diff options
Diffstat (limited to 'src/jtag/jtag.h')
| -rw-r--r-- | src/jtag/jtag.h | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h index 2c186e9c..114e6aa3 100644 --- a/src/jtag/jtag.h +++ b/src/jtag/jtag.h @@ -308,13 +308,32 @@ 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. * - * trst & srst must be 0 or 1. There is no way to - * read the current reset state. + * 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. + * + */ +extern void jtag_add_reset(int req_tms_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. + * + * the higher level jtag_add_reset will invoke jtag_add_tms() 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); |