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 8E2F2397942; Wed, 29 Jul 2026 14:51:58 +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=1785336722; cv=none; b=nQ8mD/qWSCFSmgB34zRX8bTxernTMvTnfjYLstXe+doUfp5yh55kruly5lL5FmNKw+b6PYf65Rk6eOcnUpXn7hCHtbYeaZdbuN+QOex6tEZtbSrTwSPD8LnGJEzAn5e6cd5S0F0LfHhffbyZ4yEY90+LxDf0t/hTiwTi34swE5w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785336722; c=relaxed/simple; bh=NZSdB7xkKKO5D9M3yjHPGpy+oFIC7CKGla9a9ileuaQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HMEgnnIacE7EbHG8dNUAcAd87z7GNoZ7iErsNEUCvSqKxnde7B6cuFZVMGdooJgR8kxqkhkBsplT1v1I5RwK5xAPNIOtRbl1BrZGyIpy2Y6Iroyp5HNVfW3dS1KylfxNS09QhJ+068U2H7OT+0knVF/F93eHDJ7Xj9G25tBAN4c= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=XVBDnCuR; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="XVBDnCuR" 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 2DCB31684; Wed, 29 Jul 2026 07:51:53 -0700 (PDT) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7FAB43F66F; Wed, 29 Jul 2026 07:51:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785336717; bh=NZSdB7xkKKO5D9M3yjHPGpy+oFIC7CKGla9a9ileuaQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=XVBDnCuReVZGP3SdEWYVaT7ipAbUs2c+f484eaJt87Ur9DPaiUvTTZ4NF+na90kes g5udnccYZ6xLq/WAo1Xc06w44riUKAmZb9N4ZQWhOcUlaZ0ipqvz3O0Znbn0LgkZvc L7dCE0YImNCJ/ERZrVLfqGCJ4/Q0e0+VjqgGrCwE= Message-ID: <1da9895e-eaf8-45f0-bac8-c4304a3b4f6a@arm.com> Date: Wed, 29 Jul 2026 15:51:53 +0100 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Thunderbird Daily Subject: Re: [PATCH v5 08/10] arm_mpam: add MPAM-Fb MSC firmware access support To: Andre Przywara , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Reinette Chatre , Fenghua Yu Cc: 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 References: <20260729134124.2506269-1-andre.przywara@arm.com> <20260729134124.2506269-9-andre.przywara@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20260729134124.2506269-9-andre.przywara@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Andre, On 7/29/26 14:41, Andre Przywara wrote: > The Arm MPAM Firmware-backed (Fb) Profile document[1] describes an > alternative way of accessing the "Memory System Components" (MSC) in an > MPAM enabled system. > > Normally the MSCs are MMIO mapped, but in some implementations this > might not be possible (MSC located outside of the local socket, MSC > mapped secure-only) or desirable (direct MMIO access too slow or needs > to be mediated through a control processor). MPAM-fb standardises a > protocol to abstract MSC accesses, building on the SCMI protocol. > > Add functions that do an MSC read or write access by redirecting the > request through a firmware interface. For now this done via an ACPI > PCC shared memory and mailbox combination. > > Since the protocol used is only a small subset of the full SCMI spec, > and the SCMI protocol has no full ACPI support anyway, open-code the > (simple) SCMI message generation, for just the fields we need. > > [1] https://developer.arm.com/documentation/den0144/latest > > Signed-off-by: Andre Przywara [...] > diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h > index 2b81b6b0bf4e..a2193e7df57c 100644 > --- a/drivers/resctrl/mpam_internal.h > +++ b/drivers/resctrl/mpam_internal.h > @@ -11,6 +11,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -57,6 +58,15 @@ struct mpam_garbage { > struct platform_device *pdev; > }; > > +struct mpam_pcc_chan { > + struct list_head pcc_chans; > + struct mbox_client pcc_cl; > + struct pcc_mbox_chan *pcc_chan; > + struct mutex pcc_chan_lock; /* only one message at a time */ > + struct kref refcount; > + int subspace_id; > +}; > + > struct mpam_msc { > /* member of mpam_all_msc */ > struct list_head all_msc_list; > @@ -66,6 +76,8 @@ struct mpam_msc { > > /* Not modified after mpam_is_enabled() becomes true */ > enum mpam_msc_iface iface; > + struct mpam_pcc_chan *pcc_chan; > + int mpam_fb_msc_id; /* in its own name space */ This gets removed in patch 10 now. I guess you just edited the wrong patch. Thanks, Ben