From: Balbir Singh <email@example.com>
To: Dan Williams <firstname.lastname@example.org>
Cc: Device Tree <email@example.com>,
Subject: Re: [RESEND v2 3/4] doc/devicetree: Persistent memory region bindings
Date: Thu, 5 Apr 2018 14:43:48 +1000 [thread overview]
Message-ID: <firstname.lastname@example.org> (raw)
On Wed, 4 Apr 2018 07:21:32 -0700
Dan Williams <email@example.com> wrote:
> On Wed, Apr 4, 2018 at 7:04 AM, Oliver <firstname.lastname@example.org> wrote:
> > On Wed, Apr 4, 2018 at 10:07 PM, Balbir Singh <email@example.com> wrote:
> >> On Tue, 3 Apr 2018 10:37:51 -0700
> >> Dan Williams <firstname.lastname@example.org> wrote:
> >>> On Tue, Apr 3, 2018 at 7:24 AM, Oliver O'Halloran <email@example.com> wrote:
> >>> > Add device-tree binding documentation for the nvdimm region driver.
> >>> >
> >>> > Cc: firstname.lastname@example.org
> >>> > Signed-off-by: Oliver O'Halloran <email@example.com>
> >>> > ---
> >>> > 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.
Linux-nvdimm mailing list
next prev parent reply other threads:[~2018-04-05 4:43 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-03 14:24 [RESEND v2 1/4] libnvdimm: Add of_node to region and bus descriptors Oliver O'Halloran
2018-04-03 14:24 ` [RESEND v2 2/4] libnvdimm: Add device-tree based driver Oliver O'Halloran
2018-04-03 17:34 ` Dan Williams
2018-04-03 14:24 ` [RESEND v2 3/4] doc/devicetree: Persistent memory region bindings Oliver O'Halloran
2018-04-03 17:37 ` Dan Williams
2018-04-04 12:07 ` Balbir Singh
2018-04-04 14:04 ` Oliver
2018-04-04 14:21 ` Dan Williams
2018-04-05 4:43 ` Balbir Singh [this message]
2018-04-05 11:34 ` Oliver
2018-04-05 12:11 ` Michael Ellerman
2018-04-05 12:43 ` Oliver
2018-04-05 14:43 ` Dan Williams
2018-04-06 2:14 ` Oliver
2018-04-06 2:25 ` Dan Williams
2018-04-06 3:57 ` Benjamin Herrenschmidt
2018-04-03 14:24 ` [RESEND v2 4/4] powerpc/powernv: Create platform devs for nvdimm buses Oliver O'Halloran
2018-04-04 12:20 ` Balbir Singh
2018-04-04 11:30 ` [RESEND v2 1/4] libnvdimm: Add of_node to region and bus descriptors Balbir Singh
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