David Brownell <david-b@pacbell.net> Some jtag_add_reset() cleanup:
- Track whether TRST and/or SRST actually change:
* If they're not changing, don't ask the JTAG adapter to do anything!
(JTAG TCK/TMS ops might still be used to enter TAP_RESET though.)
* Don't change their recorded values until after the adapter says it
did so ... so fault paths can't leave corrupt state.
* Detect and report jtag_execute_queue() failure mode
* Only emit messages saying what really changed; this includes adding
an omitted "deasserted TRST" message.
* Only apply delays after deasserting SRST/TRST if we *DID* deassert!
- Messages say "TLR" not "RESET", to be less confusing; there are many
kinds of reset. (Though "TLR" isn't quite ideal either, since it's
the name of the TAP state being entered by TMS+TCK or TRST; it's at
least non-ambiguous in context.)
So the main effect is to do only the work this routine was told to do;
and to have debug messaging make more sense.
git-svn-id: svn://svn.berlios.de/openocd/trunk@2621 b42882b7-edfa-0310-969c-e2dbd0fdcd60
__archive__
oharboe
parent
bd7cbd01e8
commit
6f359fba68
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@ -60,11 +60,15 @@ static int jtag_error = ERROR_OK;
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static const char *jtag_event_strings[] =
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{
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[JTAG_TRST_ASSERTED] = "JTAG controller reset (RESET or TRST)",
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[JTAG_TRST_ASSERTED] = "JTAG controller reset (TLR or TRST)",
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[JTAG_TAP_EVENT_ENABLE] = "TAP enabled",
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[JTAG_TAP_EVENT_DISABLE] = "TAP disabled",
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};
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/*
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* JTAG adapters must initialize with TRST and SRST de-asserted
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* (they're negative logic, so that means *high*)
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*/
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static int jtag_trst = 0;
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static int jtag_srst = 0;
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@ -581,6 +585,8 @@ void jtag_add_clocks(int num_cycles)
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void jtag_add_reset(int req_tlr_or_trst, int req_srst)
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{
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int trst_with_tlr = 0;
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int new_srst;
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int new_trst = 0;
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/* FIX!!! there are *many* different cases here. A better
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* approach is needed for legal combinations of transitions...
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@ -625,60 +631,74 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
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{
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if (!trst_with_tlr && (jtag_reset_config & RESET_HAS_TRST))
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{
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jtag_trst = 1;
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new_trst = 1;
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} else
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{
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trst_with_tlr = 1;
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}
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} else
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{
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jtag_trst = 0;
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}
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jtag_srst = req_srst;
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new_srst = req_srst;
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int retval = interface_jtag_add_reset(jtag_trst, jtag_srst);
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/* Maybe change TRST and/or SRST signal state */
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if (jtag_srst != new_srst || jtag_trst != new_trst) {
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int retval;
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retval = interface_jtag_add_reset(new_trst, new_srst);
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if (retval != ERROR_OK)
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{
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jtag_set_error(retval);
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else
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retval = jtag_execute_queue();
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if (retval != ERROR_OK) {
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LOG_ERROR("TRST/SRST error %d", retval);
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return;
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}
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jtag_execute_queue();
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if (jtag_srst)
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{
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LOG_DEBUG("SRST line asserted");
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}
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else
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{
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/* SRST resets everything hooked up to that signal */
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if (jtag_srst != new_srst) {
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jtag_srst = new_srst;
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if (jtag_srst)
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LOG_DEBUG("SRST line asserted");
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else {
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LOG_DEBUG("SRST line released");
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if (jtag_nsrst_delay)
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jtag_add_sleep(jtag_nsrst_delay * 1000);
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}
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if (trst_with_tlr)
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{
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LOG_DEBUG("JTAG reset with RESET instead of TRST");
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jtag_set_end_state(TAP_RESET);
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jtag_add_tlr();
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return;
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}
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if (jtag_trst)
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{
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/* we just asserted nTRST, so we're now in Test-Logic-Reset,
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* and inform possible listeners about this
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/* Maybe enter the JTAG TAP_RESET state ...
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* - using only TMS, TCK, and the JTAG state machine
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* - or else more directly, using TRST
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*
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* TAP_RESET should be invisible to non-debug parts of the system.
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*/
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if (trst_with_tlr) {
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LOG_DEBUG("JTAG reset with TLR instead of TRST");
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jtag_set_end_state(TAP_RESET);
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jtag_add_tlr();
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} else if (jtag_trst != new_trst) {
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jtag_trst = new_trst;
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if (jtag_trst) {
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/* we just asserted nTRST, so we're now in TAP_RESET;
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* inform possible listeners about this
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*
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* REVISIT asserting TRST is less significant than
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* being in TAP_RESET ... both entries (TRST, TLR)
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* should trigger a callback.
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*/
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LOG_DEBUG("TRST line asserted");
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tap_set_state(TAP_RESET);
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jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
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}
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else
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{
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} else {
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LOG_DEBUG("TRST line released");
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if (jtag_ntrst_delay)
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jtag_add_sleep(jtag_ntrst_delay * 1000);
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}
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}
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}
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tap_state_t jtag_set_end_state(tap_state_t state)
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{
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@ -1223,11 +1243,11 @@ int jtag_init_reset(struct command_context_s *cmd_ctx)
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if ((retval = jtag_interface_init(cmd_ctx)) != ERROR_OK)
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return retval;
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LOG_DEBUG("Trying to bring the JTAG controller to life by asserting TRST / RESET");
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LOG_DEBUG("Trying to bring the JTAG controller to life by asserting TRST / TLR");
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/* Reset can happen after a power cycle.
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*
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* Ideally we would only assert TRST or run RESET before the target reset.
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* Ideally we would only assert TRST or run TLR before the target reset.
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*
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* However w/srst_pulls_trst, trst is asserted together with the target
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* reset whether we want it or not.
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@ -1240,7 +1260,7 @@ int jtag_init_reset(struct command_context_s *cmd_ctx)
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* NB! order matters!!!! srst *can* disconnect JTAG circuitry
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*
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*/
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jtag_add_reset(1, 0); /* RESET or TRST */
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jtag_add_reset(1, 0); /* TAP_RESET, using TMS+TCK or TRST */
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if (jtag_reset_config & RESET_HAS_SRST)
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{
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jtag_add_reset(1, 1);
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