642 lines
17 KiB
Groff
642 lines
17 KiB
Groff
.\"
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.\" Copyright (c) 2005 Ian Dowse <iedowse@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.Dd June 24, 2009
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.Dt USBDI 9
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.Os
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.Sh NAME
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.Nm usb_fifo_alloc_buffer ,
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.Nm usb_fifo_attach ,
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.Nm usb_fifo_detach ,
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.Nm usb_fifo_free_buffer ,
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.Nm usb_fifo_get_data ,
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.Nm usb_fifo_get_data_buffer ,
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.Nm usb_fifo_get_data_error ,
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.Nm usb_fifo_get_data_linear ,
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.Nm usb_fifo_put_bytes_max ,
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.Nm usb_fifo_put_data ,
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.Nm usb_fifo_put_data_buffer ,
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.Nm usb_fifo_put_data_error ,
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.Nm usb_fifo_put_data_linear ,
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.Nm usb_fifo_reset ,
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.Nm usb_fifo_softc ,
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.Nm usb_fifo_wakeup ,
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.Nm usbd_do_request ,
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.Nm usbd_do_request_flags ,
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.Nm usbd_errstr ,
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.Nm usbd_lookup_id_by_info ,
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.Nm usbd_lookup_id_by_uaa ,
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.Nm usbd_transfer_clear_stall ,
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.Nm usbd_transfer_drain ,
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.Nm usbd_transfer_pending ,
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.Nm usbd_transfer_poll ,
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.Nm usbd_transfer_setup ,
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.Nm usbd_transfer_start ,
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.Nm usbd_transfer_stop ,
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.Nm usbd_transfer_submit ,
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.Nm usbd_transfer_unsetup ,
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.Nm usbd_xfer_clr_flag ,
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.Nm usbd_xfer_frame_data ,
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.Nm usbd_xfer_frame_len ,
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.Nm usbd_xfer_get_frame ,
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.Nm usbd_xfer_get_priv ,
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.Nm usbd_xfer_is_stalled ,
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.Nm usbd_xfer_max_framelen ,
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.Nm usbd_xfer_max_frames ,
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.Nm usbd_xfer_max_len ,
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.Nm usbd_xfer_set_flag ,
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.Nm usbd_xfer_set_frame_data ,
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.Nm usbd_xfer_set_frame_len ,
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.Nm usbd_xfer_set_frame_offset ,
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.Nm usbd_xfer_set_frames ,
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.Nm usbd_xfer_set_interval ,
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.Nm usbd_xfer_set_priv ,
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.Nm usbd_xfer_set_stall ,
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.Nm usbd_xfer_set_timeout ,
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.Nm usbd_xfer_softc ,
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.Nm usbd_xfer_state ,
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.Nm usbd_xfer_status
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.Nd Universal Serial Bus driver programming interface
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.Sh SYNOPSIS
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.In dev/usb/usb.h
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.In dev/usb/usbdi.h
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.In dev/usb/usbdi_util.h
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.Sh DESCRIPTION
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The Universal Serial Bus (USB) driver programming interface provides
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USB peripheral drivers with a host controller independent API for
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controlling and communicating with USB peripherals.
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The
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.Nm usb
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module supports both USB Host and USB Device side mode.
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.
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.Sh USB KERNEL PROGRAMMING
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Here is a list of commonly used functions:
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.Pp
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.
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.Ft "usb_error_t"
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.Fo "usbd_transfer_setup"
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.Fa "udev"
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.Fa "ifaces"
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.Fa "pxfer"
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.Fa "setup_start"
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.Fa "n_setup"
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.Fa "priv_sc"
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.Fa "priv_mtx"
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.Fc
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.
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.Pp
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.
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.Ft "void"
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.Fo "usbd_transfer_unsetup"
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.Fa "pxfer"
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.Fa "n_setup"
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.Fc
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.
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.Pp
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.
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.Ft "void"
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.Fo "usbd_transfer_start"
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.Fa "xfer"
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.Fc
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.
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.Pp
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.
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.Ft "void"
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.Fo "usbd_transfer_stop"
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.Fa "xfer"
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.Fc
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.
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.Pp
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.
