usb_wwan.c

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/*
  USB Driver layer for GSM modems

  Copyright (C) 2005  Matthias Urlichs <[email protected]>

  This driver is free software; you can redistribute it and/or modify
  it under the terms of Version 2 of the GNU General Public License as
  published by the Free Software Foundation.

  Portions copied from the Keyspan driver by Hugh Blemings <[email protected]>

  History: see the git log.

  Work sponsored by: Sigos GmbH, Germany <[email protected]>

  This driver exists because the "normal" serial driver doesn't work too well
  with GSM modems. Issues:
  - data loss -- one single Receive URB is not nearly enough
  - controlling the baud rate doesn't make sense
*/

#define DRIVER_VERSION "v0.7.2"
#define DRIVER_AUTHOR "Matthias Urlichs <[email protected]>"
#define DRIVER_DESC "USB Driver for GSM modems"

#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial.h>
#include "usb-wwan.h"

void usb_wwan_dtr_rts(struct usb_serial_port *port, int on)
{
    struct usb_serial *serial = port->serial;
    struct usb_wwan_port_private *portdata;
    struct usb_wwan_intf_private *intfdata;

    intfdata = port->serial->private;

    if (!intfdata->send_setup)
        return;

    portdata = usb_get_serial_port_data(port);
    mutex_lock(&serial->disc_mutex);
    portdata->rts_state = on;
    portdata->dtr_state = on;
    if (serial->dev)
        intfdata->send_setup(port);
    mutex_unlock(&serial->disc_mutex);
}
EXPORT_SYMBOL(usb_wwan_dtr_rts);

void usb_wwan_set_termios(struct tty_struct *tty,
              struct usb_serial_port *port,
              struct ktermios *old_termios)
{
    struct usb_wwan_intf_private *intfdata = port->serial->private;

    /* Doesn't support option setting */
    tty_termios_copy_hw(&tty->termios, old_termios);

    if (intfdata->send_setup)
        intfdata->send_setup(port);
}
EXPORT_SYMBOL(usb_wwan_set_termios);

int usb_wwan_tiocmget(struct tty_struct *tty)
{
    struct usb_serial_port *port = tty->driver_data;
    unsigned int value;
    struct usb_wwan_port_private *portdata;

    portdata = usb_get_serial_port_data(port);

    value = ((portdata->rts_state) ? TIOCM_RTS : 0) |
        ((portdata->dtr_state) ? TIOCM_DTR : 0) |
        ((portdata->cts_state) ? TIOCM_CTS : 0) |
        ((portdata->dsr_state) ? TIOCM_DSR : 0) |
        ((portdata->dcd_state) ? TIOCM_CAR : 0) |
        ((portdata->ri_state) ? TIOCM_RNG : 0);

    return value;
}
EXPORT_SYMBOL(usb_wwan_tiocmget);

int usb_wwan_tiocmset(struct tty_struct *tty,
              unsigned int set, unsigned int clear)
{
    struct usb_serial_port *port = tty->driver_data;
    struct usb_wwan_port_private *portdata;
    struct usb_wwan_intf_private *intfdata;

    portdata = usb_get_serial_port_data(port);
    intfdata = port->serial->private;

    if (!intfdata->send_setup)
        return -EINVAL;

    /* FIXME: what locks portdata fields ? */
    if (set & TIOCM_RTS)
        portdata->rts_state = 1;
    if (set & TIOCM_DTR)
        portdata->dtr_state = 1;

    if (clear & TIOCM_RTS)
        portdata->rts_state = 0;
    if (clear & TIOCM_DTR)
        portdata->dtr_state = 0;
    return intfdata->send_setup(port);
}
EXPORT_SYMBOL(usb_wwan_tiocmset);

static int get_serial_info(struct usb_serial_port *port,
               struct serial_struct __user *retinfo)
{
    struct serial_struct tmp;

    if (!retinfo)
        return -EFAULT;

    memset(&tmp, 0, sizeof(tmp));
    tmp.line            = port->serial->minor;
    tmp.port            = port->number;
    tmp.baud_base       = tty_get_baud_rate(port->port.tty);
    tmp.close_delay     = port->port.close_delay / 10;
    tmp.closing_wait    = port->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
                 ASYNC_CLOSING_WAIT_NONE :
                 port->port.closing_wait / 10;

    if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
        return -EFAULT;
    return 0;
}

