/*
 * USB IR Dongle driver
 *
 *      Copyright (C) 2001-2002 Greg Kroah-Hartman (greg@kroah.com)
 *      Copyright (C) 2002      Gary Brubaker (xavyer@ix.netcom.com)
 *      Copyright (C) 2010      Johan Hovold (jhovold@gmail.com)
 *
 *      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 <weissg@vienna.at>, Dag Brattli
 * <dag@brattli.net>, and Jean Tourrilhes <jt@hpl.hp.com>
 *
 * See Documentation/usb/usb-serial.txt for more information on using this
 * driver
 *
 * 2008_Jun_02  Felipe Balbi <me@felipebalbi.com>
 *      Introduced common header to be used also in USB Gadget Framework.
 *      Still needs some other style fixes.
 *
 * 2007_Jun_21  Alan Cox <alan@lxorguk.ukuu.org.uk>
 *      Minimal cleanups for some of the driver problens and tty layer abuse.
 *      Still needs fixing to allow multiple dongles.
 *
 * 2002_Mar_07  greg kh
 *      moved some needed structures and #define values from the
 *      net/irda/irda-usb.h file into our file, as we don't want to depend on
 *      that codebase compiling correctly :)
 *
 * 2002_Jan_14  gb
 *      Added module parameter to force specific number of XBOFs.
 *      Added ir_xbof_change().
 *      Reorganized read_bulk_callback error handling.
 *      Switched from FILL_BULK_URB() to usb_fill_bulk_urb().
 *
 * 2001_Nov_08  greg kh
 *      Changed the irda_usb_find_class_desc() function based on comments and
 *      code from Martin Diehl.
 *
 * 2001_Nov_01  greg kh
 *      Added support for more IrDA USB devices.
 *      Added support for zero packet.  Added buffer override paramater, so
 *      users can transfer larger packets at once if they wish.  Both patches
 *      came from Dag Brattli <dag@obexcode.com>.
 *
 * 2001_Oct_07  greg kh
 *      initial version released.
 */

#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>

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.5"
#define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>, Johan Hovold <jhovold@gmail.com>"
#define DRIVER_DESC "USB IR Dongle driver"

static int debug;

/* 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_driver ir_driver = {
        .name           = "ir-usb",
        .probe          = usb_serial_probe,
        .disconnect     = usb_serial_disconnect,
        .id_table       = ir_id_table,
        .no_dynamic_id  = 1,
};

static struct usb_serial_driver ir_device = {
        .driver = {
                .owner  = THIS_MODULE,
                .name   = "ir-usb",
        },
        .description            = "IR Dongle",
        .usb_driver             = &ir_driver,
        .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 inline void irda_usb_dump_class_desc(struct usb_irda_cs_descriptor *desc)
{
        dbg("bLength=%x", desc->bLength);
        dbg("bDescriptorType=%x", desc->bDescriptorType);
        dbg("bcdSpecRevision=%x", __le16_to_cpu(desc->bcdSpecRevision));
        dbg("bmDataSize=%x", desc->bmDataSize);
        dbg("bmWindowSize=%x", desc->bmWindowSize);
        dbg("bmMinTurnaroundTime=%d", desc->bmMinTurnaroundTime);
        dbg("wBaudRate=%x", __le16_to_cpu(desc->wBaudRate));
        dbg("bmAdditionalBOFs=%x", desc->bmAdditionalBOFs);
        dbg("bIrdaRateSniff=%x", desc->bIrdaRateSniff);
        dbg("bMaxUnicastList=%x", 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_device *dev, unsigned int ifnum)
{
        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);

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

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

        dbg("%s - Baud rates supported:%s%s%s%s%s%s%s%s%s",
                __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;

        dbg("%s - port %d", __func__, port->number);

        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)
{
        struct usb_serial_port *port = urb->context;
        int status = urb->status;

        dbg("%s - port %d", __func__, port->number);

        kfree(urb->transfer_buffer);

        if (status)
                dbg("%s - non-zero urb status: %d", __func__, 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;

        dbg("%s - port %d", __func__, port->number);

        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)
{
        int retval;

        if (buffer_size) {
                ir_device.bulk_in_size = buffer_size;
                ir_device.bulk_out_size = buffer_size;
        }

        retval = usb_serial_register(&ir_device);
        if (retval)
                goto failed_usb_serial_register;

        retval = usb_register(&ir_driver);
        if (retval)
                goto failed_usb_register;

        printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
               DRIVER_DESC "\n");

        return 0;

failed_usb_register:
        usb_serial_deregister(&ir_device);

failed_usb_serial_register:
        return retval;
}

static void __exit ir_exit(void)
{
        usb_deregister(&ir_driver);
        usb_serial_deregister(&ir_device);
}


module_init(ir_init);
module_exit(ir_exit);

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

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
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");