Copyright (c) 2015 Sean Levy <attila@stalphonsos.com>
Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.Dd $Mdocdate: June 27 2016 $ .Dt USBD_OPEN_PIPE 9 .Os .Sh NAME .Nm usbd_open_pipe , usbd_open_pipe_intr .Nd create USB pipe .Sh SYNOPSIS n dev/usb/usb.h n dev/usb/usbdi.h .Ft usbd_status .Fn usbd_open_pipe "struct usbd_interface *iface" "uint8_t address" "uint8_t flags" "struct usbd_pipe **pipe" .Ft usbd_status .Fn usbd_open_pipe_intr "struct usbd_interface *iface" "uint8_t address" "uint8_t flags" "struct usbd_pipe **pipe" "void *priv" "void *buffer" "uint32_t len" "usbd_callback cb" "int ival" .Sh DESCRIPTION The .Fn usbd_open_pipe and .Fn usbd_open_pipe_intr functions create pipes. A pipe is a logical connection between the host and an endpoint on a USB device. USB drivers use pipes to manage transfers to or from a USB endpoint.
p The .Fn usbd_open_pipe function takes the following arguments: l -tag -width callback t Fa iface The USB interface for which the pipe is to be created. t Fa address The address of the endpoint in that interface to which the pipe should be connected. t Fa flags A bitmask of flags. Currently there is only one flag bit defined: l -tag -width xxx -offset indent t Dv USBD_EXCLUSIVE_USE Do not allow other pipes to use this endpoint while this pipe exists. .El t Fa pipe A pointer to where the resulting .Vt struct usbd_pipe * should be stored if the call is successful. .El
p The .Fn usbd_open_pipe_intr function takes the following arguments: l -tag -width callback t Fa iface The USB interface for which the pipe is to be created. t Fa address The endpoint in that interface to which the pipe should be connected. t Fa flags A bitmask of flags. These flags are not interpreted in the same way as the .Fa flags passed to .Fn usbd_open_pipe . Instead, .Fn usbd_open_pipe_intr implicitly turns on the .Dv USBD_EXCLUSIVE_USE bit for the pipe, disallowing multiple interrupt pipes for the same endpoint. The .Fa flags argument in this case is instead passed directly to .Xr usbd_setup_xfer 9 as its .Fa flags argument, whose interpretation is documented in its man page. t Fa pipe A pointer to where the resulting .Vt struct usbd_pipe * should be stored if the call is successful. t Fa priv A pointer to a private cookie untouched by the USB stack for reuse in the callback specified by the .Fa cb argument. t Fa buffer A pointer to the data buffer for use by the implicit transfer (see below). t Fa len The length in bytes of .Fa buffer . t Fa cb A callback invoked every time the interrupt transfer completes. t Fa ival The interval in milliseconds with which the interrupt pipe should be polled by the USB stack. .El
p Pipes created by .Fn usbd_open_pipe_intr implicitly have a repeating transfer queued on them which is run every .Fa ival milliseconds. This implicit transfer is not automatically removed from the list of transfers maintained by the pipe, unlike normal transfers, and will continue to be processed every .Fa ival milliseconds. .Sh CONTEXT .Fn usbd_open_pipe and .Fn usbd_open_pipe_intr can be called during autoconf or from process context. .Sh SEE ALSO .Xr usb 4 , .Xr usbd_close_pipe 9 , .Xr usbd_transfer 9