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? > >> VHCI - this is a virtual USB host controller; keyboard, mouse and > >> other system components are provided by this component (other > >> drivers use this host controller to provide more functionality). > > > > I don't understand, why does a security chip have a USB virtual > > interface in it? What "devices" hang off of it that are found and > > enumerated by the host OS? > > The t2 chip not only handles security, but also has a usb hub, which connects the internal keyboard, trackpad, touchbar, webcam, and other internal devices. The external usb ports are separate. That feels strange, but hey, we've seen worse :) thanks, greg k-h
