kingsun-sir.c

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/*****************************************************************************
*
* Filename:      kingsun-sir.c
* Version:       0.1.1
* Description:   Irda KingSun/DonShine USB Dongle
* Status:        Experimental
* Author:        Alex Villacís Lasso <[email protected]>
*
*   Based on stir4200 and mcs7780 drivers, with (strange?) differences
*
*   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.
*
*   This program is distributed in the hope that it will be useful,
*   but WITHOUT ANY WARRANTY; without even the implied warranty of
*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*   GNU General Public License for more details.
*
*   You should have received a copy of the GNU General Public License
*   along with this program; if not, write to the Free Software
*   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*****************************************************************************/

/*
 * This is my current (2007-04-25) understanding of how this dongle is supposed
 * to work. This is based on reverse-engineering and examination of the packet
 * data sent and received by the WinXP driver using USBSnoopy. Feel free to
 * update here as more of this dongle is known:
 *
 * General: Unlike the other USB IrDA dongles, this particular dongle exposes,
 * not two bulk (in and out) endpoints, but two *interrupt* ones. This dongle,
 * like the bulk based ones (stir4200.c and mcs7780.c), requires polling in
 * order to receive data.
 * Transmission: Just like stir4200, this dongle uses a raw stream of data,
 * which needs to be wrapped and escaped in a similar way as in stir4200.c.
 * Reception: Poll-based, as in stir4200. Each read returns the contents of a
 * 8-byte buffer, of which the first byte (LSB) indicates the number of bytes
 * (1-7) of valid data contained within the remaining 7 bytes. For example, if
 * the buffer had the following contents:
 *  06 ff ff ff c0 01 04 aa
 * This means that (06) there are 6 bytes of valid data. The byte 0xaa at the
 * end is garbage (left over from a previous reception) and is discarded.
 * If a read returns an "impossible" value as the length of valid data (such as
 * 0x36) in the first byte, then the buffer is uninitialized (as is the case of
 * first plug-in) and its contents should be discarded. There is currently no
 * evidence that the top 5 bits of the 1st byte of the buffer can have values
 * other than 0 once reception begins.
 * Once valid bytes are collected, the assembled stream is a sequence of
 * wrapped IrDA frames that is unwrapped and unescaped as in stir4200.c.
 * BIG FAT WARNING: the dongle does *not* reset the RX buffer in any way after
 * a successful read from the host, which means that in absence of further
 * reception, repeated reads from the dongle will return the exact same
 * contents repeatedly. Attempts to be smart and cache a previous read seem
 * to result in corrupted packets, so this driver depends on the unwrap logic
 * to sort out any repeated reads.
 * Speed change: no commands observed so far to change speed, assumed fixed
 * 9600bps (SIR).
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/device.h>
#include <linux/crc32.h>

#include <asm/unaligned.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>

#include <net/irda/irda.h>
#include <net/irda/wrapper.h>
#include <net/irda/crc.h>

/*
 * According to lsusb, 0x07c0 is assigned to
 * "Code Mercenaries Hard- und Software GmbH"
 */
#define KING_VENDOR_ID 0x07c0
#define KING_PRODUCT_ID 0x4200

/* These are the currently known USB ids */
static struct usb_device_id dongles[] = {
    /* KingSun Co,Ltd  IrDA/USB Bridge */
    { USB_DEVICE(KING_VENDOR_ID, KING_PRODUCT_ID) },
    { }
};

MODULE_DEVICE_TABLE(usb, dongles);

#define KINGSUN_MTT 0x07

#define KINGSUN_FIFO_SIZE       4096
#define KINGSUN_EP_IN           0
#define KINGSUN_EP_OUT          1

struct kingsun_cb {
    struct usb_device *usbdev;      /* init: probe_irda */
    struct net_device *netdev;      /* network layer */
    struct irlap_cb   *irlap;       /* The link layer we are binded to */

    struct qos_info   qos;

    __u8          *in_buf;  /* receive buffer */
    __u8          *out_buf; /* transmit buffer */
    __u8          max_rx;   /* max. atomic read from dongle
                       (usually 8), also size of in_buf */
    __u8          max_tx;   /* max. atomic write to dongle
                       (usually 8) */

    iobuff_t      rx_buff;  /* receive unwrap state machine */
    struct timeval    rx_time;
    spinlock_t lock;
    int receiving;

