From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4ABC226F2B8 for ; Thu, 18 Dec 2025 10:38:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766054332; cv=none; b=b0FdVjpIXOURG2/wnhTeEju2MwZeIOTjXH/JIjOkq8cQaBK6oATEZa/6AbFf1CDepWH+n4efTdok2lVbN2ysBKVmqH5d3UojbWB0Fyiu9MAqdkjqqnmn73Nosn9mOD/Y1ZsrYsZS1XFnG9H0EdvWtdMWbONfyEG9y5vemt7P97I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766054332; c=relaxed/simple; bh=QSW8rn6QJf1jig33wB96W2+0uDAnii95vWXHNj0gbAI=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=c7n+/yy+nl4xiLlsuFwuosScSOkdvwA0ZONC1gOzmoqBhh0M4UXtjjxyz+UTkM0rNjzBcs0u+zjgjEEn9qJdlrWT7J9g4jxOX1rpfD5zDHFAob7Cl2XniTkpHiJTTzetNS9ThPGKO/CVXtyW4h/+mOVI99qj0G5oOh+NfAGigog= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.224.150]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4dX6Zc758kzJ46CP; Thu, 18 Dec 2025 18:38:16 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id CC6DC40539; Thu, 18 Dec 2025 18:38:47 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Thu, 18 Dec 2025 10:38:46 +0000 Date: Thu, 18 Dec 2025 10:38:45 +0000 From: Jonathan Cameron To: James Morse CC: , , D Scott Phillips OS , , , , , , Jamie Iles , "Xin Hao" , , , , David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , , , Gavin Shan , Ben Horgan , , , Punit Agrawal Subject: Re: [RFC PATCH 03/38] arm64: mpam: Advertise the CPUs MPAM limits to the driver Message-ID: <20251218103845.000053b3@huawei.com> In-Reply-To: <20251205215901.17772-4-james.morse@arm.com> References: <20251205215901.17772-1-james.morse@arm.com> <20251205215901.17772-4-james.morse@arm.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml100011.china.huawei.com (7.191.174.247) To dubpeml100005.china.huawei.com (7.214.146.113) On Fri, 5 Dec 2025 21:58:26 +0000 James Morse wrote: > Requestors need to populate the MPAM fields for any traffic they send > on the interconnect. For the CPUs these values are taken from the > corresponding MPAMy_ELx register. Each requestor may have a limit on > the largest PARTID or PMG value that can be used. The MPAM driver has > to determine the system-wide minimum supported PARTID and PMG values. > > To do this, the driver needs to be told what each requestor's > limit is. Trivial but this commit message line wrap isn't very consistent. > > CPUs are special, but this infrastructure is also needed for the > SMMU and GIC ITS. Call the helper to tell the MPAM driver what the > CPUs can do. > > The return value can be ignored by the arch code as it runs well > before the MPAM driver starts probing. > > Signed-off-by: James Morse