diff --git a/src/jtag/drivers/jtag_vpi.c b/src/jtag/drivers/jtag_vpi.c index c69f24fd0..1033cedb2 100644 --- a/src/jtag/drivers/jtag_vpi.c +++ b/src/jtag/drivers/jtag_vpi.c @@ -328,7 +328,27 @@ static int jtag_vpi_runtest(int cycles, tap_state_t state) static int jtag_vpi_stableclocks(int cycles) { - return jtag_vpi_queue_tdi(NULL, cycles, TAP_SHIFT); + uint8_t tms_bits[4]; + int cycles_remain = cycles; + int nb_bits; + int retval; + const int CYCLES_ONE_BATCH = sizeof(tms_bits) * 8; + + assert(cycles >= 0); + + /* use TMS=1 in TAP RESET state, TMS=0 in all other stable states */ + memset(&tms_bits, (tap_get_state() == TAP_RESET) ? 0xff : 0x00, sizeof(tms_bits)); + + /* send the TMS bits */ + while (cycles_remain > 0) { + nb_bits = (cycles_remain < CYCLES_ONE_BATCH) ? cycles_remain : CYCLES_ONE_BATCH; + retval = jtag_vpi_tms_seq(tms_bits, nb_bits); + if (retval != ERROR_OK) + return retval; + cycles_remain -= nb_bits; + } + + return ERROR_OK; } static int jtag_vpi_execute_queue(void)