From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754314AbaHFWM5 (ORCPT ); Wed, 6 Aug 2014 18:12:57 -0400 Received: from mail-pd0-f174.google.com ([209.85.192.174]:53527 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753449AbaHFWMz (ORCPT ); Wed, 6 Aug 2014 18:12:55 -0400 Message-ID: <53E2A85A.8030406@gmail.com> Date: Wed, 06 Aug 2014 15:12:42 -0700 From: Florian Fainelli User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Tim Bird , Brian Norris CC: Rob Herring , "devicetree@vger.kernel.org" , Grant Likely , Rob Herring , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] of/irq: lookup 'interrupts-extended' property first References: <1403220823-19444-1-git-send-email-f.fainelli@gmail.com> <20140806165452.GN3711@ld-irv-0074> <20140806201256.GO3711@ld-irv-0074> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/06/2014 02:50 PM, Tim Bird wrote: > On Wed, Aug 6, 2014 at 1:12 PM, Brian Norris > wrote: >> On Wed, Aug 06, 2014 at 01:42:08PM -0500, Rob Herring wrote: >>> On Wed, Aug 6, 2014 at 11:54 AM, Brian Norris wrote: >>>> On Thu, Jul 31, 2014 at 11:00:01AM -0700, Florian Fainelli wrote: >>>> I think it is important that a device tree provide some flexibility on >>>> kernel versions. We only invented 'interrupts-extended' in Linux 3.13, >>>> so it's easy to have device trees that could work only on 3.13+. >>>> >>>> Typically, we might say that new features require new kernels, but this >>>> is a very basic piece of the DT infrastructure. In our case, we have >>>> hardware whose basic features can be supported by a single interrupt >>>> parent, and so we used the 'interrupts' property pre-3.13. But when we >>>> want to add some power management features, there's an additional >>>> interrupt parent. Under the current DT binding, we have to switch over >>>> to using 'interrupts-extended' exclusively, and thus we must have a >>>> completely new DTB for >=3.13, and this DTB no longer works with the old >>>> kernels. >>> >>> "Must have" to enable the new features? >> >> Yes. The new feature requires an additional interrupt parent, and so it >> requires interrupts-extended. > > Hold on there. What about interrupt-map? That was the traditional DT > feature for > supporting multi-parented interrupts. Why couldn't the feature have been added > using that instead of interrupts-extended? As far as I read it from the ePAPR specification, you have a good point here, it looks like 'interrupt-map' could have been used as-is instead of 'interrupts-extended'. In fact it is a little more general than 'interrupts-extended' since it allows any sort of "child unit address", whether that is an actual interrupt number, or something else, is dependent on the type of node being used. > > I know interrupts-extended is preferred, but has interrupt-map support been > removed from recent kernels? I'm a bit confused. 'interrupt-map' support has not been removed since that is heavily used to cross interrupt domains, e.g: PCI relies heavily on it, other buses as well most likely. > > -- Tim Bird > Senior Software Engineer, Sony Mobile > Architecture Group Chair, CE Workgroup, Linux Foundation > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH] of/irq: lookup 'interrupts-extended' property first Date: Wed, 06 Aug 2014 15:12:42 -0700 Message-ID: <53E2A85A.8030406@gmail.com> References: <1403220823-19444-1-git-send-email-f.fainelli@gmail.com> <20140806165452.GN3711@ld-irv-0074> <20140806201256.GO3711@ld-irv-0074> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tim Bird , Brian Norris Cc: Rob Herring , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Grant Likely , Rob Herring , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org On 08/06/2014 02:50 PM, Tim Bird wrote: > On Wed, Aug 6, 2014 at 1:12 PM, Brian Norris > wrote: >> On Wed, Aug 06, 2014 at 01:42:08PM -0500, Rob Herring wrote: >>> On Wed, Aug 6, 2014 at 11:54 AM, Brian Norris wrote: >>>> On Thu, Jul 31, 2014 at 11:00:01AM -0700, Florian Fainelli wrote: >>>> I think it is important that a device tree provide some flexibility on >>>> kernel versions. We only invented 'interrupts-extended' in Linux 3.13, >>>> so it's easy to have device trees that could work only on 3.13+. >>>> >>>> Typically, we might say that new features require new kernels, but this >>>> is a very basic piece of the DT infrastructure. In our case, we have >>>> hardware whose basic features can be supported by a single interrupt >>>> parent, and so we used the 'interrupts' property pre-3.13. But when we >>>> want to add some power management features, there's an additional >>>> interrupt parent. Under the current DT binding, we have to switch over >>>> to using 'interrupts-extended' exclusively, and thus we must have a >>>> completely new DTB for >=3.13, and this DTB no longer works with the old >>>> kernels. >>> >>> "Must have" to enable the new features? >> >> Yes. The new feature requires an additional interrupt parent, and so it >> requires interrupts-extended. > > Hold on there. What about interrupt-map? That was the traditional DT > feature for > supporting multi-parented interrupts. Why couldn't the feature have been added > using that instead of interrupts-extended? As far as I read it from the ePAPR specification, you have a good point here, it looks like 'interrupt-map' could have been used as-is instead of 'interrupts-extended'. In fact it is a little more general than 'interrupts-extended' since it allows any sort of "child unit address", whether that is an actual interrupt number, or something else, is dependent on the type of node being used. > > I know interrupts-extended is preferred, but has interrupt-map support been > removed from recent kernels? I'm a bit confused. 'interrupt-map' support has not been removed since that is heavily used to cross interrupt domains, e.g: PCI relies heavily on it, other buses as well most likely. > > -- Tim Bird > Senior Software Engineer, Sony Mobile > Architecture Group Chair, CE Workgroup, Linux Foundation > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html