doc: Documentation issue in 'services/device_mgmt/smp_groups/smp_group_8' FS MGMT File Upload Request

[sgfeniex]

Describe the bug

The Zephyr SMP File upload section is unclear with respect to the required encoding of the data payload information.

The current documentation lists file upload request payload as:

{
    (str)"off"      : (uint)
    (str)"data"     : (str)
    (str)"name"     : (str)
    (str,opt)"len"  : (uint)
}

where the file download response is:

{
    (str)"off"      : (uint)
    (str)"data"     : (byte str)
    (str,opt)"len"  : (uint)
}

In an upload request, data must by a byte str by way of:
ZCBOR_MAP_DECODE_KEY_DECODER("data", zcbor_bstr_decode, &file_data),
see:

zephyr/subsys/mgmt/mcumgr/grp/fs_mgmt/src/fs_mgmt.c

Line 367 in b88d0bf

ZCBOR_MAP_DECODE_KEY_DECODER("data", zcbor_bstr_decode, &file_data),

"CBOR data of request" as well as the description of the "data" field need to be updated to reflect that only a ZCBOR_MAJOR_TYPE_BSTR is accepted.

Environment

• Page: services/device_mgmt/smp_groups/smp_group_8
• Version: main
• SHA-1: 5a5fd7c
• https://github.com/zephyrproject-rtos/zephyr/blob/main/doc/services/device_mgmt/smp_groups/smp_group_8.rst

[fabiobaltieri]

@nordicjm can you take a look please?

[JPHutchins]

Interesting, the smp package is definitely only supporting bytes: https://jphutchins.github.io/smp/latest/file_management/#smp.file_management.FileUploadRequest