metro-usb.c

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/*
  Some of this code is credited to Linux USB open source files that are
  distributed with Linux.

  Copyright:    2007 Metrologic Instruments. All rights reserved.
  Copyright:    2011 Azimut Ltd. <http://azimutrzn.ru/>
*/

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

/* Version Information */
#define DRIVER_VERSION "v1.2.0.0"
#define DRIVER_DESC "Metrologic Instruments Inc. - USB-POS driver"

/* Product information. */
#define FOCUS_VENDOR_ID         0x0C2E
#define FOCUS_PRODUCT_ID_BI     0x0720
#define FOCUS_PRODUCT_ID_UNI        0x0700

#define METROUSB_SET_REQUEST_TYPE   0x40
#define METROUSB_SET_MODEM_CTRL_REQUEST 10
#define METROUSB_SET_BREAK_REQUEST  0x40
#define METROUSB_MCR_NONE       0x08    /* Deactivate DTR and RTS. */
#define METROUSB_MCR_RTS        0x0a    /* Activate RTS. */
#define METROUSB_MCR_DTR        0x09    /* Activate DTR. */
#define WDR_TIMEOUT         5000    /* default urb timeout. */

/* Private data structure. */
struct metrousb_private {
    spinlock_t lock;
    int throttled;
    unsigned long control_state;
};

/* Device table list. */
static struct usb_device_id id_table[] = {
    { USB_DEVICE(FOCUS_VENDOR_ID, FOCUS_PRODUCT_ID_BI) },
    { USB_DEVICE(FOCUS_VENDOR_ID, FOCUS_PRODUCT_ID_UNI) },
    { }, /* Terminating entry. */
};
MODULE_DEVICE_TABLE(usb, id_table);

/* UNI-Directional mode commands for device configure */
#define UNI_CMD_OPEN    0x80
#define UNI_CMD_CLOSE   0xFF

inline int metrousb_is_unidirectional_mode(struct usb_serial_port *port)
{
    __u16 product_id = le16_to_cpu(
        port->serial->dev->descriptor.idProduct);

    return product_id == FOCUS_PRODUCT_ID_UNI;
}

static int metrousb_send_unidirectional_cmd(u8 cmd, struct usb_serial_port *port)
{
    int ret;
    int actual_len;
    u8 *buffer_cmd = NULL;

    if (!metrousb_is_unidirectional_mode(port))
        return 0;

    buffer_cmd = kzalloc(sizeof(cmd), GFP_KERNEL);
    if (!buffer_cmd)
        return -ENOMEM;

    *buffer_cmd = cmd;

    ret = usb_interrupt_msg(port->serial->dev,
        usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
        buffer_cmd, sizeof(cmd),
        &actual_len, USB_CTRL_SET_TIMEOUT);

    kfree(buffer_cmd);

    if (ret < 0)
        return ret;
    else if (actual_len != sizeof(cmd))
        return -EIO;
    return 0;
}

static void metrousb_read_int_callback(struct urb *urb)
{
    struct usb_serial_port *port = urb->context;
    struct metrousb_private *metro_priv = usb_get_serial_port_data(port);
    struct tty_struct *tty;
    unsigned char *data = urb->transfer_buffer;
    int throttled = 0;
    int result = 0;
    unsigned long flags = 0;

    dev_dbg(&port->dev, "%s\n", __func__);

    switch (urb->status) {
    case 0:
        /* Success status, read from the port. */
        break;
    case -ECONNRESET:
    case -ENOENT:
    case -ESHUTDOWN:
        /* urb has been terminated. */
        dev_dbg(&port->dev,
            "%s - urb shutting down, error code=%d\n",
            __func__, urb->status);
        return;
    default:
        dev_dbg(&port->dev,
            "%s - non-zero urb received, error code=%d\n",
            __func__, urb->status);
        goto exit;
    }


    /* Set the data read from the usb port into the serial port buffer. */
    tty = tty_port_tty_get(&port->port);
    if (tty && urb->actual_length) {
        /* Loop through the data copying each byte to the tty layer. */
        tty_insert_flip_string(tty, data, urb->actual_length);

        /* Force the data to the tty layer. */
        tty_flip_buffer_push(tty);
    }
    tty_kref_put(tty);

