Module wire 

The USB FUNCTION PROTOCOL’s numbers: what a USB host service (xhci, dwc2, ehci) answers for the one device it binds for a driver of its own, and what that driver asks. A driver package speaks it through gs::driver::bus; the WiFi dongle’s driver through godspeed_wifi::usbfn, which re-exports these and says what each one means in full (sdk/wifi/src/usbfn.rs). Every request starts with its op, and every reply with [op, status].

Constants

BULK_IN_MAX

The most one bulk IN transfer carries: seven 512-byte high-speed packets, beside the reply’s two bytes.

BULK_OUT_MAX

The most one bulk OUT transfer carries: the rest of a message after the op and the endpoint byte.

CONTROL_MAX

The most data one control transfer carries, either way.

INFO_GEN_AT

Where an OP_INFO answer’s binding generation starts.

INFO_WHERE_AT

Where the optional part of an OP_INFO answer starts (where the device is, from a host that says).

NOTE_BULK_IN

Sent by the host, unanswered: a bulk IN transfer is held - ask OP_BULK_IN.

NOTE_RADIO

Sent by the host, unanswered: the binding changed - ask OP_INFO.

OP_BULK_IN

[op] -> [op, status, transfer...]: the bulk IN transfer the host holds, if any; the IN armed again (ehci holds none: it waits briefly for the device and answers what came).

OP_BULK_OUT

[op, out, transfer...] -> [op, status]: one bulk OUT transfer to the device’s outth bulk OUT endpoint.

OP_CONTROL

[op, setup (8), data out...] -> [op, status, data in...]: one control transfer on the default endpoint.

OP_CONTROL_ONCE

OP_CONTROL, attempted exactly once: the host does not retry it.

OP_INFO

[op] -> [op, status, vid (2 LE), pid (2 LE), gen (4 LE), ...]: which device is bound, and which binding of it.

OP_REPLUG

[op] -> [op, status]: reset the device’s port and bind it afresh (dwc2 takes it; xhci and ehci answer ST_BAD_REQUEST).

OP_SYNC

[op, notice], never answered: names a notice that arrived in place of an answer.

ST_BAD_REQUEST

The request was malformed.

ST_FAILED

The host tried, and the device or the bus did not complete it.

ST_NO_DEVICE

No device is bound on this host.

ST_OK

The transfer was done (or, for OP_INFO, a device is bound).