%USB
%Thadeu Cascardo

# Universal Serial Bus

* USB 1.0 and 1.1, 1.5Mbps and 12Mbps
* USB 2.0 - up to 480Mbps
* USB 3.0 - up to 5Gbps
* Wireless USB - over Ultra Wideband

# USB - Cont.

* A master/slave bus: the master asks the slave to send data
* Auto-configurable and hotplugable
* Standards specifications, allowing device classes, with no specific driver
* HCDs, USB devices and Gadget devices and their respective drivers

# USB Basics

* Configurations
* Interfaces
* Settings
* Endpoints
* URBs

# Endpoints and URBs

* IN and OUT Endpoints
* Control Endpoints
* Interrupt Endpoints
* Bulk Endpoints
* Isochronous Endpoints

# USB IDs

* struct usb\\_device\\_id
* USB\\_DEVICE
* Others

# USB Driver

* struct usb\\_driver
	- name
	- id\\_table
	- probe
	- disconnect

# USB Interface

* struct usb\\_interface
	- struct usb\\_host\\_interface cur\\_altsetting
		* desc.bNumEndpoints
		* struct usb\\_endpoint\\_descriptor endpoint[].desc
* usb\\_get\\_intf
* usb\\_put\\_intf

# Endpoints

* struct usb\\_endpoint\\_descriptor
* usb\\_endpoint\\_is\\_isoc\\_in
* usb\\_endpoint\\_num

# URBs

* struct urb
	- status
	- transfer\\_buffer
	- actual\\_length
* usb\\_alloc\\_urb
* usb\\_free\\_usb
* usb\\_submit\\_urb
* usb\\_kill\\_urb
* usb\\_fill\\_control\\_urb
* usb\\_fill\\_bulk\\_urb
* usb\\_control\\_msg

# URBs

* Callbacks execute in interrupt context
* May resubmit an URB, but must use GFP\\_ATOMIC