Meta FBOSS EEPROM Format v6
All Field Replaceable Unit (FRU) ID EEPROMs must follow the format below. This replaces the Meta FBOSS EEPROM Format V5.
Conventions
- All fields are big endian.
- String terminator
\0is not included in the string field. The parser will determine the string size by reading the length field of TLV entries.
Header
All Meta EEPROMs must start with the 4-byte header below. This header is compatible with the past versions.
| Offset (byte) | Length (bytes) | Value | Description |
|---|---|---|---|
| 0 | 2 | 0xFBFB | Magic word |
| 2 | 1 | 0x6 | Meta EEPROM Format Version |
| 3 | 1 | 0XFF | Reserved for future use |
Body
- The body must come after the 4-byte header.
- The body consists of the following well-defined Type-Length-Value (TLV) entries.
- There must not be any gap between the TLV entries.
- The
typefield is always one byte. - The
lengthfield is always one byte. It contains the size of the correspondingvaluefield. The value of thelengthfield cannot be 0. - The CRC field must be the last entry. The other TLV entries can be in any order.
- Each field can appear no more than once in the content.
- The below table only lists the Mandatory fields from the Meta software teams. Please check with Meta Manufacturing & Quality team to ensure other Mandatory fields are taken care of.
| Type | Length (bytes) | Value | Mandatory (Y/N) | Description |
|---|---|---|---|---|
| 0 | N/A | N/A | N/A | Reserved |
| 1 | Variable | ASCII String | Y | Product Name |
| 2 | Variable | ASCII String | N | Top Level 20- Product Part Number |
| 3 | 8 | ASCII String | N | System Assembly Part Number |
| 4 | 12 | ASCII String | N | Meta PCBA Part Number |
| 5 | 12 | ASCII String | N | Meta PCB Part Number |
| 6 | Variable | ASCII String | N | ODM/JDM PCBA Part Number |
| 7 | Variable | ASCII String | N | ODM/JDM PCBA Serial Number |
| 8 | 1 | Unsigned Integer | Y | Production State. 1 denotes EVT. 2 denotes DVT, 3 denotes PVT. 4 denotes MP. This field cannot be 0. |
| 9 | 1 | Unsigned Integer | Y | Production Sub-State. Used to denote sub-phases within EVT, DVT and PVT phases. Example, 1 for EVT1, 2 for EVT2, 1 for DVT1 etc. This field cannot be 0 |
| 10 | 1 | Unsigned Integer | Y | Re-Spin/Variant Indicator. Used to uniquely identify platforms which have second-source or variance in hardware. This is not to be confused with EVT, DVT phase differences. For example, a SKU in MP might use voltage-regulators from two different vendors. But everything else (including other fields in EEPROM) will be the same across the two variants of the SKU. In this case, we assign a unique number in this field to uniquely identify the SKU with different voltage regulators. This field can be 0 if there are no respins or variants. |
| 11 | Variable | ASCII String | Y | Product Serial Number |
| 12 | Variable | ASCII String | N | System Manufacturer |
| 13 | 8 | ASCII String | N | System Manufacturing Date, in “YYYYMMDD” format. |
| 14 | Variable | ASCII String | N | PCB Manufacturer |
| 15 | Variable | ASCII String | N | Assembled at |
| 16 | Variable | ASCII String | N | EEPROM location on Fabric |
| 17 | 8 | 48 bits of Base MAC Address in the first six bytes. Unsigned Integer in the last two bytes. | N | X86 CPU MAC Addresses. The first six bytes represent the Base MAC Address, and the last two bytes represent the number of MAC Addresses from the Base. |
| 18 | 8 | 48 bits of Base MAC Address in the first six bytes. Unsigned Integer in the last two bytes. | N | BMC MAC Addresses. The first six bytes represent the Base MAC Address, and the last two bytes represent the number of MAC Addresses from the Base. |
| 19 | 8 | 48 bits of Base MAC Address in the first six bytes. Unsigned Integer in the last two bytes. | N | Switch ASIC MAC Addresses. The first six bytes represent the Base MAC Address, and the last two bytes represent the number of MAC Addresses from the Base. |
| 20 | 8 | 48 bits of Base MAC Address in the first six bytes. Unsigned Integer in the last two bytes. | N | Meta Reserved MAC Addresses. The first six bytes represent the Base MAC Address, and the last two bytes represent the number of MAC Addresses from the Base. |
| 21 | 1 | Unsigned Integer | N | A value of 1 indicates whether the unit has gone through RMA. Otherwise this field can be omitted or left with value 0 |
| 101 | Variable | Vendor Defined | N | Vendors can use this field for their own purposes. Meta EEPROM parsing tools (weutil) will just dump the contents of this field. The value will not be interpreted and used in any way. |
| 102 | Variable | Vendor Defined | N | Vendors can use this field for their own purposes. Meta EEPROM parsing tools (weutil) will just dump the contents of this field. The value will not be interpreted and used in any way. |
| 103 | Variable | Vendor Defined | N | Vendors can use this field for their own purposes. Meta EEPROM parsing tools (weutil) will just dump the contents of this field. The value will not be interpreted and used in any way. |
| 250 | 2 | Unsigned Integer | Y | CRC16. Refer to the “Checksum” section for details |
Checksum
We use the 16 bits CRC-CCITT-AUG specification with the following key attributes:
- Width \= 16 bits
- Truncated polynomial \= 0x1021
- Initial value \= 0x1D0F
- Input data is NOT reflected
- Output CRC is NOT reflected
- No XOR is performed on the output CRC
All EEPROM content bytes (starting from Meta EEPROM header up to the CRC16 TLV, but NOT including the CRC16 TLV field) are included for this CRC16 calculation. Be aware there is a 16 bits argument for CRC16 calculation. For example, if CRC16 Type field is located at offset 63, CRC16 calculation will include bytes from offset 0 to offset 62, inclusively.
