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 EE32B2D78A; Sun, 9 Mar 2025 09:56:28 +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=1741514189; cv=none; b=BWN9qLg89M+Vuac0pbnzikwmD6Ki5xLU++8cWMnTXUrZ5ghTYqtDNrDvbLgcva64CVfvIjbzoXKDY5edyrCAVJGZ+vgX/Ql9qoc4/POASTgklTtT+/z0zT6nLRY1oZIQxhBPTQBIt+k9+UTGladjVRft+glXJIRjRxvx+PAX8xM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741514189; c=relaxed/simple; bh=huC0iybV3NgoQGgAkddJITpWfu30ofxovlfYYAx92xE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pgEdCYgYmoF8e92jiLzrPPHqRMDJZthz26EtEv/VhFen9XN2db8dfpJxybp0zldS6AGicTrSaniS/ih0Kl7w3DcRoTCx1JHmP8jyXjTJT9q2xCr/snHlBTFGwyxT4PuNnrnTvN49TZiF3DBlBEfTZKlPC6h+rYvkA1nXnYDqr7M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xsi/ClbD; 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="xsi/ClbD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F625C4CEE5; Sun, 9 Mar 2025 09:56:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741514188; bh=huC0iybV3NgoQGgAkddJITpWfu30ofxovlfYYAx92xE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=xsi/ClbDrXEBsaITnP9UKIlK3u244C6Y6RmWLG83ubwKjrlUfcVncRkb0ub/3eUYX qKe7KS5fWQryykBLLmXT7v9nafrpXo57B+jsN3SrpG3eVKyjjiIUjfgQxq78V8GwJR 6es/dIuMuBRMWHBMIzf3f2lgVhPTRCqJv+BTwEMY= Date: Sun, 9 Mar 2025 10:55:12 +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: <2025030901-deceiver-jolliness-53f5@gregkh> References: <1A12CB39-B4FD-4859-9CD7-115314D97C75@live.com> <2025030931-tattoo-patriarch-006d@gregkh> <2025030937-antihero-sandblast-7c87@gregkh> <2025030935-contently-handbrake-9239@gregkh> <2025030909-recoup-unafraid-1df0@gregkh> Precedence: bulk X-Mailing-List: linux-staging@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 09:52:43AM +0000, Aditya Garg wrote: > > > > On 9 Mar 2025, at 3:21 PM, gregkh@linuxfoundation.org wrote: > > > > 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? > > So basically RE the whole driver to see what exactly should be use? I'm sorry, I can not parse this.