DavidS wrote:I have searched the forums, looked through the wiki, looked through every document that I have found related to the RPi HW, all to no avail.
That's not terribly surprising, the USB implementation is made by Synopsys, and they are not forthcoming with documentation. Some information /is/ available, but only by pulling apart various datasheets, which mainly don't include the modifications Broadcom made to the Synopsys IP
Luke Robertson's document
is probably the most complete one out there. The Ralink 3050 datasheet contains lots of handy tidbits, too.
1:) Does the USB controller generate inturpts to the ARM? if so on what events?
Yes, it can / does. Lots and lots and lots of them.
2:) Is it possible to use DMA with the USB on the RPi?
It should be, if I've read properly. The Ralink documentation seems to imply it is.
3a:) Where do I find some documentation on these points?
Luke's document, and the Linux source.