lenovo: Read mainboard version from AT24RF08C.

Tablets have different mainboard version than laptop variants.

Change-Id: I77a1e2b50d30dcf3fa064e0c378ceca7ccf96e89
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6785
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)

src/drivers/i2c/at24rf08c/lenovo_serials.c

@@ -26,35 +26,62 @@
 #include <console/console.h>
 #include "lenovo.h"
 
-static void at24rf08c_read_string(u8 bank, u8 start, u8 len, char *result)
-{
-	int i;
-	device_t dev;
+#define ERROR_STRING "*INVALID*"
 
+static device_t at24rf08c_find_bank(u8 bank)
+{
+	device_t dev;
 	dev = dev_find_slot_on_smbus(1, 0x54 | bank);
-	if (dev == 0) {
+	if (!dev)
 		printk(BIOS_WARNING, "EEPROM not found\n");
-		memcpy(result, "*INVALID*", sizeof ("*INVALID*"));
-		return;
+	return dev;
 }
 
-	for (i = 0; i < len; i++) {
-		int t;
+static int at24rf08c_read_byte(device_t dev, u8 addr)
+{
+	int t = -1;
 	int j;
-		/* After a register write AT24RF08C (which we issued in init function) sometimes stops responding.
-		   Retry several times in case of failure.
+
+        /* After a register write AT24RF08C (which we issued in init function)
+	   sometimes stops responding. Retry several times in case of failure.
 	*/
 	for (j = 0; j < 100; j++) {
-			t = smbus_read_byte(dev, start + i);
+		t = smbus_read_byte(dev, addr);
 		if (t >= 0)
-				break;
+			return t;
 	}
+
+	return t;
+}
+
+static void at24rf08c_read_string_dev(device_t dev, u8 start,
+				      u8 len, char *result)
+{
+	int i;
+	for (i = 0; i < len; i++) {
+		int t = at24rf08c_read_byte(dev, start + i);
+
 		if (t < 0x20 || t > 0x7f) {
-			memcpy(result, "*INVALID*", sizeof ("*INVALID*"));
+			memcpy(result, ERROR_STRING, sizeof (ERROR_STRING));
 			return;
 		}
 		result[i] = t;
 	}
+	result[len] = '\0';
+}
+
+static void at24rf08c_read_string(u8 bank, u8 start, u8 len, char *result)
+{
+	device_t dev;
+
+	dev = at24rf08c_find_bank(bank);
+	if (dev == 0) {
+		printk(BIOS_WARNING, "EEPROM not found\n");
+		memcpy(result, ERROR_STRING, sizeof (ERROR_STRING));
+		return;
+	}
+
+	at24rf08c_read_string_dev(dev, start, len, result);
 }
 
 const char *smbios_mainboard_serial_number(void)
@@ -141,3 +168,33 @@ void smbios_mainboard_set_uuid(u8 *uuid)
 
 	memcpy (uuid, result, 16);
 }
+
+const char *smbios_mainboard_version(void)
+{
+	static char result[100];
+	static int already_read;
+	device_t dev;
+	int len;
+
+	if (already_read)
+		return result;
+
+	memset (result, 0, sizeof (result));
+
+	dev = at24rf08c_find_bank(2);
+	if (dev == 0) {
+		memcpy(result, ERROR_STRING, sizeof (ERROR_STRING));
+		return result;
+	}
+
+	len = at24rf08c_read_byte(dev, 0x26) - 2;
+	if (len < 0 || len > sizeof(result) - 1) {
+		memcpy(result, ERROR_STRING, sizeof (ERROR_STRING));
+		return result;
+	}
+
+	at24rf08c_read_string_dev(dev, 0x27, len, result);
+
+	already_read = 1;
+	return result;
+}

src/mainboard/lenovo/t520/mainboard.c

@@ -133,11 +133,6 @@ static int int15_handler(void)
 }
 #endif
 
-const char *smbios_mainboard_version(void)
-{
-	return "ThinkPad T520";
-}
-
 /* Audio Setup */
 
 static void verb_setup(void)

src/mainboard/lenovo/t530/mainboard.c

@@ -133,11 +133,6 @@ static int int15_handler(void)
 }
 #endif
 
-const char *smbios_mainboard_version(void)
-{
-	return "ThinkPad T530";
-}
-
 /* Audio Setup */
 
 static void verb_setup(void)

src/mainboard/lenovo/x200/mainboard.c

@@ -125,11 +125,6 @@ const char *smbios_mainboard_bios_version(void)
 		return "CBET4000 " COREBOOT_VERSION;
 }
 
-const char *smbios_mainboard_version(void)
-{
-	return "Lenovo X200";
-}
-
 static int mainboard_smbios_data(device_t dev, int *handle, unsigned long *current)
 {
 	int len;

src/mainboard/lenovo/x201/mainboard.c

@@ -98,11 +98,6 @@ const char *smbios_mainboard_bios_version(void)
 		return "CBET4000 " COREBOOT_VERSION;
 }
 
-const char *smbios_mainboard_version(void)
-{
-	return "Lenovo X201";
-}
-
 /* Audio Setup */
 
 static void verb_setup(void)

src/mainboard/lenovo/x220/mainboard.c

@@ -143,11 +143,6 @@ const char *smbios_mainboard_bios_version(void)
 		return "CBET4000 " COREBOOT_VERSION;
 }
 
-const char *smbios_mainboard_version(void)
-{
-	return "ThinkPad X220";
-}
-
 /* Audio Setup */
 
 static void verb_setup(void)

src/mainboard/lenovo/x230/mainboard.c

@@ -143,11 +143,6 @@ const char *smbios_mainboard_bios_version(void)
 		return "CBET4000 " COREBOOT_VERSION;
 }
 
-const char *smbios_mainboard_version(void)
-{
-	return "ThinkPad X230";
-}
-
 /* Audio Setup */
 
 static void verb_setup(void)