[PATCH v3 2/2] powerpc/pseries: Add driver for PAPR SCM regions

[Dan Williams]

On Sun, Oct 14, 2018 at 4:19 PM Oliver O'Halloran <oohall at gmail.com> wrote:
>
> Adds a driver that implements support for enabling and accessing PAPR
> SCM regions. Unfortunately due to how the PAPR interface works we can't
> use the existing of_pmem driver (yet) because:
>
>  a) The guest is required to use the H_SCM_BIND_MEM h-call to add
>     add the SCM region to it's physical address space, and
>  b) There is currently no mechanism for relating a bare of_pmem region
>     to the backing DIMM (or not-a-DIMM for our case).
>
> Both of these are easily handled by rolling the functionality into a
> seperate driver so here we are...
>
> Acked-by: Dan Williams <dan.j.williams at intel.com>
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
> The alternative implementation here is that we have the pseries code
> do the h-calls and craft a pmem-region@<addr> node based on that.
> However, that doesn't solve b) and mpe has expressed his dislike of
> adding new stuff to the DT at runtime so i'd say that's a non-starter.
> ---
> v2: no change
> v3: Corrected the mapping to use a DPA start address of zero
>     Added cond_resched() calls in the bind/unbind loops

Looks good, could I trouble you for an ack on the build / merge fix?

https://patchwork.kernel.org/patch/10640385/