From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752529AbcBEDKr (ORCPT ); Thu, 4 Feb 2016 22:10:47 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:25316 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750929AbcBEDKo (ORCPT ); Thu, 4 Feb 2016 22:10:44 -0500 From: Shannon Zhao To: , , , CC: , , , , , , , , , , , "Rafael J. Wysocki" , Len Brown , "open list:ACPI" Subject: [PATCH v4 01/17] Xen: ACPI: Hide UART used by Xen Date: Fri, 5 Feb 2016 11:05:36 +0800 Message-ID: <1454641552-12576-2-git-send-email-zhaoshenglong@huawei.com> X-Mailer: git-send-email 1.9.0.msysgit.0 In-Reply-To: <1454641552-12576-1-git-send-email-zhaoshenglong@huawei.com> References: <1454641552-12576-1-git-send-email-zhaoshenglong@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.177.16.142] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.56B411E4.0020,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 4b027efd033464f2a7a5ede24456dc6f Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Shannon Zhao ACPI 6.0 introduces a new table STAO to list the devices which are used by Xen and can't be used by Dom0. On Xen virtual platforms, the physical UART is used by Xen. So here it hides UART from Dom0. Signed-off-by: Shannon Zhao Reviewed-by: Stefano Stabellini --- CC: "Rafael J. Wysocki" (supporter:ACPI) CC: Len Brown (supporter:ACPI) CC: linux-acpi@vger.kernel.org (open list:ACPI) --- drivers/acpi/bus.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 891c42d..5b5433d 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -46,6 +46,7 @@ ACPI_MODULE_NAME("bus"); struct acpi_device *acpi_root; struct proc_dir_entry *acpi_root_dir; EXPORT_SYMBOL(acpi_root_dir); +static u64 spcr_uart_addr; #ifdef CONFIG_X86 #ifdef CONFIG_ACPI_CUSTOM_DSDT @@ -105,6 +106,22 @@ acpi_status acpi_bus_get_status_handle(acpi_handle handle, return status; } +static bool acpi_check_device_is_ignored(acpi_handle handle) +{ + acpi_status status; + u64 addr; + + /* Check if it should ignore the UART device */ + if (spcr_uart_addr != 0) { + status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, + &addr); + if (ACPI_SUCCESS(status) && addr == spcr_uart_addr) + return true; + } + + return false; +} + int acpi_bus_get_status(struct acpi_device *device) { acpi_status status; @@ -114,7 +131,8 @@ int acpi_bus_get_status(struct acpi_device *device) if (ACPI_FAILURE(status)) return -ENODEV; - acpi_set_device_status(device, sta); + if (!acpi_check_device_is_ignored(device->handle)) + acpi_set_device_status(device, sta); if (device->status.functional && !device->status.present) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]: " @@ -1070,6 +1088,8 @@ EXPORT_SYMBOL_GPL(acpi_kobj); static int __init acpi_init(void) { int result; + acpi_status status; + struct acpi_table_stao *stao_ptr; if (acpi_disabled) { printk(KERN_INFO PREFIX "Interpreter disabled.\n"); @@ -1082,6 +1102,22 @@ static int __init acpi_init(void) acpi_kobj = NULL; } + /* If there is STAO table, check whether it needs to ignore the UART + * device in SPCR table. + */ + status = acpi_get_table(ACPI_SIG_STAO, 0, + (struct acpi_table_header **)&stao_ptr); + if (ACPI_SUCCESS(status) && stao_ptr->ignore_uart) { + struct acpi_table_spcr *spcr_ptr; + + status = acpi_get_table(ACPI_SIG_SPCR, 0, + (struct acpi_table_header **)&spcr_ptr); + if (ACPI_SUCCESS(status)) + spcr_uart_addr = spcr_ptr->serial_port.address; + else + printk(KERN_WARNING "STAO table present, but SPCR is missing.\n"); + } + init_acpi_device_notify(); result = acpi_bus_init(); if (result) { -- 2.0.4