git.gag.com Git - fw/openocd/blob - src/jtag/dummy.c

   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 tap_state_t tap_state_transition(tap_state_t cur_state, int tms);\r
  36 \r
  37 \r
  38 int dummy_speed(int speed);\r
  39 int dummy_register_commands(struct command_context_s *cmd_ctx);\r
  40 int dummy_init(void);\r
  41 int dummy_quit(void);\r
  42 static int dummy_khz(int khz, int *jtag_speed);\r
  43 static int dummy_speed_div(int speed, int *khz);\r
  44 \r
  45 \r
  46 /* The dummy driver is used to easily check the code path\r
  47  * where the target is unresponsive.\r
  48  */\r
  49 jtag_interface_t dummy_interface =\r
  50 {\r
  51         .name = "dummy",\r
  52 \r
  53         .execute_queue = bitbang_execute_queue,\r
  54 \r
  55         .speed = dummy_speed,\r
  56         .register_commands = dummy_register_commands,\r
  57         .khz = dummy_khz,\r
  58         .speed_div = dummy_speed_div,\r
  59 \r
  60         .init = dummy_init,\r
  61         .quit = dummy_quit,\r
  62 };\r
  63 \r
  64 int dummy_read(void);\r
  65 void dummy_write(int tck, int tms, int tdi);\r
  66 void dummy_reset(int trst, int srst);\r
  67 void dummy_led(int on);\r
  68 \r
  69 bitbang_interface_t dummy_bitbang =\r
  70 {\r
  71         .read = dummy_read,\r
  72         .write = dummy_write,\r
  73         .reset = dummy_reset,\r
  74         .blink = dummy_led\r
  75 };\r
  76 \r
  77 int dummy_read(void)\r
  78 {\r
  79         return 1;\r
  80 }\r
  81 \r
  82 \r
  83 void dummy_write(int tck, int tms, int tdi)\r
  84 {\r
  85         /* TAP standard: "state transitions occur on rising edge of clock" */\r
  86         if( tck != dummy_clock )\r
  87         {\r
  88                 if( tck )\r
  89                 {\r
  90                         int old_state = dummy_state;\r
  91                         dummy_state = tap_state_transition( dummy_state, tms );\r
  92                         if( old_state != dummy_state )\r
  93                                 LOG_DEBUG( "dummy_tap=%s", jtag_state_name(dummy_state) );\r
  94                 }\r
  95                 dummy_clock = tck;\r
  96         }\r
  97 }\r
  98 \r
  99 void dummy_reset(int trst, int srst)\r
 100 {\r
 101         dummy_clock = 0;\r
 102         dummy_state = TAP_RESET;\r
 103         LOG_DEBUG( "reset to %s", jtag_state_name(dummy_state) );\r
 104 }\r
 105 \r
 106 static int dummy_khz(int khz, int *jtag_speed)\r
 107 {\r
 108         if (khz==0)\r
 109         {\r
 110                 *jtag_speed=0;\r
 111         }\r
 112         else\r
 113         {\r
 114                 *jtag_speed=64000/khz;\r
 115         }\r
 116         return ERROR_OK;\r
 117 }\r
 118 \r
 119 static int dummy_speed_div(int speed, int *khz)\r
 120 {\r
 121         if (speed==0)\r
 122         {\r
 123                 *khz = 0;\r
 124         }\r
 125         else\r
 126         {\r
 127                 *khz=64000/speed;\r
 128         }\r
 129 \r
 130         return ERROR_OK;\r
 131 }\r
 132 \r
 133 int dummy_speed(int speed)\r
 134 {\r
 135         return ERROR_OK;\r
 136 }\r
 137 \r
 138 int dummy_register_commands(struct command_context_s *cmd_ctx)\r
 139 {\r
 140         return ERROR_OK;\r
 141 }\r
 142 \r
 143 int dummy_init(void)\r
 144 {\r
 145         bitbang_interface = &dummy_bitbang;\r
 146 \r
 147         return ERROR_OK;\r
 148 }\r
 149 \r
 150 int dummy_quit(void)\r
 151 {\r
 152         return ERROR_OK;\r
 153 }\r
 154 \r
 155 void dummy_led(int on)\r
 156 {\r
 157 }\r
 158 \r
 159 \r
 160 /**\r
 161  * Function tap_state_transition\r
 162  * takes a current TAP state and returns the next state according to the tms value.\r
 163  *\r
 164  * Even though there is code to duplicate this elsewhere, we do it here a little\r
 165  * differently just to get a second opinion, i.e. a verification, on state tracking\r
 166  * in that other logic. Plus array lookups without index checking are no favorite thing.\r
