From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 18B621B2EF2; Sun, 9 Mar 2025 09:51:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741513872; cv=none; b=JRj+dUdj13UTFGE78IHzOyZIQ29IvIGG94Y/Nd7+2qt6FDN3au/lMzhZzhf+z4qwnexCppR0fwr+bntnq2v4PGgf9r0CM3LEoWqkzpu/D38TKzXtLQZCZ5Qjtx4J+9rw/hklkj3hppzaMFGA8hfD4gsQT6HhqFydD+5qbh+5SYg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741513872; c=relaxed/simple; bh=1vB49cU3kZerNUwaC5QDfCUyaApa850mndtG/+7A74o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ceavnX79VYD3J95rRPJTVBFXTBo5+kzsuLpCRL8/DY94J7B4TxKFPEz1XQFXCQmGW83gsA1cn1tb7qJnRJbO/Q8z15r5MeYyFyTiUGMYC16j0inmZK68g59Kp3Pw7Q1prIbDHvkKRKbODKHLs7lhObZJHh5BaTjap47a78Ltw84= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KIT183px; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KIT183px" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64E23C4CEE5; Sun, 9 Mar 2025 09:51:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741513872; bh=1vB49cU3kZerNUwaC5QDfCUyaApa850mndtG/+7A74o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KIT183pxx0ewDo4rUkJFNJRkpdLMP9esEfaPUlrGMDWjtVE9KU90V2fyeScvTuBj2 ouD99Eca3/0BOGblGogHzLJleWGmXTVQLgVaLNK18igHrFXMVjThTu5aHjEilebKmT s5zc2dTWQS/8apj6gj3AkBtahuMz+V4UghPKlNSA= Date: Sun, 9 Mar 2025 10:48:52 +0100 From: "gregkh@linuxfoundation.org" To: Aditya Garg Cc: "bhelgaas@google.com" , "joro@8bytes.org" , "will@kernel.org" , "robin.murphy@arm.com" , "andriy.shevchenko@linux.intel.com" , "linux-staging@lists.linux.dev" , Linux Kernel Mailing List , "linux-pci@vger.kernel.org" , "iommu@lists.linux.dev" , Aun-Ali Zaidi , "paul@mrarm.io" , Orlando Chamberlain Subject: Re: [PATCH RFC] staging: Add driver to communicate with the T2 Security Chip Message-ID: <2025030909-recoup-unafraid-1df0@gregkh> References: <1A12CB39-B4FD-4859-9CD7-115314D97C75@live.com> <2025030931-tattoo-patriarch-006d@gregkh> <2025030937-antihero-sandblast-7c87@gregkh> <2025030935-contently-handbrake-9239@gregkh> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Sun, Mar 09, 2025 at 09:41:29AM +0000, Aditya Garg wrote: > > > > On 9 Mar 2025, at 3:09 PM, gregkh@linuxfoundation.org wrote: > > > > On Sun, Mar 09, 2025 at 09:28:01AM +0000, Aditya Garg wrote: > >> > >> > >>>> On 9 Mar 2025, at 2:46 PM, gregkh@linuxfoundation.org wrote: > >>> > >>> On Sun, Mar 09, 2025 at 09:03:29AM +0000, Aditya Garg wrote: > >>>> > >>>> > >>>>>> On 9 Mar 2025, at 2:24 PM, gregkh@linuxfoundation.org wrote: > >>>>> > >>>>> On Sun, Mar 09, 2025 at 08:40:31AM +0000, Aditya Garg wrote: > >>>>>> From: Paul Pawlowski > >>>>>> > >>>>>> This patch adds a driver named apple-bce, to add support for the T2 > >>>>>> Security Chip found on certain Macs. > >>>>>> > >>>>>> The driver has 3 main components: > >>>>>> > >>>>>> BCE (Buffer Copy Engine) - this is what the files in the root directory > >>>>>> are for. This estabilishes a basic communication channel with the T2. > >>>>>> VHCI and Audio both require this component. > >>>>> > >>>>> So this is a new "bus" type? Or a platform resource? Or something > >>>>> else? > >>>> > >>>> It's a PCI device > >>> > >>> Great, but then is the resources split up into smaller drivers that then > >>> bind to it? How does the other devices talk to this? > >> > >> We technically can split up these 3 into separate drivers and put then into their own trees. > > > > That's fine, but you say that the bce code is used by the other drivers, > > right? So there is some sort of "tie" between these, and that needs to > > be properly conveyed in the device tree in sysfs as that will be > > required for proper resource management. > > Yes there needs to be a tie, basically first establish a communication with the t2 using bce and then the other 2 come into the picture. I did get a basic idea from what the maintainers want, and this will be some work to do. Thanks for your inputs! If there is "communication" then that's a bus in the driver model scheme, so just use that, right? thanks, greg k-h