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 B2CDEC531FA for ; Fri, 24 Jul 2026 10:18:46 +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=fsRwQ/MRXKU69Cz45TMuvT7xD7rCK/lcxMRZ0uHACwM=; b=UM6kF7ny6iVtqip2JI7JjZ0rEI 3iWhM6yQQ33yxaQXKWJgFFKi0HDoWzO/f3BkfLlp1QfM+GKZ0Lnf8jLFKAk2ZXcnGlR2vJoPJsOpi jyMh7rlywPW23IQOjo0h4M7MdPtrC/fTJXPBB11hw0WVL4txBJXC8oXzsYMK504ZMmLYhw8b8j2kJ WP/8TNUQXFy/whv6opHtDz2Xc9nWXT7CmBlDiwI34Igva6u5jxZ0v5sJvrQZbNxIDH5zypPHmmm8f 1pNas3oLQO+m/5i07zsnd8rMPRZQJy3DTvH3OMOMF72g1FroCclPsja5XEPzfVvCyrTxJwWra/zso AD1Bn++g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wnCzI-0000000G3e6-2uWT; Fri, 24 Jul 2026 10:18:40 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wnCzH-0000000G3dw-0PNW for linux-arm-kernel@lists.infradead.org; Fri, 24 Jul 2026 10:18:39 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 5D30640143; Fri, 24 Jul 2026 10:18:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7381A1F000E9; Fri, 24 Jul 2026 10:18:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784888318; bh=fsRwQ/MRXKU69Cz45TMuvT7xD7rCK/lcxMRZ0uHACwM=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=eNeONbs9jDDO8unvLRenY4oHMgcT8mI+O7v/PPOsAMqDi1as36v3ligFWXjWwEWKH vNK0ja7HvbVS21kyI5aJBjj2v36Y+LYDRe7nSvEPWHce06WYY1nnww7zpxPaNEr1L6 U7TrsL0XPQjRIR4qWb8ar0g08f32jYwvFZmd46Uwkg9Wkk9jUD8BOLnxmNYTtayl0g hcgCy0LQ1ZwId5iSeUJoClHXuebZaHum3wSOcbFlEajhFHxkApxXFe6IyeolKbNeaM aG3qDLDvX/VTeu4frVCkNwC+BCNO13pToBrDvw+dWgO9OKgeRgaXoowS8BQxWKCpba BXBmNI+0FZP2A== Date: Fri, 24 Jul 2026 11:18:32 +0100 From: Sudeep Holla To: Andre Przywara Cc: Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Ben Horgan , Reinette Chatre , Fenghua Yu , Jonathan Cameron , Srivathsa L Rao , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , Lee Trager , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 10/10] arm_mpam: detect and enable MPAM-Fb PCC support Message-ID: <20260724-finicky-knowing-foxhound-df1e56@sudeepholla> References: <20260723155454.1760823-1-andre.przywara@arm.com> <20260723155454.1760823-11-andre.przywara@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260723155454.1760823-11-andre.przywara@arm.com> 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 On Thu, Jul 23, 2026 at 05:54:54PM +0200, Andre Przywara wrote: > The Arm MPAM-Fb specification [1] describes a protocol to access MSC > registers through a firmware interface. This requires a shared memory > region to hold the message, and a mailbox to trigger the access. > For ACPI this is wrapped as a PCC channel, described using existing > ACPI abstractions. > > Add code to parse those PCC table descriptions associated with an MSC, > and store the parsed information in the MSC struct. > There can be multiple PCC channels, and each channel can serve multiple > MSCs, so we need to keep track of the channel usage, using a list and > a refcount. > This will be used by the MPAM-Fb access wrapper code. > > [1] https://developer.arm.com/documentation/den0144/latest > > Signed-off-by: Andre Przywara > --- > drivers/acpi/arm64/mpam.c | 6 +- > drivers/resctrl/mpam_devices.c | 127 ++++++++++++++++++++++++++++++++- > 2 files changed, 129 insertions(+), 4 deletions(-) > > diff --git a/drivers/acpi/arm64/mpam.c b/drivers/acpi/arm64/mpam.c > index 84963a20c3e7..ca9b8754ae5f 100644 > --- a/drivers/acpi/arm64/mpam.c > +++ b/drivers/acpi/arm64/mpam.c > @@ -220,8 +220,8 @@ static struct platform_device * __init acpi_mpam_parse_msc(struct acpi_mpam_msc_ > struct platform_device *pdev __free(platform_device_put) = > platform_device_alloc("mpam_msc", tbl_msc->identifier); Looks like tbl_msc->identifier is getting stashed as pdev->id... > int next_res = 0, next_prop = 0, err; > - /* pcc, nrdy, affinity and a sentinel */ > - struct property_entry props[4] = { 0 }; > + /* pcc, msc-id, nrdy, affinity and a sentinel */ > + struct property_entry props[5] = { 0 }; > /* mmio, 2xirq, no sentinel. */ > struct resource res[3] = { 0 }; > struct acpi_device *companion; > @@ -256,6 +256,8 @@ static struct platform_device * __init acpi_mpam_parse_msc(struct acpi_mpam_msc_ > } else if (iface == MPAM_IFACE_PCC) { > props[next_prop++] = PROPERTY_ENTRY_U32("pcc-channel", > tbl_msc->base_address); > + props[next_prop++] = PROPERTY_ENTRY_U32("msc-id", > + tbl_msc->identifier); Why is this needed then as you can fetch it as pdev->id ? -- Regards, Sudeep