target/riscv: dump_field() shouldn't always decode

Sometimes, the value from of some DMI scans has no meaning (e.g. when
`op` is read). Such values should not be decoded. To make the dumps more
consistent, `<no decoding available>` when there is no decoding for a
register.

Change-Id: I415f06a5a80f2fc8fb8ab3f79132bdf0602c8ad6
Signed-off-by: Evgeniy Naydanov <evgeniy.naydanov@syntacore.com>

src/target/riscv/riscv-013.c

@@ -371,7 +371,7 @@ static unsigned int decode_dmi(struct target *target, char *text, unsigned int a
 	return decode_dm(text, address - dm->base, data);
 }
 
-static void dump_field(struct target *target, int idle, const struct scan_field *field)
+static void dump_field(struct target *target, int idle, const struct scan_field *field, bool decode_in)
 {
 	static const char * const op_string[] = {"-", "r", "w", "?"};
 	static const char * const status_string[] = {"+", "?", "F", "b"};
@@ -390,18 +390,29 @@ static void dump_field(struct target *target, int idle, const struct scan_field
 	unsigned int in_address = in >> DTM_DMI_ADDRESS_OFFSET;
 
 	log_printf_lf(LOG_LVL_DEBUG,
-			__FILE__, __LINE__, "scan",
+			__FILE__, __LINE__, __PRETTY_FUNCTION__,
 			"%db %s %08x @%02x -> %s %08x @%02x; %di",
 			field->num_bits, op_string[out_op], out_data, out_address,
 			status_string[in_op], in_data, in_address, idle);
 
-	char out_text[decode_dmi(target, NULL, out_address, out_data) + 1];
-	unsigned int out_len = decode_dmi(target, out_text, out_address, out_data);
-	char in_text[decode_dmi(target, NULL, in_address, in_data) + 1];
-	unsigned int in_len = decode_dmi(target, in_text, in_address, in_data);
-	if (in_text[0] || out_text[0]) {
-		log_printf_lf(LOG_LVL_DEBUG, __FILE__, __LINE__, "scan", "%.*s -> %.*s",
-				out_len, out_text, in_len, in_text);
+	const bool decode_out = out_op == DTM_DMI_OP_WRITE;
+	char out_decoded[decode_dmi(target, NULL, out_address, out_data) + 1];
+	const char *out_text = "";
+	if (decode_out)
+		out_text = decode_dmi(target, out_decoded, out_address, out_data)
+			? out_decoded
+			: "<no decoding available>";
+
+	char in_decoded[decode_dmi(target, NULL, in_address, in_data) + 1];
+	const char *in_text = "";
+	if (decode_in)
+		in_text = decode_dmi(target, in_decoded, in_address, in_data)
+			? in_decoded
+			: "<no decoding available>";
+
+	if (decode_out || decode_in) {
+		log_printf_lf(LOG_LVL_DEBUG, __FILE__, __LINE__, __PRETTY_FUNCTION__,
+				"%s -> %s", out_text, in_text);
 	}
 }
 
@@ -542,7 +553,7 @@ static dmi_status_t dmi_scan(struct target *target, uint32_t *address_in,
 
 	if (address_in)
 		*address_in = buf_get_u32(in, DTM_DMI_ADDRESS_OFFSET, info->abits);
-	dump_field(target, idle_count, &field);
+	dump_field(target, idle_count, &field, /*decode_in*/ data_in);
 	return buf_get_u32(in, DTM_DMI_OP_OFFSET, DTM_DMI_OP_LENGTH);
 }