-*- lisp -*-

Some dev notes on the usb driver.


DEV DOC -- USB TRANSFER TREE

An attempt to make sense of the of USB requests. The idea is to
compile a decoder from a description, instead of writing all by
hand.

There's two sides to the story.

(A) getting a set of records about the device on the chip
(B) generating the usb service routine

I'd like to keep both as minimal as possible. Since the (A) part
is just data, it should be entered in the form of s
expressions. A lot of defaults could be used. Given (A), there
should be enough data to perform (B). Tasks to do:

Some simplifications and random implementation remarks
- support only one configuration
- need string management
- need pluggable descriptor management (i.e. HID)
- interfaces are 'virtual devices'
- without bAlternateSetting, is there need for SetInterface?
- string index 0 returns a list of languages

see
http://www.beyondlogic.org/usbnutshell/



Transfers are most easily routed by bRequest first, then divide
further down. It's all pretty straightforward.