Check https://github.com/facebook/fboss/blob/main/fboss/platform/weutil/Crc16CcittAug.cpp for CRC16 CCITT AUG implementation.
The below list shows the CRC16 output values for corner cases of byte streams and can be used as the reference to check the correctness of the algorithm.
| Byte Stream | Length | CRC16 (per CRC-CCITT) |
|---|---|---|
| NULL | 0 | 0x1D0F |
| A | 1 | 0x9479 |
| 123456789 | 9 | 0xE5CC |
| A string of 256 upper case “A” characters with no line breaks | 256 | 0XE938 |
Example
Raw EEPROM BLOB
> cat eeprom_file | hexdump -C
00000000 fb fb 06 ff 01 0d 46 49 52 53 54 5f 53 51 55 45 |......FIRST_SQUE|
00000010 45 5a 45 02 08 32 30 31 32 33 34 35 36 03 08 53 |EZE..20123456..S|
00000020 59 53 41 31 32 33 34 04 0c 50 43 42 41 31 32 33 |YSA1234..PCBA123|
00000030 34 35 36 37 20 05 0c 50 43 42 31 32 33 34 35 36 |4567 ..PCB123456|
00000040 37 38 20 06 0c 4d 59 4f 44 4d 31 32 33 34 35 36 |78 ..MYODM123456|
00000050 37 07 0d 4f 53 31 32 33 34 35 36 37 38 39 41 42 |7..OS123456789AB|
00000060 08 01 01 09 01 00 0a 01 01 0b 0d 50 53 31 32 33 |...........PS123|
00000070 34 35 36 37 38 39 30 41 0c 07 55 4e 41 5f 4d 41 |4567890A..UNA_MA|
00000080 53 0d 08 32 30 31 33 30 32 30 33 0e 05 54 45 52 |S..20130203..TER|
00000090 5a 4f 0f 09 4a 55 49 43 45 54 4f 52 59 10 07 42 |ZO..JUICETORY..B|
000000a0 55 44 4f 4b 41 4e 11 08 11 22 33 44 55 66 01 02 |UDOKAN..."3DUf..|
000000b0 12 08 12 34 56 78 9a bc 03 04 13 08 66 55 44 33 |...4Vx......fUD3|
000000c0 22 11 02 00 14 08 fe dc ba 98 76 54 00 02 15 01 |".........vT....|
000000d0 01 65 05 01 01 01 01 01 66 05 48 65 6c 6c 6f fa |.e......f.Hello.|
000000e0 02 4a 05 ff ff ff ff ff ff ff ff ff ff ff ff ff |.J..............|
000000f0 ff |.|
Output after parsing
> ./weutil --path eeprom_file
Version: 6
Product Name: FIRST_SQUEEZE
Product Part Number: 20123456
System Assembly Part Number: SYSA1234
Meta PCBA Part Number: PCBA1234567
Meta PCB Part Number: PCB12345678
ODM/JDM PCBA Part Number: MYODM1234567
ODM/JDM PCBA Serial Number: OS123456789AB
Product Production State: 1
Product Version: 0
Product Sub-Version: 1
Product Serial Number: PS1234567890A
System Manufacturer: UNA_MAS
System Manufacturing Date: 20130203
PCB Manufacturer: TERZO
Assembled At: JUICETORY
EEPROM location on Fabric: BUDOKAN
X86 CPU MAC Base: 11:22:33:44:55:66
X86 CPU MAC Address Size: 258
BMC MAC Base: 12:34:56:78:9a:bc
BMC MAC Address Size: 772
Switch ASIC MAC Base: 66:55:44:33:22:11
Switch ASIC MAC Address Size: 512
META Reserved MAC Base: fe:dc:ba:98:76:54
META Reserved MAC Address Size: 2
RMA: 1
Vendor Defined Field 1: 0x0101010101
Vendor Defined Field 2: 0x48656c6c6f
Vendor Defined Field 3:
CRC16: 0x4a05 (CRC Matched)
Note: In case the CRC programmed in the EEPROM mismatches the CRC calculated by weutil, the last line printing will display the programmed CRC and expected CRC.
CRC16: 0xa6b7 (CRC Mismatch. Expected 0x4a05)