From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-x242.google.com (mail-pl0-x242.google.com [IPv6:2607:f8b0:400e:c01::242]) (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 D6D8522526483 for ; Wed, 4 Apr 2018 21:43:57 -0700 (PDT) Received: by mail-pl0-x242.google.com with SMTP id bj1-v6so15068613plb.8 for ; Wed, 04 Apr 2018 21:43:57 -0700 (PDT) Date: Thu, 5 Apr 2018 14:43:48 +1000 From: Balbir Singh Subject: Re: [RESEND v2 3/4] doc/devicetree: Persistent memory region bindings Message-ID: <20180405144348.141fd93f@gmail.com> In-Reply-To: References: <20180403142415.30083-1-oohall@gmail.com> <20180403142415.30083-3-oohall@gmail.com> <20180404220750.0436bbe1@gmail.com> MIME-Version: 1.0 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: Dan Williams Cc: Device Tree , linuxppc-dev , linux-nvdimm List-ID: On Wed, 4 Apr 2018 07:21:32 -0700 Dan Williams wrote: > 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? 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. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm