@end deffn
@deffn {Command} reset_config mode_flag ...
-This command tells OpenOCD the reset configuration
+This command displays or modifies the reset configuration
of your combination of JTAG board and target in target
configuration scripts.
with a board that only wires up SRST.)
The @var{mode_flag} options can be specified in any order, but only one
-of each type -- @var{signals}, @var{combination}, @var{trst_type},
+of each type -- @var{signals}, @var{combination},
+@var{gates},
+@var{trst_type},
and @var{srst_type} -- may be specified at a time.
If you don't provide a new value for a given type, its previous
value (perhaps the default) is unchanged.
TRST just to declare that if the JTAG adapter should want to drive SRST,
it must explicitly be driven high (@option{srst_push_pull}).
+@itemize
+@item
@var{signals} can specify which of the reset signals are connected.
For example, If the JTAG interface provides SRST, but the board doesn't
connect that signal properly, then OpenOCD can't use it.
@option{srst_only} and @option{trst_and_srst}.
@quotation Tip
-If your board provides SRST or TRST through the JTAG connector,
+If your board provides SRST and/or TRST through the JTAG connector,
you must declare that or else those signals will not be used.
@end quotation
+@item
The @var{combination} is an optional value specifying broken reset
signal implementations.
The default behaviour if no option given is @option{separate},
@option{combined} implies both @option{srst_pulls_trst} and
@option{trst_pulls_srst}.
-@option{srst_gates_jtag} indicates that asserting SRST gates the
+@item
+The @var{gates} tokens control flags that describe some cases where
+JTAG may be unvailable during reset.
+@option{srst_gates_jtag} (default)
+indicates that asserting SRST gates the
JTAG clock. This means that no communication can happen on JTAG
while SRST is asserted.
+Its converse is @option{srst_nogate}, indicating that JTAG commands
+can safely be issued while SRST is active.
+@end itemize
The optional @var{trst_type} and @var{srst_type} parameters allow the
driver mode of each reset line to be specified. These values only affect
JTAG interfaces with support for different driver modes, like the Amontec
-JTAGkey and JTAGAccelerator. Also, they are necessarily ignored if the
+JTAGkey and JTAG Accelerator. Also, they are necessarily ignored if the
relevant signal (TRST or SRST) is not connected.
+@itemize
+@item
Possible @var{trst_type} driver modes for the test reset signal (TRST)
-are @option{trst_push_pull} (default) and @option{trst_open_drain}.
+are the default @option{trst_push_pull}, and @option{trst_open_drain}.
Most boards connect this signal to a pulldown, so the JTAG TAPs
never leave reset unless they are hooked up to a JTAG adapter.
+@item
Possible @var{srst_type} driver modes for the system reset signal (SRST)
are the default @option{srst_open_drain}, and @option{srst_push_pull}.
Most boards connect this signal to a pullup, and allow the
signal to be pulled low by various events including system
powerup and pressing a reset button.
+@end itemize
@end deffn
RESET_TRST_PULLS_SRST = 0x8,
RESET_TRST_OPEN_DRAIN = 0x10,
RESET_SRST_PUSH_PULL = 0x20,
- RESET_SRST_GATES_JTAG = 0x40,
+ RESET_SRST_NO_GATING = 0x40,
};
enum reset_types jtag_get_reset_config(void);
COMMAND_CONFIG, "(DEPRECATED) jtag_device <ir_length> <ir_expected> <ir_mask>");
register_command(cmd_ctx, NULL, "reset_config", handle_reset_config_command,
COMMAND_ANY,
- "[none/trst_only/srst_only/trst_and_srst] [srst_pulls_trst/trst_pulls_srst] [combined/separate] [trst_push_pull/trst_open_drain] [srst_push_pull/srst_open_drain]");
+ "reset_config "
+ "[none|trst_only|srst_only|trst_and_srst] "
+ "[srst_pulls_trst|trst_pulls_srst|combined|separate] "
+ "[srst_gates_jtag|srst_nogate] "
+ "[trst_push_pull|trst_open_drain] "
+ "[srst_push_pull|srst_open_drain]");
register_command(cmd_ctx, NULL, "jtag_nsrst_delay", handle_jtag_nsrst_delay_command,
COMMAND_ANY, "jtag_nsrst_delay <ms> - delay after deasserting srst in ms");
register_command(cmd_ctx, NULL, "jtag_ntrst_delay", handle_jtag_ntrst_delay_command,
int new_cfg = 0;
int mask = 0;
- if (argc < 1)
- return ERROR_COMMAND_SYNTAX_ERROR;
-
/* Original versions cared about the order of these tokens:
* reset_config signals [combination [trst_type [srst_type]]]
* They also clobbered the previous configuration even on error.
