src/jtag/bitbang.c

   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 bitbang_interface_t *bitbang_interface;
  41
  42 /* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
  43  *
  44  * Set this to 1 and str912 reset halt will fail.
  45  *
  46  * If someone can submit a patch with an explanation it will be greatly
  47  * appreciated, but as far as I can tell (ØH) DCLK is generated upon
  48  * clk=0 in TAP_IDLE. Good luck deducing that from the ARM documentation!
  49  * The ARM documentation uses the term "DCLK is asserted while in the TAP_IDLE
  50  * state". With hardware there is no such thing as *while* in a state. There
  51  * are only edges. So clk => 0 is in fact a very subtle state transition that
  52  * happens *while* in the TAP_IDLE state. "#&¤"#¤&"#&"#&
  53  *
  54  * For "reset halt" the last thing that happens before srst is asserted
  55  * is that the breakpoint is set up. If DCLK is not wiggled one last
  56  * time before the reset, then the breakpoint is not set up and
  57  * "reset halt" will fail to halt.
  58  *
  59  */
  60 #define CLOCK_IDLE() 0
  61
  62 int bitbang_execute_queue(void);
  63
  64 /* The bitbang driver leaves the TCK 0 when in idle */
  65
  66 void bitbang_end_state(enum tap_state state)
  67 {
  68         if (tap_move_map[state] != -1)
  69                 end_state = state;
  70         else
  71         {
  72                 LOG_ERROR("BUG: %i is not a valid end state", state);
  73                 exit(-1);
  74         }
  75 }
  76
  77 void bitbang_state_move(void) {
  78
  79         int i=0, tms=0;
  80         u8 tms_scan = TAP_MOVE(cur_state, end_state);
  81
  82         for (i = 0; i < 7; i++)
  83         {
  84                 tms = (tms_scan >> i) & 1;
  85                 bitbang_interface->write(0, tms, 0);
  86                 bitbang_interface->write(1, tms, 0);
  87         }
  88         bitbang_interface->write(CLOCK_IDLE(), tms, 0);
  89
  90         cur_state = end_state;
  91 }
  92
  93 void bitbang_path_move(pathmove_command_t *cmd)
  94 {
  95         int num_states = cmd->num_states;
  96         int state_count;
  97         int tms = 0;
  98
  99         state_count = 0;
 100         while (num_states)
 101         {
 102                 if (tap_transitions[cur_state].low == cmd->path[state_count])
 103                 {
 104                         tms = 0;
 105                 }
 106                 else if (tap_transitions[cur_state].high == cmd->path[state_count])
 107                 {
 108                         tms = 1;
 109                 }
 110                 else
 111                 {
 112                         LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", jtag_state_name(cur_state), jtag_state_name(cmd->path[state_count]));
 113                         exit(-1);
 114                 }
 115
 116                 bitbang_interface->write(0, tms, 0);
 117                 bitbang_interface->write(1, tms, 0);
 118
 119                 cur_state = cmd->path[state_count];
 120                 state_count++;
 121                 num_states--;
 122         }
 123
 124         bitbang_interface->write(CLOCK_IDLE(), tms, 0);
 125
 126         end_state = cur_state;
 127 }
 128
 129 void bitbang_runtest(int num_cycles)
 130 {
 131         int i;
 132
 133         enum tap_state saved_end_state = end_state;
 134
 135         /* only do a state_move when we're not already in IDLE */
 136         if (cur_state != TAP_IDLE)
 137         {
 138                 bitbang_end_state(TAP_IDLE);
 139                 bitbang_state_move();
 140         }
 141
 142         /* execute num_cycles */
 143         for (i = 0; i < num_cycles; i++)
 144         {
 145                 bitbang_interface->write(0, 0, 0);
 146                 bitbang_interface->write(1, 0, 0);
 147         }
 148         bitbang_interface->write(CLOCK_IDLE(), 0, 0);
 149
 150         /* finish in end_state */
 151         bitbang_end_state(saved_end_state);
 152         if (cur_state != end_state)
 153                 bitbang_state_move();
 154 }
 155
 156 void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size)
 157 {
 158         enum tap_state saved_end_state = end_state;
 159         int bit_cnt;
 160
 161         if (!((!ir_scan && (cur_state == TAP_DRSHIFT)) || (ir_scan && (cur_state == TAP_IRSHIFT))))
 162         {
 163                 if (ir_scan)
 164                         bitbang_end_state(TAP_IRSHIFT);
 165                 else
 166                         bitbang_end_state(TAP_DRSHIFT);
 167
 168                 bitbang_state_move();
 169                 bitbang_end_state(saved_end_state);
 170         }
 171
 172         for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++)
 173         {
 174                 int val=0;
 175                 int tms=(bit_cnt==scan_size-1) ? 1 : 0;
 176                 int tdi;
 177                 int bytec=bit_cnt/8;
 178                 int bcval=1<<(bit_cnt % 8);
 179
 180                 /* if we're just reading the scan, but don't care about the output
 181                  * default to outputting 'low', this also makes valgrind traces more readable,
 182                  * as it removes the dependency on an uninitialised value
 183                  */
 184                 tdi=0;
 185                 if ((type != SCAN_IN) && (buffer[bytec] & bcval))
 186                         tdi=1;
 187
 188                 bitbang_interface->write(0, tms, tdi);
 189
 190                 if (type!=SCAN_OUT)
 191                         val=bitbang_interface->read();
 192
 193                 bitbang_interface->write(1, tms, tdi);
 194
 195                 if (type != SCAN_OUT)
 196                 {
 197                         if (val)
 198                                 buffer[bytec] |= bcval;
 199                         else
 200                                 buffer[bytec] &= ~bcval;
 201                 }
 202         }
 203
 204         /* TAP_DRSHIFT & TAP_IRSHIFT are illegal end states, so we always transition to the pause
 205          * state which is a legal stable state from which statemove will work.
