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 687B9C433FE for ; Tue, 18 Oct 2022 02:07:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230167AbiJRCHC (ORCPT ); Mon, 17 Oct 2022 22:07:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231271AbiJRCGo (ORCPT ); Mon, 17 Oct 2022 22:06:44 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 061B67B7AC for ; Mon, 17 Oct 2022 19:05:47 -0700 (PDT) Received: from dggpemm500020.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MrxxW5LR1zHv2H; Tue, 18 Oct 2022 10:04:15 +0800 (CST) Received: from dggpemm500002.china.huawei.com (7.185.36.229) by dggpemm500020.china.huawei.com (7.185.36.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 18 Oct 2022 10:04:17 +0800 Received: from [10.174.179.5] (10.174.179.5) by dggpemm500002.china.huawei.com (7.185.36.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 18 Oct 2022 10:04:16 +0800 To: CC: , wanghuiqiang , "Linux Kernel Mailing List" , "linux-arm-kernel@lists.infradead.org" , , "Catalin Marinas" From: Xiongfeng Wang Subject: [Question] Question about supporting sysreg only CoreSight ETMv4.4 on ACPI machines Message-ID: <6e85db13-a65f-d4c6-1b6b-660a94cb7060@huawei.com> Date: Tue, 18 Oct 2022 10:04:16 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.5] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500002.china.huawei.com (7.185.36.229) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Suzuki We are testing CoreSight ETMv4.4 and TRBE recently. ETMv4.4 obsoletes memory mapped access to ETM and mandates the system registers. The following commit add driver for sysreg only devices, but it only support device tree. commit 5214b563588e8414193bd7a174c52350256942a6 coresight: etm4x: Add support for sysreg only devices ACPI machine can use 'ARMHC500' to report a ETM4x device. But the corresponding driver is etm4x_amba_driver. It needs memory resouces and doesn't support sysreg only device. Do we have some other way to use CoreSight ETMv4.4 on ACPI machines. Thanks a lot. Thanks, Xiongfeng