ir-usb.c

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/*
 * USB IR Dongle driver
 *
 *  Copyright (C) 2001-2002 Greg Kroah-Hartman ([email protected])
 *  Copyright (C) 2002  Gary Brubaker ([email protected])
 *  Copyright (C) 2010  Johan Hovold ([email protected])
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 * This driver allows a USB IrDA device to be used as a "dumb" serial device.
 * This can be useful if you do not have access to a full IrDA stack on the
 * other side of the connection.  If you do have an IrDA stack on both devices,
 * please use the usb-irda driver, as it contains the proper error checking and
 * other goodness of a full IrDA stack.
 *
 * Portions of this driver were taken from drivers/net/irda/irda-usb.c, which
 * was written by Roman Weissgaerber <[email protected]>, Dag Brattli
 * <[email protected]>, and Jean Tourrilhes <[email protected]>
 *
 * See Documentation/usb/usb-serial.txt for more information on using this
 * driver
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/usb/irda.h>

#define DRIVER_AUTHOR "Greg Kroah-Hartman <[email protected]>, Johan Hovold <[email protected]>"
#define DRIVER_DESC "USB IR Dongle driver"

/* if overridden by the user, then use their value for the size of the read and
 * write urbs */
static int buffer_size;

/* if overridden by the user, then use the specified number of XBOFs */
static int xbof = -1;

static int  ir_startup (struct usb_serial *serial);
static int  ir_open(struct tty_struct *tty, struct usb_serial_port *port);
static int ir_prepare_write_buffer(struct usb_serial_port *port,
                        void *dest, size_t size);
static void ir_process_read_urb(struct urb *urb);
static void ir_set_termios(struct tty_struct *tty,
        struct usb_serial_port *port, struct ktermios *old_termios);

/* Not that this lot means you can only have one per system */
static u8 ir_baud;
static u8 ir_xbof;
static u8 ir_add_bof;

static const struct usb_device_id ir_id_table[] = {
    { USB_DEVICE(0x050f, 0x0180) },     /* KC Technology, KC-180 */
    { USB_DEVICE(0x08e9, 0x0100) },     /* XTNDAccess */
    { USB_DEVICE(0x09c4, 0x0011) },     /* ACTiSys ACT-IR2000U */
    { USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, USB_SUBCLASS_IRDA, 0) },
    { }                 /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, ir_id_table);

static struct usb_serial_driver ir_device = {
    .driver = {
        .owner  = THIS_MODULE,
        .name   = "ir-usb",
    },
    .description        = "IR Dongle",
    .id_table       = ir_id_table,
    .num_ports      = 1,
    .set_termios        = ir_set_termios,
    .attach         = ir_startup,
    .open           = ir_open,
    .prepare_write_buffer   = ir_prepare_write_buffer,
    .process_read_urb   = ir_process_read_urb,
};

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

static inline void irda_usb_dump_class_desc(struct usb_serial *serial,
                        struct usb_irda_cs_descriptor *desc)
{
    struct device *dev = &serial->dev->dev;

    dev_dbg(dev, "bLength=%x\n", desc->bLength);
    dev_dbg(dev, "bDescriptorType=%x\n", desc->bDescriptorType);
    dev_dbg(dev, "bcdSpecRevision=%x\n", __le16_to_cpu(desc->bcdSpecRevision));
    dev_dbg(dev, "bmDataSize=%x\n", desc->bmDataSize);
    dev_dbg(dev, "bmWindowSize=%x\n", desc->bmWindowSize);
    dev_dbg(dev, "bmMinTurnaroundTime=%d\n", desc->bmMinTurnaroundTime);
    dev_dbg(dev, "wBaudRate=%x\n", __le16_to_cpu(desc->wBaudRate));
    dev_dbg(dev, "bmAdditionalBOFs=%x\n", desc->bmAdditionalBOFs);
    dev_dbg(dev, "bIrdaRateSniff=%x\n", desc->bIrdaRateSniff);
    dev_dbg(dev, "bMaxUnicastList=%x\n", desc->bMaxUnicastList);
}

