On Mon, Mar 2, 2020, at 4:48 PM, Hans Petter Selasky wrote: > On 2020-03-02 22:19, Farhan Khan wrote: > > Hi all, > > > > I am trying to understand how FreeBSD's usb transfers work compared to > > OpenBSD by using the rum(4) driver. I am a little confused how the FreeBSD > > side works. > > In FreeBSD USB transfers are a statemachine. In the beginning you call > the start method, and that invokes the statemachine callback in the > SETUP state. There you setup all parameters, buffers, lengths etc. and > then you can submit the USB transfer, which invoke the host controller > drivers routines, which actually lay out the required DMA descriptors > for data transfer. When the USB transfer is completed the statemachine > callback is invoked again and you can choose what to do. > > --HPS >
Thank you so much for your prompt response! I understand that you are the one who wrote the USB stack? If so, I am honored. Can you please clarify a few points you made? > In the beginning you call the start method Within rum(4), would that be rum_start()? If not, which function is that? > then you can submit the USB transfer Would that function be usbd_transfer_submit(9)? Thanks again! -- Farhan Khan PGP Fingerprint: 1312 89CE 663E 1EB2 179C 1C83 C41D 2281 F8DA C0DE _______________________________________________ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