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.Ft "void"
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.Fo "usbd_transfer_drain"
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.Fa "xfer"
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.Fc
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.
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.
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.
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.Sh USB TRANSFER MANAGEMENT FUNCTIONS
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The USB standard defines four types of USB transfers.
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.
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Control transfers, Bulk transfers, Interrupt transfers and Isochronous
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transfers.
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.
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All the transfer types are managed using the following five functions:
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.
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.Pp
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.
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.Fn usbd_transfer_setup
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This function will allocate memory for and initialise an array of USB
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transfers and all required DMA memory.
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.
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This function can sleep or block waiting for resources to become
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available.
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.Fa udev
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is a pointer to "struct usb_device".
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.Fa ifaces
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is an array of interface index numbers to use. See "if_index".
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.Fa pxfer
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is a pointer to an array of USB transfer pointers that are initialized
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to NULL, and then pointed to allocated USB transfers.
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.Fa setup_start
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is a pointer to an array of USB config structures.
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.Fa n_setup
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is a number telling the USB system how many USB transfers should be
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setup.
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.Fa priv_sc
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is the private softc pointer, which will be used to initialize
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"xfer->priv_sc".
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.Fa priv_mtx
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is the private mutex protecting the transfer structure and the
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softc. This pointer is used to initialize "xfer->priv_mtx".
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This function returns
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zero upon success. A non-zero return value indicates failure.
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.
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.Pp
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.
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.Fn usbd_transfer_unsetup
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This function will release the given USB transfers and all allocated
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resources associated with these USB transfers.
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.Fa pxfer
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is a pointer to an array of USB transfer pointers, that may be NULL,
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that should be freed by the USB system.
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.Fa n_setup
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is a number telling the USB system how many USB transfers should be
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unsetup.
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.
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This function can sleep waiting for USB transfers to complete.
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.
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This function is NULL safe with regard to the USB transfer structure
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pointer.
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.
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It is not allowed to call this function from the USB transfer
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callback.
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.
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.Pp
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.
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.Fn usbd_transfer_start
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This function will start the USB transfer pointed to by
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.Fa xfer,
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if not already started.
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.
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This function is always non-blocking and must be called with the
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so-called private USB mutex locked.
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.
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This function is NULL safe with regard to the USB transfer structure
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pointer.
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.
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.Pp
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.
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.Fn usbd_transfer_stop
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This function will stop the USB transfer pointed to by
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.Fa xfer,
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if not already stopped.
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.
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This function is always non-blocking and must be called with the
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so-called private USB mutex locked.
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.
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This function can return before the USB callback has been called.
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.
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This function is NULL safe with regard to the USB transfer structure
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pointer.
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.
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If the transfer was in progress, the callback will called with
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"USB_ST_ERROR" and "error = USB_ERR_CANCELLED".
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.
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.Pp
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.
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.Fn usbd_transfer_drain
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This function will stop an USB transfer, if not already stopped and
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wait for any additional USB hardware operations to complete.
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.
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Buffers that are loaded into DMA using "usbd_xfer_set_frame_data()" can
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safely be freed after that this function has returned.
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.
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This function can block the caller and will not return before the USB
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callback has been called.
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.
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This function is NULL safe with regard to the USB transfer structure
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pointer.
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.
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.Sh USB TRANSFER CALLBACK
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.
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The USB callback has three states.
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.
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USB_ST_SETUP, USB_ST_TRANSFERRED and USB_ST_ERROR. USB_ST_SETUP is the
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initial state.
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.
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After the callback has been called with this state it will always be
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called back at a later stage in one of the other two states.
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.
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The USB callback should not restart the USB transfer in case the error
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cause is USB_ERR_CANCELLED.
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.
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The USB callback is protected from recursion.
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.
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That means one can start and stop whatever transfer from the callback
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of another transfer one desires.
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.
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Also the transfer that is currently called back.
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.
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Recursion is handled like this that when the callback that wants to
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recurse returns it is called one more time.
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.
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.
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.Pp
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.
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.Fn usbd_transfer_submit
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This function should only be called from within the USB callback and
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is used to start the USB hardware.
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.
