Commit 46c1cb25 authored by oharboe's avatar oharboe
Browse files

Dick Hollenbeck <dick@softplc.com> - This patch adds JTAG state tracking to dummy.c

git-svn-id: svn://svn.berlios.de/openocd/trunk@1263 b42882b7-edfa-0310-969c-e2dbd0fdcd60
parent ca805a47
......@@ -26,6 +26,15 @@
#include "jtag.h"
#include "bitbang.h"
/* my private tap controller state, which tracks state for calling code */
static tap_state_t dummy_state = TAP_RESET;
static int dummy_clock; /* edge detector */
static tap_state_t tap_state_transition(tap_state_t cur_state, int tms);
int dummy_speed(int speed);
int dummy_register_commands(struct command_context_s *cmd_ctx);
int dummy_init(void);
......@@ -70,12 +79,28 @@ int dummy_read(void)
return 1;
}
void dummy_write(int tck, int tms, int tdi)
{
/* TAP standard: "state transitions occur on rising edge of clock" */
if( tck != dummy_clock )
{
if( tck )
{
int old_state = dummy_state;
dummy_state = tap_state_transition( dummy_state, tms );
if( old_state != dummy_state )
LOG_INFO( "dummy_tap=%s", jtag_state_name(dummy_state) );
}
dummy_clock = tck;
}
}
void dummy_reset(int trst, int srst)
{
dummy_clock = 0;
dummy_state = TAP_RESET;
LOG_DEBUG( "reset to %s", jtag_state_name(dummy_state) );
}
static int dummy_khz(int khz, int *jtag_speed)
......@@ -130,3 +155,107 @@ int dummy_quit(void)
void dummy_led(int on)
{
}
/**
* Function tap_state_transition
* takes a current TAP state and returns the next state according to the tms value.
*
* Even though there is code to duplicate this elsewhere, we do it here a little
* differently just to get a second opinion, i.e. a verification, on state tracking
* in that other logic. Plus array lookups without index checking are no favorite thing.
* This is educational for developers new to TAP controllers.
*/
static tap_state_t tap_state_transition(tap_state_t cur_state, int tms)
{
tap_state_t new_state;
if (tms)
{
switch (cur_state)
{
case TAP_RESET:
new_state = cur_state;
break;
case TAP_IDLE:
case TAP_DRUPDATE:
case TAP_IRUPDATE:
new_state = TAP_DRSELECT;
break;
case TAP_DRSELECT:
new_state = TAP_IRSELECT;
break;
case TAP_DRCAPTURE:
case TAP_DRSHIFT:
new_state = TAP_DREXIT1;
break;
case TAP_DREXIT1:
case TAP_DREXIT2:
new_state = TAP_DRUPDATE;
break;
case TAP_DRPAUSE:
new_state = TAP_DREXIT2;
break;
case TAP_IRSELECT:
new_state = TAP_RESET;
break;
case TAP_IRCAPTURE:
case TAP_IRSHIFT:
new_state = TAP_IREXIT1;
break;
case TAP_IREXIT1:
case TAP_IREXIT2:
new_state = TAP_IRUPDATE;
break;
case TAP_IRPAUSE:
new_state = TAP_IREXIT2;
break;
default:
LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );
exit(1);
break;
}
}
else
{
switch (cur_state)
{
case TAP_RESET:
case TAP_IDLE:
case TAP_DRUPDATE:
case TAP_IRUPDATE:
new_state = TAP_IDLE;
break;
case TAP_DRSELECT:
new_state = TAP_DRCAPTURE;
break;
case TAP_DRCAPTURE:
case TAP_DRSHIFT:
case TAP_DREXIT2:
new_state = TAP_DRSHIFT;
break;
case TAP_DREXIT1:
case TAP_DRPAUSE:
new_state = TAP_DRPAUSE;
break;
case TAP_IRSELECT:
new_state = TAP_IRCAPTURE;
break;
case TAP_IRCAPTURE:
case TAP_IRSHIFT:
case TAP_IREXIT2:
new_state = TAP_IRSHIFT;
break;
case TAP_IREXIT1:
case TAP_IRPAUSE:
new_state = TAP_IRPAUSE;
break;
default:
LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );
exit(1);
break;
}
}
return new_state;
}
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