    __u8 ep_in;
    __u8 ep_out;

    struct urb   *tx_urb;
    struct urb   *rx_urb;
};

/* Callback transmission routine */
static void kingsun_send_irq(struct urb *urb)
{
    struct kingsun_cb *kingsun = urb->context;
    struct net_device *netdev = kingsun->netdev;

    /* in process of stopping, just drop data */
    if (!netif_running(kingsun->netdev)) {
        dev_err(&kingsun->usbdev->dev,
            "kingsun_send_irq: Network not running!\n");
        return;
    }

    /* unlink, shutdown, unplug, other nasties */
    if (urb->status != 0) {
        dev_err(&kingsun->usbdev->dev,
            "kingsun_send_irq: urb asynchronously failed - %d\n",
            urb->status);
    }
    netif_wake_queue(netdev);
}

/*
 * Called from net/core when new frame is available.
 */
static netdev_tx_t kingsun_hard_xmit(struct sk_buff *skb,
                       struct net_device *netdev)
{
    struct kingsun_cb *kingsun;
    int wraplen;
    int ret = 0;

    netif_stop_queue(netdev);

    /* the IRDA wrapping routines don't deal with non linear skb */
    SKB_LINEAR_ASSERT(skb);

    kingsun = netdev_priv(netdev);

    spin_lock(&kingsun->lock);

    /* Append data to the end of whatever data remains to be transmitted */
    wraplen = async_wrap_skb(skb,
        kingsun->out_buf,
        KINGSUN_FIFO_SIZE);

    /* Calculate how much data can be transmitted in this urb */
    usb_fill_int_urb(kingsun->tx_urb, kingsun->usbdev,
        usb_sndintpipe(kingsun->usbdev, kingsun->ep_out),
        kingsun->out_buf, wraplen, kingsun_send_irq,
        kingsun, 1);

    if ((ret = usb_submit_urb(kingsun->tx_urb, GFP_ATOMIC))) {
        dev_err(&kingsun->usbdev->dev,
            "kingsun_hard_xmit: failed tx_urb submit: %d\n", ret);
        switch (ret) {
        case -ENODEV:
        case -EPIPE:
            break;
        default:
            netdev->stats.tx_errors++;
            netif_start_queue(netdev);
        }
    } else {
        netdev->stats.tx_packets++;
        netdev->stats.tx_bytes += skb->len;
    }

    dev_kfree_skb(skb);
    spin_unlock(&kingsun->lock);

    return NETDEV_TX_OK;
}

/* Receive callback function */
static void kingsun_rcv_irq(struct urb *urb)
{
    struct kingsun_cb *kingsun = urb->context;
    int ret;

    /* in process of stopping, just drop data */
    if (!netif_running(kingsun->netdev)) {
        kingsun->receiving = 0;
        return;
    }

    /* unlink, shutdown, unplug, other nasties */
    if (urb->status != 0) {
        dev_err(&kingsun->usbdev->dev,
            "kingsun_rcv_irq: urb asynchronously failed - %d\n",
            urb->status);
        kingsun->receiving = 0;
        return;
    }

    if (urb->actual_length == kingsun->max_rx) {
        __u8 *bytes = urb->transfer_buffer;
        int i;

        /* The very first byte in the buffer indicates the length of
           valid data in the read. This byte must be in the range
           1..kingsun->max_rx -1 . Values outside this range indicate
           an uninitialized Rx buffer when the dongle has just been
           plugged in. */
        if (bytes[0] >= 1 && bytes[0] < kingsun->max_rx) {
            for (i = 1; i <= bytes[0]; i++) {
                async_unwrap_char(kingsun->netdev,
                          &kingsun->netdev->stats,
                          &kingsun->rx_buff, bytes[i]);
            }
            do_gettimeofday(&kingsun->rx_time);
            kingsun->receiving =
                (kingsun->rx_buff.state != OUTSIDE_FRAME)
                ? 1 : 0;
        }
    } else if (urb->actual_length > 0) {
        dev_err(&kingsun->usbdev->dev,
            "%s(): Unexpected response length, expected %d got %d\n",
            __func__, kingsun->max_rx, urb->actual_length);
    }
    /* This urb has already been filled in kingsun_net_open */
    ret = usb_submit_urb(urb, GFP_ATOMIC);
}

