From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from co1outboundpool.messaging.microsoft.com (co1ehsobe001.messaging.microsoft.com [216.32.180.184]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Microsoft Secure Server Authority" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 985602C0088 for ; Wed, 15 Aug 2012 07:20:54 +1000 (EST) Message-ID: <502AC12C.2010808@freescale.com> Date: Tue, 14 Aug 2012 16:20:44 -0500 From: Scott Wood MIME-Version: 1.0 To: Wang Dongsheng-B40534 Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support References: <1344578081-8095-1-git-send-email-Dongsheng.wang@freescale.com> <50257116.3030207@freescale.com> <50293B36.1000408@freescale.com> <5029B25E.4010708@freescale.com> <5029B576.7070900@freescale.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Cc: Wood Scott-B07421 , Li Yang-R58472 , "paulus@samba.org" , Gala Kumar-B11780 , "linuxppc-dev@lists.ozlabs.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 08/13/2012 09:32 PM, Wang Dongsheng-B40534 wrote: > > >> -----Original Message----- >> From: Wood Scott-B07421 >> Sent: Tuesday, August 14, 2012 10:19 AM >> To: Wang Dongsheng-B40534 >> Cc: Wood Scott-B07421; benh@kernel.crashing.org; paulus@samba.org; >> linuxppc-dev@lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472 >> Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support >> >> On 08/13/2012 09:15 PM, Wang Dongsheng-B40534 wrote: >>> >>> >>>> -----Original Message----- >>>> From: Wood Scott-B07421 >>>> Sent: Tuesday, August 14, 2012 10:05 AM >>>> To: Wang Dongsheng-B40534 >>>> Cc: Wood Scott-B07421; benh@kernel.crashing.org; paulus@samba.org; >>>> linuxppc-dev@lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472 >>>> Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support >>>> >>>> On 08/13/2012 09:00 PM, Wang Dongsheng-B40534 wrote: >>>>> >>>>> >>>>>> -----Original Message----- >>>>>> From: Wood Scott-B07421 >>>>>> Sent: Tuesday, August 14, 2012 1:37 AM >>>>>> To: Wang Dongsheng-B40534 >>>>>> Cc: Wood Scott-B07421; benh@kernel.crashing.org; paulus@samba.org; >>>>>> linuxppc-dev@lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472 >>>>>> Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support >>>>>> >>>>>> On 08/13/2012 01:18 AM, Wang Dongsheng-B40534 wrote: >>>>>>>>> + p = of_get_property(np, "available-ranges", &len); >>>>>>>>> + if (p && len % (2 * sizeof(u32)) != 0) { >>>>>>>>> + pr_err("%s: malformed fsl,available-ranges property.\n", >>>>>>>>> + np->full_name); >>>>>>>>> + return -EINVAL; >>>>>>>>> + } >>>>>>>> >>>>>>>> You need to support fsl,available-ranges since that's in an >>>>>>>> accepted binding and people could have partitioned setups already >>>> using it. >>>>>>>> >>>>>>> [Wang Dongsheng] FSL chip or OPEN-PIC specification(Only a group) >>>>>>> in each group only four timer. This is unified. So i use a generic >> name. >>>>>>> I think there is not compatible with existing mpic timer nodes. >>>>>> >>>>>> We need to be compatible with existing trees, so you'd need to >>>>>> check for both -- but I think any further discussion of the details >>>>>> is premature until we decide whether this is worthwhile to begin >>>>>> with (both the support of non-FSL timers, and the creation of a new >>>>>> device tree binding which will not be implemented by many of the >>>>>> machines that have non-FSL openpic because they run real Open >> Firmware). >>>>>> >>>>> [Wang Dongsheng] >>>>> p = of_get_property(np, "available-ranges", &len); >>>>> if (!p) >>>>> p = of_get_property(np, "fsl,available-ranges", &len); >>>>> >>>>> this code be compatible with existing trees. >>>> >>>> Yes, that's what I meant by checking both. >>>> >>>> I still think we need to discuss why we're doing this first. What >>>> specific machines are going to have these new openpic timer nodes? >>>> >>> [Wang Dongsheng] It's support to power management awakening. At >>> present, the power management more and more important. This way is >>> important to wake up machine. At least need support power management >>> of machine still needs such a driver. >> >> I mean specifically for the non-Freescale openpic nodes. >> > [Wang Dongsheng] I think non-Freescale chips can also use this function > to wake up the machine. Maybe (it's very machine-specific what can be used as a wake source), but what I asked was what specific machines could make use of this. Name *one* machine for which these new openpic timer nodes will actually be created. > And There is also an important feature, It can > periodically generate an interrupt. That's not important at all. We already have a way to do that using the decrementer. > For example, the network periodically check the hardware device(link status). And it uses standard Linux software timers to do it. -Scott