From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <4D55736D.2070606@mentor.com> Date: Fri, 11 Feb 2011 11:35:41 -0600 From: Meador Inge MIME-Version: 1.0 To: Yoder Stuart-B08248 Subject: Re: [PATCH v3 0/4] powerpc: Open PIC binding and "pic-no-reset" References: <1296861941-3370-1-git-send-email-meador_inge@mentor.com> <4D54986A.60907@mentor.com> <9F6FE96B71CF29479FF1CDC8046E15030C485D@039-SN1MPN1-002.039d.mgd.msft.net> In-Reply-To: <9F6FE96B71CF29479FF1CDC8046E15030C485D@039-SN1MPN1-002.039d.mgd.msft.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: "devicetree-discuss@lists.ozlabs.org" , "linuxppc-dev@lists.ozlabs.org" , Meador Inge List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 02/11/2011 08:58 AM, Yoder Stuart-B08248 wrote: > > >> -----Original Message----- >> From: Meador Inge [mailto:meadori@gmail.com] >> Sent: Thursday, February 10, 2011 9:26 PM >> To: Benjamin Herrenschmidt >> Cc: Yoder Stuart-B08248; devicetree-discuss@lists.ozlabs.org; linuxppc- >> dev@lists.ozlabs.org >> Subject: Re: [PATCH v3 0/4] powerpc: Open PIC binding and "pic-no-reset" >> >> Apologies for the bad post. Bad day for email ... Please ignore the top >> reply in my previous reply. The full reply is the below the quote. >> >> On Thu, Feb 10, 2011 at 8:01 PM, Meador Inge >> wrote: >>> >>> On 02/10/2011 02:42 PM, Meador Inge wrote: >>>> >>>> ---------- Forwarded message ---------- >>>> From: Meador Inge >>>> Date: Fri, Feb 4, 2011 at 5:25 PM >>>> Subject: [PATCH v3 0/4] powerpc: Open PIC binding and "pic-no-reset" >>>> To: linuxppc-dev@lists.ozlabs.org >>>> Cc: devicetree-discuss@lists.ozlabs.org, Hollis Blanchard< >>>> hollis_blanchard@mentor.com> >>>> >>>> >>>> This patch set provides a binding for Open PIC and implements support >>>> for a new property, specified by that binding, called "pic-no-reset". >>>> With "pic-no-reset" in place the "protected-sources" property is no >>>> longer needed and its full implementation was removed. >>>> "protected-sources" is still checked for, however, for legacy >>>> purposes. >>>> >>>> For v3 of this patch the Open PIC binding was changed to be more >>>> consistent with existing bindings, several DTS files were cleaned up, >>>> "no-reset" was changed to "pic-no-reset", and a check to treat >>>> "protected-sources" as a synonym for "pic-no-reset" was added. >>>> >> >> From the feedback I have received so far, the fundamental ideas in this >> patch set are sane. However, the following issues still need agreement: >> >> 1. What should be the name of the no reset property? >> "pic-no-reset" or "no-reset"? >> 2. Should we just keep the existing protected sources implementation >> in place? >> >> For (1), I prefer "no-reset". > > I also prefer plain "no-reset". The property is on a pic node so > "pic" on the property seems redundant. > >> For (2), I still think that we can make "no- >> reset" a synonym for "protected-sources" and that things will work out. >> >> Ben, you said that you would really like to leave the protected sources >> implementation alone. Is the mechanism implemented in "PATCH >> v3 3/4" [1] of having "protected-sources" as a synonym for "pic-no-reset" >> not suitable? > > I thought what Ben was getting at was that there is existing > firmware that may provide a device tree with protected-sources, > and thus we should continue supporting it for backwards > compatibility. Yup, Arnd pointed that out as well. That is why in "PATCH v3 3/4" I added a check for "protected-sources". If it is found, then it is treated exactly the same way as "no-reset", which should give equivalent behavior. For example, say we have 100 sources and the sources [1, 50] are the only ones actually mentioned in the device tree. Also assume we set "protected-sources = <51 52 53>". Then, with the protected sources model sources [1, 50] and [54, 100] would have there VECPRI/cpu binding initialization. Where as in the enhanced "no-reset" model, only sources [1, 50] would have the initialization done. So unless there is some problem with not initializing the remaining sources, e.g. sources [51, 100] in the previous example, then the expanded "no-reset" should offer equivalent behavior to "protected-sources". > So, I would say add "no-reset" as the preferred mechanism > going forward, but keep "protected-sources" for backwards > compatibility. > > Stuart > > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/devicetree-discuss -- Meador Inge | meador_inge AT mentor.com Mentor Embedded | http://www.mentor.com/embedded-software