/*
 * Function kingsun_net_open (dev)
 *
 *    Network device is taken up. Usually this is done by "ifconfig irda0 up"
 */
static int kingsun_net_open(struct net_device *netdev)
{
    struct kingsun_cb *kingsun = netdev_priv(netdev);
    int err = -ENOMEM;
    char hwname[16];

    /* At this point, urbs are NULL, and skb is NULL (see kingsun_probe) */
    kingsun->receiving = 0;

    /* Initialize for SIR to copy data directly into skb.  */
    kingsun->rx_buff.in_frame = FALSE;
    kingsun->rx_buff.state = OUTSIDE_FRAME;
    kingsun->rx_buff.truesize = IRDA_SKB_MAX_MTU;
    kingsun->rx_buff.skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
    if (!kingsun->rx_buff.skb)
        goto free_mem;

    skb_reserve(kingsun->rx_buff.skb, 1);
    kingsun->rx_buff.head = kingsun->rx_buff.skb->data;
    do_gettimeofday(&kingsun->rx_time);

    kingsun->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
    if (!kingsun->rx_urb)
        goto free_mem;

    kingsun->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
    if (!kingsun->tx_urb)
        goto free_mem;

    /*
     * Now that everything should be initialized properly,
     * Open new IrLAP layer instance to take care of us...
     */
    sprintf(hwname, "usb#%d", kingsun->usbdev->devnum);
    kingsun->irlap = irlap_open(netdev, &kingsun->qos, hwname);
    if (!kingsun->irlap) {
        dev_err(&kingsun->usbdev->dev, "irlap_open failed\n");
        goto free_mem;
    }

    /* Start first reception */
    usb_fill_int_urb(kingsun->rx_urb, kingsun->usbdev,
              usb_rcvintpipe(kingsun->usbdev, kingsun->ep_in),
              kingsun->in_buf, kingsun->max_rx,
              kingsun_rcv_irq, kingsun, 1);
    kingsun->rx_urb->status = 0;
    err = usb_submit_urb(kingsun->rx_urb, GFP_KERNEL);
    if (err) {
        dev_err(&kingsun->usbdev->dev,
            "first urb-submit failed: %d\n", err);
        goto close_irlap;
    }

    netif_start_queue(netdev);

    /* Situation at this point:
       - all work buffers allocated
       - urbs allocated and ready to fill
       - max rx packet known (in max_rx)
       - unwrap state machine initialized, in state outside of any frame
       - receive request in progress
       - IrLAP layer started, about to hand over packets to send
     */

    return 0;

 close_irlap:
    irlap_close(kingsun->irlap);
 free_mem:
    if (kingsun->tx_urb) {
        usb_free_urb(kingsun->tx_urb);
        kingsun->tx_urb = NULL;
    }
    if (kingsun->rx_urb) {
        usb_free_urb(kingsun->rx_urb);
        kingsun->rx_urb = NULL;
    }
    if (kingsun->rx_buff.skb) {
        kfree_skb(kingsun->rx_buff.skb);
        kingsun->rx_buff.skb = NULL;
        kingsun->rx_buff.head = NULL;
    }
    return err;
}

/*
 * Function kingsun_net_close (kingsun)
 *
 *    Network device is taken down. Usually this is done by
 *    "ifconfig irda0 down"
 */
static int kingsun_net_close(struct net_device *netdev)
{
    struct kingsun_cb *kingsun = netdev_priv(netdev);

    /* Stop transmit processing */
    netif_stop_queue(netdev);

    /* Mop up receive && transmit urb's */
    usb_kill_urb(kingsun->tx_urb);
    usb_kill_urb(kingsun->rx_urb);

    usb_free_urb(kingsun->tx_urb);
    usb_free_urb(kingsun->rx_urb);

    kingsun->tx_urb = NULL;
    kingsun->rx_urb = NULL;

    kfree_skb(kingsun->rx_buff.skb);
    kingsun->rx_buff.skb = NULL;
    kingsun->rx_buff.head = NULL;
    kingsun->rx_buff.in_frame = FALSE;
    kingsun->rx_buff.state = OUTSIDE_FRAME;
    kingsun->receiving = 0;

    /* Stop and remove instance of IrLAP */
    if (kingsun->irlap)
        irlap_close(kingsun->irlap);

    kingsun->irlap = NULL;

    return 0;
}

/*
 * IOCTLs : Extra out-of-band network commands...
 */
static int kingsun_net_ioctl(struct net_device *netdev, struct ifreq *rq,
                 int cmd)
{
    struct if_irda_req *irq = (struct if_irda_req *) rq;
    struct kingsun_cb *kingsun = netdev_priv(netdev);
    int ret = 0;

    switch (cmd) {
    case SIOCSBANDWIDTH: /* Set bandwidth */
        if (!capable(CAP_NET_ADMIN))
            return -EPERM;

