[PATCH 2/2] arm64: imx8mp: Read item and serial number from EEPROM ID page on DH i.MX8MP DHCOM

[Christoph Niedermaier]

The new i.MX8M Plus DHCOM rev.200 is populated with M24C32-D EEPROM
which contains additional write-lockable page called ID page, which
is populated with a structure containing the item and serial number.

Extend the support for parsing the item and serial number of the
EEPROM ID page. Write the item and serial number to the U-Boot
environment if the aren't there. If the environment is already
there compare it with the one from the EEPROM ID page and output
a warning if it differs.

Signed-off-by: Christoph Niedermaier <cniedermaier at dh-electronics.com>
---
Cc: "NXP i.MX U-Boot Team" <uboot-imx at nxp.com>
Cc: Marek Vasut <marex at denx.de>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Stefano Babic <sbabic at denx.de>
Cc: Tom Rini <trini at konsulko.com>
Cc: u-boot at dh-electronics.com
---
 board/dhelectronics/common/dh_common.c        | 51 ++++++++++++++++++
 board/dhelectronics/common/dh_common.h        |  2 +
 .../dh_imx8mp/imx8mp_dhcom_pdk2.c             | 53 +++++++++++++++++++
 3 files changed, 106 insertions(+)

diff --git a/board/dhelectronics/common/dh_common.c b/board/dhelectronics/common/dh_common.c
index 8ea70fc984..4c31b32e0c 100644
--- a/board/dhelectronics/common/dh_common.c
+++ b/board/dhelectronics/common/dh_common.c
@@ -11,6 +11,23 @@
 
 #include "dh_common.h"
 
+/* DH item: Vendor coding */
+#define ITEM_PREFIX_NXP		0x01
+#define ITEM_PREFIX_NXP_CHR	'I'
+#define ITEM_PREFIX_ST		0x02
+#define ITEM_PREFIX_ST_CHR	'S'
+
+/*
+ * DH item: Finished state coding
+ * Bit = 0 means half finished
+ *         Prefix is 'H'
+ * Bit = 1 means finished with a customer image flashed
+ *         Prefix is 'F'
+ */
+#define ITEM_PREFIX_FIN_BIT		BIT(7)
+#define ITEM_PREFIX_FIN_HALF_CHR	'H'
+#define ITEM_PREFIX_FIN_FLASHED_CHR	'F'
+
 struct eeprom_id_page {
 	u8	id[3];		/* Identifier 'D', 'H', 'E' - 'D' is at index 0 */
 	u8	version;	/* 0x10 -- Version 1.0 */
@@ -54,6 +71,7 @@ int dh_get_value_from_eeprom_id_page(enum eip_request_values request, u8 *data,
 	ofnode node;
 	u16 c16;
 	u8 c8;
+	char soc;
 
 	eipp = (struct eeprom_id_page *)eipa;
 
@@ -136,6 +154,39 @@ int dh_get_value_from_eeprom_id_page(enum eip_request_values request, u8 *data,
 		else
 			return -EINVAL;
 		break;
+	case ITEM_NUMBER:
+		if (data_len >= 8) { /* String with 7 characters + string termination */
+			switch (eipp->item_prefix & 0xf) {
+			case ITEM_PREFIX_NXP:
+				soc = ITEM_PREFIX_NXP_CHR;
+				break;
+			case ITEM_PREFIX_ST:
+				soc = ITEM_PREFIX_ST_CHR;
+				break;
+			default:
+				return -EINVAL;
+			}
+			snprintf(data, data_len, "%c%c%05d",
+				 (eipp->item_prefix & ITEM_PREFIX_FIN_BIT) ?
+				 ITEM_PREFIX_FIN_FLASHED_CHR : ITEM_PREFIX_FIN_HALF_CHR,
+				 soc, (eipp->item_num[0] << 16) | (eipp->item_num[1] << 8)
+				       | eipp->item_num[2]);
+		} else {
+			return -EINVAL;
+		}
+		break;
+	case SN:
+		/*
+		 * data_len must be greater than the size of eipp->serial,
+		 * because there is a string termination needed.
+		 */
+		if (data_len > sizeof(eipp->serial)) {
+			data[sizeof(eipp->serial)] = 0;
+			memcpy(data, eipp->serial, sizeof(eipp->serial));
+		} else {
+			return -EINVAL;
+		}
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/board/dhelectronics/common/dh_common.h b/board/dhelectronics/common/dh_common.h
index 4c22ece435..1baa45e340 100644
--- a/board/dhelectronics/common/dh_common.h
+++ b/board/dhelectronics/common/dh_common.h
@@ -6,6 +6,8 @@
 enum eip_request_values {
 	MAC0,
 	MAC1,
+	ITEM_NUMBER,
+	SN,
 };
 
 /*
diff --git a/board/dhelectronics/dh_imx8mp/imx8mp_dhcom_pdk2.c b/board/dhelectronics/dh_imx8mp/imx8mp_dhcom_pdk2.c
index 9a8f09fcd4..8970c8fc2d 100644
--- a/board/dhelectronics/dh_imx8mp/imx8mp_dhcom_pdk2.c
+++ b/board/dhelectronics/dh_imx8mp/imx8mp_dhcom_pdk2.c
@@ -116,6 +116,56 @@ int dh_setup_mac_address(void)
 	return ret;
 }
 
+void dh_add_item_number_and_serial_to_env(void)
+{
+	char item_number[8];	/* String with 7 characters + string termination */
+	char *item_number_env;
+	char serial[10];	/* String with 9 characters + string termination */
+	char *serial_env;
+	int ret;
+
+	ret = dh_get_value_from_eeprom_id_page(ITEM_NUMBER, item_number, sizeof(item_number),
+					       "eeprom0");
+	if (ret) {
+		/*
+		 * The function only returns the value -ENOENT for SoM rev.100, because
+		 * the EEPROM ID page isn't available there. Therefore the output makes
+		 * no sense and will be suppressed here.
+		 */
+		if (ret != -ENOENT)
+			printf("%s: Unable to get item number form EEPROM ID page! ret = %d\n",
+			       __func__, ret);
+	} else {
+		item_number_env = env_get("vendor_item_number");
+		if (!item_number_env)
+			env_set("vendor_item_number", item_number);
+		else
+			if (strcmp(item_number_env, item_number) != 0)
+				printf("Warning: Environment vendor_item_number differs from EEPROM ID page value (%s != %s)\n",
+				       item_number_env, item_number);
+	}
+
+	ret = dh_get_value_from_eeprom_id_page(SN, serial, sizeof(serial), "eeprom0");
+	if (ret) {
+		/*
+		 * The function only returns the value -ENOENT for SoM rev.100, because
+		 * the EEPROM ID page isn't available there. Therefore the output makes
+		 * no sense and will be suppressed here.
+		 */
+		if (ret != -ENOENT)
+			printf("%s: Unable to get serial form EEPROM ID page! ret = %d\n",
+			       __func__, ret);
+	} else {
+		serial_env = env_get("SN");
+		if (!serial_env)
+			env_set("SN", serial);
+		else
+			if (strcmp(serial_env, serial) != 0)
+				printf("Warning: Environment SN differs from EEPROM ID page value (%s != %s)\n",
+				       serial_env, serial);
+	}
+}
+
 int board_init(void)
 {
 	return 0;
@@ -124,6 +174,9 @@ int board_init(void)
 int board_late_init(void)
 {
 	dh_setup_mac_address();
+
+	dh_add_item_number_and_serial_to_env();
+
 	return 0;
 }
 
-- 
2.30.2