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 DEEF1C4332F for ; Fri, 4 Nov 2022 13:47:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231699AbiKDNrB (ORCPT ); Fri, 4 Nov 2022 09:47:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231642AbiKDNq7 (ORCPT ); Fri, 4 Nov 2022 09:46:59 -0400 Received: from mail-qv1-xf2c.google.com (mail-qv1-xf2c.google.com [IPv6:2607:f8b0:4864:20::f2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8307D28707 for ; Fri, 4 Nov 2022 06:46:57 -0700 (PDT) Received: by mail-qv1-xf2c.google.com with SMTP id ml12so3230835qvb.0 for ; Fri, 04 Nov 2022 06:46:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=YiGpPdNoX5wXGMSfdL1E0pP/7NaEZ2Lyn9DqVTYL4cU=; b=Fk19rTDVzKv8kKsxmUBsegCLoZW/VV9ZiXJjNmW4BAma68sdE9nEb/NXffuA+Aa63b Un6WxnKoaX8D+3rnNfZ7P41JfEKTQxQAGgQxzI3YA4SjmEWV78Rtp7jGPeV0CyZEGeup Ew6yFOXShZMQ6nxmbdDR86y43iCK40N9odgCyuLaTl6lm9pm6cKMMIyOq+ItjL+KiQFr qNz+58Zvv7EzCnjmU3wu3/xxNAAmbZ/uhYtXcIi7enEJn1yi0fXKSlQHdK7OZAF2io1m yExNneixU8vLCf4WVtes44qCqgPFxd8abddPYaJdgzXvdVSsj2gEsurnJXZDJYBrnIoj 0kRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=YiGpPdNoX5wXGMSfdL1E0pP/7NaEZ2Lyn9DqVTYL4cU=; b=FW2hc4/UCcoF9N2rEdaCyFDUApPl7jNXiUfd/pxHxqYqMIFPs7Cn2iwrNUnJCkWF2Y Q2VL8ZLIIkGPShr4rItDqSraXDsO6EVeDankITrvRqrpQ/ksd4Sb2y5YQlXv64fgOGYO ZKYo4u3ikZ9+cGSLlZ9rrsBCeGxHR1C6olMD2twBVZEuD+stVTIHUJ3lGChPEym3xrSZ 3STbykDbtj6gWSHo5+3diC517LydBUT5vg9C9ngxi68aAXjDpEim1X8uHzYLYSy1cFzs ebEOhUXST7TyaKMW/T48+48DCor/z2gcLipw7Z1nqvlv/90iH0vbwkG9XNNs6ViJ6+/A vUbQ== X-Gm-Message-State: ACrzQf0VnMOmlQLWYEdO0B3nGbZSIqKB+gwp0eT1VkpScHr9VPD192+x ZPc0SBzUZC3bVSYDO7XMxG8rzA== X-Google-Smtp-Source: AMsMyM4nfPfuMMdhpgKN4gcbMIFUHuGFeGmMgyIyZnd6J0DPxQafmKAbs4A5+ytwpCb9x+wMPqxG+g== X-Received: by 2002:a05:6214:f22:b0:4bb:728b:b592 with SMTP id iw2-20020a0562140f2200b004bb728bb592mr32034191qvb.130.1667569616736; Fri, 04 Nov 2022 06:46:56 -0700 (PDT) Received: from ?IPV6:2601:586:5000:570:aad6:acd8:4ed9:299b? ([2601:586:5000:570:aad6:acd8:4ed9:299b]) by smtp.gmail.com with ESMTPSA id v3-20020a05620a440300b006b929a56a2bsm3136177qkp.3.2022.11.04.06.46.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 04 Nov 2022 06:46:56 -0700 (PDT) Message-ID: Date: Fri, 4 Nov 2022 09:46:54 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH v2 3/6] iommu/exynos: Modularize the driver Content-Language: en-US To: Sam Protsenko , Marek Szyprowski Cc: Joerg Roedel , Will Deacon , Robin Murphy , Sumit Semwal , Alim Akhtar , Janghyuck Kim , Cho KyongHo , Daniel Mentz , David Virag , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org References: <20221103195154.21495-1-semen.protsenko@linaro.org> <20221103195154.21495-4-semen.protsenko@linaro.org> From: Krzysztof Kozlowski In-Reply-To: <20221103195154.21495-4-semen.protsenko@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/11/2022 15:51, Sam Protsenko wrote: > Rework the driver so it can be built as a loadable module. That can be > useful as not all ARM64 platforms need it. And that's ok for it to be a > module because it's not a critical driver (platform can work when it's > disabled). > > Remove method and module exit function are not implemented, as the > removal of IOMMUs cannot be done reliably. As Robin Murphy mentioned in > [1]: > > ...it's better not to even pretend that removing an IOMMU's driver > while other drivers are using it (usually via DMA ops without even > realising) is going to have anything other than catastrophic > results. > > [1] https://lore.kernel.org/lkml/20220702213724.3949-2-semen.protsenko@linaro.org/T/#md7e1e3f5b2c9e7fa5bc28fe33e818b6aa4a7237c > > Signed-off-by: Sam Protsenko Acked-by: Krzysztof Kozlowski Best regards, Krzysztof