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David Brownell <david-b@pacbell.net> More jtag_add_reset() cleanup: 

Unify the handling of the req_srst parameter, and rip out a
large NOP branch and its associated FIXME.  (There didn't seem
to be anything that needs fixing; but that was unclear since
the constraints were scattered all over the place not unified.)

git-svn-id: svn://svn.berlios.de/openocd/trunk@2623 b42882b7-edfa-0310-969c-e2dbd0fdcd60
This commit is contained in:
oharboe 2009-08-25 19:59:55 +00:00
parent 86b49612a6
commit 24f011ebb4
1 changed files with 23 additions and 36 deletions
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59
src/jtag/core.c
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@ -585,9 +585,31 @@ void jtag_add_clocks(int num_cycles)
void jtag_add_reset(int req_tlr_or_trst, int req_srst) void jtag_add_reset(int req_tlr_or_trst, int req_srst)
{ {
int trst_with_tlr = 0; int trst_with_tlr = 0;
int new_srst; int new_srst = 0;
int new_trst = 0; int new_trst = 0;
/* Without SRST, we must use target-specific JTAG operations
* on each target; callers should not be requesting SRST when
* that signal doesn't exist.
*
* RESET_SRST_PULLS_TRST is a board or chip level quirk, which
* can kick in even if the JTAG adapter can't drive TRST.
*/
if (req_srst) {
if (!(jtag_reset_config & RESET_HAS_SRST)) {
LOG_ERROR("BUG: can't assert SRST");
jtag_set_error(ERROR_FAIL);
return;
}
if ((jtag_reset_config & RESET_SRST_PULLS_TRST) != 0
&& !req_tlr_or_trst) {
LOG_ERROR("BUG: can't assert only SRST");
jtag_set_error(ERROR_FAIL);
return;
}
new_srst = 1;
}
/* JTAG reset (entry to TAP_RESET state) can always be achieved /* JTAG reset (entry to TAP_RESET state) can always be achieved
* using TCK and TMS; that may go through a TAP_{IR,DR}UPDATE * using TCK and TMS; that may go through a TAP_{IR,DR}UPDATE
* state first. TRST accelerates it, and bypasses those states. * state first. TRST accelerates it, and bypasses those states.
@ -605,41 +627,6 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
new_trst = 1; new_trst = 1;
} }
/* FIX!!! there are *many* different cases here. A better
* approach is needed for legal combinations of transitions...
*/
if ((jtag_reset_config & RESET_HAS_SRST)&&
(jtag_reset_config & RESET_HAS_TRST)&&
((jtag_reset_config & RESET_SRST_PULLS_TRST) == 0))
{
if (((req_tlr_or_trst&&!jtag_trst)||
(!req_tlr_or_trst && jtag_trst))&&
((req_srst&&!jtag_srst)||
(!req_srst && jtag_srst)))
{
/* FIX!!! srst_pulls_trst allows 1,1 => 0,0 transition.... */
//LOG_ERROR("BUG: transition of req_tlr_or_trst and req_srst in the same jtag_add_reset() call is undefined");
}
}
/* Make sure that jtag_reset_config allows the requested reset */
/* if SRST pulls TRST, we can't fulfill srst == 1 with trst == 0 */
if (((jtag_reset_config & RESET_SRST_PULLS_TRST) && (req_srst == 1)) && (!req_tlr_or_trst))
{
LOG_ERROR("BUG: requested reset would assert trst");
jtag_set_error(ERROR_FAIL);
return;
}
if (req_srst && !(jtag_reset_config & RESET_HAS_SRST))
{
LOG_ERROR("BUG: requested SRST assertion, but the current configuration doesn't support this");
jtag_set_error(ERROR_FAIL);
return;
}
new_srst = req_srst;
/* Maybe change TRST and/or SRST signal state */ /* Maybe change TRST and/or SRST signal state */
if (jtag_srst != new_srst || jtag_trst != new_trst) { if (jtag_srst != new_srst || jtag_trst != new_trst) {
int retval; int retval;