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bumped a LOG_INFO to LOG_DEBUG level to reduce excessive output for normal execution
[openocd.git] / src / jtag / dummy.c
diff --git a/src/jtag/dummy.c b/src/jtag/dummy.c
index 90c60db8d7cd9b187cd4caf3158bbdb1e8562364..bfdf0dcccfe37c757b8248f85d5c0ad19f96fb68 100644 (file)
--- a/src/jtag/dummy.c
+++ b/src/jtag/dummy.c
@@ -27,22 +27,36 @@
 #include "bitbang.h"\r
 \r
 \r
+/* my private tap controller state, which tracks state for calling code */\r
+static tap_state_t dummy_state = TAP_RESET;\r
+\r
+static int dummy_clock;         /* edge detector */\r
+\r
+static tap_state_t tap_state_transition(tap_state_t cur_state, int tms);\r
+\r
+\r
 int dummy_speed(int speed);\r
 int dummy_register_commands(struct command_context_s *cmd_ctx);\r
 int dummy_init(void);\r
 int dummy_quit(void);\r
+static int dummy_khz(int khz, int *jtag_speed);\r
+static int dummy_speed_div(int speed, int *khz);\r
+\r
 \r
-/* The dummy driver is used to easily check the code path \r
+/* The dummy driver is used to easily check the code path\r
  * where the target is unresponsive.\r
  */\r
-jtag_interface_t dummy_interface = \r
+jtag_interface_t dummy_interface =\r
 {\r
        .name = "dummy",\r
-       \r
+\r
        .execute_queue = bitbang_execute_queue,\r
 \r
-       .speed = dummy_speed,   \r
+       .speed = dummy_speed,\r
        .register_commands = dummy_register_commands,\r
+       .khz = dummy_khz,\r
+       .speed_div = dummy_speed_div,\r
+\r
        .init = dummy_init,\r
        .quit = dummy_quit,\r
 };\r
@@ -68,12 +82,53 @@ int dummy_read(void)
 \r
 void dummy_write(int tck, int tms, int tdi)\r
 {\r
+       /* TAP standard: "state transitions occur on rising edge of clock" */\r
+       if( tck != dummy_clock )\r
+       {\r
+               if( tck )\r
+               {\r
+                       int old_state = dummy_state;\r
+                       dummy_state = tap_state_transition( dummy_state, tms );\r
+                       if( old_state != dummy_state )\r
+                               LOG_DEBUG( "dummy_tap=%s", jtag_state_name(dummy_state) );\r
+               }\r
+               dummy_clock = tck;\r
+       }\r
 }\r
 \r
 void dummy_reset(int trst, int srst)\r
 {\r
+       dummy_clock = 0;\r
+       dummy_state = TAP_RESET;\r
+       LOG_DEBUG( "reset to %s", jtag_state_name(dummy_state) );\r
+}\r
+\r
+static int dummy_khz(int khz, int *jtag_speed)\r
+{\r
+       if (khz==0)\r
+       {\r
+               *jtag_speed=0;\r
+       }\r
+       else\r
+       {\r
+               *jtag_speed=64000/khz;\r
+       }\r
+       return ERROR_OK;\r
+}\r
+\r
+static int dummy_speed_div(int speed, int *khz)\r
+{\r
+       if (speed==0)\r
+       {\r
+               *khz = 0;\r
+       }\r
+       else\r
+       {\r
+               *khz=64000/speed;\r
+       }\r
+\r
+       return ERROR_OK;\r
 }\r
-       \r
 \r
 int dummy_speed(int speed)\r
 {\r
@@ -85,10 +140,9 @@ int dummy_register_commands(struct command_context_s *cmd_ctx)
        return ERROR_OK;\r
 }\r
 \r
-\r
 int dummy_init(void)\r
 {\r
-       bitbang_interface = &dummy_bitbang;     \r
+       bitbang_interface = &dummy_bitbang;\r
 \r
        return ERROR_OK;\r
 }\r
@@ -98,8 +152,110 @@ int dummy_quit(void)
        return ERROR_OK;\r
 }\r
 \r
-\r
 void dummy_led(int on)\r
 {\r
 }\r
 \r
+\r
+/**\r
+ * Function tap_state_transition\r
+ * takes a current TAP state and returns the next state according to the tms value.\r
+ *\r
+ * Even though there is code to duplicate this elsewhere, we do it here a little\r
