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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 EC88BC87FCB for ; Wed, 6 Aug 2025 18:24:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Om4ps8LWfWrE7iytBcnEp0gl/lf6uH6lcmL7E5D5m/8=; b=lqK2zhtbXxpfsPsJcMBYkFYOKC poOfIJzC3sDSGpMHthVzYpxatjxZIGfEx10iJ+jv5R6DxZe6SlZKq7WNXKVTzcqgLftkL/8/mZE5P 6yvOYBtR1ARU6BSfNYNoTZcVy3Uprrr0pqDkveCdMT7gpCe9ylqPKAiOhm8tRFyhlsgUpBccEBo+U tTVASTvHYQwX2Cm0fdwfQ8ym7juUifPX2jz17P71v/oJ5IFsIIL/dShY/VkSmuJ/ml3fI1/nLXaik GY6daavYuz2ZU67DUoNQD7ApxpUhhFTo23sq/aEOlpPen6ZNVl8LtTw+Gy+2SElnecrySHJ0UWgHY UQgoeWEA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ujioD-0000000G3jM-24Bz; Wed, 06 Aug 2025 18:24:17 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ujiXo-0000000G1aE-2uoD for linux-arm-kernel@lists.infradead.org; Wed, 06 Aug 2025 18:07:21 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 05FBB176C; Wed, 6 Aug 2025 11:07:12 -0700 (PDT) Received: from [10.1.197.43] (eglon.cambridge.arm.com [10.1.197.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 81FBC3F738; Wed, 6 Aug 2025 11:07:16 -0700 (PDT) Message-ID: <4da6ec99-0de5-46f1-859e-8246bc3025ff@arm.com> Date: Wed, 6 Aug 2025 19:07:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 17/36] arm_mpam: Add cpuhp callbacks to probe MSC hardware To: Ben Horgan , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Rob Herring , Rohit Mathew , Shanker Donthineni , Zeng Heng , Lecopzer Chen , Carl Worth , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Rex Nie , Dave Martin , Koba Ko References: <20250711183648.30766-1-james.morse@arm.com> <20250711183648.30766-18-james.morse@arm.com> <48e482f2-e7a8-4d6a-bf16-ad29f9331e3b@arm.com> Content-Language: en-GB From: James Morse In-Reply-To: <48e482f2-e7a8-4d6a-bf16-ad29f9331e3b@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250806_110720_774816_850B8D58 X-CRM114-Status: GOOD ( 13.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Ben, On 24/07/2025 15:13, Ben Horgan wrote: > On 11/07/2025 19:36, James Morse wrote: >> Because an MSC can only by accessed from the CPUs in its cpu-affinity >> set we need to be running on one of those CPUs to probe the MSC >> hardware. >> >> Do this work in the cpuhp callback. Probing the hardware will only >> happen before MPAM is enabled, walk all the MSCs and probe those we can >> reach that haven't already been probed. >> >> Later once MPAM is enabled, this cpuhp callback will be replaced by >> one that avoids the global list. >> >> Enabling a static key will also take the cpuhp lock, so can't be done >> from the cpuhp callback. Whenever a new MSC has been probed schedule >> work to test if all the MSCs have now been probed. >> diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/ >> mpam_devices.c >> index 0d6d5180903b..89434ae3efa6 100644 >> --- a/drivers/platform/arm64/mpam/mpam_devices.c >> +++ b/drivers/platform/arm64/mpam/mpam_devices.c >> @@ -513,9 +541,84 @@ int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx, >>       return err; >>   } >>   -static void mpam_discovery_complete(void) >> +static int mpam_msc_hw_probe(struct mpam_msc *msc) >>   { >> -    pr_err("Discovered all MSC\n"); >> +    u64 idr; >> +    int err; >> + >> +    lockdep_assert_held(&msc->probe_lock); >> + >> +    mutex_lock(&msc->part_sel_lock); >> +    idr = mpam_read_partsel_reg(msc, AIDR); >> +    if ((idr & MPAMF_AIDR_ARCH_MAJOR_REV) != MPAM_ARCHITECTURE_V1) { >> +        pr_err_once("%s does not match MPAM architecture v1.0\n", >> +                dev_name(&msc->pdev->dev)); > The error message need only mention the major revision. You've added support for v1.1 and > v1.0. Makes sense, Thanks, James