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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DD51C4741F for ; Thu, 5 Nov 2020 18:27:46 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1D5072078E for ; Thu, 5 Nov 2020 18:27:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="UmiByDTi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1D5072078E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BCeOFAlMlTrpyqwp0rs1YGzlV+uGH1UiUUBrXJNCVgU=; b=UmiByDTikOk1ewJ7fP9VmOQ0t SdcFnA7D2TdS3mZt2ABvOphtqPE8pR4HsN51LJQBQU/OHQ3wV3h79EmV4IkN9cn4yM2xmGAKqpB3L s5aFPZ1GZGZW1YrJ3W6MbQACERWqy14Thz7tkzmf+Wh99wVVaFfdUqgqAdi92PkryOqmWzsjlNbz2 QWdMclL5sIjiXKpspAGcTLRfQkpfwvU47SVSkI5XKm5xU0yp9D+O1A9HyCTLry7Wv8/W8FV9LhS2I KAtpom/kOHLt5LzGr/WDOYIgKDMfmcD3BjeJLxXbPtNyAqntCOpjA/b2mOzWbbK46OCMnHcwUHbjb Cbn/nuLTw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kajyj-0007HF-6Z; Thu, 05 Nov 2020 18:27:21 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kajyg-0007GS-SL for linux-arm-kernel@lists.infradead.org; Thu, 05 Nov 2020 18:27:19 +0000 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 02CC01474; Thu, 5 Nov 2020 10:27:15 -0800 (PST) Received: from bogus (unknown [10.57.22.191]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BEDDE3F719; Thu, 5 Nov 2020 10:27:13 -0800 (PST) Date: Thu, 5 Nov 2020 18:27:07 +0000 From: Sudeep Holla To: Jim Quinlan Subject: Re: [PATCH v4 1/2] dt-bindings: Add bindings for BrcmSTB SCMI mailbox driver Message-ID: <20201105182707.l4xx3wu2ch22qysi@bogus> References: <20201029195913.5927-1-james.quinlan@broadcom.com> <20201029195913.5927-2-james.quinlan@broadcom.com> <20201104215050.GA4180546@bogus> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20171215 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201105_132719_098883_C89B3DAA X-CRM114-Status: GOOD ( 27.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rob Herring , Florian Fainelli , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list , "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" , Sudeep Holla , "moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Nov 05, 2020 at 10:28:25AM -0500, Jim Quinlan wrote: > On Thu, Nov 5, 2020 at 10:13 AM Rob Herring wrote: > > > > On Wed, Nov 4, 2020 at 4:04 PM Jim Quinlan wrote: > > > > > > On Wed, Nov 4, 2020 at 4:50 PM Rob Herring wrote: > > > > > > > > On Thu, Oct 29, 2020 at 03:59:06PM -0400, Jim Quinlan wrote: > > > > > Bindings are added. Only one interrupt is needed because > > > > > we do not yet employ the SCMI p2a channel. > > > > > > > > I still don't understand what this is. To repeat from v1: I thought SCMI > > > > was a mailbox consumer, not provider? > > > > > > Hi Rob, > > > > > > I'm not sure where I am implying that SCMI is a mailbox provider? > > > Should I not mention "SCMI" in the subject line? > > > > > > This is just a mailbox driver, "consumed" by SCMI. Our SCMI DT node > > > looks like this: > > > > > > brcm_scmi_mailbox: brcm_scmi_mailbox@0 { > > > #mbox-cells = <1>; > > > compatible = "brcm,brcmstb-mbox"; > > > }; > > > > > > brcm_scmi@0 { > > > compatible = "arm,scmi"; > > > mboxes = <&brcm_scmi_mailbox 0>;; > > > mbox-names = "tx"; > > > shmem = <&NWMBOX>; > > > /* ... */ > > > }; > > > > Okay, that makes more sense. Though it seems like this is just adding > > a pointless level of indirection to turn an interrupt into a mailbox. > > There's nothing more to 'the mailbox' is there? > > Correct. Although you can see that it uses both interrupts and SMC > calls to get the job done. > I was against having 2 separate solutions and would have raised my concern again. As I mentioned earlier, either extend what we have or move the existing SMC solution into this mailbox driver. Having 2 different solution for this just because you have extra interrupt to deal with is definite NACK from me as I had previously mentioned. > > So why not either > > allow SCMI to have an interrupt directly > Not sure here -- perhaps the SCMI folks have an answer? > I did ask why can't you extend the existing SCMI/SMC binding to add this as optional feature ? > > or have a generic irq mailbox driver? Fine with this too. > The SCMI implementation doesn't offer a generic irq mailbox driver > AFAICT. The SCMI folks recently provided an "smc transport" driver > in "drivers/firmware/arm_scmi/smc.c" -- it is close to what we need > but is missing interrupts. IIRC, you were using SGIs and it can't be represented and use today as is ? Am I missing something or anything has changed ? -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel