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-rw-r--r--src/xsvf/xsvf.c101
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;