Slight restructure of SPI probe_ functions

Preparation for a probe optimization patch. This patch does not change any
functionality. spi_probe_rdid was tested to still work on my M57SLI rev 2.

The idea is to have error checks return error immediately when something
fails, rather than having code inside an if block where the condition
tests for success.

This means: Less indentation, more clear what the code is checking.

Corresponding to flashrom svn r272 and coreboot v2 svn r3386.
Signed-off-by: Peter Stuge <peter@stuge.se>
Acked-by: Ward Vandewege <ward@gnu.org>

spi.c

@@ -82,35 +82,41 @@ int probe_spi_rdid(struct flashchip *flash)
 	unsigned char readarr[3];
 	uint32_t manuf_id;
 	uint32_t model_id;
-	if (!spi_rdid(readarr)) {
-		if (!oddparity(readarr[0]))
-			printf_debug("RDID byte 0 parity violation.\n");
-		/* Check if this is a continuation vendor ID */
-		if (readarr[0] == 0x7f) {
-			if (!oddparity(readarr[1]))
-				printf_debug("RDID byte 1 parity violation.\n");
-			manuf_id = (readarr[0] << 8) | readarr[1];
-			model_id = readarr[2];
-		} else {
-			manuf_id = readarr[0];
-			model_id = (readarr[1] << 8) | readarr[2];
-		}
-		printf_debug("%s: id1 0x%x, id2 0x%x\n", __FUNCTION__, manuf_id, model_id);
-		if (manuf_id == flash->manufacture_id &&
-		    model_id == flash->model_id) {
-			/* Print the status register to tell the
-			 * user about possible write protection.
-			 */
-			spi_prettyprint_status_register(flash);
-
-			return 1;
-		}
-		/* Test if this is a pure vendor match. */
-		if (manuf_id == flash->manufacture_id &&
-		    GENERIC_DEVICE_ID == flash->model_id)
-			return 1;
+
+	if (spi_rdid(readarr))
+		return 0;
+
+	if (!oddparity(readarr[0]))
+		printf_debug("RDID byte 0 parity violation.\n");
+
+	/* Check if this is a continuation vendor ID */
+	if (readarr[0] == 0x7f) {
+		if (!oddparity(readarr[1]))
+			printf_debug("RDID byte 1 parity violation.\n");
+		manuf_id = (readarr[0] << 8) | readarr[1];
+		model_id = readarr[2];
+	} else {
+		manuf_id = readarr[0];
+		model_id = (readarr[1] << 8) | readarr[2];
 	}
 
+	printf_debug("%s: id1 0x%x, id2 0x%x\n", __FUNCTION__, manuf_id, model_id);
+
+	if (manuf_id == flash->manufacture_id &&
+	    model_id == flash->model_id) {
+		/* Print the status register to tell the
+		 * user about possible write protection.
+		 */
+		spi_prettyprint_status_register(flash);
+
+		return 1;
+	}
+
+	/* Test if this is a pure vendor match. */
+	if (manuf_id == flash->manufacture_id &&
+	    GENERIC_DEVICE_ID == flash->model_id)
+		return 1;
+
 	return 0;
 }
 
@@ -118,29 +124,29 @@ int probe_spi_res(struct flashchip *flash)
 {
 	unsigned char readarr[3];
 	uint32_t model_id;
-	if (!spi_rdid(readarr)) {
-		/* Check if RDID returns 0xff 0xff 0xff, then we use RES. */
-		if ((readarr[0] != 0xff) || (readarr[1] != 0xff) ||
-		    (readarr[2] != 0xff))
-			return 0;
-	} else {
+
+	if (spi_rdid(readarr))
 		/* We couldn't issue RDID, it's pointless to try RES. */
 		return 0;
-	}
-	if (!spi_res(readarr)) {
-		model_id = readarr[0];
-		printf_debug("%s: id 0x%x\n", __FUNCTION__, model_id);
-		if (model_id == flash->model_id) {
-			/* Print the status register to tell the
-			 * user about possible write protection.
-			 */
-			spi_prettyprint_status_register(flash);
-
-			return 1;
-		}
-	}
 
-	return 0;
+	/* Check if RDID returns 0xff 0xff 0xff, then we use RES. */
+	if ((readarr[0] != 0xff) || (readarr[1] != 0xff) ||
+	    (readarr[2] != 0xff))
+		return 0;
+
+	if (spi_res(readarr))
+		return 0;
+
+	model_id = readarr[0];
+	printf_debug("%s: id 0x%x\n", __FUNCTION__, model_id);
+	if (model_id != flash->model_id)
+		return 0;
+
+	/* Print the status register to tell the
+	 * user about possible write protection.
+	 */
+	spi_prettyprint_status_register(flash);
+	return 1;
 }
 
 uint8_t spi_read_status_register()