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diff --git a/Documentation/driver-api/pldmfw/file-format.rst b/Documentation/driver-api/pldmfw/file-format.rst new file mode 100644 index 000000000000..b7a9cebe09c6 --- /dev/null +++ b/Documentation/driver-api/pldmfw/file-format.rst @@ -0,0 +1,203 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +================================== +PLDM Firmware file format overview +================================== + +A PLDM firmware package is a binary file which contains a header that +describes the contents of the firmware package. This includes an initial +package header, one or more firmware records, and one or more components +describing the actual flash contents to program. + +This diagram provides an overview of the file format:: + + overall file layout + +----------------------+ + | | + | Package Header | + | | + +----------------------+ + | | + | Device Records | + | | + +----------------------+ + | | + | Component Info | + | | + +----------------------+ + | | + | Package Header CRC | + | | + +----------------------+ + | | + | Component Image 1 | + | | + +----------------------+ + | | + | Component Image 2 | + | | + +----------------------+ + | | + | ... | + | | + +----------------------+ + | | + | Component Image N | + | | + +----------------------+ + +Package Header +============== + +The package header begins with the UUID of the PLDM file format, and +contains information about the version of the format that the file uses. It +also includes the total header size, a release date, the size of the +component bitmap, and an overall package version. + +The following diagram provides an overview of the package header:: + + header layout + +-------------------------+ + | PLDM UUID | + +-------------------------+ + | Format Revision | + +-------------------------+ + | Header Size | + +-------------------------+ + | Release Date | + +-------------------------+ + | Component Bitmap Length | + +-------------------------+ + | Package Version Info | + +-------------------------+ + +Device Records +============== + +The device firmware records area starts with a count indicating the total +number of records in the file, followed by each record. A single device +record describes what device matches this record. All valid PLDM firmware +files must contain at least one record, but optionally may contain more than +one record if they support multiple devices. + +Each record will identify the device it supports via TLVs that describe the +device, such as the PCI device and vendor information. It will also indicate +which set of components that are used by this device. It is possible that +only subset of provided components will be used by a given record. A record +may also optionally contain device-specific package data that will be used +by the device firmware during the update process. + +The following diagram provides an overview of the device record area:: + + area layout + +---------------+ + | | + | Record Count | + | | + +---------------+ + | | + | Record 1 | + | | + +---------------+ + | | + | Record 2 | + | | + +---------------+ + | | + | ... | + | | + +---------------+ + | | + | Record N | + | | + +---------------+ + + record layout + +-----------------------+ + | Record Length | + +-----------------------+ + | Descriptor Count | + +-----------------------+ + | Option Flags | + +-----------------------+ + | Version Settings | + +-----------------------+ + | Package Data Length | + +-----------------------+ + | Applicable Components | + +-----------------------+ + | Version String | + +-----------------------+ + | Descriptor TLVs | + +-----------------------+ + | Package Data | + +-----------------------+ + +Component Info +============== + +The component information area begins with a count of the number of +components. Following this count is a description for each component. The +component information points to the location in the file where the component +data is stored, and includes version data used to identify the version of +the component. + +The following diagram provides an overview of the component area:: + + area layout + +-----------------+ + | | + | Component Count | + | | + +-----------------+ + | | + | Component 1 | + | | + +-----------------+ + | | + | Component 2 | + | | + +-----------------+ + | | + | ... | + | | + +-----------------+ + | | + | Component N | + | | + +-----------------+ + + component layout + +------------------------+ + | Classification | + +------------------------+ + | Component Identifier | + +------------------------+ + | Comparison Stamp | + +------------------------+ + | Component Options | + +------------------------+ + | Activation Method | + +------------------------+ + | Location Offset | + +------------------------+ + | Component Size | + +------------------------+ + | Component Version Info | + +------------------------+ + | Package Data | + +------------------------+ + + +Package Header CRC +================== + +Following the component information is a short 4-byte CRC calculated over +the contents of all of the header information. + +Component Images +================ + +The component images follow the package header information in the PLDM +firmware file. Each of these is simply a binary chunk with its start and +size defined by the matching component structure in the component info area. |