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? -- 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
