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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 26BC8C2D0DB for ; Fri, 31 Jan 2020 14:29:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAAE1215A4 for ; Fri, 31 Jan 2020 14:29:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="ShZjamFM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728901AbgAaO3h (ORCPT ); Fri, 31 Jan 2020 09:29:37 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:60056 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728827AbgAaO3h (ORCPT ); Fri, 31 Jan 2020 09:29:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=wII15MgeqWbZfMqpukw8WbJXMIjvvlTLwoyDgIUTqRM=; b=ShZjamFMEFEi8ZK6lvRTAfg72t Vnb01CyPnJ7r54jskpVozNRpja4cak/rpQ3EA+z8tdCxGk/ma0n7XNXXYSzDi8aJs81HiyfqbzIDI TBwGIdJHIzI15tZXE3NfSucMK1mqWPVg/4N3IYkodR379POfvridvakg2WpfKOtGPAOs=; Received: from andrew by vps0.lunn.ch with local (Exim 4.93) (envelope-from ) id 1ixXIA-0007bY-Q6; Fri, 31 Jan 2020 15:29:06 +0100 Date: Fri, 31 Jan 2020 15:29:06 +0100 From: Andrew Lunn To: Robin Murphy Cc: Jon Nettleton , Ard Biesheuvel , Marc Zyngier , Makarand Pawagi , Calvin Johnson , stuyoder@gmail.com, nleeder@codeaurora.org, Ioana Ciornei , Cristi Sovaiala , Hanjun Guo , Will Deacon , Lorenzo Pieralisi , Pankaj Bansal , Russell King , ACPI Devel Maling List , Len Brown , Jason Cooper , Andy Wang , Varun Sethi , Thomas Gleixner , linux-arm-kernel , Laurentiu Tudor , Paul Yang , "" , "Rafael J. Wysocki" , Linux Kernel Mailing List , Shameerali Kolothum Thodi , Sudeep Holla Subject: Re: [EXT] Re: [PATCH] bus: fsl-mc: Add ACPI support for fsl-mc Message-ID: <20200131142906.GG9639@lunn.ch> References: <1580198925-50411-1-git-send-email-makarand.pawagi@nxp.com> <20200128110916.GA491@e121166-lin.cambridge.arm.com> <12531d6c569c7e14dffe8e288d9f4a0b@kernel.org> <0680c2ce-cff0-d163-6bd9-1eb39be06eee@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org > > But by design SFP, SFP+, and QSFP cages are not fixed function network > > adapters. They are physical and logical devices that can adapt to > > what is plugged into them. How the devices are exposed should be > > irrelevant to this conversation it is about the underlying > > connectivity. > > Apologies - I was under the impression that SFP and friends were a > physical-layer thing and that a MAC in the SoC would still be fixed such > that its DMA and interrupt configuration could be statically described > regardless of what transceiver was plugged in (even if some configurations > might not use every interrupt/stream ID/etc.) If that isn't the case I shall > go and educate myself further. Hi Robin It gets interesting with QSFP cages. The Q is quad, there are 4 SERDES lanes. You can use them for 1x 40G link, or you can split them into 4x 10G links. So you either need one MAC or 4 MACs connecting to the cage, and this can change on the fly when a modules is ejected and replaced with another module. There are only one set of control pins for i2c, loss of signal, TX disable, module inserted. So where the interrupt/stream ID/etc are mapped needs some flexibility. There is also to some degree a conflict with hiding all this inside firmware. This is complex stuff. It is much better to have one core implementing in Linux plus some per hardware driver support, than having X firmware blobs, generally closed source, each with there own bugs which nobody can fix. Andrew