From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031505AbbDYAy0 (ORCPT ); Fri, 24 Apr 2015 20:54:26 -0400 Received: from g4t3427.houston.hp.com ([15.201.208.55]:56233 "EHLO g4t3427.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030989AbbDYAyW (ORCPT ); Fri, 24 Apr 2015 20:54:22 -0400 Message-ID: <1429922126.23761.42.camel@misato.fc.hp.com> Subject: Re: [Linux-nvdimm] [PATCH 08/21] nd: ndctl.h, the nd ioctl abi From: Toshi Kani To: Dan Williams Cc: "linux-nvdimm@lists.01.org" , linux-acpi@vger.kernel.org, "Rafael J. Wysocki" , Robert Moore , "linux-kernel@vger.kernel.org" Date: Fri, 24 Apr 2015 18:35:26 -0600 In-Reply-To: References: <20150418013256.25237.96403.stgit@dwillia2-desk3.amr.corp.intel.com> <20150418013557.25237.81354.stgit@dwillia2-desk3.amr.corp.intel.com> <1429890991.16996.55.camel@misato.fc.hp.com> <1429895881.23761.16.camel@misato.fc.hp.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2015-04-24 at 10:45 -0700, Dan Williams wrote: > On Fri, Apr 24, 2015 at 10:18 AM, Toshi Kani wrote: > > On Fri, 2015-04-24 at 09:25 -0700, Dan Williams wrote: > >> On Fri, Apr 24, 2015 at 8:56 AM, Toshi Kani wrote: > >> > On Fri, 2015-04-17 at 21:35 -0400, Dan Williams wrote: > >> >> Most configuration of the nd-subsystem is done via nd-sysfs. However, > >> >> the NFIT specification defines a small set of messages that can be > >> >> passed to the subsystem via platform-firmware-defined methods. The > >> >> command set (as of the current version of the NFIT-DSM spec) is: > >> >> > >> >> NFIT_CMD_SMART: media health and diagnostics > >> >> NFIT_CMD_GET_CONFIG_SIZE: size of the label space > >> >> NFIT_CMD_GET_CONFIG_DATA: read label > >> >> NFIT_CMD_SET_CONFIG_DATA: write label > >> >> NFIT_CMD_VENDOR: vendor-specific command passthrough > >> >> NFIT_CMD_ARS_CAP: report address-range-scrubbing capabilities > >> >> NFIT_CMD_START_ARS: initiate scrubbing > >> >> NFIT_CMD_QUERY_ARS: report on scrubbing state > >> >> NFIT_CMD_SMART_THRESHOLD: configure alarm thresholds for smart events > >> > > >> > "nd/bus.c" provides two features, 1) the top level ND bus driver which > >> > is the central part of the ND, and 2) the ioctl interface specific to > >> > the example-DSM-interface. I think the example-DSM-specific part should > >> > be put into an example-DSM-support module, so that the ND can support > >> > other _DSMs as necessary. Also, _DSM needs to be handled as optional. > >> > >> I don't think it needs to be separated, they'll both end up using the > >> same infrastructure just with different UUIDs on the ACPI device > >> interface or different format-interface-codes. A firmware > >> implementation is also free to disable individual DSMs (see > >> nd_acpi_add_dimm). > > > > Well, ioctl cmd# is essentially func# of the _DSM, and each cmd > > structure needs to match with its _DSM output data structure. So, I do > > not think these cmds will work for other _DSMs. That said, the ND is > > complex enough already, and we should not make it more complicated for > > the initial version... So, how about changing the name of /dev/ndctl0 > > to indicate RFIC 0x0201, ex. /dev/nd0201ctl0? That should allow > > separate ioctl()s for other RFICs. The code can be updated when other > > _DSM actually needs to be supported by the ND. > > No, all you need is unique command names (see libndctl > ndctl_{bus|dimm}_is_cmd_supported()) and then translate the ND cmd > number to the firmware function number in the "provider". It just so > happens that for these first set of commands the ND cmd number matches > the ACPI device function number in the DSM-interface-example, but > there is no reason that need always be the case. I misread the code -- /dev/ndctlN is for a bus, and /dev/nmemN is for a DIMM. RFIC 0x0201 matches to DIMMs, not the bus. Since the _DSM under ACPI0013 is generic, we are probably OK with ndctl. The DIMM driver is fully integrated with the example-DSM. Separating nd/acpi.c alone would not solve it... In your fix that will make the DIMM _DSM optional, do you plan to make the DIMM driver more independent from the example-DIMM _DSM? Thanks, -Toshi