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An USB transfer can have multiple frames consisting of one or more USB
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packets making up an I/O vector for all USB transfer types.
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.
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.Bd -literal -offset indent
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void
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usb_default_callback(struct usb_xfer *xfer, usb_error_t error)
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{
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int actlen;
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usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
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switch (USB_GET_STATE(xfer)) {
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case USB_ST_SETUP:
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/*
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* Setup xfer frame lengths/count and data
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*/
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usbd_transfer_submit(xfer);
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break;
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case USB_ST_TRANSFERRED:
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/*
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* Read usb frame data, if any.
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* "actlen" has the total length for all frames
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* transferred.
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*/
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break;
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default: /* Error */
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/*
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* Print error message and clear stall
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* for example.
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*/
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break;
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}
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/*
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* Here it is safe to do something without the private
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* USB mutex locked.
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*/
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return;
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}
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.Ed
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.
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.Sh USB CONTROL TRANSFERS
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An USB control transfer has three parts.
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.
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First the SETUP packet, then DATA packet(s) and then a STATUS
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packet.
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.
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The SETUP packet is always pointed to by frame 0 and the
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length is set by
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.Fn usbd_xfer_frame_len
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also if there should not be
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sent any SETUP packet! If an USB control transfer has no DATA stage,
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then the number of frames should be set to 1.
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.
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Else the default number of frames is 2.
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.
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.Bd -literal -offset indent
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Example1: SETUP + STATUS
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usbd_xfer_set_frames(xfer, 1);
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usbd_xfer_set_frame_len(xfer, 0, 8);
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usbd_transfer_submit(xfer);
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Example2: SETUP + DATA + STATUS
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usbd_xfer_set_frames(xfer, 2);
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usbd_xfer_set_frame_len(xfer, 0, 8);
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usbd_xfer_set_frame_len(xfer, 1, 1);
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usbd_transfer_submit(xfer);
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Example3: SETUP + DATA + STATUS - split
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1st callback:
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usbd_xfer_set_frames(xfer, 1);
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usbd_xfer_set_frame_len(xfer, 0, 8);
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usbd_transfer_submit(xfer);
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2nd callback:
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/* IMPORTANT: frbuffers[0] must still point at the setup packet! */
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usbd_xfer_set_frames(xfer, 2);
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usbd_xfer_set_frame_len(xfer, 0, 0);
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usbd_xfer_set_frame_len(xfer, 1, 1);
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usbd_transfer_submit(xfer);
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Example4: SETUP + STATUS - split
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1st callback:
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usbd_xfer_set_frames(xfer, 1);
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usbd_xfer_set_frame_len(xfer, 0, 8);
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usbd_xfer_set_flag(xfer, USB_MANUAL_STATUS);
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usbd_transfer_submit(xfer);
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2nd callback:
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usbd_xfer_set_frames(xfer, 1);
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usbd_xfer_set_frame_len(xfer, 0, 0);
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usbd_xfer_clr_flag(xfer, USB_MANUAL_STATUS);
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usbd_transfer_submit(xfer);
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.Ed
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.Sh USB TRANSFER CONFIG
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To simply the search for endpoints the
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.Nm usb
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module defines a USB config structure where it is possible to specify
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the characteristics of the wanted endpoint.
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.Bd -literal -offset indent
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struct usb_config {
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bufsize,
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callback
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direction,
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endpoint,
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frames,
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index flags,
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interval,
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timeout,
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type,
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};
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.Ed
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.
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.Pp
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.Fa type
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field selects the USB pipe type.
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.
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Valid values are: UE_INTERRUPT, UE_CONTROL, UE_BULK,
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UE_ISOCHRONOUS.
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.
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The special value UE_BULK_INTR will select BULK and INTERRUPT pipes.
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.
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This field is mandatory.
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.
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.Pp
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.Fa endpoint
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field selects the USB endpoint number.
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.
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A value of 0xFF, "-1" or "UE_ADDR_ANY" will select the first matching
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endpoint.
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.
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This field is mandatory.
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.
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.Pp
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.Fa direction
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field selects the USB endpoint direction.
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.
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A value of "UE_DIR_ANY" will select the first matching endpoint.
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.
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Else valid values are: "UE_DIR_IN" and "UE_DIR_OUT".
