Re: [PATCH 3/6] libnvdimm: Add device-tree based driver

On Sat, Mar 24, 2018 at 4:07 AM, Dan Williams [off-list ref] wrote:

On Fri, Mar 23, 2018 at 1:12 AM, Oliver O'Halloran [off-list ref] wrote:

quoted

This patch adds peliminary device-tree bindings for the NVDIMM driver.

*preliminary

quoted

Currently this only supports one bus (created at probe time) which all
regions are added to with individual regions being created by a platform
device driver.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
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I suspect the platform driver should be holding a reference to the
created region. I left that out here since previously Dan has said
he'd rather keep the struct device internal to libnvdimm and the only
other way a region device can disappear is when the bus is unregistered.

Hmm, but this still seems broken if bus teardown races region
teardown.

Yeah looks like it.

I think the more natural model, given the way libnvdimm is
structured, to have each of these of_nd_region instances create their
own nvdimm bus. Thoughts?

I'd prefer this too tbh. The main reason I'm looking at this approach
is that we plan on doing all interleave set configuration, etc from
Linux. So we'd like to have "similar" region/dimm devices end up in
the same bus to simplify validating managment ops, etc. That said, the
real enablement work for that is blocked on teams so I'm ok with
ignoring all of that for now.

Oliver