From patchwork Wed Sep 18 13:06:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shameerali Kolothum Thodi X-Patchwork-Id: 11150341 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1DE1576 for ; Wed, 18 Sep 2019 13:11:50 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id F240320678 for ; Wed, 18 Sep 2019 13:11:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F240320678 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:58876 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAZkK-0007fK-5d for patchwork-qemu-devel@patchwork.kernel.org; Wed, 18 Sep 2019 09:11:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58800) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAZhH-0004dw-7i for qemu-devel@nongnu.org; Wed, 18 Sep 2019 09:08:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iAZhF-0003YG-UI for qemu-devel@nongnu.org; Wed, 18 Sep 2019 09:08:39 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:43064 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iAZhD-0003U1-1m; Wed, 18 Sep 2019 09:08:35 -0400 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 1EE1B9715570B0A05909; Wed, 18 Sep 2019 21:08:33 +0800 (CST) Received: from S00345302A-PC.china.huawei.com (10.202.227.237) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.439.0; Wed, 18 Sep 2019 21:08:23 +0800 From: Shameer Kolothum To: , , , Date: Wed, 18 Sep 2019 14:06:31 +0100 Message-ID: <20190918130633.4872-10-shameerali.kolothum.thodi@huawei.com> X-Mailer: git-send-email 2.12.0.windows.1 In-Reply-To: <20190918130633.4872-1-shameerali.kolothum.thodi@huawei.com> References: <20190918130633.4872-1-shameerali.kolothum.thodi@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.202.227.237] X-CFilter-Loop: Reflected X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 45.249.212.35 Subject: [Qemu-devel] [PATCH-for-4.2 v11 09/11] docs/specs: Add ACPI GED documentation X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, sameo@linux.intel.com, ard.biesheuvel@linaro.org, mst@redhat.com, linuxarm@huawei.com, xuwei5@hisilicon.com, shannon.zhaosl@gmail.com, sebastien.boeuf@intel.com, lersek@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" Documents basic concepts of ACPI Generic Event device(GED) and interface between QEMU and the ACPI BIOS. Signed-off-by: Shameer Kolothum Reviewed-by: Eric Auger Reviewed-by: Igor Mammedov --- Addressed Peter's comments, -changed to rst format. -typo/grammer corrections. --- docs/specs/acpi_hw_reduced_hotplug.rst | 70 ++++++++++++++++++++++++++ docs/specs/index.rst | 1 + 2 files changed, 71 insertions(+) create mode 100644 docs/specs/acpi_hw_reduced_hotplug.rst diff --git a/docs/specs/acpi_hw_reduced_hotplug.rst b/docs/specs/acpi_hw_reduced_hotplug.rst new file mode 100644 index 0000000000..911a98255b --- /dev/null +++ b/docs/specs/acpi_hw_reduced_hotplug.rst @@ -0,0 +1,70 @@ +================================================== +QEMU and ACPI BIOS Generic Event Device interface +================================================== + +The ACPI *Generic Event Device* (GED) is a HW reduced platform +specific device introduced in ACPI v6.1 that handles all platform +events, including the hotplug ones. GED is modelled as a device +in the namespace with a _HID defined to be ACPI0013. This document +describes the interface between QEMU and the ACPI BIOS. + +GED allows HW reduced platforms to handle interrupts in ACPI ASL +statements. It follows a very similar approach to the _EVT method +from GPIO events. All interrupts are listed in _CRS and the handler +is written in _EVT method. However, the QEMU implementation uses a +single interrupt for the GED device, relying on an IO memory region +to communicate the type of device affected by the interrupt. This way, +we can support up to 32 events with a unique interrupt. + +**Here is an example,** + +:: + + Device (\_SB.GED) + { + Name (_HID, "ACPI0013") + Name (_UID, Zero) + Name (_CRS, ResourceTemplate () + { + Interrupt (ResourceConsumer, Edge, ActiveHigh, Exclusive, ,, ) + { + 0x00000029, + } + }) + OperationRegion (EREG, SystemMemory, 0x09080000, 0x04) + Field (EREG, DWordAcc, NoLock, WriteAsZeros) + { + ESEL, 32 + } + Method (_EVT, 1, Serialized) + { + Local0 = ESEL // ESEL = IO memory region which specifies the + // device type. + If (((Local0 & One) == One)) + { + MethodEvent1() + } + If ((Local0 & 0x2) == 0x2) + { + MethodEvent2() + } + ... + } + } + +GED IO interface (4 byte access) +-------------------------------- +**read access:** + +:: + + [0x0-0x3] Event selector bit field (32 bit) set by QEMU. + + bits: + 0: Memory hotplug event + 1: System power down event + 2-31: Reserved + +**write_access:** + +Nothing is expected to be written into GED IO memory diff --git a/docs/specs/index.rst b/docs/specs/index.rst index 40adb97c5e..984ba44029 100644 --- a/docs/specs/index.rst +++ b/docs/specs/index.rst @@ -12,3 +12,4 @@ Contents: ppc-xive ppc-spapr-xive + acpi_hw_reduced_hotplug