind.harboe@zylin.com                                               *
   7  *                                                                         *
   8  *   This program is free software; you can redistribute it and/or modify  *
   9  *   it under the terms of the GNU General Public License as published by  *
  10  *   the Free Software Foundation; either version 2 of the License, or     *
  11  *   (at your option) any later version.                                   *
  12  *                                                                         *
  13  *   This program is distributed in the hope that it will be useful,       *
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  16  *   GNU General Public License for more details.                          *
  17  *                                                                         *
  18  *   You should have received a copy of the GNU General Public License     *
  19  *   along with this program; if not, write to the                         *
  20  *   Free Software Foundation, Inc.,                                       *
  21  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  22  ***************************************************************************/
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include "bitbang.h"
  28
  29 /* project specific includes */
  30 #include "log.h"
  31 #include "types.h"
  32 #include "jtag.h"
  33 #include "configuration.h"
  34
  35 /* system includes */
  36 #include <string.h>
  37 #include <stdlib.h>
  38 #include <unistd.h>
  39
  40
  41 /**
  42  * Function bitbang_stableclocks
  43  * issues a number of clock cycles while staying in a stable state.
  44  * Because the TMS value required to stay in the RESET state is a 1, whereas
  45  * the TMS value required to stay in any of the other stable states is a 0,
  46  * this function checks the current stable state to decide on the value of TMS
  47  * to use.
  48  */
  49 static void bitbang_stableclocks(int num_cycles);
  50
  51
  52 bitbang_interface_t *bitbang_interface;
  53
  54 /* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
  55  *
  56  * Set this to 1 and str912 reset halt will fail.
  57  *
  58  * If someone can submit a patch with an explanation it will be greatly
  59  * appreciated, but as far as I can tell (ØH) DCLK is generated upon
  60  * clk=0 in TAP_IDLE. Good luck deducing that from the ARM documentation!
  61  * The ARM documentation uses the term "DCLK is asserted while in the TAP_IDLE
  62  * state". With hardware there is no such thing as *while* in a state. There
  63  * are only edges. So clk => 0 is in fact a very subtle state transition that
  64  * happens *while* in the TAP_IDLE state. "#&¤"#¤&"#&"#&
  65  *
  66  * For "reset halt" the last thing that happens before srst is asserted
  67  * is that the breakpoint is set up. If DCLK is not wiggled one last
  68  * time before the reset, then the breakpoint is not set up and
  69  * "reset halt" will fail to halt.
  70  *
  71  */
  72 #define CLOCK_IDLE() 0
  73
  74 int bitbang_execute_queue(void);
  75
  76
  77 /* The bitbang driver leaves the TCK 0 when in idle */
  78
  79 void bitbang_end_state(tap_state_t state)
  80 {
  81         if (tap_is_state_stable(state))
  82                 tap_set_end_state(state);
  83         else
  84         {
  85                 LOG_ERROR("BUG: %i is not a valid end state", state);
  86                 exit(-1);
  87         }
  88 }
  89
  90 void bitbang_state_move(void)
  91 {
  92         int i=0, tms=0;
  93         u8 tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
  94
  95         for (i = 0; i < 7; i++)
  96         {
  97                 tms = (tms_scan >> i) & 1;
  98                 bitbang_interface->write(0, tms, 0);
  99                 bitbang_interface->write(1, tms, 0);
 100         }
 101         bitbang_interface->write(CLOCK_IDLE(), tms, 0);
 102
 103         tap_set_state(tap_get_end_state());
 104 }
 105
 106 void bitbang_path_move(pathmove_command_t *cmd)
 107 {
 108         int num_states = cmd->num_states;
 109         int state_count;
 110         int tms = 0;
 111
 112         state_count = 0;
 113         while (num_states)
 114         {
 115                 if (tap_state_transition(tap_get_state(), false) == cmd->path[state_count])
