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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 D6244C4320D for ; Wed, 25 Sep 2019 09:15:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC045214DA for ; Wed, 25 Sep 2019 09:15:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569402947; bh=Z2Uag+DwW909ph/1HOySpUCCmNKluWCbwO7QFKK6F8E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=qhKcrUAiHAsuov38DXtjQfbpbsORG7pItHobTZQdqsIfHacjWuMTU6oec1IEjhYEM c1F5F3Yc8V5xKZfJa8EyQH6InOyeNj6DKFbAEuRmiEb9SWeQhTyuIqmZze4sxhWw7D vB9yAiTxJU/10RW/gxbXqhBv6Y6RsFUIMYkzfqLQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726545AbfIYJPl (ORCPT ); Wed, 25 Sep 2019 05:15:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:52126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726185AbfIYJPb (ORCPT ); Wed, 25 Sep 2019 05:15:31 -0400 Received: from localhost (lfbn-1-10718-76.w90-89.abo.wanadoo.fr [90.89.68.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C17A020673; Wed, 25 Sep 2019 09:15:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569402925; bh=Z2Uag+DwW909ph/1HOySpUCCmNKluWCbwO7QFKK6F8E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LUAdHLEB0Njr3vPkEeYEnn9UJ65aNeraXjCw8vvFf6X7fzKvIP2kobELTTOGaz+Ai F/6Pk5OGh6G++u9o8W46kH+kpymk6XLNk9oIVvO3P5dgTlNDCS89SC0ZdQYzlIooNS HHynK47zEbah8oMWrSK4ChXXBYoripfPPxhyqVt0= Date: Wed, 25 Sep 2019 11:15:22 +0200 From: Maxime Ripard To: Stephen Boyd Cc: Georgi Djakov , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, Rob Herring , devicetree@vger.kernel.org, Bjorn Andersson , Evan Green , David Dai Subject: Re: [RFC PATCH] interconnect: Replace of_icc_get() with icc_get() and reduce DT binding Message-ID: <20190925091522.jf5q2jdo6njfkxto@gilmour> References: <20190925054133.206992-1-swboyd@chromium.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="aomtcuidegtr2wsv" Content-Disposition: inline In-Reply-To: <20190925054133.206992-1-swboyd@chromium.org> User-Agent: NeoMutt/20180716 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org --aomtcuidegtr2wsv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi Stephen, On Tue, Sep 24, 2019 at 10:41:33PM -0700, Stephen Boyd wrote: > The DT binding could also be simplified somewhat. Currently a path needs > to be specified in DT for each and every use case that is possible for a > device to want. Typically the path is to memory, which looks to be > reserved for in the binding with the "dma-mem" named path, but sometimes > the path is from a device to the CPU or more generically from a device > to another device which could be a CPU, cache, DMA master, or another > device if some sort of DMA to DMA scenario is happening. Let's remove > the pair part of the binding so that we just list out a device's > possible endpoints on the bus or busses that it's connected to. > > If the kernel wants to figure out what the path is to memory or the CPU > or a cache or something else it should be able to do that by finding the > node for the "destination" endpoint, extracting that node's > "interconnects" property, and deriving the path in software. For > example, we shouldn't need to write out each use case path by path in DT > for each endpoint node that wants to set a bandwidth to memory. We > should just be able to indicate what endpoint(s) a device sits on based > on the interconnect provider in the system and then walk the various > interconnects to find the path from that source endpoint to the > destination endpoint. The dma-mem name is used by the OF core to adjust the mapping of the devices as well. So, any solution needs to be generic (or provide a generic helper). Maxime --aomtcuidegtr2wsv Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXYswKgAKCRDj7w1vZxhR xe8UAQC3EqIcKg882wsQj/TdlIO/sf9HoBIDnQnVNJ2t2kaPsAD/Qsa+D9ZQUlKc qhYx4agifh1/WXVN4H+Wb39VO4vx5wk= =Z0s1 -----END PGP SIGNATURE----- --aomtcuidegtr2wsv--