int tmp = 0;
int m;
- m = RESET_SRST_GATES_JTAG;
- tmp = 0;
+ /* gating */
+ m = RESET_SRST_NO_GATING;
if (strcmp(*args, "srst_gates_jtag") == 0)
- {
- tmp = RESET_SRST_GATES_JTAG;
- goto next;
+ /* default: don't use JTAG while SRST asserted */;
+ else if (strcmp(*args, "srst_nogate") == 0)
+ tmp = RESET_SRST_NO_GATING;
+ else
+ m = 0;
+ if (mask & m) {
+ LOG_ERROR("extra reset_config %s spec (%s)",
+ "gating", *args);
+ return ERROR_INVALID_ARGUMENTS;
}
+ if (m)
+ goto next;
/* signals */
m = RESET_HAS_TRST | RESET_HAS_SRST;
}
/* clear previous values of those bits, save new values */
- enum reset_types old_cfg = jtag_get_reset_config();
- old_cfg &= ~mask;
- new_cfg |= old_cfg;
- jtag_set_reset_config(new_cfg);
+ if (mask) {
+ int old_cfg = jtag_get_reset_config();
+
+ old_cfg &= ~mask;
+ new_cfg |= old_cfg;
+ jtag_set_reset_config(new_cfg);
+ } else
+ new_cfg = jtag_get_reset_config();
+
+
+ /*
+ * Display the (now-)current reset mode
+ */
+ char *modes[5];
+
+ /* minimal JTAG has neither SRST nor TRST (so that's the default) */
+ switch (new_cfg & (RESET_HAS_TRST | RESET_HAS_SRST)) {
+ case RESET_HAS_SRST:
+ modes[0] = "srst_only";
+ break;
+ case RESET_HAS_TRST:
+ modes[0] = "trst_only";
+ break;
+ case RESET_TRST_AND_SRST:
+ modes[0] = "trst_and_srst";
+ break;
+ default:
+ modes[0] = "none";
+ break;
+ }
+
+ /* normally SRST and TRST are decoupled; but bugs happen ... */
+ switch (new_cfg & (RESET_SRST_PULLS_TRST | RESET_TRST_PULLS_SRST)) {
+ case RESET_SRST_PULLS_TRST:
+ modes[1] = "srst_pulls_trst";
+ break;
+ case RESET_TRST_PULLS_SRST:
+ modes[1] = "trst_pulls_srst";
+ break;
+ case RESET_SRST_PULLS_TRST | RESET_TRST_PULLS_SRST:
+ modes[1] = "combined";
+ break;
+ default:
+ modes[1] = "separate";
+ break;
+ }
+
+ /* TRST-less connectors include Altera, Xilinx, and minimal JTAG */
+ if (new_cfg & RESET_HAS_TRST) {
+ if (new_cfg & RESET_TRST_OPEN_DRAIN)
+ modes[3] = " trst_open_drain";
+ else
+ modes[3] = " trst_push_pull";
+ } else
+ modes[3] = "";
+
+ /* SRST-less connectors include TI-14, Xilinx, and minimal JTAG */
+ if (new_cfg & RESET_HAS_SRST) {
+ if (new_cfg & RESET_SRST_NO_GATING)
+ modes[2] = " srst_nogate";
+ else
+ modes[2] = " srst_gates_jtag";
+
+ if (new_cfg & RESET_SRST_PUSH_PULL)
+ modes[4] = " srst_push_pull";
+ else
+ modes[4] = " srst_open_drain";
+ } else {
+ modes[2] = "";
+ modes[4] = "";
+ }
+
+ command_print(cmd_ctx, "%s %s%s%s%s",
+ modes[0], modes[1],
+ modes[2], modes[3], modes[4]);
return ERROR_OK;
}
return ERROR_FAIL;
}
- /* at this point trst has been asserted/deasserted once. We want to
- * program embedded ice while SRST is asserted, but some CPUs gate
- * the JTAG clock while SRST is asserted
+ /* At this point trst has been asserted/deasserted once. We would
+ * like to program EmbeddedICE while SRST is asserted, instead of
+ * depending on SRST to leave that module alone. However, many CPUs
+ * gate the JTAG clock while SRST is asserted; or JTAG may need
+ * clock stability guarantees (adaptive clocking might help).
+ *
+ * So we assume JTAG access during SRST is off the menu unless it's
+ * been specifically enabled.
*/
bool srst_asserted = false;
- if (((jtag_reset_config & RESET_SRST_PULLS_TRST) == 0) && ((jtag_reset_config & RESET_SRST_GATES_JTAG) == 0))
+
+ if (((jtag_reset_config & RESET_SRST_PULLS_TRST) == 0)
+ && (jtag_reset_config & RESET_SRST_NO_GATING))
{
jtag_add_reset(0, 1);
srst_asserted = true;
projects / openocd / commitdiff