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.
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"UE_DIR_IN" and "UE_DIR_OUT" can be binary OR'ed by "UE_DIR_SID" which
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means that the direction will be swapped in case of
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USB_MODE_DEVICE.
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.
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Note that "UE_DIR_IN" refers to the data transfer direction of the
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"IN" tokens and "UE_DIR_OUT" refers to the data transfer direction of
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the "OUT" tokens.
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.
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This field is mandatory.
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.
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.Pp
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.Fa interval
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field selects the interrupt interval.
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.
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The value of this field is given in milliseconds and is independent of
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device speed.
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.
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Depending on the endpoint type, this field has different meaning:
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.Bl -tag
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.It UE_INTERRUPT
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"0" use the default interrupt interval based on endpoint descriptor.
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"Else" use the given value for polling rate.
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.It UE_ISOCHRONOUS
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"0" use default. "Else" the value is ignored.
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.It UE_BULK
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.It UE_CONTROL
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"0" no transfer pre-delay. "Else" a delay as given by this field in
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milliseconds is inserted before the hardware is started when
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"usbd_transfer_submit()" is called.
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.Pp
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NOTE: The transfer timeout, if any, is started after that the
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pre-delay has elapsed!
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.El
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.
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.Pp
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.Fa timeout
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field, if non-zero, will set the transfer timeout in milliseconds. If
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the "timeout" field is zero and the transfer type is ISOCHRONOUS a
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timeout of 250ms will be used.
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.
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.Pp
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.Fa frames
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field sets the maximum number of frames. If zero is specified it will
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yield the following results:
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.Bl -tag
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.It UE_BULK
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xfer->nframes = 1;
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.It UE_INTERRUPT
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xfer->nframes = 1;
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.It UE_CONTROL
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xfer->nframes = 2;
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.It UE_ISOCHRONOUS
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Not allowed. Will cause an error.
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.El
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.
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.Pp
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.Fa ep_index
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field allows you to give a number, in case more endpoints match the
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description, that selects which matching "ep_index" should be used.
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.
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.Pp
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.Fa if_index
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|
field allows you to select which of the interface numbers in the
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"ifaces" array parameter passed to "usbd_transfer_setup" that should
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be used when setting up the given USB transfer.
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.
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.Pp
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.Fa flags
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field has type "struct usb_xfer_flags" and allows one to set initial
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flags an USB transfer. Valid flags are:
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.Bl -tag
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.It force_short_xfer
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This flag forces the last transmitted USB packet to be short. A short
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packet has a length of less than "xfer->max_packet_size", which
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derives from "wMaxPacketSize". This flag can be changed during
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operation.
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.It short_xfer_ok
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|
This flag allows the received transfer length, "xfer->actlen" to be
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less than "xfer->sumlen" upon completion of a transfer. This flag can
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be changed during operation.
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.It short_frames_ok
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|
This flag allows the reception of multiple short USB frames. This flag
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only has effect for BULK and INTERRUPT endpoints and if the number of
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frames received is greater than 1. This flag can be changed during
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operation.
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.It pipe_bof
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|
This flag causes a failing USB transfer to remain first in the PIPE
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queue except in the case of "xfer->error" equal to
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"USB_ERR_CANCELLED". No other USB transfers in the affected PIPE queue
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will be started until either:
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.Bl -tag
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.It 1
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The failing USB transfer is stopped using "usbd_transfer_stop()".
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.It 2
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The failing USB transfer performs a successful transfer.
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.El
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|
The purpose of this flag is to avoid races when multiple transfers are
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queued for execution on an USB endpoint, and the first executing
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transfer fails leading to the need for clearing of stall for
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example.
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.
