From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 924861A00C8 for ; Fri, 31 Oct 2014 03:21:56 +1100 (AEDT) Received: from na01-bl2-obe.outbound.protection.outlook.com (mail-bl2on0125.outbound.protection.outlook.com [65.55.169.125]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 8F16414009D for ; Fri, 31 Oct 2014 03:21:54 +1100 (AEDT) Message-ID: <54526521.1090601@Freescale.com> Date: Thu, 30 Oct 2014 11:19:45 -0500 From: Emil Medve MIME-Version: 1.0 To: Scott Wood Subject: Re: [PATCH 1/4] dt/bindings: Introduce the FSL QorIQ DPAA BMan References: <1413986972-621-1-git-send-email-Emilian.Medve@Freescale.com> <1414519738.23458.84.camel__4795.38602890006$1414521743$gmane$org@snotra.buserror.net> <54515ECB.70404@Freescale.com> <1414620996.23458.141.camel__29590.7804662876$1414621051$gmane$org@snotra.buserror.net> <5451BF49.6050106@Freescale.com> <1414680683.23458.148.camel__4514.07629666409$1414680744$gmane$org@snotra.buserror.net> In-Reply-To: <1414680683.23458.148.camel__4514.07629666409$1414680744$gmane$org@snotra.buserror.net> Content-Type: text/plain; charset="utf-8" Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, Geoff.Thorpe@Freescale.com, corbet@lwn.net, linux-doc@vger.kernel.org, linuxppc-dev@ozlabs.org, robh+dt@kernel.org, Kumar Gala List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello Scott, On 10/30/2014 09:51 AM, Scott Wood wrote: > On Wed, 2014-10-29 at 23:32 -0500, Emil Medve wrote: >> Hello Scott, >> >> >> On 10/29/2014 05:16 PM, Scott Wood wrote: >>> On Wed, 2014-10-29 at 16:40 -0500, Emil Medve wrote: >>>> Hello Scott, >>>> >>>> >>>> On 10/28/2014 01:08 PM, Scott Wood wrote: >>>>> On Tue, 2014-10-28 at 09:36 -0500, Kumar Gala wrote: >>>>>> On Oct 22, 2014, at 9:09 AM, Emil Medve wrote: >>>>>> >>>>>>> The Buffer Manager is part of the Data-Path Acceleration Architecture (DPAA). >>>>>>> BMan supports hardware allocation and deallocation of buffers belonging to >>>>>>> pools originally created by software with configurable depletion thresholds. >>>>>>> This binding covers the CCSR space programming model >>>>>>> >>>>>>> Signed-off-by: Emil Medve >>>>>>> Change-Id: I3ec479bfb3c91951e96902f091f5d7d2adbef3b2 >>>>>>> --- >>>>>>> .../devicetree/bindings/powerpc/fsl/bman.txt | 98 ++++++++++++++++++++++ >>>>>>> 1 file changed, 98 insertions(+) >>>>>>> create mode 100644 Documentation/devicetree/bindings/powerpc/fsl/bman.txt >>>>>> >>>>>> Should these really be in bindings/powerpc/fsl, aren’t you guys using this on ARM SoCs as well? >>>>> >>>>> The hardware on the ARM SoCs is different enough that I'm not sure the >>>>> same binding will cover it. That said, putting things under >>>>> should be a last resort if nowhere else fits. >>>> >>>> OTC started ported the driver to the the ARM SoC and the feedback has >>>> been that the driver needed minimal changes. The IOMMU has been the only >>>> area of concern, and a small change to the binding has been suggested >>> >>> Do we need something in the binding to indicate device endianness? >> >> As I said, I didn't have enough exposure to the ARM SoC so I can't >> answer that >> >>> If this binding is going to continue to be relevant to future DPAA >>> generations, I think we really ought to deal with the possibility that >>> there is more than one datapath instance >> >> I'm unsure how relevant this will be going forward. In LS2 B/QMan is >> abstracted/hidden away behind the MC (firmware). > > This is why I was wondering whether the binding would be at all the > same... > >> I wouldn't over-engineer this without a clear picture of what multiple >> data-paths per SoC even means at this point > > I don't think it's over-engineering. Assuming only one instance of > something is generally sloppy engineering. Linux doesn't need to > actually pay attention to it until and unless it becomes necessary, but > it's good to have the information in the device tree up front. I asked around and the "multiple data-path SoC" seems to be at this point a speculation. It seems unclear how would it work, what requirements/problems it would address/solve, what programming interface it would have. I'm not sure what do you suggest we do In order to reduce the sloppiness of this binding. I'll add a memory-region phandle to connect each B/QMan node to their reserved-memory node >>> by having phandles and/or a parent container to connect the related >>> components. >> >> Connecting the related components is beyond the scope of this binding. >> It will soon hit the e-mail list(s) as part of upstreaming the Ethernet >> driver > > So you want us to merge this binding without being told how this works? This binding stands on its own and each block (B/QMan) can be used for some useful purpose by itself. All other blocks/applications that use the B/QMan use the same basic interface acquire/release a "buffer" and enqueue/dequeue a "packet". I'm not sure what you feel I didn't share > Or by "soon" do you mean before this binding is accepted? No. The Ethernet driver, the QI SEC driver, RMan driver, etc. employ the B/QMan and *other* hardware resources in some specific way. I don't think their binding/drivers condition accepting the B/QMan binding/driver Cheers,