From patchwork Tue Mar 26 09:58:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcin Juszkiewicz X-Patchwork-Id: 13603797 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2EA03C6FD1F for ; Tue, 26 Mar 2024 09:59:02 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rp3a2-00039m-H6; Tue, 26 Mar 2024 05:58:54 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rp3Zl-0002xa-3l; Tue, 26 Mar 2024 05:58:38 -0400 Received: from muminek.juszkiewicz.com.pl ([213.251.184.221]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rp3Zj-0007R0-CV; Tue, 26 Mar 2024 05:58:36 -0400 Received: from localhost (localhost [127.0.0.1]) by muminek.juszkiewicz.com.pl (Postfix) with ESMTP id 4E0AD2610DF; Tue, 26 Mar 2024 10:58:31 +0100 (CET) X-Virus-Scanned: Debian amavis at juszkiewicz.com.pl Received: from muminek.juszkiewicz.com.pl ([127.0.0.1]) by localhost (muminek.juszkiewicz.com.pl [127.0.0.1]) (amavis, port 10024) with ESMTP id gEVyC9WYKWfv; Tue, 26 Mar 2024 10:58:29 +0100 (CET) Received: from applejack.lan (83.11.22.169.ipv4.supernova.orange.pl [83.11.22.169]) by muminek.juszkiewicz.com.pl (Postfix) with ESMTPSA id 8144A260259; Tue, 26 Mar 2024 10:58:27 +0100 (CET) From: Marcin Juszkiewicz To: qemu-devel@nongnu.org Cc: qemu-arm@nongnu.org, Leif Lindholm , Peter Maydell , Radoslaw Biernacki , Marcin Juszkiewicz Subject: [PATCH 1/1] docs: sbsa: update specs, add dt note Date: Tue, 26 Mar 2024 10:58:19 +0100 Message-ID: <20240326095819.1268062-1-marcin.juszkiewicz@linaro.org> X-Mailer: git-send-email 2.44.0 MIME-Version: 1.0 Received-SPF: softfail client-ip=213.251.184.221; envelope-from=marcin.juszkiewicz@linaro.org; helo=muminek.juszkiewicz.com.pl X-Spam_score_int: -11 X-Spam_score: -1.2 X-Spam_bar: - X-Spam_report: (-1.2 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hardware of sbsa-ref board is nowadays defined by both BSA and SBSA specifications. Then BBR defines firmware interface. Added note about DeviceTree data passed from QEMU to firmware. It is very minimal and provides only data we use in firmware. Added NUMA information to list of things reported by DeviceTree. Signed-off-by: Marcin Juszkiewicz --- docs/system/arm/sbsa.rst | 37 ++++++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-) diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst index bca61608ff..d4d1f2efe3 100644 --- a/docs/system/arm/sbsa.rst +++ b/docs/system/arm/sbsa.rst @@ -1,12 +1,16 @@ Arm Server Base System Architecture Reference board (``sbsa-ref``) ================================================================== -While the ``virt`` board is a generic board platform that doesn't match -any real hardware the ``sbsa-ref`` board intends to look like real -hardware. The `Server Base System Architecture -`_ defines a -minimum base line of hardware support and importantly how the firmware -reports that to any operating system. +The ``sbsa-ref`` board intends to look like real hardware (while the ``virt`` +board is a generic board platform that doesn't match any real hardware). + +The hardware part is defined by two specifications: + + - `Base System Architecture `__ (BSA) + - `Server Base System Architecture `__ (SBSA) + +The `Arm Base Boot Requirements `__ (BBR) +specification defines how the firmware reports that to any operating system. It is intended to be a machine for developing firmware and testing standards compliance with operating systems. @@ -35,16 +39,31 @@ includes both internal hardware and parts affected by the qemu command line (i.e. CPUs and memory). As a result it must have a firmware specifically built to expect a certain hardware layout (as you would in a real machine). +Note +'''' + +QEMU provides us with minimal information about hardware platform using +minimalistic devicetree. This is not a Linux devicetree. It is not even a +firmware devicetree. + +It is information passed from QEMU to describe the information a hardware +platform would have other mechanisms to discover at runtime, that are affected +by the QEMU command line. + +Ultimately this devicetree will be replaced by IPC calls to an emulated SCP. +And when we do that, we won't then have to rewrite Normal world firmware to +cope. + DeviceTree information '''''''''''''''''''''' -The devicetree provided by the board model to the firmware is not intended -to be a complete compliant DT. It currently reports: +The devicetree reports: - CPUs - memory - platform version - GIC addresses + - NUMA node id for CPUs and memory Platform version '''''''''''''''' @@ -70,4 +89,4 @@ Platform version changes: GIC ITS information is present in devicetree. 0.3 - The USB controller is an XHCI device, not EHCI + The USB controller is an XHCI device, not EHCI.