        /* Check if the device is still there */
        if (netif_device_present(kingsun->netdev))
            /* No observed commands for speed change */
            ret = -EOPNOTSUPP;
        break;

    case SIOCSMEDIABUSY: /* Set media busy */
        if (!capable(CAP_NET_ADMIN))
            return -EPERM;

        /* Check if the IrDA stack is still there */
        if (netif_running(kingsun->netdev))
            irda_device_set_media_busy(kingsun->netdev, TRUE);
        break;

    case SIOCGRECEIVING:
        /* Only approximately true */
        irq->ifr_receiving = kingsun->receiving;
        break;

    default:
        ret = -EOPNOTSUPP;
    }

    return ret;
}

static const struct net_device_ops kingsun_ops = {
    .ndo_start_xmit      = kingsun_hard_xmit,
    .ndo_open            = kingsun_net_open,
    .ndo_stop            = kingsun_net_close,
    .ndo_do_ioctl        = kingsun_net_ioctl,
};

/*
 * This routine is called by the USB subsystem for each new device
 * in the system. We need to check if the device is ours, and in
 * this case start handling it.
 */
static int kingsun_probe(struct usb_interface *intf,
              const struct usb_device_id *id)
{
    struct usb_host_interface *interface;
    struct usb_endpoint_descriptor *endpoint;

    struct usb_device *dev = interface_to_usbdev(intf);
    struct kingsun_cb *kingsun = NULL;
    struct net_device *net = NULL;
    int ret = -ENOMEM;
    int pipe, maxp_in, maxp_out;
    __u8 ep_in;
    __u8 ep_out;

    /* Check that there really are two interrupt endpoints.
       Check based on the one in drivers/usb/input/usbmouse.c
     */
    interface = intf->cur_altsetting;
    if (interface->desc.bNumEndpoints != 2) {
        dev_err(&intf->dev,
            "kingsun-sir: expected 2 endpoints, found %d\n",
            interface->desc.bNumEndpoints);
        return -ENODEV;
    }
    endpoint = &interface->endpoint[KINGSUN_EP_IN].desc;
    if (!usb_endpoint_is_int_in(endpoint)) {
        dev_err(&intf->dev,
            "kingsun-sir: endpoint 0 is not interrupt IN\n");
        return -ENODEV;
    }

    ep_in = endpoint->bEndpointAddress;
    pipe = usb_rcvintpipe(dev, ep_in);
    maxp_in = usb_maxpacket(dev, pipe, usb_pipeout(pipe));
    if (maxp_in > 255 || maxp_in <= 1) {
        dev_err(&intf->dev,
            "endpoint 0 has max packet size %d not in range\n",
            maxp_in);
        return -ENODEV;
    }

    endpoint = &interface->endpoint[KINGSUN_EP_OUT].desc;
    if (!usb_endpoint_is_int_out(endpoint)) {
        dev_err(&intf->dev,
            "kingsun-sir: endpoint 1 is not interrupt OUT\n");
        return -ENODEV;
    }

    ep_out = endpoint->bEndpointAddress;
    pipe = usb_sndintpipe(dev, ep_out);
    maxp_out = usb_maxpacket(dev, pipe, usb_pipeout(pipe));

    /* Allocate network device container. */
    net = alloc_irdadev(sizeof(*kingsun));
    if(!net)
        goto err_out1;

    SET_NETDEV_DEV(net, &intf->dev);
    kingsun = netdev_priv(net);
    kingsun->irlap = NULL;
    kingsun->tx_urb = NULL;
    kingsun->rx_urb = NULL;
    kingsun->ep_in = ep_in;
    kingsun->ep_out = ep_out;
    kingsun->in_buf = NULL;
    kingsun->out_buf = NULL;
    kingsun->max_rx = (__u8)maxp_in;
    kingsun->max_tx = (__u8)maxp_out;
    kingsun->netdev = net;
    kingsun->usbdev = dev;
    kingsun->rx_buff.in_frame = FALSE;
    kingsun->rx_buff.state = OUTSIDE_FRAME;
    kingsun->rx_buff.skb = NULL;
    kingsun->receiving = 0;
    spin_lock_init(&kingsun->lock);

