Minor ETB and ETM bugfixes and doc updates

- ETB
    * report _actual_ hardware status, not just expected status
    * add a missing diagnostic on a potential ETB setup error
    * prefix any diagnostics with "ETB"
 - ETM
    * make "etm status" show ETM hardware status too, instead of
      just traceport status (which previously was fake, sigh)
 - Docs
    * flesh out "etm tracemode" docs a bit
    * clarify "etm status" ... previously it was traceport status
    * explain "etm trigger_percent" as a *traceport* option

ETM+ETB tracing still isn't behaving, but now I can see that part of 
the reason is that the ETB turns itself off almost immediately after
being enabled, and before collecting any data.


git-svn-id: svn://svn.berlios.de/openocd/trunk@2790 b42882b7-edfa-0310-969c-e2dbd0fdcd60

doc/openocd.texi

@@ -4891,7 +4891,7 @@ Displays information about the current target's ETM.
 @end deffn
 
 @deffn Command {etm status}
-Displays status of the current target's ETM:
+Displays status of the current target's ETM and trace port driver:
 is the ETM idle, or is it collecting data?
 Did trace data overflow?
 Was it triggered?
@@ -4904,19 +4904,43 @@ When the configuration changes, tracing is stopped
 and any buffered trace data is invalidated.
 
 @itemize
-@item @var{type} ... one of
+@item @var{type} ... describing how data accesses are traced,
+when they pass any ViewData filtering that that was set up.
+The value is one of
 @option{none} (save nothing),
 @option{data} (save data),
 @option{address} (save addresses),
 @option{all} (save data and addresses)
 @item @var{context_id_bits} ... 0, 8, 16, or 32
 @item @var{cycle_accurate} ...  @option{enable} or @option{disable}
-@item @var{branch_output} ...  @option{enable} or @option{disable}
+cycle-accurate instruction tracing.
+Before ETMv3, enabling this causes much extra data to be recorded.
+@item @var{branch_output} ...  @option{enable} or @option{disable}.
+Disable this unless you need to try reconstructing the instruction
+trace stream without an image of the code.
 @end itemize
 @end deffn
 
-@deffn Command {etm trigger_percent} percent
+@deffn Command {etm trigger_percent} [percent]
-@emph{Buggy and effectively a NOP ... @var{percent} from 2..100}
+This displays, or optionally changes, the trace port driver's
+behavior after the ETM's configured @emph{trigger} event fires.
+It controls how much more trace data is saved after the (single)
+trace trigger becomes active.
+
+@itemize
+@item The default corresponds to @emph{trace around} usage,
+recording 50 percent data before the event and the rest
+afterwards.
+@item The minimum value of @var{percent} is 2 percent,
+recording almost exclusively data before the trigger.
+Such extreme @emph{trace before} usage can help figure out
+what caused that event to happen.
+@item The maximum value of @var{percent} is 100 percent,
+recording data almost exclusively after the event.
+This extreme @emph{trace after} usage might help sort out
+how the event caused trouble.
+@end itemize
+@c REVISIT allow "break" too -- enter debug mode.
 @end deffn
 
 @subsection ETM Trace Operation

src/target/etb.c

@@ -110,13 +110,13 @@ static int etb_get_reg(reg_t *reg)
 
 	if ((retval = etb_read_reg(reg)) != ERROR_OK)
 	{
-		LOG_ERROR("BUG: error scheduling etm register read");
+		LOG_ERROR("BUG: error scheduling ETB register read");
 		return retval;
 	}
 
 	if ((retval = jtag_execute_queue()) != ERROR_OK)
 	{
-		LOG_ERROR("register read failed");
+		LOG_ERROR("ETB register read failed");
 		return retval;
 	}
 
@@ -288,7 +288,7 @@ static int etb_set_reg(reg_t *reg, uint32_t value)
 
 	if ((retval = etb_write_reg(reg, value)) != ERROR_OK)
 	{
-		LOG_ERROR("BUG: error scheduling etm register write");
+		LOG_ERROR("BUG: error scheduling ETB register write");
 		return retval;
 	}
 
