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-rw-r--r--src/jtag/jtag.h2
-rw-r--r--src/jtag/tcl.c107
-rw-r--r--src/target/arm7_9_common.c15
3 files changed, 106 insertions, 18 deletions
diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h
index 786b2b83..60774589 100644
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -286,7 +286,7 @@ enum reset_types {
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);
diff --git a/src/jtag/tcl.c b/src/jtag/tcl.c
index 9101d31e..e080279a 100644
--- a/src/jtag/tcl.c
+++ b/src/jtag/tcl.c
@@ -631,7 +631,12 @@ int jtag_register_commands(struct command_context_s *cmd_ctx)
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,
@@ -851,9 +856,6 @@ static int handle_reset_config_command(struct command_context_s *cmd_ctx, char *
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.
@@ -865,13 +867,21 @@ static int handle_reset_config_command(struct command_context_s *cmd_ctx, char *
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;
@@ -958,10 +968,81 @@ next:
}
/* 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;
}
diff --git a/src/target/arm7_9_common.c b/src/target/arm7_9_common.c
index 40dddda6..2b064f23 100644
--- a/src/target/arm7_9_common.c
+++ b/src/target/arm7_9_common.c
@@ -1021,12 +1021,19 @@ int arm7_9_assert_reset(target_t *target)
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;