Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753299AbbDVSBG (ORCPT ); Wed, 22 Apr 2015 14:01:06 -0400 Received: from g9t5009.houston.hp.com ([15.240.92.67]:51725 "EHLO g9t5009.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752957AbbDVSBD (ORCPT ); Wed, 22 Apr 2015 14:01:03 -0400 Message-ID: <5537E1D9.6010609@hp.com> Date: Wed, 22 Apr 2015 14:00:57 -0400 From: Linda Knippers User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Dan Williams , Toshi Kani CC: "linux-kernel@vger.kernel.org" , "linux-nvdimm@lists.01.org" Subject: Re: [Linux-nvdimm] [PATCH 04/21] nd: create an 'nd_bus' from an 'nfit_desc' References: <20150418013256.25237.96403.stgit@dwillia2-desk3.amr.corp.intel.com> <20150418013535.25237.4770.stgit@dwillia2-desk3.amr.corp.intel.com> <1429644912.17259.31.camel@misato.fc.hp.com> <1429646156.17259.39.camel@misato.fc.hp.com> <1429720742.15952.30.camel@misato.fc.hp.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4206 Lines: 94 On 4/22/2015 1:03 PM, Dan Williams wrote: > On Wed, Apr 22, 2015 at 9:39 AM, Toshi Kani wrote: >> On Tue, 2015-04-21 at 13:35 -0700, Dan Williams wrote: >>> On Tue, Apr 21, 2015 at 12:55 PM, Toshi Kani wrote: >>>> On Tue, 2015-04-21 at 12:58 -0700, Dan Williams wrote: >>>>> On Tue, Apr 21, 2015 at 12:35 PM, Toshi Kani wrote: >>>>>> On Fri, 2015-04-17 at 21:35 -0400, Dan Williams wrote: >>>>>> : >>>>>>> + >>>>>>> +static int nd_mem_init(struct nd_bus *nd_bus) >>>>>>> +{ >>>>>>> + struct nd_spa *nd_spa; >>>>>>> + >>>>>>> + /* >>>>>>> + * For each SPA-DCR address range find its corresponding >>>>>>> + * MEMDEV(s). From each MEMDEV find the corresponding DCR. >>>>>>> + * Then, try to find a SPA-BDW and a corresponding BDW that >>>>>>> + * references the DCR. Throw it all into an nd_mem object. >>>>>>> + * Note, that BDWs are optional. >>>>>>> + */ >>>>>>> + list_for_each_entry(nd_spa, &nd_bus->spas, list) { >>>>>>> + u16 spa_index = readw(&nd_spa->nfit_spa->spa_index); >>>>>>> + int type = nfit_spa_type(nd_spa->nfit_spa); >>>>>>> + struct nd_mem *nd_mem, *found; >>>>>>> + struct nd_memdev *nd_memdev; >>>>>>> + u16 dcr_index; >>>>>>> + >>>>>>> + if (type != NFIT_SPA_DCR) >>>>>>> + continue; >>>>>> >>>>>> This function requires NFIT_SPA_DCR, SPA Range Structure with NVDIMM >>>>>> Control Region GUID, for initializing an nd_mem object. However, >>>>>> battery-backed DIMMs do not have such control region SPA. IIUC, the >>>>>> NFIT spec does not require NFIT_SPA_DCR. >>>>>> >>>>>> Can you change this function to work with NFIT_SPA_PM as well? >>>>> >>>>> NFIT_SPA_PM ranges are handled separately from nd_mem_init(). See >>>>> nd_region_create() in patch 10. >>>> >>>> If nd_mem_init() does not initialize nd_mem objects, nd_bus_probe() in >>>> core.c fails in nd_bus_init_interleave_sets() and skips all subsequent >>>> nd_bus_xxx() calls. So, nd_region_create() won't be called. >>>> >>>> nd_bus_init_interleave_sets() fails because init_interleave_set() >>>> returns -ENODEV if (!nd_mem). >>> >>> Ah, ok your test case is specifying PMEM backed by memory device >>> info. We have a test case for simple ranges (nfit_test1_setup()), but >>> it doesn't hit this bug because it does not specify any memory-device >>> tables. >> >> Yes, we have NFIT table with SPA range (PM), memory device to SPA, and >> NVDIMM control region structures. With the memory device to SPA >> structure, this code requires full sets of information, including the >> namespace label data in _DSM [1], which is outside of ACPI 6.0 and is >> optional. Battery-backed DIMMs do not have such label data. > > This is what "nd_namespace_io" devices are for, they do not require labels. > > Question, if you don't have labels and you don't have DSMs then why > publish a MEMDEV table at all? Why not simply publish an anonymous > range? See nfit_test1_setup(). The MEMDEV table provides useful information, and there may be _DSMs, perhaps just not the same _DSM as some other devices. >> It needs >> to work with NFIT table with these structures without this _DSM or with >> a different type of _DSM which this code may or may not need to support. >> It should also check Region Format Interface Code (RFIC) in the NVDIMM >> control region structure before assuming this _DSM is present to >> implement RFIC 0x0201. > > Ok I can look into adding this check, but I don't think it is > necessary if you simply refrain from publishing a MEMDEV entry. But we need the MEMDEV. And as Toshi mentions, we could have other RFICs with other _DSMs than your example. That's why there is an RFIC. -- ljk > _______________________________________________ > Linux-nvdimm mailing list > Linux-nvdimm@lists.01.org > https://lists.01.org/mailman/listinfo/linux-nvdimm > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/