 116                 {
 117                         tms = 0;
 118                 }
 119                 else if (tap_state_transition(tap_get_state(), true) == cmd->path[state_count])
 120                 {
 121                         tms = 1;
 122                 }
 123                 else
 124                 {
 125                         LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_name(tap_get_state()), tap_state_name(cmd->path[state_count]));
 126                         exit(-1);
 127                 }
 128
 129                 bitbang_interface->write(0, tms, 0);
 130                 bitbang_interface->write(1, tms, 0);
 131
 132                 tap_set_state(cmd->path[state_count]);
 133                 state_count++;
 134                 num_states--;
 135         }
 136
 137         bitbang_interface->write(CLOCK_IDLE(), tms, 0);
 138
 139         tap_set_end_state(tap_get_state());
 140 }
 141
 142 void bitbang_runtest(int num_cycles)
 143 {
 144         int i;
 145
 146         tap_state_t saved_end_state = tap_get_end_state();
 147
 148         /* only do a state_move when we're not already in IDLE */
 149         if (tap_get_state() != TAP_IDLE)
 150         {
 151                 bitbang_end_state(TAP_IDLE);
 152                 bitbang_state_move();
 153         }
 154
 155         /* execute num_cycles */
 156         for (i = 0; i < num_cycles; i++)
 157         {
 158                 bitbang_interface->write(0, 0, 0);
 159                 bitbang_interface->write(1, 0, 0);
 160         }
 161         bitbang_interface->write(CLOCK_IDLE(), 0, 0);
 162
 163         /* finish in end_state */
 164         bitbang_end_state(saved_end_state);
 165         if (tap_get_state() != tap_get_end_state())
 166                 bitbang_state_move();
 167 }
 168
 169
 170 static void bitbang_stableclocks(int num_cycles)
 171 {
 172         int tms = (tap_get_state() == TAP_RESET ? 1 : 0);
 173         int i;
 174
 175         /* send num_cycles clocks onto the cable */
 176         for (i = 0; i < num_cycles; i++)
 177         {
 178                 bitbang_interface->write(1, tms, 0);
 179                 bitbang_interface->write(0, tms, 0);
 180         }
 181 }
 182
 183
 184
 185 void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
 186 {
 187         tap_state_t saved_end_state = tap_get_end_state();
 188         int bit_cnt;
 189
 190         if (!((!ir_scan && (tap_get_state() == TAP_DRSHIFT)) || (ir_scan && (tap_get_state() == TAP_IRSHIFT))))
 191         {
 192                 if (ir_scan)
 193                         bitbang_end_state(TAP_IRSHIFT);
 194                 else
 195                         bitbang_end_state(TAP_DRSHIFT);
 196
 197                 bitbang_state_move();
 198                 bitbang_end_state(saved_end_state);
 199         }
 200
 201         for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++)
 202         {
 203                 int val=0;
 204                 int tms=(bit_cnt==scan_size-1) ? 1 : 0;
 205                 int tdi;
 206                 int bytec=bit_cnt/8;
 207                 int bcval=1<<(bit_cnt % 8);
 208
 209                 /* if we're just reading the scan, but don't care about the output
 210                  * default to outputting 'low', this also makes valgrind traces more readable,
 211                  * as it removes the dependency on an uninitialised value
 212                  */
 213                 tdi=0;
 214                 if ((type != SCAN_IN) && (buffer[bytec] & bcval))
 215                         tdi=1;
 216
 217                 bitbang_interface->write(0, tms, tdi);
 218
 219                 if (type!=SCAN_OUT)
 220                         val=bitbang_interface->read();
 221
 222                 bitbang_interface->write(1, tms, tdi);
 223
 224                 if (type != SCAN_OUT)
 225                 {
 226                         if (val)
 227                                 buffer[bytec] |= bcval;
 228                         else
 229                                 buffer[bytec] &= ~bcval;
 230                 }
 231         }
 232
 233         /* TAP_DRSHIFT & TAP_IRSHIFT are illegal end states, so we always transition to the pause
 234          * state which is a legal stable state from which statemove will work.
