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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 EE024C433E2 for ; Fri, 4 Sep 2020 13:01:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5FB12073B for ; Fri, 4 Sep 2020 13:01:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VRnez5fn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730363AbgIDNBL (ORCPT ); Fri, 4 Sep 2020 09:01:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728588AbgIDNAH (ORCPT ); Fri, 4 Sep 2020 09:00:07 -0400 Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5539BC061244; Fri, 4 Sep 2020 06:00:07 -0700 (PDT) Received: by mail-ed1-x541.google.com with SMTP id c10so5998765edk.6; Fri, 04 Sep 2020 06:00:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=eoJIkDtT5yIdSXOyl7ZSN/ybf/6ZO2PtqfzMV2ShYXs=; b=VRnez5fnDdx4YUTxOQcGHIgidGmKBkEm+asD3J7ZNJR0U26yYQNito/FHsTVC9QD2G TgWilTQTk6y65Pl3jvfV4kCh0JVkQI31zt1OAWkm8sLSOuarYbuGbHJC6D6oVSmAewgL g3OHoNtWlAF1SNGok1YGYsjQ+oMxxkFaGZxrfDImowRjeeE8IFhSxATxJGLaQbCZqfP2 HhFmFH2qxDy8cE6xtXfRevpSQY0Z+jikSIIyNsZweyH1Onsyijgmp6EnUxl7VJR1Ot7/ UPitx57LX3xiP8znCQItX5MnrMHaL6oZauMvAH5WWAXcpN49HgYFTThYPCYW+aCiaAi6 S3OQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=eoJIkDtT5yIdSXOyl7ZSN/ybf/6ZO2PtqfzMV2ShYXs=; b=JuhMq3/NgXO3D8Vu6/dva8CFNBcb6YqjDlKSUon/Eumnkgf8RiITAeUlgB0lg6H40z SubTksnq9CLhD3UKX72lfc4zeO4b96KMV4Ln/5SBs/cJ+0Ysmpvx+J+H0eiMlxn0ni8n 2Sf85vhaS39pq3YkAMCGor8Qz+dnVT8petJ3Z8cAeqmG6eecFEvXL3TIY6fbZ6TggV+y mKIy6E28/3DrCLA9wMyMf5J/4+J3qjFnM+tgztgxg5cidOJkmesDbiMixbxKRMm+xcjG TOXjUZuLbk+diH0N2YyhSTnnUHuSP2qdhyuBRwayxpUd9UIOCEROZBiJJNoeZxA5mcmU JWkQ== X-Gm-Message-State: AOAM530m+ufy3L+JvGlw7unfNo+vsV7KhMSfVJ82t7I7SEORE2C1UobH P4D+wABOGy5p6fR5pawk7Bs= X-Google-Smtp-Source: ABdhPJyd3GfRiKMW3Hv1SXKOXdFm20VEy4aybXXN4EDdDImnvlQLArlBx5ZgWZXwJPMnMy22iZIX8g== X-Received: by 2002:a50:fe98:: with SMTP id d24mr2605949edt.223.1599224405833; Fri, 04 Sep 2020 06:00:05 -0700 (PDT) Received: from localhost ([62.96.65.119]) by smtp.gmail.com with ESMTPSA id w1sm5839816eds.18.2020.09.04.06.00.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Sep 2020 06:00:04 -0700 (PDT) From: Thierry Reding To: Joerg Roedel Cc: Rob Herring , Frank Rowand , Will Deacon , Robin Murphy , iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/4] dt-bindings: reserved-memory: Document "active" property Date: Fri, 4 Sep 2020 14:59:57 +0200 Message-Id: <20200904130000.691933-1-thierry.reding@gmail.com> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thierry Reding Reserved memory regions can be marked as "active" if hardware is expected to access the regions during boot and before the operating system can take control. One example where this is useful is for the operating system to infer whether the region needs to be identity- mapped through an IOMMU. Signed-off-by: Thierry Reding --- .../bindings/reserved-memory/reserved-memory.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt index 4dd20de6977f..163d2927e4fc 100644 --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt @@ -63,6 +63,13 @@ reusable (optional) - empty property able to reclaim it back. Typically that means that the operating system can use that region to store volatile or cached data that can be otherwise regenerated or migrated elsewhere. +active (optional) - empty property + - If this property is set for a reserved memory region, it indicates + that some piece of hardware may be actively accessing this region. + Should the operating system want to enable IOMMU protection for a + device, all active memory regions must have been identity-mapped + in order to ensure that non-quiescent hardware during boot can + continue to access the memory. Linux implementation note: - If a "linux,cma-default" property is present, then Linux will use the -- 2.28.0