NVMe Base 2.4: Firmware Update and LID 03h Verification

01 Capabilities and limits before an update

01.01.Firmware update is not a fixed command recipe. FRMW controls slots and activation capability, FWUG controls download granularity and alignment, MTFA and MPTFAWR bound waiting time, and MDS/DID define which controllers share the result.

MPTFAWR

Maximum Processing Time for Firmware Activation Without Reset, the maximum processing time for immediate activation without a reset.

FRMW

Firmware Updates, the Identify Controller field reporting slot count, slot-1 read-only state, and activation capabilities.

FWUG

Firmware Update Granularity, the capability field governing download-portion granularity and alignment.

MTFA

Maximum Time for Firmware Activation, the maximum time activation may pause command processing.

DID

Domain Identifier, the identifier of a domain within an NVM subsystem.

MDS

Multiple Domain Subsystem, the capability bit indicating whether an NVM subsystem contains multiple domains.

01.02.FRMW.SMUD, FAWR, NOFS, and FFSRO describe overlapping-update detection, activation without reset, the domain's supported slot count (1 through 7), and whether slot 1 is read-only.

portion

A contiguous portion sent in one firmware-download transfer.

CA

Commit Action, the Firmware Commit field selecting replacement, activation, and reset policy.

FS

Firmware Slot, the Firmware Commit field selecting the target slot.

02 Download lengths, offsets, and portions

02.01.Firmware Download uses NUMD as a zero-based length and OFST as a dword offset from the image start. Use the index-offset contrast: an index selects an item, while an offset measures distance from the start; neither value can be converted without its field definition.

index-offset

index-offset contrast: an index selects an item, while an offset measures a position. Zero-based Format Index=2 selects the third format; OFST=256 is a 256-Dword displacement from the image start.

zero-based

zero-based: numbering starts at zero, so raw=3 can mean the fourth item or four units; the field definition still decides which.

offset

offset: a displacement measured from a stated start. It answers “how far from the start,” unlike an index.

Dword

Dword (double word): 32 bits, or 4 bytes. A word is 16 bits; for example, a zero-based dword count of 3 represents 4 Dwords, or 16 bytes.

index

index: selects an item or format in a list. It answers “which one,” not “how far from the start.”

NUMD

Number of Dwords, a zero-based transfer-dword count; actual bytes = (NUMD + 1) × 4.

OFST

Offset, the dword-based image-relative offset in Firmware Image Download.

02.02.Firmware Image Download may split an image into portions, and firmware-image portions may arrive out of order. The host should avoid overlapping ranges and comply with FWUG. Boot Partition portions shall be submitted in order.

Host

The system running the operating system and issuing NVMe commands.

DPTR

Data Pointer, the SQE field identifying a command data buffer.

03 Commit storage and activation choices

03.01.Commit Action (CA) is not a success flag; it selects replacement, activation, and reset boundary. Firmware Slot (FS) selects the target slot, while CQE status determines whether software verifies, performs a specific reset, waits, or stops.

CQE

Completion Queue Entry, one completion-result structure in a CQ.

03.02.Firmware Commit validates the last downloaded image, places it in a firmware slot, and uses Commit Action to choose placement only, activation at a later Controller Level Reset, or immediate activation. Successful commit does not by itself mean the image is currently active.

controller

Controller, the entity that implements the NVMe interface, fetches commands, and reports completions.

MUD

Multiple Update Detected, the completion bit indicating detection of overlapping firmware-update sequences.

SCT

Status Code Type: selects the completion-status category and is interpreted with SC.

SC

Status Code: identifies the completion result within the selected SCT category.

04 Current and pending versions in LID 03h

04.01.Get Log Page first builds a 512-byte transfer from common command fields and selects Firmware Slot Information with LID=03h. AFI separates CAFS from NAFS, FRS1-FRS7 report slot revisions, and Identify.FR plus domain scope provide the final cross-check.

CAFS

Current Active Firmware Slot, the low three AFI bits identifying the currently executing firmware slot.

NAFS

Next Active Firmware Slot, AFI bits 6:4 identifying the slot scheduled for the next reset; zero means none is scheduled.

AFI

Active Firmware Info, the LID 03h byte containing the current active slot and the slot scheduled for the next reset.

04.02.When reading LID 03h, no namespace is used, so NSID shall be 0h, and DPTR uses PRPs to identify the 512-byte destination buffer. The required CDW10-CDW14 slice is LID=03h, LSP=0, RAE=0, NUMDL/NUMDU for 512 bytes, LSI=0, LPOL/LPOU=0, OT=0, and UIDX=0. LID 03h does not use CSI, which the controller ignores under Figure 208's rule.

namespace

Namespace, a formatted quantity of non-volatile memory accessed by a host through a controller.

NUMDL

Number of Dwords Lower, the low 16 bits of Get Log Page NUMD.

NUMDU

Number of Dwords Upper, the high 16 bits of Get Log Page NUMD.

LPOL

Log Page Offset Lower, the low 32 bits of the Get Log Page byte offset.

LPOU

Log Page Offset Upper, the high 32 bits of the Get Log Page byte offset.

NSID

Namespace Identifier, a controller-visible numeric handle for a namespace; the identifier is not the namespace object itself.

UIDX

UUID Index, an index into the UUID List; zero indicates that no UUID is specified.

CDW

CDW (Command Dword): a 32-bit command field. In CDW10, 10 is the field index, not a byte offset.

CSI

I/O Command Set Identifier: selects an I/O command set; NVM uses 00h.

LSI

Log Specific Identifier, an identifier whose meaning is defined by the selected log page.

LSP

Log Specific Field, a command selector whose meaning is defined by the selected log page.

RAE

Retain Asynchronous Event, the Get Log Page selector controlling retention of a related asynchronous event.