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   1 /***************************************************************************\r
   2  *   Copyright (C) 2008 by Øyvind Harboe                                   *\r
   3  *   oyvind.harboe@zylin.com                                               *\r
   4  *                                                                         *\r
   5  *   This program is free software; you can redistribute it and/or modify  *\r
   6  *   it under the terms of the GNU General Public License as published by  *\r
   7  *   the Free Software Foundation; either version 2 of the License, or     *\r
   8  *   (at your option) any later version.                                   *\r
   9  *                                                                         *\r
  10  *   This program is distributed in the hope that it will be useful,       *\r
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *\r
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *\r
  13  *   GNU General Public License for more details.                          *\r
  14  *                                                                         *\r
  15  *   You should have received a copy of the GNU General Public License     *\r
  16  *   along with this program; if not, write to the                         *\r
  17  *   Free Software Foundation, Inc.,                                       *\r
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *\r
  19  ***************************************************************************/\r
  20 #ifdef HAVE_CONFIG_H\r
  21 #include "config.h"\r
  22 #endif\r
  23 \r
  24 #include "replacements.h"\r
  25 \r
  26 #include "jtag.h"\r
  27 #include "bitbang.h"\r
  28 \r
  29 \r
  30 /* my private tap controller state, which tracks state for calling code */\r
  31 static tap_state_t dummy_state = TAP_RESET;\r
  32 \r
  33 static int dummy_clock;         /* edge detector */\r
  34 \r
  35 static int clock_count;         /* count clocks in any stable state, only stable states */\r
  36 \r
  37 \r
  38 static tap_state_t tap_state_transition(tap_state_t cur_state, int tms);\r
  39 \r
  40 static u32 dummy_data;\r
  41 \r
  42 \r
  43 int dummy_speed(int speed);\r
  44 int dummy_register_commands(struct command_context_s *cmd_ctx);\r
  45 int dummy_init(void);\r
  46 int dummy_quit(void);\r
  47 static int dummy_khz(int khz, int *jtag_speed);\r
  48 static int dummy_speed_div(int speed, int *khz);\r
  49 \r
  50 \r
  51 /* The dummy driver is used to easily check the code path\r
  52  * where the target is unresponsive.\r
  53  */\r
  54 jtag_interface_t dummy_interface =\r
  55 {\r
  56         .name = "dummy",\r
  57 \r
  58         .execute_queue = bitbang_execute_queue,\r
  59 \r
  60         .speed = dummy_speed,\r
  61         .register_commands = dummy_register_commands,\r
  62         .khz = dummy_khz,\r
  63         .speed_div = dummy_speed_div,\r
  64 \r
  65         .init = dummy_init,\r
  66         .quit = dummy_quit,\r
  67 };\r
  68 \r
  69 int dummy_read(void);\r
  70 void dummy_write(int tck, int tms, int tdi);\r
  71 void dummy_reset(int trst, int srst);\r
  72 void dummy_led(int on);\r
  73 \r
  74 bitbang_interface_t dummy_bitbang =\r
  75 {\r
  76         .read = dummy_read,\r
  77         .write = dummy_write,\r
  78         .reset = dummy_reset,\r
  79         .blink = dummy_led\r
  80 };\r
  81 \r
  82 int dummy_read(void)\r
  83 {\r
  84         int data = 1 & dummy_data;\r
  85         dummy_data = (dummy_data >> 1) | (1<<31);\r
  86         return data;\r
  87 }\r
  88 \r
  89 \r
  90 void dummy_write(int tck, int tms, int tdi)\r
  91 {\r
  92         /* TAP standard: "state transitions occur on rising edge of clock" */\r
  93         if( tck != dummy_clock )\r
  94         {\r
  95                 if( tck )\r
  96                 {\r
  97                         int old_state = dummy_state;\r
  98                         dummy_state = tap_state_transition( old_state, tms );\r
  99 \r
 100                         if( old_state != dummy_state )\r
 101                         {\r
 102                                 if( clock_count )\r
 103                                 {\r
 104                                         LOG_DEBUG("dummy_tap: %d stable clocks", clock_count);\r
 105                                         clock_count = 0;\r
 106                                 }\r
 107 \r
 108                                 LOG_DEBUG("dummy_tap: %s", jtag_state_name(dummy_state) );\r
 109 \r
 110 #if defined(DEBUG)\r
 111                                 if(dummy_state == TAP_DRCAPTURE)\r
 112                                         dummy_data = 0x01255043;\r
 113 #endif\r
 114                         }\r
 115                         else\r
 116                         {\r
 117                                 /* this is a stable state clock edge, no change of state here,\r
 118                                  * simply increment clock_count for subsequent logging\r
 119                                  */\r
 120                                 ++clock_count;\r
 121                         }\r
 122                 }\r
 123                 dummy_clock = tck;\r
 124         }\r
 125 }\r
 126 \r
 127 void dummy_reset(int trst, int srst)\r
 128 {\r
 129         dummy_clock = 0;\r
 130 \r
 131         if (trst || (srst && (jtag_reset_config & RESET_SRST_PULLS_TRST)))\r
 132                 dummy_state = TAP_RESET;\r
 133 \r