static int set_serial_info(struct usb_serial_port *port,
               struct serial_struct __user *newinfo)
{
    struct serial_struct new_serial;
    unsigned int closing_wait, close_delay;
    int retval = 0;

    if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
        return -EFAULT;

    close_delay = new_serial.close_delay * 10;
    closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
            ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;

    mutex_lock(&port->port.mutex);

    if (!capable(CAP_SYS_ADMIN)) {
        if ((close_delay != port->port.close_delay) ||
            (closing_wait != port->port.closing_wait))
            retval = -EPERM;
        else
            retval = -EOPNOTSUPP;
    } else {
        port->port.close_delay  = close_delay;
        port->port.closing_wait = closing_wait;
    }

    mutex_unlock(&port->port.mutex);
    return retval;
}

int usb_wwan_ioctl(struct tty_struct *tty,
           unsigned int cmd, unsigned long arg)
{
    struct usb_serial_port *port = tty->driver_data;

    dev_dbg(&port->dev, "%s cmd 0x%04x\n", __func__, cmd);

    switch (cmd) {
    case TIOCGSERIAL:
        return get_serial_info(port,
                       (struct serial_struct __user *) arg);
    case TIOCSSERIAL:
        return set_serial_info(port,
                       (struct serial_struct __user *) arg);
    default:
        break;
    }

    dev_dbg(&port->dev, "%s arg not supported\n", __func__);

    return -ENOIOCTLCMD;
}
EXPORT_SYMBOL(usb_wwan_ioctl);

/* Write */
int usb_wwan_write(struct tty_struct *tty, struct usb_serial_port *port,
           const unsigned char *buf, int count)
{
    struct usb_wwan_port_private *portdata;
    struct usb_wwan_intf_private *intfdata;
    int i;
    int left, todo;
    struct urb *this_urb = NULL;    /* spurious */
    int err;
    unsigned long flags;

    portdata = usb_get_serial_port_data(port);
    intfdata = port->serial->private;

    dev_dbg(&port->dev, "%s: write (%d chars)\n", __func__, count);

    i = 0;
    left = count;
    for (i = 0; left > 0 && i < N_OUT_URB; i++) {
        todo = left;
        if (todo > OUT_BUFLEN)
            todo = OUT_BUFLEN;

        this_urb = portdata->out_urbs[i];
        if (test_and_set_bit(i, &portdata->out_busy)) {
            if (time_before(jiffies,
                    portdata->tx_start_time[i] + 10 * HZ))
                continue;
            usb_unlink_urb(this_urb);
            continue;
        }
        dev_dbg(&port->dev, "%s: endpoint %d buf %d\n", __func__,
            usb_pipeendpoint(this_urb->pipe), i);

        err = usb_autopm_get_interface_async(port->serial->interface);
        if (err < 0)
            break;

        /* send the data */
        memcpy(this_urb->transfer_buffer, buf, todo);
        this_urb->transfer_buffer_length = todo;

        spin_lock_irqsave(&intfdata->susp_lock, flags);
        if (intfdata->suspended) {
            usb_anchor_urb(this_urb, &portdata->delayed);
            spin_unlock_irqrestore(&intfdata->susp_lock, flags);
        } else {
            intfdata->in_flight++;
            spin_unlock_irqrestore(&intfdata->susp_lock, flags);
            err = usb_submit_urb(this_urb, GFP_ATOMIC);
            if (err) {
                dev_dbg(&port->dev,
                    "usb_submit_urb %p (write bulk) failed (%d)\n",
                    this_urb, err);
                clear_bit(i, &portdata->out_busy);
                spin_lock_irqsave(&intfdata->susp_lock, flags);
                intfdata->in_flight--;
                spin_unlock_irqrestore(&intfdata->susp_lock,
                               flags);
                usb_autopm_put_interface_async(port->serial->interface);
                break;
            }
        }

        portdata->tx_start_time[i] = jiffies;
        buf += todo;
        left -= todo;
    }

    count -= left;
    dev_dbg(&port->dev, "%s: wrote (did %d)\n", __func__, count);
    return count;
}
EXPORT_SYMBOL(usb_wwan_write);

static void usb_wwan_indat_callback(struct urb *urb)
{
    int err;
    int endpoint;
    struct usb_serial_port *port;
    struct tty_struct *tty;
    struct device *dev;
    unsigned char *data = urb->transfer_buffer;
    int status = urb->status;

    endpoint = usb_pipeendpoint(urb->pipe);
    port = urb->context;
    dev = &port->dev;

    if (status) {
        dev_dbg(dev, "%s: nonzero status: %d on endpoint %02x.\n",
            __func__, status, endpoint);
    } else {
        tty = tty_port_tty_get(&port->port);
        if (tty) {
            if (urb->actual_length) {
                tty_insert_flip_string(tty, data,
                        urb->actual_length);
                tty_flip_buffer_push(tty);
            } else
                dev_dbg(dev, "%s: empty read urb received\n", __func__);
            tty_kref_put(tty);
        }

