From patchwork Thu May 21 09:38:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: chenzhou X-Patchwork-Id: 1295055 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=devicetree-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49SPcM3b8Pz9sRY for ; Thu, 21 May 2020 19:35:31 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728848AbgEUJf0 (ORCPT ); Thu, 21 May 2020 05:35:26 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:49102 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728720AbgEUJfO (ORCPT ); Thu, 21 May 2020 05:35:14 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 9BA5FE96E50757FA2EB1; Thu, 21 May 2020 17:35:12 +0800 (CST) Received: from localhost.localdomain.localdomain (10.175.113.25) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.487.0; Thu, 21 May 2020 17:35:06 +0800 From: Chen Zhou To: , , , , , , CC: , , , , , , , , , , Subject: [PATCH v8 5/5] dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump Date: Thu, 21 May 2020 17:38:05 +0800 Message-ID: <20200521093805.64398-6-chenzhou10@huawei.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200521093805.64398-1-chenzhou10@huawei.com> References: <20200521093805.64398-1-chenzhou10@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Add documentation for DT property used by arm64 kdump: linux,low-memory-range. "linux,low-memory-range" is an another memory region used for crash dump kernel devices. Signed-off-by: Chen Zhou --- Documentation/devicetree/bindings/chosen.txt | 25 ++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt index 45e79172a646..bfe6fb6976e6 100644 --- a/Documentation/devicetree/bindings/chosen.txt +++ b/Documentation/devicetree/bindings/chosen.txt @@ -103,6 +103,31 @@ While this property does not represent a real hardware, the address and the size are expressed in #address-cells and #size-cells, respectively, of the root node. +linux,low-memory-range +---------------------- +This property (arm64 only) holds a base address and size, describing a +limited region below 4G. Similar to "linux,usable-memory-range", it is +an another memory range which may be considered available for use by the +kernel. + +e.g. + +/ { + chosen { + linux,low-memory-range = <0x0 0x70000000 0x0 0x10000000>; + linux,usable-memory-range = <0x202f 0xc0000000 0x0 0x40000000>; + }; +}; + +The main usage is for crash dump kernel devices when reserving crashkernel +above 4G. When reserving crashkernel above 4G, there may be two crash kernel +regions, one is below 4G, the other is above 4G. In order to distinct from +the high region, use this property to pass the low region. + +While this property does not represent a real hardware, the address +and the size are expressed in #address-cells and #size-cells, +respectively, of the root node. + linux,elfcorehdr ----------------