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 26ABAC43334 for ; Wed, 29 Jun 2022 20:48:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230514AbiF2Us2 (ORCPT ); Wed, 29 Jun 2022 16:48:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229698AbiF2Us1 (ORCPT ); Wed, 29 Jun 2022 16:48:27 -0400 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0EC73FBCC; Wed, 29 Jun 2022 13:48:21 -0700 (PDT) Received: by mail-pl1-x633.google.com with SMTP id r1so15172525plo.10; Wed, 29 Jun 2022 13:48:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=qhsFUjH+wI94oun4uxuL1yuFWLai9/RJksYgc2AjR00=; b=bju/ywKNEIT0oyzLLDdIcnsCfM8AryG+PYC0jGE2sDzfsHT2+5BWJHi0iLsisKFqcK LERHVeMHOtzvKnTQmjozdmvxpQjPS0+rsTVboV33yfFfMZCg4ptp+8qI5G6ait9mHVJQ B02YpSjDbnwBY9+7Os/gAecjvFLDknT2t8KgUAvgXGDxtPF+32wVnsauC4GocS1boiYy 6lIgTVwaJpiAc+5i5EWyZyVGXw6M6plYkPRKG/jZf4wVdzddyPYFgfklZi7UUgMILA+/ uqFwvykP3fJ6QFqdW6sRBXvexF8Sifc76CoNTgiMRGAWoKDhS3K66c3rVRH/5bgrQqC8 ZusQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=qhsFUjH+wI94oun4uxuL1yuFWLai9/RJksYgc2AjR00=; b=TP7cfDys9+G8aphilZWWUISdkiRIfp1LDwzAFi4IoNk65Jq/4Bt5kK0iO8v4TyeLNU DCcCR7iU43iH5g0LTYQnezRIQQBu0mI+cT6NgD0a/hwAYDWjfALy9cqn6TOKAL+7QXbE mCB4zq4b15NnvWRo5UxZv+MqiHjRyqxveL00DaeAptrLPEeJqYujn7Wh/y8sXmsbXN2z m+huBJ+bi+ujXGEqEPiIU7JioQZdIlClFa1b6MaSZZt4S/SYWKSfgwSattKDh8i7u4Dl YixQmHURlw21Qa0k4VCRYkfe454bBj0lP0FBOaEuSy+MfbEbo0nj2L1URoEg/wLNZK6j Qpww== X-Gm-Message-State: AJIora9oZJq9+iv7d4I3nPO2lo5NqKw7bNwH30KG+H+IHNZ8uAPBtD3D NVaesgXadAalWttMojS6eFynAHuQ5Tcv5A== X-Google-Smtp-Source: AGRyM1t76qqv2RVL0T0jTVMhkfsPOaCn3fxyNGUq9Zl1nwTuV15oXJk0dK/UWSbShXfEesWoGQ5uIg== X-Received: by 2002:a17:903:124f:b0:16b:8167:e34e with SMTP id u15-20020a170903124f00b0016b8167e34emr12016165plh.52.1656535701216; Wed, 29 Jun 2022 13:48:21 -0700 (PDT) Received: from ?IPV6:2001:df0:0:200c:b411:35d2:9458:bbe5? ([2001:df0:0:200c:b411:35d2:9458:bbe5]) by smtp.gmail.com with ESMTPSA id t4-20020a17090340c400b001616723b8ddsm11756842pld.45.2022.06.29.13.48.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Jun 2022 13:48:20 -0700 (PDT) Message-ID: <39114583-9c4a-7b19-54d5-516feb556fac@gmail.com> Date: Thu, 30 Jun 2022 08:48:16 +1200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v1 2/3] scsi - a2091.c: convert m68k WD33C93 drivers to DMA API Content-Language: en-US To: Geert Uytterhoeven Cc: Arnd Bergmann , Linux/m68k , linux-scsi References: <20220629011638.21783-1-schmitzmic@gmail.com> <20220629011638.21783-3-schmitzmic@gmail.com> <554d6fa7-01b7-d3c8-a72a-6474e9c5038e@gmail.com> From: Michael Schmitz In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi Geert, On 30/06/22 03:55, Geert Uytterhoeven wrote: > Hi Michael, > > On Wed, Jun 29, 2022 at 9:27 AM Michael Schmitz wrote: >> Most users will opt for loading the kernel to a RAM chunk at a higher >> physical address, making the lower chunk unusable (except as chip RAM), >> meaning allocating a bounce buffer within the first 16 MB will most >> likely fail anyway AIUI (but Geert would know that for sure). > Exactly. On Zorro III-capable machines, Zorro II RAM is not mapped > for general use, but can be used by the z2ram block device. Is there any DMA capable memory other than chip and ZorroII RAM on these machines? > Note that you can use it as a bounce buffer, by looking for and marking > free chunks in the zorro_unused_z2ram bitmap. That would be similar to what amiga_chip_alloc() does, right? Any advantages over using chip RAM (faster, perhaps)? Cheers,     Michael > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds