- added "init" command. "init" and "reset" at end of startup script is equivalent

[openocd.git] / src / jtag / jtag.h

diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h
index 2c186e9cbc3b028a4543a41ae9a2d49d8a15f2d0..b7ce094d6aeec0f17d6e9ffa639fc70dfa408eed 100644 (file)
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -241,8 +241,12 @@ enum reset_types
 
 extern enum reset_types jtag_reset_config;
 
-/* JTAG subsystem */
+/* initialize JTAG chain using only a TLR reset. If init fails,
+ * try reset + init.
+ */
 extern int jtag_init(struct command_context_s *cmd_ctx);
+/* reset, then initialize JTAG chain */
+extern int jtag_init_reset(struct command_context_s *cmd_ctx);
 extern int jtag_register_commands(struct command_context_s *cmd_ctx);
 
 /* JTAG interface, can be implemented with a software or hardware fifo
@@ -268,8 +272,8 @@ extern int interface_jtag_add_plain_dr_scan(int num_fields, scan_field_t *fields
 /* run a TAP_TLR reset. End state is TAP_TLR, regardless
  * of start state.
  */
-extern void jtag_add_tms();
-extern int interface_jtag_add_tms();
+extern void jtag_add_tlr();
+extern int interface_jtag_add_tlr();
 /* Do not use jtag_add_pathmove() unless you need to, but do use it
  * if you have to. 
  *
@@ -308,13 +312,36 @@ extern int interface_jtag_add_pathmove(int num_states, enum tap_state *path);
  */
 extern void jtag_add_runtest(int num_cycles, enum tap_state endstate);
 extern int interface_jtag_add_runtest(int num_cycles, enum tap_state endstate);
-/* Invoking jtag_add_reset() with unsupported combinations is
- * not allowed and constitutes a bug in the calling code.
+/* A reset of the TAP state machine can be requested.
+ * 
+ * Whether tms or trst reset is used depends on the capabilities of 
+ * the target and jtag interface(reset_config  command configures this).
+ * 
+ * srst can driver a reset of the TAP state machine and vice
+ * versa
+ * 
+ * Application code may need to examine value of jtag_reset_config
+ * to determine the proper codepath
+ * 
+ * DANGER! Even though srst drives trst, trst might not be connected to
+ * the interface, and it might actually be *harmful* to assert trst in this case.
+ * 
+ * This is why combinations such as "reset_config srst_only srst_pulls_trst"
+ * are supported. 
+ *
+ * only req_tlr_or_trst and srst can have a transition for a
+ * call as the effects of transitioning both at the "same time" 
+ * are undefined, but when srst_pulls_trst or vice versa,
+ * then trst & srst *must* be asserted together.
+ */
+extern void jtag_add_reset(int req_tlr_or_trst, int srst);
+/* this drives the actual srst and trst pins. srst will always be 0
+ * if jtag_reset_config & RESET_SRST_PULLS_TRST != 0 and ditto for
+ * trst.
  * 
- * trst & srst must be 0 or 1. There is no way to 
- * read the current reset state.
+ * the higher level jtag_add_reset will invoke jtag_add_tlr() if 
+ * approperiate
  */
-extern void jtag_add_reset(int trst, int srst);
 extern int interface_jtag_add_reset(int trst, int srst);
 extern void jtag_add_end_state(enum tap_state endstate);
 extern int interface_jtag_add_end_state(enum tap_state endstate);