board: turris: Initialize serial# env

Store serial number from atsha cryptochip into the serial# env variable.
U-Boot automatically puts content of this variable into the root device
tree property serial-number when booting Linux kernel. Refactor turris
atsha code and from turris_atsha_otp_get_serial_number() function returns
directly string suitable for printing or storing into device tree. Because
during different boot stages is env storage read-only, it is not possible
to always store serial number into env storage. So introduce a new function
turris_atsha_otp_init_serial_number() which is called at later stage and
which ensures that serial number is correctly stored into env.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>

board/CZ.NIC/turris_atsha_otp.c

@@ -93,30 +93,57 @@ int turris_atsha_otp_init_mac_addresses(int first_idx)
 	return 0;
 }
 
-int turris_atsha_otp_get_serial_number(u32 *version_num, u32 *serial_num)
+int turris_atsha_otp_init_serial_number(void)
+{
+	char serial[17];
+	int ret;
+
+	ret = turris_atsha_otp_get_serial_number(serial);
+	if (ret)
+		return ret;
+
+	if (!env_get("serial#"))
+		return -1;
+
+	return 0;
+}
+
+int turris_atsha_otp_get_serial_number(char serial[17])
 {
 	struct udevice *dev = get_atsha204a_dev();
+	u32 version_num, serial_num;
+	const char *serial_env;
 	int ret;
 
 	if (!dev)
 		return -1;
 
+	serial_env = env_get("serial#");
+	if (serial_env && strlen(serial_env) == 16) {
+		memcpy(serial, serial_env, 17);
+		return 0;
+	}
+
 	ret = atsha204a_wakeup(dev);
 	if (ret)
 		return ret;
 
 	ret = atsha204a_read(dev, ATSHA204A_ZONE_OTP, false,
 			     TURRIS_ATSHA_OTP_VERSION,
-			     (u8 *)version_num);
+			     (u8 *)&version_num);
 	if (ret)
 		return ret;
 
 	ret = atsha204a_read(dev, ATSHA204A_ZONE_OTP, false,
 			     TURRIS_ATSHA_OTP_SERIAL,
-			     (u8 *)serial_num);
+			     (u8 *)&serial_num);
 	if (ret)
 		return ret;
 
 	atsha204a_sleep(dev);
+
+	sprintf(serial, "%08X%08X", be32_to_cpu(version_num), be32_to_cpu(serial_num));
+	env_set("serial#", serial);
+
 	return 0;
 }

board/CZ.NIC/turris_atsha_otp.h

@@ -4,6 +4,7 @@
 #define TURRIS_ATSHA_OTP_H
 
 int turris_atsha_otp_init_mac_addresses(int first_idx);
-int turris_atsha_otp_get_serial_number(u32 *version_num, u32 *serial_num);
+int turris_atsha_otp_init_serial_number(void);
+int turris_atsha_otp_get_serial_number(char serial[17]);
 
 #endif

board/CZ.NIC/turris_omnia/turris_omnia.c

@@ -963,19 +963,15 @@ int board_late_init(void)
 
 int show_board_info(void)
 {
-	u32 version_num, serial_num;
+	char serial[17];
 	int err;
 
-	err = turris_atsha_otp_get_serial_number(&version_num, &serial_num);
+	err = turris_atsha_otp_get_serial_number(serial);
 	printf("Model: Turris Omnia\n");
 	printf("  MCU type: %s\n", omnia_get_mcu_type());
 	printf("  MCU version: %s\n", omnia_get_mcu_version());
 	printf("  RAM size: %i MiB\n", omnia_get_ram_size_gb() * 1024);
-	if (err)
+	printf("  Serial Number: %s\n", !err ? serial : "unknown");
-		printf("  Serial Number: unknown\n");
-	else
-		printf("  Serial Number: %08X%08X\n", be32_to_cpu(version_num),
-		       be32_to_cpu(serial_num));
 
 	return 0;
 }
@@ -983,6 +979,7 @@ int show_board_info(void)
 int misc_init_r(void)
 {
 	turris_atsha_otp_init_mac_addresses(1);
+	turris_atsha_otp_init_serial_number();
 	return 0;
 }