    /* Set any port variables. */
    spin_lock_irqsave(&metro_priv->lock, flags);
    throttled = metro_priv->throttled;
    spin_unlock_irqrestore(&metro_priv->lock, flags);

    /* Continue trying to read if set. */
    if (!throttled) {
        usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
                 usb_rcvintpipe(port->serial->dev, port->interrupt_in_endpointAddress),
                 port->interrupt_in_urb->transfer_buffer,
                 port->interrupt_in_urb->transfer_buffer_length,
                 metrousb_read_int_callback, port, 1);

        result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);

        if (result)
            dev_err(&port->dev,
                "%s - failed submitting interrupt in urb, error code=%d\n",
                __func__, result);
    }
    return;

exit:
    /* Try to resubmit the urb. */
    result = usb_submit_urb(urb, GFP_ATOMIC);
    if (result)
        dev_err(&port->dev,
            "%s - failed submitting interrupt in urb, error code=%d\n",
            __func__, result);
}

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

    dev_warn(&port->dev, "%s not implemented yet.\n",
        __func__);
}

static void metrousb_cleanup(struct usb_serial_port *port)
{
    dev_dbg(&port->dev, "%s\n", __func__);

    usb_unlink_urb(port->interrupt_in_urb);
    usb_kill_urb(port->interrupt_in_urb);

    mutex_lock(&port->serial->disc_mutex);
    if (!port->serial->disconnected)
        metrousb_send_unidirectional_cmd(UNI_CMD_CLOSE, port);
    mutex_unlock(&port->serial->disc_mutex);
}

static int metrousb_open(struct tty_struct *tty, struct usb_serial_port *port)
{
    struct usb_serial *serial = port->serial;
    struct metrousb_private *metro_priv = usb_get_serial_port_data(port);
    unsigned long flags = 0;
    int result = 0;

    dev_dbg(&port->dev, "%s\n", __func__);

    /* Make sure the urb is initialized. */
    if (!port->interrupt_in_urb) {
        dev_err(&port->dev, "%s - interrupt urb not initialized\n",
            __func__);
        return -ENODEV;
    }

    /* Set the private data information for the port. */
    spin_lock_irqsave(&metro_priv->lock, flags);
    metro_priv->control_state = 0;
    metro_priv->throttled = 0;
    spin_unlock_irqrestore(&metro_priv->lock, flags);

    /* Clear the urb pipe. */
    usb_clear_halt(serial->dev, port->interrupt_in_urb->pipe);

    /* Start reading from the device */
    usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
              usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
               port->interrupt_in_urb->transfer_buffer,
               port->interrupt_in_urb->transfer_buffer_length,
               metrousb_read_int_callback, port, 1);
    result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);

    if (result) {
        dev_err(&port->dev,
            "%s - failed submitting interrupt in urb, error code=%d\n",
            __func__, result);
        goto exit;
    }

    /* Send activate cmd to device */
    result = metrousb_send_unidirectional_cmd(UNI_CMD_OPEN, port);
    if (result) {
        dev_err(&port->dev,
            "%s - failed to configure device for port number=%d, error code=%d\n",
            __func__, port->number, result);
        goto exit;
    }

    dev_dbg(&port->dev, "%s - port open\n", __func__);
exit:
    return result;
}

static int metrousb_set_modem_ctrl(struct usb_serial *serial, unsigned int control_state)
{
    int retval = 0;
    unsigned char mcr = METROUSB_MCR_NONE;

    dev_dbg(&serial->dev->dev, "%s - control state = %d\n",
        __func__, control_state);

    /* Set the modem control value. */
    if (control_state & TIOCM_DTR)
        mcr |= METROUSB_MCR_DTR;
    if (control_state & TIOCM_RTS)
        mcr |= METROUSB_MCR_RTS;