 206          *
 207          * Exit1 -> Pause
 208          */
 209         bitbang_interface->write(0, 0, 0);
 210         bitbang_interface->write(1, 0, 0);
 211         bitbang_interface->write(CLOCK_IDLE(), 0, 0);
 212
 213         if (ir_scan)
 214                 cur_state = TAP_IRPAUSE;
 215         else
 216                 cur_state = TAP_DRPAUSE;
 217
 218         if (cur_state != end_state)
 219                 bitbang_state_move();
 220 }
 221
 222 int bitbang_execute_queue(void)
 223 {
 224         jtag_command_t *cmd = jtag_command_queue; /* currently processed command */
 225         int scan_size;
 226         enum scan_type type;
 227         u8 *buffer;
 228         int retval;
 229
 230         if (!bitbang_interface)
 231         {
 232                 LOG_ERROR("BUG: Bitbang interface called, but not yet initialized");
 233                 exit(-1);
 234         }
 235
 236         /* return ERROR_OK, unless a jtag_read_buffer returns a failed check
 237          * that wasn't handled by a caller-provided error handler
 238          */
 239         retval = ERROR_OK;
 240
 241         if(bitbang_interface->blink)
 242                 bitbang_interface->blink(1);
 243
 244         while (cmd)
 245         {
 246                 switch (cmd->type)
 247                 {
 248                         case JTAG_END_STATE:
 249 #ifdef _DEBUG_JTAG_IO_
 250                                 LOG_DEBUG("end_state: %i", cmd->cmd.end_state->end_state);
 251 #endif
 252                                 if (cmd->cmd.end_state->end_state != -1)
 253                                         bitbang_end_state(cmd->cmd.end_state->end_state);
 254                                 break;
 255                         case JTAG_RESET:
 256 #ifdef _DEBUG_JTAG_IO_
 257                                 LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 258 #endif
 259                                 if ((cmd->cmd.reset->trst == 1) || (cmd->cmd.reset->srst && (jtag_reset_config & RESET_SRST_PULLS_TRST)))
 260                                 {
 261                                         cur_state = TAP_RESET;
 262                                 }
 263                                 bitbang_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 264                                 break;
 265                         case JTAG_RUNTEST:
 266 #ifdef _DEBUG_JTAG_IO_
 267                                 LOG_DEBUG("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, cmd->cmd.runtest->end_state);
 268 #endif
 269                                 if (cmd->cmd.runtest->end_state != -1)
 270                                         bitbang_end_state(cmd->cmd.runtest->end_state);
 271                                 bitbang_runtest(cmd->cmd.runtest->num_cycles);
 272                                 break;
 273                         case JTAG_STATEMOVE:
 274 #ifdef _DEBUG_JTAG_IO_
 275                                 LOG_DEBUG("statemove end in %i", cmd->cmd.statemove->end_state);
 276 #endif
 277                                 if (cmd->cmd.statemove->end_state != -1)
 278                                         bitbang_end_state(cmd->cmd.statemove->end_state);
 279                                 bitbang_state_move();
 280                                 break;
 281                         case JTAG_PATHMOVE:
 282 #ifdef _DEBUG_JTAG_IO_
 283                                 LOG_DEBUG("pathmove: %i states, end in %i", cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
 284 #endif
 285                                 bitbang_path_move(cmd->cmd.pathmove);
 286                                 break;
 287                         case JTAG_SCAN:
 288 #ifdef _DEBUG_JTAG_IO_
 289                                 LOG_DEBUG("%s scan end in %i",  (cmd->cmd.scan->ir_scan) ? "IR" : "DR", cmd->cmd.scan->end_state);
 290 #endif
 291                                 if (cmd->cmd.scan->end_state != -1)
 292                                         bitbang_end_state(cmd->cmd.scan->end_state);
 293                                 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
 294                                 type = jtag_scan_type(cmd->cmd.scan);
 295                                 bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
 296                                 if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
 297                                         retval = ERROR_JTAG_QUEUE_FAILED;
 298                                 if (buffer)
 299                                         free(buffer);
 300                                 break;
 301                         case JTAG_SLEEP:
 302 #ifdef _DEBUG_JTAG_IO_
 303                                 LOG_DEBUG("sleep %i", cmd->cmd.sleep->us);
 304 #endif
 305                                 jtag_sleep(cmd->cmd.sleep->us);
 306                                 break;
 307                         default:
 308                                 LOG_ERROR("BUG: unknown JTAG command type encountered");
 309                                 exit(-1);
 310                 }
 311                 cmd = cmd->next;
 312         }
 313         if(bitbang_interface->blink)
 314                 bitbang_interface->blink(0);
 315
 316         return retval;
 317 }