/*------------------------------------------------------------------*/
/*
 * Function irda_usb_find_class_desc(dev, ifnum)
 *
 *    Returns instance of IrDA class descriptor, or NULL if not found
 *
 * The class descriptor is some extra info that IrDA USB devices will
 * offer to us, describing their IrDA characteristics. We will use that in
 * irda_usb_init_qos()
 *
 * Based on the same function in drivers/net/irda/irda-usb.c
 */
static struct usb_irda_cs_descriptor *
irda_usb_find_class_desc(struct usb_serial *serial, unsigned int ifnum)
{
    struct usb_device *dev = serial->dev;
    struct usb_irda_cs_descriptor *desc;
    int ret;

    desc = kzalloc(sizeof(*desc), GFP_KERNEL);
    if (!desc)
        return NULL;

    ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
            USB_REQ_CS_IRDA_GET_CLASS_DESC,
            USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
            0, ifnum, desc, sizeof(*desc), 1000);

    dev_dbg(&serial->dev->dev, "%s -  ret=%d\n", __func__, ret);
    if (ret < sizeof(*desc)) {
        dev_dbg(&serial->dev->dev,
            "%s - class descriptor read %s (%d)\n", __func__,
            (ret < 0) ? "failed" : "too short", ret);
        goto error;
    }
    if (desc->bDescriptorType != USB_DT_CS_IRDA) {
        dev_dbg(&serial->dev->dev, "%s - bad class descriptor type\n",
            __func__);
        goto error;
    }

    irda_usb_dump_class_desc(serial, desc);
    return desc;

error:
    kfree(desc);
    return NULL;
}

static u8 ir_xbof_change(u8 xbof)
{
    u8 result;

    /* reference irda-usb.c */
    switch (xbof) {
    case 48:
        result = 0x10;
        break;
    case 28:
    case 24:
        result = 0x20;
        break;
    default:
    case 12:
        result = 0x30;
        break;
    case  5:
    case  6:
        result = 0x40;
        break;
    case  3:
        result = 0x50;
        break;
    case  2:
        result = 0x60;
        break;
    case  1:
        result = 0x70;
        break;
    case  0:
        result = 0x80;
        break;
    }

    return(result);
}

static int ir_startup(struct usb_serial *serial)
{
    struct usb_irda_cs_descriptor *irda_desc;

    irda_desc = irda_usb_find_class_desc(serial, 0);
    if (!irda_desc) {
        dev_err(&serial->dev->dev,
            "IRDA class descriptor not found, device not bound\n");
        return -ENODEV;
    }

    dev_dbg(&serial->dev->dev,
        "%s - Baud rates supported:%s%s%s%s%s%s%s%s%s\n",
        __func__,
        (irda_desc->wBaudRate & USB_IRDA_BR_2400) ? " 2400" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_9600) ? " 9600" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_19200) ? " 19200" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_38400) ? " 38400" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_57600) ? " 57600" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_115200) ? " 115200" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_576000) ? " 576000" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_1152000) ? " 1152000" : "",
        (irda_desc->wBaudRate & USB_IRDA_BR_4000000) ? " 4000000" : "");

    switch (irda_desc->bmAdditionalBOFs) {
    case USB_IRDA_AB_48:
        ir_add_bof = 48;
        break;
    case USB_IRDA_AB_24:
        ir_add_bof = 24;
        break;
    case USB_IRDA_AB_12:
        ir_add_bof = 12;
        break;
    case USB_IRDA_AB_6:
        ir_add_bof = 6;
        break;
    case USB_IRDA_AB_3:
        ir_add_bof = 3;
        break;
    case USB_IRDA_AB_2:
        ir_add_bof = 2;
        break;
    case USB_IRDA_AB_1:
        ir_add_bof = 1;
        break;
    case USB_IRDA_AB_0:
        ir_add_bof = 0;
        break;
    default:
        break;
    }

    kfree(irda_desc);

    return 0;
}

static int ir_open(struct tty_struct *tty, struct usb_serial_port *port)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
        port->write_urbs[i]->transfer_flags = URB_ZERO_PACKET;

    /* Start reading from the device */
    return usb_serial_generic_open(tty, port);
}

static int ir_prepare_write_buffer(struct usb_serial_port *port,
                        void *dest, size_t size)
{
    unsigned char *buf = dest;
    int count;