    /* Send the command to the usb port. */
    retval = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                METROUSB_SET_REQUEST_TYPE, METROUSB_SET_MODEM_CTRL_REQUEST,
                control_state, 0, NULL, 0, WDR_TIMEOUT);
    if (retval < 0)
        dev_err(&serial->dev->dev,
            "%s - set modem ctrl=0x%x failed, error code=%d\n",
            __func__, mcr, retval);

    return retval;
}

static int metrousb_port_probe(struct usb_serial_port *port)
{
    struct metrousb_private *metro_priv;

    metro_priv = kzalloc(sizeof(*metro_priv), GFP_KERNEL);
    if (!metro_priv)
        return -ENOMEM;

    spin_lock_init(&metro_priv->lock);

    usb_set_serial_port_data(port, metro_priv);

    return 0;
}

static int metrousb_port_remove(struct usb_serial_port *port)
{
    struct metrousb_private *metro_priv;

    metro_priv = usb_get_serial_port_data(port);
    kfree(metro_priv);

    return 0;
}

static void metrousb_throttle(struct tty_struct *tty)
{
    struct usb_serial_port *port = tty->driver_data;
    struct metrousb_private *metro_priv = usb_get_serial_port_data(port);
    unsigned long flags = 0;

    dev_dbg(tty->dev, "%s\n", __func__);

    /* Set the private information for the port to stop reading data. */
    spin_lock_irqsave(&metro_priv->lock, flags);
    metro_priv->throttled = 1;
    spin_unlock_irqrestore(&metro_priv->lock, flags);
}

static int metrousb_tiocmget(struct tty_struct *tty)
{
    unsigned long control_state = 0;
    struct usb_serial_port *port = tty->driver_data;
    struct metrousb_private *metro_priv = usb_get_serial_port_data(port);
    unsigned long flags = 0;

    dev_dbg(tty->dev, "%s\n", __func__);

    spin_lock_irqsave(&metro_priv->lock, flags);
    control_state = metro_priv->control_state;
    spin_unlock_irqrestore(&metro_priv->lock, flags);

    return control_state;
}

static int metrousb_tiocmset(struct tty_struct *tty,
                 unsigned int set, unsigned int clear)
{
    struct usb_serial_port *port = tty->driver_data;
    struct usb_serial *serial = port->serial;
    struct metrousb_private *metro_priv = usb_get_serial_port_data(port);
    unsigned long flags = 0;
    unsigned long control_state = 0;

    dev_dbg(tty->dev, "%s - set=%d, clear=%d\n", __func__, set, clear);

    spin_lock_irqsave(&metro_priv->lock, flags);
    control_state = metro_priv->control_state;

    /* Set the RTS and DTR values. */
    if (set & TIOCM_RTS)
        control_state |= TIOCM_RTS;
    if (set & TIOCM_DTR)
        control_state |= TIOCM_DTR;
    if (clear & TIOCM_RTS)
        control_state &= ~TIOCM_RTS;
    if (clear & TIOCM_DTR)
        control_state &= ~TIOCM_DTR;

    metro_priv->control_state = control_state;
    spin_unlock_irqrestore(&metro_priv->lock, flags);
    return metrousb_set_modem_ctrl(serial, control_state);
}

static void metrousb_unthrottle(struct tty_struct *tty)
{
    struct usb_serial_port *port = tty->driver_data;
    struct metrousb_private *metro_priv = usb_get_serial_port_data(port);
    unsigned long flags = 0;
    int result = 0;

    dev_dbg(tty->dev, "%s\n", __func__);

    /* Set the private information for the port to resume reading data. */
    spin_lock_irqsave(&metro_priv->lock, flags);
    metro_priv->throttled = 0;
    spin_unlock_irqrestore(&metro_priv->lock, flags);

    /* Submit the urb to read from the port. */
    port->interrupt_in_urb->dev = port->serial->dev;
    result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
    if (result)
        dev_err(tty->dev,
            "failed submitting interrupt in urb error code=%d\n",
            result);
}

static struct usb_serial_driver metrousb_device = {
    .driver = {
        .owner =    THIS_MODULE,
        .name =     "metro-usb",
    },
    .description        = "Metrologic USB to Serial",
    .id_table       = id_table,
    .num_ports      = 1,
    .open           = metrousb_open,
    .close          = metrousb_cleanup,
    .read_int_callback  = metrousb_read_int_callback,
    .write_int_callback = metrousb_write_int_callback,
    .port_probe     = metrousb_port_probe,
    .port_remove        = metrousb_port_remove,
    .throttle       = metrousb_throttle,
    .unthrottle     = metrousb_unthrottle,
    .tiocmget       = metrousb_tiocmget,
    .tiocmset       = metrousb_tiocmset,
};

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

module_usb_serial_driver(serial_drivers, id_table);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Philip Nicastro");
MODULE_AUTHOR("Aleksey Babahin <[email protected]>");
MODULE_DESCRIPTION(DRIVER_DESC);