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 E54B2C4332F for ; Tue, 4 Jan 2022 10:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231555AbiADKpv (ORCPT ); Tue, 4 Jan 2022 05:45:51 -0500 Received: from ivanoab7.miniserver.com ([37.128.132.42]:36320 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229644AbiADKpt (ORCPT ); Tue, 4 Jan 2022 05:45:49 -0500 Received: from [192.168.18.6] (helo=jain.kot-begemot.co.uk) by www.kot-begemot.co.uk with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1n4hJo-00089g-BW; Tue, 04 Jan 2022 10:45:32 +0000 Received: from jain.kot-begemot.co.uk ([192.168.3.3]) by jain.kot-begemot.co.uk with esmtp (Exim 4.94.2) (envelope-from ) id 1n4hJi-001BhW-DX; Tue, 04 Jan 2022 10:45:24 +0000 From: anton.ivanov@cambridgegreys.com To: linux-um@lists.infradead.org Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, kernel@axis.com, robh+dt@kernel.org, jdike@addtoit.com, johannes@sipsolutions.net, vincent.whitchurch@axis.com, richard@nod.at, linux-doc@vger.kernel.org, Anton Ivanov Subject: [PATCH] um: Document dtb command line option Date: Tue, 4 Jan 2022 10:44:57 +0000 Message-Id: <20220104104457.282828-1-anton.ivanov@cambridgegreys.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <1118129237.194759.1640202076897.JavaMail.zimbra@nod.at> References: <1118129237.194759.1640202076897.JavaMail.zimbra@nod.at> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Clacks-Overhead: GNU Terry Pratchett Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anton Ivanov Add documentation for the dtb command line option and the ability to load/parse device trees. Signed-off-by: Anton Ivanov --- .../virt/uml/user_mode_linux_howto_v2.rst | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/Documentation/virt/uml/user_mode_linux_howto_v2.rst b/Documentation/virt/uml/user_mode_linux_howto_v2.rst index 2cafd3c3c6cb..81986fe014d4 100644 --- a/Documentation/virt/uml/user_mode_linux_howto_v2.rst +++ b/Documentation/virt/uml/user_mode_linux_howto_v2.rst @@ -1189,6 +1189,26 @@ E.g. ``os_close_file()`` is just a wrapper around ``close()`` which ensures that the userspace function close does not clash with similarly named function(s) in the kernel part. +Using UML as a Test Platform +============================ + +UML is an excellent test platform for device driver development. As +with most things UML, "some user assembly may be required". It is +up to the user to build their emulation environment. UML at present +provides only the kernel infrastructure. + +Part of this infrastructure is the ability to load and parse fdt +device tree blobs as used in Arm or Open Firmware platforms. These +are supplied as an optional extra argument to the kernel command +line:: + + dtb=filename + +The device tree is loaded and parsed at boottime and is accessible by +drivers which query it. At this moment in time this facility is +intended solely for development purposes. UML's own devices do not +query the device tree. + Security Considerations ----------------------- -- 2.30.2 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ivanoab7.miniserver.com ([37.128.132.42] helo=www.kot-begemot.co.uk) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1n4hK2-00BBjJ-1K for linux-um@lists.infradead.org; Tue, 04 Jan 2022 10:45:43 +0000 From: anton.ivanov@cambridgegreys.com Subject: [PATCH] um: Document dtb command line option Date: Tue, 4 Jan 2022 10:44:57 +0000 Message-Id: <20220104104457.282828-1-anton.ivanov@cambridgegreys.com> In-Reply-To: <1118129237.194759.1640202076897.JavaMail.zimbra@nod.at> References: <1118129237.194759.1640202076897.JavaMail.zimbra@nod.at> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: linux-um@lists.infradead.org Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, kernel@axis.com, robh+dt@kernel.org, jdike@addtoit.com, johannes@sipsolutions.net, vincent.whitchurch@axis.com, richard@nod.at, linux-doc@vger.kernel.org, Anton Ivanov From: Anton Ivanov Add documentation for the dtb command line option and the ability to load/parse device trees. Signed-off-by: Anton Ivanov --- .../virt/uml/user_mode_linux_howto_v2.rst | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/Documentation/virt/uml/user_mode_linux_howto_v2.rst b/Documentation/virt/uml/user_mode_linux_howto_v2.rst index 2cafd3c3c6cb..81986fe014d4 100644 --- a/Documentation/virt/uml/user_mode_linux_howto_v2.rst +++ b/Documentation/virt/uml/user_mode_linux_howto_v2.rst @@ -1189,6 +1189,26 @@ E.g. ``os_close_file()`` is just a wrapper around ``close()`` which ensures that the userspace function close does not clash with similarly named function(s) in the kernel part. +Using UML as a Test Platform +============================ + +UML is an excellent test platform for device driver development. As +with most things UML, "some user assembly may be required". It is +up to the user to build their emulation environment. UML at present +provides only the kernel infrastructure. + +Part of this infrastructure is the ability to load and parse fdt +device tree blobs as used in Arm or Open Firmware platforms. These +are supplied as an optional extra argument to the kernel command +line:: + + dtb=filename + +The device tree is loaded and parsed at boottime and is accessible by +drivers which query it. At this moment in time this facility is +intended solely for development purposes. UML's own devices do not +query the device tree. + Security Considerations ----------------------- -- 2.30.2 _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um