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[2620:137:e000::1:18]) by mx.google.com with ESMTPS id b9-20020adfd1c9000000b00207ac23fc63si4923868wrd.1017.2022.05.13.20.35.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 May 2022 20:35:22 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=IUC0DpXb; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 162E1439B95; Fri, 13 May 2022 17:11:12 -0700 (PDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348983AbiEKXAb (ORCPT + 99 others); Wed, 11 May 2022 19:00:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234959AbiEKXA2 (ORCPT ); Wed, 11 May 2022 19:00:28 -0400 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BDD58A7CA for ; Wed, 11 May 2022 16:00:26 -0700 (PDT) Received: by mail-io1-xd2a.google.com with SMTP id e3so3616617ios.6 for ; Wed, 11 May 2022 16:00:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:from:date:message-id:subject:to; bh=MI1e77NG2MLHV0OL9aS/H9bc3NGijrDFsz/FahQ7nNg=; b=IUC0DpXbEo3chYIKlYqeDAlUPjO7udTU9gR9oVwhGdHmO+uoIp9dMVW5WiOGwngZDt vxBdslP469ph+Ra+rKcFIFnw/LwFad2JT59/afNxvEOieJihVoKxgjxljXNwcgLMrgw4 puRSISqD3dYEnNKdaAm1w3tM1N0Nnj5ZAGn5KEjn8D+2FaleZG/A/VtetdP5mOSAf75Q STCsP7ZchBEgZlM8eKQ83Ujhew8xLkNWDsjCUrn2FgB+vz+sNGTptkZmUcO2XR+IAB2/ 0bKOG67YVweWHm+Z18o7B3JX5Q8sJAmCI1cGExuFy7phuHpvyZYU9Z9Jryvk2yjCCD0t /Cag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=MI1e77NG2MLHV0OL9aS/H9bc3NGijrDFsz/FahQ7nNg=; b=zgtpZlKGNo1Gnnix8xVE1qs/eDsfD0GcVDp7xvbCfBGvkp7oW3k7ts4I37d78iNnlZ Op6GdDJR1HCyp3ZhnjfZlTN0fuUEfp/DqO178q92qLCyzTsKYG8HpLkZ4xCfYJxcZ411 J/Yt8zoqjFZlaU++mUw0tlOGkQJSL+NKCPjF2ynZFvY5KHe5Ams37dPKrkaRvHSxXaB3 B0ueAneMuF7TcLXMtwqNF94O4bZDhPUyOPNDJClXrwHNWkwerINrK4q6bE9Jgrl9W1H0 9YRk1iuM91XR75+H9fa38hq9fuu7YabQG0J7yFWqjy9Sh163gEH2I9hyoDDCsQNEIZwz 3UHg== X-Gm-Message-State: AOAM533gVL6j0LBYP/KtmZntlRn4l5rXSEiU+lpMlsu/KOP5HoEzruKX GcP976mRnzOSAKXum8VtymtJe3mBVF7nS5sUQE4DBqbSRq4aqA== X-Received: by 2002:a05:6638:1487:b0:32b:e970:2acf with SMTP id j7-20020a056638148700b0032be9702acfmr10255965jak.109.1652310025623; Wed, 11 May 2022 16:00:25 -0700 (PDT) MIME-Version: 1.0 From: noman pouigt Date: Wed, 11 May 2022 16:00:14 -0700 Message-ID: Subject: Mapping ram memory using ioremap To: linux-kernel@vger.kernel.org, kernelnewbies Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RDNS_NONE, SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We are using part of DRAM as shared memory between DSP and SoC. However, DSP can only access higher 1GB of DRAM. In order to map the aforementioned memory I tried using ioremap and it blurted out the warning as mentioned in this article. https://lwn.net/Articles/409700/ What is the alternative to using ioremap to map specific RAM memory region for use in the driver as shared memory? I tried memremap + reserved memory as well and it failed.