        /* Resubmit urb so we continue receiving */
        err = usb_submit_urb(urb, GFP_ATOMIC);
        if (err) {
            if (err != -EPERM) {
                dev_err(dev, "%s: resubmit read urb failed. (%d)\n", __func__, err);
                /* busy also in error unless we are killed */
                usb_mark_last_busy(port->serial->dev);
            }
        } else {
            usb_mark_last_busy(port->serial->dev);
        }
    }
}

static void usb_wwan_outdat_callback(struct urb *urb)
{
    struct usb_serial_port *port;
    struct usb_wwan_port_private *portdata;
    struct usb_wwan_intf_private *intfdata;
    int i;

    port = urb->context;
    intfdata = port->serial->private;

    usb_serial_port_softint(port);
    usb_autopm_put_interface_async(port->serial->interface);
    portdata = usb_get_serial_port_data(port);
    spin_lock(&intfdata->susp_lock);
    intfdata->in_flight--;
    spin_unlock(&intfdata->susp_lock);

    for (i = 0; i < N_OUT_URB; ++i) {
        if (portdata->out_urbs[i] == urb) {
            smp_mb__before_clear_bit();
            clear_bit(i, &portdata->out_busy);
            break;
        }
    }
}

int usb_wwan_write_room(struct tty_struct *tty)
{
    struct usb_serial_port *port = tty->driver_data;
    struct usb_wwan_port_private *portdata;
    int i;
    int data_len = 0;
    struct urb *this_urb;

    portdata = usb_get_serial_port_data(port);

    for (i = 0; i < N_OUT_URB; i++) {
        this_urb = portdata->out_urbs[i];
        if (this_urb && !test_bit(i, &portdata->out_busy))
            data_len += OUT_BUFLEN;
    }

    dev_dbg(&port->dev, "%s: %d\n", __func__, data_len);
    return data_len;
}
EXPORT_SYMBOL(usb_wwan_write_room);

int usb_wwan_chars_in_buffer(struct tty_struct *tty)
{
    struct usb_serial_port *port = tty->driver_data;
    struct usb_wwan_port_private *portdata;
    int i;
    int data_len = 0;
    struct urb *this_urb;

    portdata = usb_get_serial_port_data(port);

    for (i = 0; i < N_OUT_URB; i++) {
        this_urb = portdata->out_urbs[i];
        /* FIXME: This locking is insufficient as this_urb may
           go unused during the test */
        if (this_urb && test_bit(i, &portdata->out_busy))
            data_len += this_urb->transfer_buffer_length;
    }
    dev_dbg(&port->dev, "%s: %d\n", __func__, data_len);
    return data_len;
}
EXPORT_SYMBOL(usb_wwan_chars_in_buffer);

int usb_wwan_open(struct tty_struct *tty, struct usb_serial_port *port)
{
    struct usb_wwan_port_private *portdata;
    struct usb_wwan_intf_private *intfdata;
    struct usb_serial *serial = port->serial;
    int i, err;
    struct urb *urb;

    portdata = usb_get_serial_port_data(port);
    intfdata = serial->private;

    /* Start reading from the IN endpoint */
    for (i = 0; i < N_IN_URB; i++) {
        urb = portdata->in_urbs[i];
        if (!urb)
            continue;
        err = usb_submit_urb(urb, GFP_KERNEL);
        if (err) {
            dev_dbg(&port->dev, "%s: submit urb %d failed (%d) %d\n",
                __func__, i, err, urb->transfer_buffer_length);
        }
    }

    if (intfdata->send_setup)
        intfdata->send_setup(port);

    serial->interface->needs_remote_wakeup = 1;
    spin_lock_irq(&intfdata->susp_lock);
    portdata->opened = 1;
    spin_unlock_irq(&intfdata->susp_lock);
    /* this balances a get in the generic USB serial code */
    usb_autopm_put_interface(serial->interface);

