From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x243.google.com (mail-oi0-x243.google.com [IPv6:2607:f8b0:4003:c06::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 3FAD62264A216 for ; Wed, 4 Apr 2018 07:21:34 -0700 (PDT) Received: by mail-oi0-x243.google.com with SMTP id 71-v6so19366315oie.12 for ; Wed, 04 Apr 2018 07:21:34 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20180403142415.30083-1-oohall@gmail.com> <20180403142415.30083-3-oohall@gmail.com> <20180404220750.0436bbe1@gmail.com> From: Dan Williams Date: Wed, 4 Apr 2018 07:21:32 -0700 Message-ID: Subject: Re: [RESEND v2 3/4] doc/devicetree: Persistent memory region bindings List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Oliver Cc: Device Tree , linuxppc-dev , linux-nvdimm List-ID: On Wed, Apr 4, 2018 at 7:04 AM, Oliver wrote: > On Wed, Apr 4, 2018 at 10:07 PM, Balbir Singh wrote: >> On Tue, 3 Apr 2018 10:37:51 -0700 >> Dan Williams wrote: >> >>> On Tue, Apr 3, 2018 at 7:24 AM, Oliver O'Halloran wrote: >>> > Add device-tree binding documentation for the nvdimm region driver. >>> > >>> > Cc: devicetree@vger.kernel.org >>> > Signed-off-by: Oliver O'Halloran >>> > --- >>> > 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? _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm