diff options
| -rw-r--r-- | src/xsvf/xsvf.c | 101 |
1 files changed, 83 insertions, 18 deletions
diff --git a/src/xsvf/xsvf.c b/src/xsvf/xsvf.c index 17dec493..24a14de7 100644 --- a/src/xsvf/xsvf.c +++ b/src/xsvf/xsvf.c @@ -177,13 +177,13 @@ static tap_state_t xsvf_to_tap( int xsvf_state ) /** * Function xsvf_add_statemove * moves from the current state to the goal \a state. This needs - * to be handled according to the xsvf spec, which has nothing - * to do with the JTAG spec or OpenOCD as such. - * - * Implemented via jtag_add_pathmove(). + * to be handled according to the xsvf spec, see the XSTATE command + * description. */ -static void xsvf_add_statemove(tap_state_t goal_state) +static int xsvf_add_statemove(tap_state_t goal_state) { + int retval = ERROR_OK; + tap_state_t moves[8]; tap_state_t cur_state = cmd_queue_cur_state; int i; @@ -194,29 +194,69 @@ static void xsvf_add_statemove(tap_state_t goal_state) tap_state_name(cur_state), tap_state_name(goal_state) ); + + /* From the XSVF spec, pertaining to XSTATE: + + For special states known as stable states (Test-Logic-Reset, + Run-Test/Idle, Pause-DR, Pause- IR), an XSVF interpreter follows + predefined TAP state paths when the starting state is a stable state and + when the XSTATE specifies a new stable state (see the STATE command in + the [Ref 5] for the TAP state paths between stable states). For + non-stable states, XSTATE should specify a state that is only one TAP + state transition distance from the current TAP state to avoid undefined + TAP state paths. A sequence of multiple XSTATE commands can be issued to + transition the TAP through a specific state path. + */ + if (goal_state==cur_state ) - return; + ; /* nothing to do */ - if( goal_state==TAP_RESET ) + else if( goal_state==TAP_RESET ) { jtag_add_tlr(); - return; } - tms_bits = tap_get_tms_path(cur_state, goal_state); - tms_count = tap_get_tms_path_len(cur_state, goal_state); + else if( tap_is_state_stable(cur_state) && tap_is_state_stable(goal_state) ) + { + /* note: unless tms_bits holds a path that agrees with [Ref 5] in above + spec, then this code is not fully conformant to the xsvf spec. This + puts a burden on tap_get_tms_path() function from the xsvf spec. + If in doubt, you should confirm that that burden is being met. + */ + + tms_bits = tap_get_tms_path(cur_state, goal_state); + tms_count = tap_get_tms_path_len(cur_state, goal_state); - assert( (unsigned) tms_count < DIM(moves) ); + assert( (unsigned) tms_count < DIM(moves) ); - for (i=0; i<tms_count; i++, tms_bits>>=1) + for (i=0; i<tms_count; i++, tms_bits>>=1) + { + bool bit = tms_bits & 1; + + cur_state = tap_state_transition(cur_state, bit); + moves[i] = cur_state; + } + + jtag_add_pathmove(tms_count, moves); + } + + /* else state must be immediately reachable in one clock cycle, and does not + need to be a stable state. + */ + else if( tap_state_transition(cur_state, true) == goal_state + || tap_state_transition(cur_state, false) == goal_state ) { - bool bit = tms_bits & 1; + /* move a single state */ + moves[0] = goal_state; + jtag_add_pathmove( 1, moves ); + } - cur_state = tap_state_transition(cur_state, bit); - moves[i] = cur_state; + else + { + retval = ERROR_FAIL; } - jtag_add_pathmove(tms_count, moves); + return retval; } @@ -557,7 +597,32 @@ static int handle_xsvf_command(struct command_context_s *cmd_ctx, char *cmd, cha LOG_DEBUG("XSTATE 0x%02X %s", uc, tap_state_name(mystate) ); - xsvf_add_statemove( mystate ); + /* there is no need for the lookahead code that was here since we + queue up the jtag commands anyway. This is a simple way to handle + the XSTATE. + */ + + if( xsvf_add_statemove( mystate ) != ERROR_OK ) + { + /* For special states known as stable states + (Test-Logic-Reset, Run-Test/Idle, Pause-DR, Pause- IR), + an XSVF interpreter follows predefined TAP state paths + when the starting state is a stable state and when the + XSTATE specifies a new stable state (see the STATE + command in the [Ref 5] for the TAP state paths between + stable states). For non-stable states, XSTATE should + specify a state that is only one TAP state transition + distance from the current TAP state to avoid undefined + TAP state paths. A sequence of multiple XSTATE commands + can be issued to transition the TAP through a specific + state path. + */ + + LOG_ERROR("XSTATE %s is not reachable from current state %s in one clock cycle", + tap_state_name(mystate), + tap_state_name(cmd_queue_cur_state) + ); + } } break; @@ -703,7 +768,7 @@ static int handle_xsvf_command(struct command_context_s *cmd_ctx, char *cmd, cha comment[sizeof(comment)-1] = 0; /* regardless, terminate */ if (verbose) - LOG_USER("\"# %s\"", comment); + LOG_USER("# %s", comment); } break; |