 235          *
 236          * Exit1 -> Pause
 237          */
 238         bitbang_interface->write(0, 0, 0);
 239         bitbang_interface->write(1, 0, 0);
 240         bitbang_interface->write(CLOCK_IDLE(), 0, 0);
 241
 242         if (ir_scan)
 243                 tap_set_state(TAP_IRPAUSE);
 244         else
 245                 tap_set_state(TAP_DRPAUSE);
 246
 247         if (tap_get_state() != tap_get_end_state())
 248                 bitbang_state_move();
 249 }
 250
 251 int bitbang_execute_queue(void)
 252 {
 253         jtag_command_t *cmd = jtag_command_queue; /* currently processed command */
 254         int scan_size;
 255         enum scan_type type;
 256         u8 *buffer;
 257         int retval;
 258
 259         if (!bitbang_interface)
 260         {
 261                 LOG_ERROR("BUG: Bitbang interface called, but not yet initialized");
 262                 exit(-1);
 263         }
 264
 265         /* return ERROR_OK, unless a jtag_read_buffer returns a failed check
 266          * that wasn't handled by a caller-provided error handler
 267          */
 268         retval = ERROR_OK;
 269
 270         if(bitbang_interface->blink)
 271                 bitbang_interface->blink(1);
 272
 273         while (cmd)
 274         {
 275                 switch (cmd->type)
 276                 {
 277                         case JTAG_END_STATE:
 278 #ifdef _DEBUG_JTAG_IO_
 279                                 LOG_DEBUG("end_state: %s", tap_state_name(cmd->cmd.end_state->end_state) );
 280 #endif
 281                                 if (cmd->cmd.end_state->end_state != TAP_INVALID)
 282                                         bitbang_end_state(cmd->cmd.end_state->end_state);
 283                                 break;
 284                         case JTAG_RESET:
 285 #ifdef _DEBUG_JTAG_IO_
 286                                 LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 287 #endif
 288                                 if ((cmd->cmd.reset->trst == 1) || (cmd->cmd.reset->srst && (jtag_reset_config & RESET_SRST_PULLS_TRST)))
 289                                 {
 290                                         tap_set_state(TAP_RESET);
 291                                 }
 292                                 bitbang_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 293                                 break;
 294                         case JTAG_RUNTEST:
 295 #ifdef _DEBUG_JTAG_IO_
 296                                 LOG_DEBUG("runtest %i cycles, end in %s", cmd->cmd.runtest->num_cycles, tap_state_name(cmd->cmd.runtest->end_state) );
 297 #endif
 298                                 if (cmd->cmd.runtest->end_state != TAP_INVALID)
 299                                         bitbang_end_state(cmd->cmd.runtest->end_state);
 300                                 bitbang_runtest(cmd->cmd.runtest->num_cycles);
 301                                 break;
 302
 303                         case JTAG_STABLECLOCKS:
 304                                 /* this is only allowed while in a stable state.  A check for a stable
 305                                  * state was done in jtag_add_clocks()
 306                                  */
 307                                 bitbang_stableclocks(cmd->cmd.stableclocks->num_cycles);
 308                                 break;
 309
 310                         case JTAG_STATEMOVE:
 311 #ifdef _DEBUG_JTAG_IO_
 312                                 LOG_DEBUG("statemove end in %s", tap_state_name(cmd->cmd.statemove->end_state));
 313 #endif
 314                                 if (cmd->cmd.statemove->end_state != TAP_INVALID)
 315                                         bitbang_end_state(cmd->cmd.statemove->end_state);
 316                                 bitbang_state_move();
 317                                 break;
 318                         case JTAG_PATHMOVE:
 319 #ifdef _DEBUG_JTAG_IO_
 320                                 LOG_DEBUG("pathmove: %i states, end in %s", cmd->cmd.pathmove->num_states,
 321                                         tap_state_name(cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]));
 322 #endif
 323                                 bitbang_path_move(cmd->cmd.pathmove);
 324                                 break;
 325                         case JTAG_SCAN:
 326 #ifdef _DEBUG_JTAG_IO_
 327                                 LOG_DEBUG("%s scan end in %s",  (cmd->cmd.scan->ir_scan) ? "IR" : "DR", tap_state_name(cmd->cmd.scan->end_state) );
 328 #endif
 329                                 if (cmd->cmd.scan->end_state != TAP_INVALID)
 330                                         bitbang_end_state(cmd->cmd.scan->end_state);
 331                                 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
 332                                 type = jtag_scan_type(cmd->cmd.scan);
 333                                 bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
 334                                 if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
 335                                         retval = ERROR_JTAG_QUEUE_FAILED;
 336                                 if (buffer)
 337                                         free(buffer);
 338                                 break;
 339                         case JTAG_SLEEP:
 340 #ifdef _DEBUG_JTAG_IO_
 341                                 LOG_DEBUG("sleep %i", cmd->cmd.sleep->us);
 342 #endif
 343                                 jtag_sleep(cmd->cmd.sleep->us);
 344                                 break;
 345                         default:
 346                                 LOG_ERROR("BUG: unknown JTAG command type encountered");
 347                                 exit(-1);
 348                 }
 349                 cmd = cmd->next;
 350         }
 351         if(bitbang_interface->blink)
 352                 bitbang_interface->blink(0);
 353
 354         return retval;
 355 }