usb_debug.c

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/*
 * USB Debug cable driver
 *
 * Copyright (C) 2006 Greg Kroah-Hartman <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License version
 *  2 as published by the Free Software Foundation.
 */

#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>

#define USB_DEBUG_MAX_PACKET_SIZE   8
#define USB_DEBUG_BRK_SIZE      8
static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
    0x00,
    0xff,
    0x01,
    0xfe,
    0x00,
    0xfe,
    0x01,
    0xff,
};

static const struct usb_device_id id_table[] = {
    { USB_DEVICE(0x0525, 0x127a) },
    { },
};
MODULE_DEVICE_TABLE(usb, id_table);

/* This HW really does not support a serial break, so one will be
 * emulated when ever the break state is set to true.
 */
static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
{
    struct usb_serial_port *port = tty->driver_data;
    if (!break_state)
        return;
    usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
}

static void usb_debug_process_read_urb(struct urb *urb)
{
    struct usb_serial_port *port = urb->context;

    if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
        memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
                        USB_DEBUG_BRK_SIZE) == 0) {
        usb_serial_handle_break(port);
        return;
    }

    usb_serial_generic_process_read_urb(urb);
}

static struct usb_serial_driver debug_device = {
    .driver = {
        .owner =    THIS_MODULE,
        .name =     "debug",
    },
    .id_table =     id_table,
    .num_ports =        1,
    .bulk_out_size =    USB_DEBUG_MAX_PACKET_SIZE,
    .break_ctl =        usb_debug_break_ctl,
    .process_read_urb = usb_debug_process_read_urb,
};

static struct usb_serial_driver * const serial_drivers[] = {
    &debug_device, NULL
};

module_usb_serial_driver(serial_drivers, id_table);
MODULE_LICENSE("GPL");