From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7940AC74A5B for ; Wed, 29 Mar 2023 17:45:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229909AbjC2RpK (ORCPT ); Wed, 29 Mar 2023 13:45:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229842AbjC2RpJ (ORCPT ); Wed, 29 Mar 2023 13:45:09 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 3F1ED525E; Wed, 29 Mar 2023 10:45:08 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 295332F4; Wed, 29 Mar 2023 10:45:52 -0700 (PDT) Received: from bogus (unknown [10.57.52.160]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3795D3F6C4; Wed, 29 Mar 2023 10:45:05 -0700 (PDT) Date: Wed, 29 Mar 2023 18:44:31 +0100 From: Sudeep Holla To: Cristian Marussi Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, vincent.guittot@linaro.org, souvik.chakravarty@arm.com, nicola.mazzucato@arm.com, Tushar.Khandelwal@arm.com, viresh.kumar@linaro.org, jassisinghbrar@gmail.com, Rob Herring , Sudeep Holla , Krzysztof Kozlowski , devicetree@vger.kernel.org Subject: Re: [PATCH 1/2] dt-bindings: mailbox : arm,mhuv2: Allow for more RX interrupts Message-ID: <20230329174431.yga3c233sazimane@bogus> References: <20230329153936.394911-1-cristian.marussi@arm.com> <20230329153936.394911-2-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230329153936.394911-2-cristian.marussi@arm.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, Mar 29, 2023 at 04:39:35PM +0100, Cristian Marussi wrote: > The ARM MHUv2 Receiver block can indeed support more interrupts, up to the > maximum number of available channels, but anyway no more than the maximum > number of supported interrupt for an AMBA device. > > Signed-off-by: Cristian Marussi > --- > Cc: Rob Herring > Cc: Krzysztof Kozlowski > Cc: devicetree@vger.kernel.org > > .../devicetree/bindings/mailbox/arm,mhuv2.yaml | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml > index a4f1fe63659a..5a57f4e2a623 100644 > --- a/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml > +++ b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml > @@ -69,10 +69,15 @@ properties: > > interrupts: > description: | > - The MHUv2 controller always implements an interrupt in the "receiver" > - mode, while the interrupt in the "sender" mode was not available in the > - version MHUv2.0, but the later versions do have it. > - maxItems: 1 > + The MHUv2 controller always implements at least an interrupt in the > + "receiver" mode, while the interrupt in the "sender" mode was not > + available in the version MHUv2.0, but the later versions do have it. > + In "receiver" mode, beside a single combined interrupt, there could be > + multiple interrupts, up to the number of implemented channels but anyway > + no more than the maximum number of interrupts potentially supported by > + AMBA. > + minItems: 1 > + maxItems: 9 I am not sure 9 is the correct value here. IIUC it is just what Linux defines as AMBA_NR_IRQS. Looking at the history it was bumped from 2 to 9 for use by PL330 DMA driver. I couldn't find anything to relate this 9 in any AMBA or other related specification. Ideally I would say we don't know what the max here. We just have a platform implementing 2 interrupts now. Do we for with 2 for now and change it if some new users require more in the future ? I will leave that to the DT maintainers but 9 is simply random based on Linux code so I would rather choose some other random number with a better reasoning than 9 as AMBA code in the kernel is limiting it to 9. -- Regards, Sudeep