On Wed, 4 Apr 2018 07:21:32 -0700 Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > On Wed, Apr 4, 2018 at 7:04 AM, Oliver <oohall@xxxxxxxxx> wrote: > > On Wed, Apr 4, 2018 at 10:07 PM, Balbir Singh <bsingharora@xxxxxxxxx> wrote: > >> On Tue, 3 Apr 2018 10:37:51 -0700 > >> Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > >> > >>> On Tue, Apr 3, 2018 at 7:24 AM, Oliver O'Halloran <oohall@xxxxxxxxx> wrote: > >>> > Add device-tree binding documentation for the nvdimm region driver. > >>> > > >>> > Cc: devicetree@xxxxxxxxxxxxxxx > >>> > Signed-off-by: Oliver O'Halloran <oohall@xxxxxxxxx> > >>> > --- > >>> > v2: Changed name from nvdimm-region to pmem-region. > >>> > Cleaned up the example binding and fixed the overlapping regions. > >>> > Added support for multiple regions in a single reg. > >>> > --- > >>> > .../devicetree/bindings/pmem/pmem-region.txt | 80 ++++++++++++++++++++++ > >>> > MAINTAINERS | 1 + > >>> > 2 files changed, 81 insertions(+) > >>> > create mode 100644 Documentation/devicetree/bindings/pmem/pmem-region.txt > >>> > >>> Device-tree folks, does this look, ok? > >>> > >>> Oliver, is there any concept of a management interface to the > >>> device(s) backing these regions? libnvdimm calls these "nmem" devices > >>> and support operations like health status and namespace label > >>> management. > > > > It's something I'm planning on implementing as soon as someone gives > > me some hardware that isn't hacked up lab crap. I'm posting this > > version with just regions since people have been asking for something > > in upstream even if it's not fully featured. > > > > Grumbling aside, the plan is to have separate drivers for the DIMM > > type. Discovering DIMM devices happens via the normal discovery > > mechanisms (e.g. an NVDIMM supporting the JEDEC interface is an I2C > > device) and when binding to a specific DIMM device it registers a DIMM > > descriptor structure and a ndctl implementation for that DIMM type > > with of_pmem. When of_pmem binds to a region it can plug everything > > into the region specific bus. There's a few details to work out, but I > > think it's a reasonable approach. > > Yeah, that sounds reasonable. It would mean that your management > interface would need to understand that nmems on different buses could > potentially move to another bus after a reconfiguration, but that's > not too much different than the ACPI case where nmems can join and > leave regions after a reset / reconfig. > > >> We would need a way to have nmem and pmem-regions find each other. Since we > >> don't have the ACPI abstractions, the nmem region would need to add the > >> ability for a driver to have a phandle to the interleaving and nmem properties. > >> > >> I guess that would be a separate driver, that would manage the nmem devices > >> and there would be a way to relate the pmem and nmems. Oliver? > > > > Yes, that's the plan. > > So Balbir, is that enough for an Acked-by for this device-tree proposal? I don't see any major problems with the binding, but I think Oliver wanted to send in a few clarifications based on a private discussion. Balbir Singh. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
