Note: this series does not add fully functional driver as its size would get out of control. Here, focus is put on adding IPC protocol and code loading code.
This series is much simpler indeed, see comments in patches, but that leaves the next steps completely open. It's not quite clear to me how the previous feedback on trying to up-level the DSP management functionality might be handled, and if/when you are planning to submit follow-up patchsets that would implement the required functionality to at least match what the Skylake driver can do today.
To repeat my previous points: the existing DPCM FE/BE split does not even being to represent how a DSP might be handled. The BE typically represents a physical DAI connected to a codec, and the FE pretty much everything else between a host DMA and the DAI. All the internal format conversions, mixers and processing are not really represented other than with DAPM logical widgets, and that's a big miss. There's room for a lot of improvements that would be of interest to all DSP users.