From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9BD423451B4; Tue, 9 Sep 2025 14:23:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757427814; cv=none; b=f/LCvqsIagk2A/17h/vNQzHtoTQ3pNtZc/FBsabCNtots9k00KIKfPOvkcgbgFWgGzP6Gjfi0DngUeX7B4WcQDohvPAUkp60v095+tNC4TexrdE4KG+QtucDD+sTXm7yXYDRfXv2O+0kK8ge/+c1jlinB9RvBTgBU9mZiBlz8ks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757427814; c=relaxed/simple; bh=lfKJwavK2NEanN+cL6edfbgdRn0pD99g6SQzNtIfe2U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eWdj9EdP0x6SHGKe6vxtn+7t1kB/GSGyNBJQu1KRsa9vrK3too8rUN5OZBZ0ARNvF7wTHcSW4GuYqbc7q0FhFW4KPaJTuqiEGVMeqHG0LLw2z6KWgn7A+5zQIxYmmTK6A8nmsO9PonsM9azmGq/8liy+TaTl6oAxLXTxA2uukMQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250822153048.2287-15-james.morse@arm.com> 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