diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/jtag/drivers/ft2232.c | 74 |
1 files changed, 72 insertions, 2 deletions
diff --git a/src/jtag/drivers/ft2232.c b/src/jtag/drivers/ft2232.c index 4b84fa83..5c6b655c 100644 --- a/src/jtag/drivers/ft2232.c +++ b/src/jtag/drivers/ft2232.c @@ -1678,6 +1678,72 @@ static int ft2232_execute_statemove(struct jtag_command *cmd) return retval; } +/** + * Clock a bunch of TMS (or SWDIO) transitions, to change the JTAG + * (or SWD) state machine. + */ +static int ft2232_execute_tms(struct jtag_command *cmd) +{ + int retval = ERROR_OK; + unsigned num_bits = cmd->cmd.tms->num_bits; + const uint8_t *bits = cmd->cmd.tms->bits; + unsigned count; + + DEBUG_JTAG_IO("TMS: %d bits", num_bits); + + /* only send the maximum buffer size that FT2232C can handle */ + count = 3 * DIV_ROUND_UP(num_bits, 4); + if (ft2232_buffer_size + 3*count + 1 > FT2232_BUFFER_SIZE) { + if (ft2232_send_and_recv(first_unsent, cmd) != ERROR_OK) + retval = ERROR_JTAG_QUEUE_FAILED; + + require_send = 0; + first_unsent = cmd; + } + + /* Shift out in batches of at most 6 bits; there's a report of an + * FT2232 bug in this area, where shifting exactly 7 bits can make + * problems with TMS signaling for the last clock cycle: + * + * http://developer.intra2net.com/mailarchive/html/ + * libftdi/2009/msg00292.html + * + * Command 0x4b is: "Clock Data to TMS/CS Pin (no Read)" + * + * Note that pathmoves in JTAG are not often seven bits, so that + * isn't a particularly likely situation outside of "special" + * signaling such as switching between JTAG and SWD modes. + */ + while (num_bits) { + if (num_bits <= 6) { + buffer_write(0x4b); + buffer_write(num_bits - 1); + buffer_write(*bits & 0x3f); + break; + } + + /* Yes, this is lazy ... we COULD shift out more data + * bits per operation, but doing it in nybbles is easy + */ + buffer_write(0x4b); + buffer_write(3); + buffer_write(*bits & 0xf); + num_bits -= 4; + + count = (num_bits > 4) ? 4 : num_bits; + + buffer_write(0x4b); + buffer_write(count - 1); + buffer_write((*bits >> 4) & 0xf); + num_bits -= count; + + bits++; + } + + require_send = 1; + return retval; +} + static int ft2232_execute_pathmove(struct jtag_command *cmd) { int predicted_size = 0; @@ -1830,7 +1896,6 @@ static int ft2232_execute_stableclocks(struct jtag_command *cmd) static int ft2232_execute_command(struct jtag_command *cmd) { int retval; - retval = ERROR_OK; switch (cmd->type) { @@ -1841,9 +1906,13 @@ static int ft2232_execute_command(struct jtag_command *cmd) case JTAG_SCAN: retval = ft2232_execute_scan(cmd); break; case JTAG_SLEEP: retval = ft2232_execute_sleep(cmd); break; case JTAG_STABLECLOCKS: retval = ft2232_execute_stableclocks(cmd); break; + case JTAG_TMS: + retval = ft2232_execute_tms(cmd); + break; default: LOG_ERROR("BUG: unknown JTAG command type encountered"); - exit(-1); + retval = ERROR_JTAG_QUEUE_FAILED; + break; } return retval; } @@ -4108,6 +4177,7 @@ static const struct command_registration ft2232_command_handlers[] = { struct jtag_interface ft2232_interface = { .name = "ft2232", + .supported = DEBUG_CAP_TMS_SEQ, .commands = ft2232_command_handlers, .init = ft2232_init, |