@@ -307,7 +307,7 @@ static int etb_set_reg_w_exec(reg_t *reg, uint8_t *buf)
 
 	if ((retval = jtag_execute_queue()) != ERROR_OK)
 	{
-		LOG_ERROR("register write failed");
+		LOG_ERROR("ETB: register write failed");
 		return retval;
 	}
 	return ERROR_OK;
@@ -378,20 +378,20 @@ static int handle_etb_config_command(struct command_context_s *cmd_ctx, char *cm
 
 	if (!target)
 	{
-		LOG_ERROR("target '%s' not defined", args[0]);
+		LOG_ERROR("ETB: target '%s' not defined", args[0]);
 		return ERROR_FAIL;
 	}
 
 	if (arm7_9_get_arch_pointers(target, &armv4_5, &arm7_9) != ERROR_OK)
 	{
-		command_print(cmd_ctx, "current target isn't an ARM7/ARM9 target");
+		command_print(cmd_ctx, "ETB: current target isn't an ARM7/ARM9 target");
 		return ERROR_FAIL;
 	}
 
 	tap = jtag_tap_by_string(args[1]);
 	if (tap == NULL)
 	{
-		command_print(cmd_ctx, "Tap: %s does not exist", args[1]);
+		command_print(cmd_ctx, "ETB: TAP %s does not exist", args[1]);
 		return ERROR_FAIL;
 	}
 
@@ -409,7 +409,7 @@ static int handle_etb_config_command(struct command_context_s *cmd_ctx, char *cm
 	}
 	else
 	{
-		LOG_ERROR("target has no ETM defined, ETB left unconfigured");
+		LOG_ERROR("ETM: target has no ETM defined, ETB left unconfigured");
 		return ERROR_FAIL;
 	}
 
@@ -436,56 +436,53 @@ static int etb_init(etm_context_t *etm_ctx)
 static trace_status_t etb_status(etm_context_t *etm_ctx)
 {
 	etb_t *etb = etm_ctx->capture_driver_priv;
+	reg_t *control = &etb->reg_cache->reg_list[ETB_CTRL];
+	reg_t *status = &etb->reg_cache->reg_list[ETB_STATUS];
+	trace_status_t retval = 0;
+	int etb_timeout = 100;
 
 	etb->etm_ctx = etm_ctx;
 
-	/* if tracing is currently idle, return this information */
+	/* read control and status registers */
-	if (etm_ctx->capture_status == TRACE_IDLE)
+	etb_read_reg(control);
-	{
+	etb_read_reg(status);
-		return etm_ctx->capture_status;
+	jtag_execute_queue();
-	}
-	else if (etm_ctx->capture_status & TRACE_RUNNING)
-	{
-		reg_t *etb_status_reg = &etb->reg_cache->reg_list[ETB_STATUS];
-		int etb_timeout = 100;
 
-		/* trace is running, check the ETB status flags */
+	/* See if it's (still) active */
-		etb_get_reg(etb_status_reg);
+	retval = buf_get_u32(control->value, 0, 1) ? TRACE_RUNNING : TRACE_IDLE;
 
-		/* check Full bit to identify an overflow */
+	/* check Full bit to identify wraparound/overflow */
-		if (buf_get_u32(etb_status_reg->value, 0, 1) == 1)
+	if (buf_get_u32(status->value, 0, 1) == 1)
-			etm_ctx->capture_status |= TRACE_OVERFLOWED;
+		retval |= TRACE_OVERFLOWED;
 
 	/* check Triggered bit to identify trigger condition */
-		if (buf_get_u32(etb_status_reg->value, 1, 1) == 1)
+	if (buf_get_u32(status->value, 1, 1) == 1)
-			etm_ctx->capture_status |= TRACE_TRIGGERED;
+		retval |= TRACE_TRIGGERED;
 
-		/* check AcqComp to identify trace completion */
+	/* check AcqComp to see if trigger counter dropped to zero */
-		if (buf_get_u32(etb_status_reg->value, 2, 1) == 1)
+	if (buf_get_u32(status->value, 2, 1) == 1) {
-		{
+		/* wait for DFEmpty */
-			while (etb_timeout-- && (buf_get_u32(etb_status_reg->value, 3, 1) == 0))
+		while (etb_timeout-- && buf_get_u32(status->value, 3, 1) == 0)
-			{
+			etb_get_reg(status);
-				/* wait for data formatter idle */
-				etb_get_reg(etb_status_reg);
-			}
 
 		if (etb_timeout == 0)
-			{
+			LOG_ERROR("ETB:  DFEmpty won't go high, status 0x%02x",
-				LOG_ERROR("AcqComp set but DFEmpty won't go high, ETB status: 0x%" PRIx32 "",
+				(unsigned) buf_get_u32(status->value, 0, 4));
-					buf_get_u32(etb_status_reg->value, 0, etb_status_reg->size));
+
+		if (!(etm_ctx->capture_status & TRACE_TRIGGERED))
+			LOG_WARNING("ETB: trace complete without triggering?");
+
+		retval |= TRACE_COMPLETED;
 	}
 