+ * differently just to get a second opinion, i.e. a verification, on state tracking\r
+ * in that other logic. Plus array lookups without index checking are no favorite thing.\r
+ * This is educational for developers new to TAP controllers.\r
+ */\r
+static tap_state_t tap_state_transition(tap_state_t cur_state, int tms)\r
+{\r
+       tap_state_t new_state;\r
+\r
+       if (tms)\r
+       {\r
+               switch (cur_state)\r
+               {\r
+               case TAP_RESET:\r
+                       new_state = cur_state;\r
+                       break;\r
+               case TAP_IDLE:\r
+               case TAP_DRUPDATE:\r
+               case TAP_IRUPDATE:\r
+                       new_state = TAP_DRSELECT;\r
+                       break;\r
+               case TAP_DRSELECT:\r
+                       new_state = TAP_IRSELECT;\r
+                       break;\r
+               case TAP_DRCAPTURE:\r
+               case TAP_DRSHIFT:\r
+                       new_state = TAP_DREXIT1;\r
+                       break;\r
+               case TAP_DREXIT1:\r
+               case TAP_DREXIT2:\r
+                       new_state = TAP_DRUPDATE;\r
+                       break;\r
+               case TAP_DRPAUSE:\r
+                       new_state = TAP_DREXIT2;\r
+                       break;\r
+               case TAP_IRSELECT:\r
+                       new_state = TAP_RESET;\r
+                       break;\r
+               case TAP_IRCAPTURE:\r
+               case TAP_IRSHIFT:\r
+                       new_state = TAP_IREXIT1;\r
+                       break;\r
+               case TAP_IREXIT1:\r
+               case TAP_IREXIT2:\r
+                       new_state = TAP_IRUPDATE;\r
+                       break;\r
+               case TAP_IRPAUSE:\r
+                       new_state = TAP_IREXIT2;\r
+                       break;\r
+               default:\r
+                       LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
+                       exit(1);\r
+                       break;\r
+               }\r
+       }\r
+       else\r
+       {\r
+               switch (cur_state)\r
+               {\r
+               case TAP_RESET:\r
+               case TAP_IDLE:\r
+               case TAP_DRUPDATE:\r
+               case TAP_IRUPDATE:\r
+                       new_state = TAP_IDLE;\r
+                       break;\r
+               case TAP_DRSELECT:\r
+                       new_state = TAP_DRCAPTURE;\r
+                       break;\r
+               case TAP_DRCAPTURE:\r
+               case TAP_DRSHIFT:\r
+               case TAP_DREXIT2:\r
+                       new_state = TAP_DRSHIFT;\r
+                       break;\r
+               case TAP_DREXIT1:\r
+               case TAP_DRPAUSE:\r
+                       new_state = TAP_DRPAUSE;\r
+                       break;\r
+               case TAP_IRSELECT:\r
+                       new_state = TAP_IRCAPTURE;\r
+                       break;\r
+               case TAP_IRCAPTURE:\r
+               case TAP_IRSHIFT:\r
+               case TAP_IREXIT2:\r
+                       new_state = TAP_IRSHIFT;\r
+                       break;\r
+               case TAP_IREXIT1:\r
+               case TAP_IRPAUSE:\r
+                       new_state = TAP_IRPAUSE;\r
+                       break;\r
+               default:\r
+                       LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
+                       exit(1);\r
+                       break;\r
+               }\r
+       }\r
+\r
+       return new_state;\r
+}\r
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