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 463B7CA0FED for ; Tue, 9 Sep 2025 17:21:09 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=gUr1Dp1JYlyFc6Syl+BqKy2O7GxRfGrb0yjK+byR+8g=; b=Vfl63c/FtlNGprEoFUzNeZ9TBQ UhoNuldW6SKhWTtGwIcoRmxa1sfBu9t56kInJYe38QZwQVyyOokS12vb7OT9ichs3Gu+pF1r5vdw5 +F/6IYD9xUlMgjHhugY/n0TyRhzmgb8DdM4ywZ4fhhql9DyTk01fU9BjfO0jpE+f9X6FtMpQIcpW+ i6dL9YxAun0wz2J6XkPOg7UcBQPe5eYDacKuZ2/7K4ne1llZHD9UGMQvlo2fYuZ9/wG/E+beFCcdn Gb+ogI8kgO7aP+5ZJ7OZSsqp2w+QBj8cldwSa2FkvbKdRD45CdAAPOqWwjiRbhG61CJu9ABw9CACd Ie0xNN7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uw21Y-00000008x2p-1fl9; Tue, 09 Sep 2025 17:20:56 +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 1uvzFu-00000007i46-2liE for linux-arm-kernel@lists.infradead.org; Tue, 09 Sep 2025 14:23:35 +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 906B91424; Tue, 9 Sep 2025 07:23:23 -0700 (PDT) Received: from e133380.arm.com (e133380.arm.com [10.1.197.68]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2519D3F66E; Tue, 9 Sep 2025 07:23:26 -0700 (PDT) Date: Tue, 9 Sep 2025 15:23:23 +0100 From: Dave Martin To: James Morse Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, D Scott Phillips OS , carl@os.amperecomputing.com, 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 , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich , Lecopzer Chen Subject: Re: [PATCH 14/33] arm_mpam: Add cpuhp callbacks to probe MSC hardware Message-ID: References: <20250822153048.2287-1-james.morse@arm.com> <20250822153048.2287-15-james.morse@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250822153048.2287-15-james.morse@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250909_072334_775867_0FE8148E X-CRM114-Status: GOOD ( 24.11 ) 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 James, While I'm here: On Fri, Aug 22, 2025 at 03:29:55PM +0000, 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. > > CC: Lecopzer Chen > Signed-off-by: James Morse > --- > drivers/resctrl/mpam_devices.c | 144 +++++++++++++++++++++++++++++++- > drivers/resctrl/mpam_internal.h | 8 +- > 2 files changed, 147 insertions(+), 5 deletions(-) > > diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c > index 5baf2a8786fb..9d6516f98acf 100644 > --- a/drivers/resctrl/mpam_devices.c > +++ b/drivers/resctrl/mpam_devices.c [...] > @@ -511,9 +539,84 @@ 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) > +{ > + u64 idr; > + int err; Redundant variable which gets removed again in the next patch? > + > + 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.x\n", > + dev_name(&msc->pdev->dev)); > + err = -EIO; > + } else { > + msc->probed = true; > + err = 0; > + } > + mutex_unlock(&msc->part_sel_lock); > + > + return err; > +} [...] Cheers ---Dave