-			if (!(etm_ctx->capture_status && TRACE_TRIGGERED))
+	/* NOTE: using a trigger is optional; and at least ETB11 has a mode
-			{
+	 * where it can ignore the trigger counter.
-				LOG_ERROR("trace completed, but no trigger condition detected");
+	 */
-			}
 
-			etm_ctx->capture_status &= ~TRACE_RUNNING;
+	/* update recorded state */
-			etm_ctx->capture_status |= TRACE_COMPLETED;
+	etm_ctx->capture_status = retval;
-		}
-	}
 
-	return etm_ctx->capture_status;
+	return retval;
 }
 
 static int etb_read_trace(etm_context_t *etm_ctx)
@@ -654,8 +651,10 @@ static int etb_start_capture(etm_context_t *etm_ctx)
 		etb_ctrl_value |= 0x2;
 	}
 
-	if ((etm_ctx->portmode & ETM_PORT_MODE_MASK) == ETM_PORT_MUXED)
+	if ((etm_ctx->portmode & ETM_PORT_MODE_MASK) == ETM_PORT_MUXED) {
+		LOG_ERROR("ETB: can't run in multiplexed mode");
 		return ERROR_ETM_PORTMODE_NOT_SUPPORTED;
+	}
 
 	trigger_count = (etb->ram_depth * etm_ctx->trigger_percent) / 100;
 

src/target/etm.c

@@ -1567,6 +1567,7 @@ static int handle_etm_status_command(struct command_context_s *cmd_ctx, char *cm
 	target_t *target;
 	armv4_5_common_t *armv4_5;
 	arm7_9_common_t *arm7_9;
+	etm_context_t *etm;
 	trace_status_t trace_status;
 
 	target = get_current_target(cmd_ctx);
@@ -1582,28 +1583,56 @@ static int handle_etm_status_command(struct command_context_s *cmd_ctx, char *cm
 		command_print(cmd_ctx, "current target doesn't have an ETM configured");
 		return ERROR_OK;
 	}
+	etm = arm7_9->etm_ctx;
 
-	trace_status = arm7_9->etm_ctx->capture_driver->status(arm7_9->etm_ctx);
+	/* ETM status */
+	if (etm->bcd_vers >= 0x11) {
+		reg_t *reg;
 
+		reg = etm_reg_lookup(etm, ETM_STATUS);
+		if (!reg)
+			return ERROR_OK;
+		if (etm_get_reg(reg) == ERROR_OK) {
+			unsigned s = buf_get_u32(reg->value, 0, reg->size);
+
+			command_print(cmd_ctx, "etm: %s%s%s%s",
+				/* bit(1) == progbit */
+				(etm->bcd_vers >= 0x12)
+					? ((s & (1 << 1))
+						? "disabled" : "enabled")
+					: "?",
+				((s & (1 << 3)) && etm->bcd_vers >= 0x31)
+					? " triggered" : "",
+				((s & (1 << 2)) && etm->bcd_vers >= 0x12)
+					? " start/stop" : "",
+				((s & (1 << 0)) && etm->bcd_vers >= 0x11)
+					? " untraced-overflow" : "");
+		} /* else ignore and try showing trace port status */
+	}
+
+	/* Trace Port Driver status */
+	trace_status = etm->capture_driver->status(etm);
 	if (trace_status == TRACE_IDLE)
 	{
-		command_print(cmd_ctx, "tracing is idle");
+		command_print(cmd_ctx, "%s: idle", etm->capture_driver->name);
 	}
 	else
 	{
 		static char *completed = " completed";
 		static char *running = " is running";
-		static char *overflowed = ", trace overflowed";
+		static char *overflowed = ", overflowed";
-		static char *triggered = ", trace triggered";
+		static char *triggered = ", triggered";
 
-		command_print(cmd_ctx, "trace collection%s%s%s",
+		command_print(cmd_ctx, "%s: trace collection%s%s%s",
+			etm->capture_driver->name,
 			(trace_status & TRACE_RUNNING) ? running : completed,
 			(trace_status & TRACE_OVERFLOWED) ? overflowed : "",
 			(trace_status & TRACE_TRIGGERED) ? triggered : "");
 
-		if (arm7_9->etm_ctx->trace_depth > 0)
+		if (etm->trace_depth > 0)
 		{
-			command_print(cmd_ctx, "%i frames of trace data read", (int)(arm7_9->etm_ctx->trace_depth));
+			command_print(cmd_ctx, "%i frames of trace data read",
+					(int)(etm->trace_depth));
 		}
 	}