 134         LOG_DEBUG("reset to: %s", jtag_state_name(dummy_state) );\r
 135 }\r
 136 \r
 137 static int dummy_khz(int khz, int *jtag_speed)\r
 138 {\r
 139         if (khz==0)\r
 140         {\r
 141                 *jtag_speed=0;\r
 142         }\r
 143         else\r
 144         {\r
 145                 *jtag_speed=64000/khz;\r
 146         }\r
 147         return ERROR_OK;\r
 148 }\r
 149 \r
 150 static int dummy_speed_div(int speed, int *khz)\r
 151 {\r
 152         if (speed==0)\r
 153         {\r
 154                 *khz = 0;\r
 155         }\r
 156         else\r
 157         {\r
 158                 *khz=64000/speed;\r
 159         }\r
 160 \r
 161         return ERROR_OK;\r
 162 }\r
 163 \r
 164 int dummy_speed(int speed)\r
 165 {\r
 166         return ERROR_OK;\r
 167 }\r
 168 \r
 169 int dummy_register_commands(struct command_context_s *cmd_ctx)\r
 170 {\r
 171         return ERROR_OK;\r
 172 }\r
 173 \r
 174 int dummy_init(void)\r
 175 {\r
 176         bitbang_interface = &dummy_bitbang;\r
 177 \r
 178         return ERROR_OK;\r
 179 }\r
 180 \r
 181 int dummy_quit(void)\r
 182 {\r
 183         return ERROR_OK;\r
 184 }\r
 185 \r
 186 void dummy_led(int on)\r
 187 {\r
 188 }\r
 189 \r
 190 \r
 191 /**\r
 192  * Function tap_state_transition\r
 193  * takes a current TAP state and returns the next state according to the tms value.\r
 194  *\r
 195  * Even though there is code to duplicate this elsewhere, we do it here a little\r
 196  * differently just to get a second opinion, i.e. a verification, on state tracking\r
 197  * in that other logic. Plus array lookups without index checking are no favorite thing.\r
 198  * This is educational for developers new to TAP controllers.\r
 199  */\r
 200 static tap_state_t tap_state_transition(tap_state_t cur_state, int tms)\r
 201 {\r
 202         tap_state_t new_state;\r
 203 \r
 204         if (tms)\r
 205         {\r
 206                 switch (cur_state)\r
 207                 {\r
 208                 case TAP_RESET:\r
 209                         new_state = cur_state;\r
 210                         break;\r
 211                 case TAP_IDLE:\r
 212                 case TAP_DRUPDATE:\r
 213                 case TAP_IRUPDATE:\r
 214                         new_state = TAP_DRSELECT;\r
 215                         break;\r
 216                 case TAP_DRSELECT:\r
 217                         new_state = TAP_IRSELECT;\r
 218                         break;\r
 219                 case TAP_DRCAPTURE:\r
 220                 case TAP_DRSHIFT:\r
 221                         new_state = TAP_DREXIT1;\r
 222                         break;\r
 223                 case TAP_DREXIT1:\r
 224                 case TAP_DREXIT2:\r
 225                         new_state = TAP_DRUPDATE;\r
 226                         break;\r
 227                 case TAP_DRPAUSE:\r
 228                         new_state = TAP_DREXIT2;\r
 229                         break;\r
 230                 case TAP_IRSELECT:\r
 231                         new_state = TAP_RESET;\r
 232                         break;\r
 233                 case TAP_IRCAPTURE:\r
 234                 case TAP_IRSHIFT:\r
 235                         new_state = TAP_IREXIT1;\r
 236                         break;\r
 237                 case TAP_IREXIT1:\r
 238                 case TAP_IREXIT2:\r
 239                         new_state = TAP_IRUPDATE;\r
 240                         break;\r
 241                 case TAP_IRPAUSE:\r
 242                         new_state = TAP_IREXIT2;\r
 243                         break;\r
 244                 default:\r
 245                         LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
 246                         exit(1);\r
 247                         break;\r
 248                 }\r
 249         }\r
 250         else\r
 251         {\r
 252                 switch (cur_state)\r
 253                 {\r
 254                 case TAP_RESET:\r
 255                 case TAP_IDLE:\r
 256                 case TAP_DRUPDATE:\r
 257                 case TAP_IRUPDATE:\r
 258                         new_state = TAP_IDLE;\r
 259                         break;\r
 260                 case TAP_DRSELECT:\r
 261                         new_state = TAP_DRCAPTURE;\r
 262                         break;\r
 263                 case TAP_DRCAPTURE:\r
 264                 case TAP_DRSHIFT:\r
 265                 case TAP_DREXIT2:\r
 266                         new_state = TAP_DRSHIFT;\r
 267                         break;\r
 268                 case TAP_DREXIT1:\r
 269                 case TAP_DRPAUSE:\r
 270                         new_state = TAP_DRPAUSE;\r
 271                         break;\r
 272                 case TAP_IRSELECT:\r
 273                         new_state = TAP_IRCAPTURE;\r
 274                         break;\r
 275                 case TAP_IRCAPTURE:\r
 276                 case TAP_IRSHIFT:\r
 277                 case TAP_IREXIT2:\r
 278                         new_state = TAP_IRSHIFT;\r
 279                         break;\r
 280                 case TAP_IREXIT1:\r
 281                 case TAP_IRPAUSE:\r
 282                         new_state = TAP_IRPAUSE;\r
 283                         break;\r
 284                 default:\r
 285                         LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
 286                         exit(1);\r
 287                         break;\r
 288                 }\r
 289         }\r
 290 \r
 291         return new_state;\r
 292 }\r