The protocol to transmit and receive audio and music data over IEEE 1394 is compliant to the operations described in IEC 61883-1/6, however the other operations such as device initialization is the matter. I guess that it is out of the mLAN protocol itself.

You can see my initial and abandoned work to add support for mLAN devices:
* github.com/takaswie/lin...

This is the list of mLAN devices:

The mLAN 2nd generation:
* Yamaha 01x
* Yamaha i88x
* Yamaha mLAN16E
* Yamaha MY16-mLAN

The mLAN 3rd generation:
* Yamaha n8
* Yamaha n12
* Yamaha FW16E
* Yamaha mLAN16E2
* Steinberg MR816X
* Steinberg MR816CX

Yep. I've already investigated some devices of mLAN 2nd and 3rd generations, then realized that these devices have their specific operations to communicate to host system. The operations include interactions with tons of meta data, and it is hard to diagnose the content...

page_to_phys() を使っていたのが原因だった。dma_addr_t 返すじゃんだって・・・IOMMU配下だと確かにヒットしないわな。