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In this case this flag is used to prevent the following USB transfers
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from being executed at the same time the clear-stall command is
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executed on the USB control endpoint.
|
|
.
|
|
This flag can be changed during operation.
|
|
.Pp
|
|
"BOF" is short for "Block On Failure"
|
|
.Pp
|
|
NOTE: This flag should be set on all BULK and INTERRUPT USB transfers
|
|
which use an endpoint that can be shared between userland and kernel.
|
|
.
|
|
.
|
|
.It proxy_buffer
|
|
Setting this flag will cause that the total buffer size will be
|
|
rounded up to the nearest atomic hardware transfer size.
|
|
.
|
|
The maximum data length of any USB transfer is always stored in the
|
|
"xfer->max_data_length".
|
|
.
|
|
For control transfers the USB kernel will allocate additional space
|
|
for the 8-bytes of SETUP header.
|
|
.
|
|
These 8-bytes are not counted by the "xfer->max_data_length"
|
|
variable.
|
|
.
|
|
This flag can not be changed during operation.
|
|
.
|
|
.
|
|
.It ext_buffer
|
|
Setting this flag will cause that no data buffer will be
|
|
allocated.
|
|
.
|
|
Instead the USB client must supply a data buffer.
|
|
.
|
|
This flag can not be changed during operation.
|
|
.
|
|
.
|
|
.It manual_status
|
|
Setting this flag prevents an USB STATUS stage to be appended to the
|
|
end of the USB control transfer.
|
|
.
|
|
If no control data is transferred this flag must be cleared.
|
|
.
|
|
Else an error will be returned to the USB callback.
|
|
.
|
|
This flag is mostly useful for the USB device side.
|
|
.
|
|
This flag can be changed during operation.
|
|
.
|
|
.
|
|
.It no_pipe_ok
|
|
Setting this flag causes the USB_ERR_NO_PIPE error to be ignored. This
|
|
flag can not be changed during operation.
|
|
.
|
|
.
|
|
.It stall_pipe
|
|
.Bl -tag
|
|
.It Device Side Mode
|
|
Setting this flag will cause STALL pids to be sent to the endpoint
|
|
belonging to this transfer before the transfer is started.
|
|
.
|
|
The transfer is started at the moment the host issues a clear-stall
|
|
command on the STALL'ed endpoint.
|
|
.
|
|
This flag can be changed during operation.
|
|
.It Host Side Mode
|
|
Setting this flag will cause a clear-stall control request to be
|
|
executed on the endpoint before the USB transfer is started.
|
|
.El
|
|
.Pp
|
|
If this flag is changed outside the USB callback function you have to
|
|
use the "usbd_xfer_set_stall()" and "usbd_transfer_clear_stall()"
|
|
functions! This flag is automatically cleared after that the stall or
|
|
clear stall has been executed.
|
|
.
|
|
.It pre_scale_frames
|
|
If this flag is set the number of frames specified is assumed to give the buffering time in milliseconds instead of frames.
|
|
During transfer setup the frames field is pre scaled with the corresponding value for the endpoint and rounded to the nearest number of frames greater than zero.
|
|
This option only has effect for ISOCHRONOUS transfers.
|
|
.El
|
|
.Pp
|
|
.Fa bufsize
|
|
field sets the total buffer size in bytes.
|
|
.
|
|
If this field is zero, "wMaxPacketSize" will be used, multiplied by
|
|
the "frames" field if the transfer type is ISOCHRONOUS.
|
|
.
|
|
This is useful for setting up interrupt pipes.
|
|
.
|
|
This field is mandatory.
|
|
.Pp
|
|
NOTE: For control transfers "bufsize" includes the length of the
|
|
request structure.
|
|
.
|
|
.Pp
|
|
.Fa callback
|
|
pointer sets the USB callback. This field is mandatory.
|
|
.
|
|
.
|
|
.Sh USB LINUX COMPAT LAYER
|
|
The
|
|
.Nm usb
|
|
module supports the Linux USB API.
|
|
.
|
|
.
|
|
.Sh SEE ALSO
|
|
.Xr libusb 3 ,
|
|
.Xr usb 4 ,
|
|
.Xr usbconfig 8
|
|
.Sh STANDARDS
|
|
The
|
|
.Nm usb
|
|
module complies with the USB 2.0 standard.
|
|
.Sh HISTORY
|
|
The
|
|
.Nm usb
|
|
module has been inspired by the NetBSD USB stack initially written by
|
|
Lennart Augustsson. The
|
|
.Nm usb
|
|
module was written by
|
|
.An Hans Petter Selasky Aq hselasky@FreeBSD.org .
|