    /*
     * The first byte of the packet we send to the device contains an
     * inbound header which indicates an additional number of BOFs and
     * a baud rate change.
     *
     * See section 5.4.2.2 of the USB IrDA spec.
     */
    *buf = ir_xbof | ir_baud;

    count = kfifo_out_locked(&port->write_fifo, buf + 1, size - 1,
                                &port->lock);
    return count + 1;
}

static void ir_process_read_urb(struct urb *urb)
{
    struct usb_serial_port *port = urb->context;
    unsigned char *data = urb->transfer_buffer;
    struct tty_struct *tty;

    if (!urb->actual_length)
        return;
    /*
     * The first byte of the packet we get from the device
     * contains a busy indicator and baud rate change.
     * See section 5.4.1.2 of the USB IrDA spec.
     */
    if (*data & 0x0f)
        ir_baud = *data & 0x0f;

    if (urb->actual_length == 1)
        return;

    tty = tty_port_tty_get(&port->port);
    if (!tty)
        return;
    tty_insert_flip_string(tty, data + 1, urb->actual_length - 1);
    tty_flip_buffer_push(tty);
    tty_kref_put(tty);
}

static void ir_set_termios_callback(struct urb *urb)
{
    kfree(urb->transfer_buffer);

    if (urb->status)
        dev_dbg(&urb->dev->dev, "%s - non-zero urb status: %d\n",
            __func__, urb->status);
}

static void ir_set_termios(struct tty_struct *tty,
        struct usb_serial_port *port, struct ktermios *old_termios)
{
    struct urb *urb;
    unsigned char *transfer_buffer;
    int result;
    speed_t baud;
    int ir_baud;

    baud = tty_get_baud_rate(tty);

    /*
     * FIXME, we should compare the baud request against the
     * capability stated in the IR header that we got in the
     * startup function.
     */

    switch (baud) {
    case 2400:
        ir_baud = USB_IRDA_BR_2400;
        break;
    case 9600:
        ir_baud = USB_IRDA_BR_9600;
        break;
    case 19200:
        ir_baud = USB_IRDA_BR_19200;
        break;
    case 38400:
        ir_baud = USB_IRDA_BR_38400;
        break;
    case 57600:
        ir_baud = USB_IRDA_BR_57600;
        break;
    case 115200:
        ir_baud = USB_IRDA_BR_115200;
        break;
    case 576000:
        ir_baud = USB_IRDA_BR_576000;
        break;
    case 1152000:
        ir_baud = USB_IRDA_BR_1152000;
        break;
    case 4000000:
        ir_baud = USB_IRDA_BR_4000000;
        break;
    default:
        ir_baud = USB_IRDA_BR_9600;
        baud = 9600;
    }

    if (xbof == -1)
        ir_xbof = ir_xbof_change(ir_add_bof);
    else
        ir_xbof = ir_xbof_change(xbof) ;

    /* Only speed changes are supported */
    tty_termios_copy_hw(&tty->termios, old_termios);
    tty_encode_baud_rate(tty, baud, baud);

    /*
     * send the baud change out on an "empty" data packet
     */
    urb = usb_alloc_urb(0, GFP_KERNEL);
    if (!urb) {
        dev_err(&port->dev, "%s - no more urbs\n", __func__);
        return;
    }
    transfer_buffer = kmalloc(1, GFP_KERNEL);
    if (!transfer_buffer) {
        dev_err(&port->dev, "%s - out of memory\n", __func__);
        goto err_buf;
    }

    *transfer_buffer = ir_xbof | ir_baud;

    usb_fill_bulk_urb(
        urb,
        port->serial->dev,
        usb_sndbulkpipe(port->serial->dev,
            port->bulk_out_endpointAddress),
        transfer_buffer,
        1,
        ir_set_termios_callback,
        port);

    urb->transfer_flags = URB_ZERO_PACKET;

    result = usb_submit_urb(urb, GFP_KERNEL);
    if (result) {
        dev_err(&port->dev, "%s - failed to submit urb: %d\n",
                            __func__, result);
        goto err_subm;
    }

    usb_free_urb(urb);

    return;
err_subm:
    kfree(transfer_buffer);
err_buf:
    usb_free_urb(urb);
}

static int __init ir_init(void)
{
    if (buffer_size) {
        ir_device.bulk_in_size = buffer_size;
        ir_device.bulk_out_size = buffer_size;
    }

    return usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME, ir_id_table);
}

static void __exit ir_exit(void)
{
    usb_serial_deregister_drivers(serial_drivers);
}


module_init(ir_init);
module_exit(ir_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

module_param(xbof, int, 0);
MODULE_PARM_DESC(xbof, "Force specific number of XBOFs");
module_param(buffer_size, int, 0);
MODULE_PARM_DESC(buffer_size, "Size of the transfer buffers");