> On 9 Mar 2025, at 3:54 PM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > On Sun, Mar 09, 2025 at 10:12:06AM +0000, Aditya Garg wrote: >> >> >>>> On 9 Mar 2025, at 3:26 PM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: >>> >>> On Sun, Mar 09, 2025 at 09:52:43AM +0000, Aditya Garg wrote: >>>> >>>> >>>>>> On 9 Mar 2025, at 3:21 PM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: >>>>> >>>>> On Sun, Mar 09, 2025 at 09:41:29AM +0000, Aditya Garg wrote: >>>>>> >>>>>> >>>>>>>> On 9 Mar 2025, at 3:09 PM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: >>>>>>> >>>>>>> On Sun, Mar 09, 2025 at 09:28:01AM +0000, Aditya Garg wrote: >>>>>>>> >>>>>>>> >>>>>>>>>> On 9 Mar 2025, at 2:46 PM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: >>>>>>>>> >>>>>>>>> On Sun, Mar 09, 2025 at 09:03:29AM +0000, Aditya Garg wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>>>> On 9 Mar 2025, at 2:24 PM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: >>>>>>>>>>> >>>>>>>>>>> On Sun, Mar 09, 2025 at 08:40:31AM +0000, Aditya Garg wrote: >>>>>>>>>>>> From: Paul Pawlowski <paul@xxxxxxxx> >>>>>>>>>>>> >>>>>>>>>>>> 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. >> >> >> I was asking that should I introduce a completely new bus instead of >> pci and probably reverse engineer the original macOS driver to see >> what exactly is going on there? > > No, if it's a PCI device on a PCI bus, then use the PCI api for all of > that. > > It's what that PCI device "exposes" here, are the other devices, like > the USB host controller, hanging off of that, or are they real PCI > devices as well? > > What exactly does this BCE driver do? > >> I might not have been clear, but I'm not the author of this patch. > > That's fine, but why doesn't the original author want to do this work? Lack of motivation I suppose. The driver was getting more and more annoying to fix bugs IIRC. > Have you asked them if they want this code included in the kernel tree? He had permitted me to send whatever I want upstream in a conversation. > Who is going to do the maintenance for it and who is going to answer > questions like the ones I have here? I cannot answer this rn, I suppose I acknowledged my lack of Maintainers being added. Since I am a part of a small group of developers who aim to bring support for t2 macs, one of us will take up. Currently I am just trying to get an overview which can guide me further on what can be improved as far as maintainers are concerned. > > And again, what is with the new user/kernel api being added? What is > all of that for? Please give me time to read the driver a bit more, so that I can answer it better. I need to find the notes of the author who actually wrote the driver. > > thanks, > > greg k-h
