[SeaBIOS] [PATCH v3 3/3] usb: add xhci support

[Gerd Hoffmann]

  Hi,

> Booting an Asus F2A85-M, with CONFIG_DEBUG_LEVEL=7 and a keyboard
> (Chesen PS/2-to-USB bridge) in one of its USB3 ports:

Two devices actually, one on each of the two xhci controllers.

First control transfer fails for both devices:

> |bf0fe000| xhci_trb_queue: ring 0xbf11e500 [nidx 1, len 8]
> |bf0fe000| xhci_trb_queue: ring 0xbf11e500 [nidx 2, len 8]
> |bf0fe000| xhci_trb_queue: ring 0xbf11e500 [nidx 3, len 0]
> |bf0fe000| xhci_xfer_kick: ring 0xbf11e500, slotid 1, epid 1

> |bf0fb000| xhci_trb_queue: ring 0xbf11e300 [nidx 1, len 8]
> |bf0fb000| xhci_trb_queue: ring 0xbf11e300 [nidx 2, len 8]
> |bf0fb000| xhci_trb_queue: ring 0xbf11e300 [nidx 3, len 0]
> |bf0fb000| xhci_xfer_kick: ring 0xbf11e300, slotid 1, epid 1

> |bf0fb000| xhci_control: control xfer failed (cc 6)

cc 6 is "STALL ERROR"

> |bf0fe000| WARNING - Timeout at xhci_event_wait:403!

Probably there is something wrong with our control xfer trbs, which the
qemu emulation is tolerant enough to accept but real hardware doesn't.

cheers,
  Gerd