 167  * This is educational for developers new to TAP controllers.\r
 168  */\r
 169 static tap_state_t tap_state_transition(tap_state_t cur_state, int tms)\r
 170 {\r
 171         tap_state_t new_state;\r
 172 \r
 173         if (tms)\r
 174         {\r
 175                 switch (cur_state)\r
 176                 {\r
 177                 case TAP_RESET:\r
 178                         new_state = cur_state;\r
 179                         break;\r
 180                 case TAP_IDLE:\r
 181                 case TAP_DRUPDATE:\r
 182                 case TAP_IRUPDATE:\r
 183                         new_state = TAP_DRSELECT;\r
 184                         break;\r
 185                 case TAP_DRSELECT:\r
 186                         new_state = TAP_IRSELECT;\r
 187                         break;\r
 188                 case TAP_DRCAPTURE:\r
 189                 case TAP_DRSHIFT:\r
 190                         new_state = TAP_DREXIT1;\r
 191                         break;\r
 192                 case TAP_DREXIT1:\r
 193                 case TAP_DREXIT2:\r
 194                         new_state = TAP_DRUPDATE;\r
 195                         break;\r
 196                 case TAP_DRPAUSE:\r
 197                         new_state = TAP_DREXIT2;\r
 198                         break;\r
 199                 case TAP_IRSELECT:\r
 200                         new_state = TAP_RESET;\r
 201                         break;\r
 202                 case TAP_IRCAPTURE:\r
 203                 case TAP_IRSHIFT:\r
 204                         new_state = TAP_IREXIT1;\r
 205                         break;\r
 206                 case TAP_IREXIT1:\r
 207                 case TAP_IREXIT2:\r
 208                         new_state = TAP_IRUPDATE;\r
 209                         break;\r
 210                 case TAP_IRPAUSE:\r
 211                         new_state = TAP_IREXIT2;\r
 212                         break;\r
 213                 default:\r
 214                         LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
 215                         exit(1);\r
 216                         break;\r
 217                 }\r
 218         }\r
 219         else\r
 220         {\r
 221                 switch (cur_state)\r
 222                 {\r
 223                 case TAP_RESET:\r
 224                 case TAP_IDLE:\r
 225                 case TAP_DRUPDATE:\r
 226                 case TAP_IRUPDATE:\r
 227                         new_state = TAP_IDLE;\r
 228                         break;\r
 229                 case TAP_DRSELECT:\r
 230                         new_state = TAP_DRCAPTURE;\r
 231                         break;\r
 232                 case TAP_DRCAPTURE:\r
 233                 case TAP_DRSHIFT:\r
 234                 case TAP_DREXIT2:\r
 235                         new_state = TAP_DRSHIFT;\r
 236                         break;\r
 237                 case TAP_DREXIT1:\r
 238                 case TAP_DRPAUSE:\r
 239                         new_state = TAP_DRPAUSE;\r
 240                         break;\r
 241                 case TAP_IRSELECT:\r
 242                         new_state = TAP_IRCAPTURE;\r
 243                         break;\r
 244                 case TAP_IRCAPTURE:\r
 245                 case TAP_IRSHIFT:\r
 246                 case TAP_IREXIT2:\r
 247                         new_state = TAP_IRSHIFT;\r
 248                         break;\r
 249                 case TAP_IREXIT1:\r
 250                 case TAP_IRPAUSE:\r
 251                         new_state = TAP_IRPAUSE;\r
 252                         break;\r
 253                 default:\r
 254                         LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
 255                         exit(1);\r
 256                         break;\r
 257                 }\r
 258         }\r
 259 \r
 260         return new_state;\r
 261 }\r