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 77A8EC433EF for ; Wed, 18 May 2022 09:20:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234110AbiERJUr (ORCPT ); Wed, 18 May 2022 05:20:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234045AbiERJUm (ORCPT ); Wed, 18 May 2022 05:20:42 -0400 Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [IPv6:2a00:1450:4864:20::330]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62EA414A272 for ; Wed, 18 May 2022 02:20:40 -0700 (PDT) Received: by mail-wm1-x330.google.com with SMTP id v191-20020a1cacc8000000b00397001398c0so2797210wme.5 for ; Wed, 18 May 2022 02:20:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=vrull.eu; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=eBrgiBGzrk60kAZSEVCexv1pWJW5TTEZ8MUjnMwLi/I=; b=bKCZxRM1GoQTtqmmmW5HOA0FKMOGvKrMx1cl1ODcLG19yE2nCh9+52uWp5JEeiUWWT 2yNY2n6uNTiOKmM/R87OZFim/s1zQgcicxY8uILlNGsvr2dtMxiV23UqCIOTL7sIh0qF pkY1FHbSxwLaPZRBeC5eKzoLHMDkHbETzTE9n6jZcz32Y2p4o1lHbljlyPCDMNYHgE+l 6V1kkUxJfqmqCSYSS5lXO6fjWiIbZqHVb0LYZurFDtChM14eTJdDJVBuDLFupp3ocNRc 5xO40GRRBQOLSkH6zjsCE7Nqo1y8/PzivfcxGMJgfnCsczobb4a+pKR6J/XC3tCd0C00 CKmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=eBrgiBGzrk60kAZSEVCexv1pWJW5TTEZ8MUjnMwLi/I=; b=0fowZHyeFJBjMLBDrlEzuBp28qq6ynqQYJcQGEmcpoPBn8oeX1OtRoV8tRHBqzdB/e 06sz3f4fS0pbq7lGq1qYKYk4JOv9N7V/G66zsgytOWPLtmlP2ykKHckgWmmU5CRG+Xh8 olIHs+7gGeqDKsYXi/pqfD8jx/6xNtyFCxFPSgw+m+MAW/b8lZVHNCt5cJc9XQYz3h/V VLaxlaEeWrsXMTjxv/QLoB2FESNAE6ZnJrueZhIbkchLLfek2UzxYAU3iah7lHgpCMDW enTXA97N/m+xb/rGFXlRJ4ElVvdtiUzVvSAluucTqNI0y+jvQLMzsJ+TBbUnAWSZjIYh OXyQ== X-Gm-Message-State: AOAM533pHdaeYZHt4KnXbEt8vVCDKBmXmFXhgkNcePZTG3g2+VBwG9fx 7BZ/ITsNwpV9KPhMD4mUXturip/uZFDMAmXBcqJBJU14IggbEA== X-Google-Smtp-Source: ABdhPJyNgdytB47LUliXc+x/PU5W1Vst1F3N/U9fluyBnS+APsQi7/YRSS6Psb+Lcx8jhj0DGPUy4mF0djw+vfks62s= X-Received: by 2002:a05:600c:35c1:b0:394:8621:a1d5 with SMTP id r1-20020a05600c35c100b003948621a1d5mr35267641wmq.196.1652865638784; Wed, 18 May 2022 02:20:38 -0700 (PDT) MIME-Version: 1.0 References: <20220511214132.2281431-1-heiko@sntech.de> <20220518002529.GA1928329-robh@kernel.org> <1893094.PYKUYFuaPT@diego> In-Reply-To: From: Philipp Tomsich Date: Wed, 18 May 2022 11:20:27 +0200 Message-ID: Subject: Re: [PATCH v2 1/3] dt-bindings: riscv: document cbom-block-size To: Anup Patel Cc: =?UTF-8?Q?Heiko_St=C3=BCbner?= , Rob Herring , Palmer Dabbelt , Paul Walmsley , linux-riscv , "linux-kernel@vger.kernel.org List" , Wei Fu , Guo Ren , Atish Patra , Nick Kossifidis , Samuel Holland , Christoph Muellner , krzk+dt@kernel.org, DTML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 18 May 2022 at 11:10, Anup Patel wrote: > > > > > + description: > > > > > + Blocksize in bytes for the Zicbom cache operations. The bl= ock > > > > > + size is a property of the core itself and does not necessa= rily > > > > > + match other software defined cache sizes. > > > > > > > > What about hardware defined cache sizes? I'm scratching my head as = to > > > > what a 'software defined cache size' is. > > > > I agree that this should be worded better. The intent was to tell that = this > > is different from say the l1-cache-block-size. > > > > I.e. these values can be the same but don't need to be. But I guess I g= ot > > too much lead on by a kernel implementation detail (L1_CACHE_BYTES cons= tant) > > Better to just call it as "the cache block-size expected by Zicbom cache > operations" without getting details of relation with L1 cache block size. I would make this an even stronger statement and assert that Anup's recommended rewording (and staying away from L1 block/line sizes in terminology) is required to accurately reflect the design of the RISC-V CMOs. The Zicbom operation size is in fact decoupled from the l1-cache-block-size (as that would be the cache line size =E2=80=94 and therefore the size of fetches/replacements to the cache) as the deliberations within the CMO group showed. This is only the granule that Zicbom instructions operate on (and there might be additional mechanisms at work in the background that ensure that this is safe for any given underlying cache implementation). Cheers, Philipp. 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 18846C433F5 for ; Wed, 18 May 2022 09:20:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=PIiC/Kj/MZ1pvXcafoM0uhkHu1ygs78okKkWD+eD7Ek=; b=kJqKIAv3S78xDK mcWtSeBInus09WUPeg3vAVFf48krVhJpzZNts/KqGmM6Dv9zwTKcvgH7SoKTP5hWswfzgSMQ+TB10 LU/jLFYf6arFNutjrFL0HTfR0IbAOh9HUNFsdUB2vytF4k8I7QNRDwZlDERzi8mrwP/U6tzJrEQrL uTQFH8HkO1eNnATADW7MYYb8js7Q7y8ZqOSy1s6C8YVc2W7QeT0Jk6Rvr9XBP1fWzMAFTMlVJPnUv 2N31O2wBKriW9KWvYUBO8Mlr40eUViXC5q8oErEJCazBAPKC5uYIeTP8Y9oko8XshXld7elOrK3P3 yzQhimP6XjgsF+bPpeIw==; 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