    /* Allocate input buffer */
    kingsun->in_buf = kmalloc(kingsun->max_rx, GFP_KERNEL);
    if (!kingsun->in_buf)
        goto free_mem;

    /* Allocate output buffer */
    kingsun->out_buf = kmalloc(KINGSUN_FIFO_SIZE, GFP_KERNEL);
    if (!kingsun->out_buf)
        goto free_mem;

    printk(KERN_INFO "KingSun/DonShine IRDA/USB found at address %d, "
        "Vendor: %x, Product: %x\n",
           dev->devnum, le16_to_cpu(dev->descriptor.idVendor),
           le16_to_cpu(dev->descriptor.idProduct));

    /* Initialize QoS for this device */
    irda_init_max_qos_capabilies(&kingsun->qos);

    /* That's the Rx capability. */
    kingsun->qos.baud_rate.bits       &= IR_9600;
    kingsun->qos.min_turn_time.bits   &= KINGSUN_MTT;
    irda_qos_bits_to_value(&kingsun->qos);

    /* Override the network functions we need to use */
    net->netdev_ops = &kingsun_ops;

    ret = register_netdev(net);
    if (ret != 0)
        goto free_mem;

    dev_info(&net->dev, "IrDA: Registered KingSun/DonShine device %s\n",
         net->name);

    usb_set_intfdata(intf, kingsun);

    /* Situation at this point:
       - all work buffers allocated
       - urbs not allocated, set to NULL
       - max rx packet known (in max_rx)
       - unwrap state machine (partially) initialized, but skb == NULL
     */

    return 0;

free_mem:
    if (kingsun->out_buf) kfree(kingsun->out_buf);
    if (kingsun->in_buf) kfree(kingsun->in_buf);
    free_netdev(net);
err_out1:
    return ret;
}

/*
 * The current device is removed, the USB layer tell us to shut it down...
 */
static void kingsun_disconnect(struct usb_interface *intf)
{
    struct kingsun_cb *kingsun = usb_get_intfdata(intf);

    if (!kingsun)
        return;

    unregister_netdev(kingsun->netdev);

    /* Mop up receive && transmit urb's */
    if (kingsun->tx_urb != NULL) {
        usb_kill_urb(kingsun->tx_urb);
        usb_free_urb(kingsun->tx_urb);
        kingsun->tx_urb = NULL;
    }
    if (kingsun->rx_urb != NULL) {
        usb_kill_urb(kingsun->rx_urb);
        usb_free_urb(kingsun->rx_urb);
        kingsun->rx_urb = NULL;
    }

    kfree(kingsun->out_buf);
    kfree(kingsun->in_buf);
    free_netdev(kingsun->netdev);

    usb_set_intfdata(intf, NULL);
}

#ifdef CONFIG_PM
/* USB suspend, so power off the transmitter/receiver */
static int kingsun_suspend(struct usb_interface *intf, pm_message_t message)
{
    struct kingsun_cb *kingsun = usb_get_intfdata(intf);

    netif_device_detach(kingsun->netdev);
    if (kingsun->tx_urb != NULL) usb_kill_urb(kingsun->tx_urb);
    if (kingsun->rx_urb != NULL) usb_kill_urb(kingsun->rx_urb);
    return 0;
}

/* Coming out of suspend, so reset hardware */
static int kingsun_resume(struct usb_interface *intf)
{
    struct kingsun_cb *kingsun = usb_get_intfdata(intf);

    if (kingsun->rx_urb != NULL)
        usb_submit_urb(kingsun->rx_urb, GFP_KERNEL);
    netif_device_attach(kingsun->netdev);

    return 0;
}
#endif

/*
 * USB device callbacks
 */
static struct usb_driver irda_driver = {
    .name       = "kingsun-sir",
    .probe      = kingsun_probe,
    .disconnect = kingsun_disconnect,
    .id_table   = dongles,
#ifdef CONFIG_PM
    .suspend    = kingsun_suspend,
    .resume     = kingsun_resume,
#endif
};

module_usb_driver(irda_driver);

MODULE_AUTHOR("Alex Villacís Lasso <[email protected]>");
MODULE_DESCRIPTION("IrDA-USB Dongle Driver for KingSun/DonShine");
MODULE_LICENSE("GPL");