    return 0;
}
EXPORT_SYMBOL(usb_wwan_open);

void usb_wwan_close(struct usb_serial_port *port)
{
    int i;
    struct usb_serial *serial = port->serial;
    struct usb_wwan_port_private *portdata;
    struct usb_wwan_intf_private *intfdata = port->serial->private;

    portdata = usb_get_serial_port_data(port);

    if (serial->dev) {
        /* Stop reading/writing urbs */
        spin_lock_irq(&intfdata->susp_lock);
        portdata->opened = 0;
        spin_unlock_irq(&intfdata->susp_lock);

        for (i = 0; i < N_IN_URB; i++)
            usb_kill_urb(portdata->in_urbs[i]);
        for (i = 0; i < N_OUT_URB; i++)
            usb_kill_urb(portdata->out_urbs[i]);
        /* balancing - important as an error cannot be handled*/
        usb_autopm_get_interface_no_resume(serial->interface);
        serial->interface->needs_remote_wakeup = 0;
    }
}
EXPORT_SYMBOL(usb_wwan_close);

/* Helper functions used by usb_wwan_setup_urbs */
static struct urb *usb_wwan_setup_urb(struct usb_serial_port *port,
                      int endpoint,
                      int dir, void *ctx, char *buf, int len,
                      void (*callback) (struct urb *))
{
    struct usb_serial *serial = port->serial;
    struct urb *urb;

    urb = usb_alloc_urb(0, GFP_KERNEL); /* No ISO */
    if (urb == NULL) {
        dev_dbg(&serial->interface->dev,
            "%s: alloc for endpoint %d failed.\n", __func__,
            endpoint);
        return NULL;
    }

    /* Fill URB using supplied data. */
    usb_fill_bulk_urb(urb, serial->dev,
              usb_sndbulkpipe(serial->dev, endpoint) | dir,
              buf, len, callback, ctx);

    return urb;
}

int usb_wwan_port_probe(struct usb_serial_port *port)
{
    struct usb_wwan_port_private *portdata;
    struct urb *urb;
    u8 *buffer;
    int err;
    int i;

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

    init_usb_anchor(&portdata->delayed);

    for (i = 0; i < N_IN_URB; i++) {
        if (!port->bulk_in_size)
            break;

        buffer = (u8 *)__get_free_page(GFP_KERNEL);
        if (!buffer)
            goto bail_out_error;
        portdata->in_buffer[i] = buffer;

        urb = usb_wwan_setup_urb(port, port->bulk_in_endpointAddress,
                        USB_DIR_IN, port,
                        buffer, IN_BUFLEN,
                        usb_wwan_indat_callback);
        portdata->in_urbs[i] = urb;
    }

    for (i = 0; i < N_OUT_URB; i++) {
        if (!port->bulk_out_size)
            break;

        buffer = kmalloc(OUT_BUFLEN, GFP_KERNEL);
        if (!buffer)
            goto bail_out_error2;
        portdata->out_buffer[i] = buffer;

        urb = usb_wwan_setup_urb(port, port->bulk_out_endpointAddress,
                        USB_DIR_OUT, port,
                        buffer, OUT_BUFLEN,
                        usb_wwan_outdat_callback);
        portdata->out_urbs[i] = urb;
    }

    usb_set_serial_port_data(port, portdata);

    if (port->interrupt_in_urb) {
        err = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
        if (err)
            dev_dbg(&port->dev, "%s: submit irq_in urb failed %d\n",
                __func__, err);
    }

    return 0;

bail_out_error2:
    for (i = 0; i < N_OUT_URB; i++) {
        usb_free_urb(portdata->out_urbs[i]);
        kfree(portdata->out_buffer[i]);
    }
bail_out_error:
    for (i = 0; i < N_IN_URB; i++) {
        usb_free_urb(portdata->in_urbs[i]);
        free_page((unsigned long)portdata->in_buffer[i]);
    }
    kfree(portdata);

    return -ENOMEM;
}
EXPORT_SYMBOL_GPL(usb_wwan_port_probe);

int usb_wwan_port_remove(struct usb_serial_port *port)
{
    int i;
    struct usb_wwan_port_private *portdata;

    portdata = usb_get_serial_port_data(port);
    usb_set_serial_port_data(port, NULL);

    /* Stop reading/writing urbs and free them */
    for (i = 0; i < N_IN_URB; i++) {
        usb_kill_urb(portdata->in_urbs[i]);
        usb_free_urb(portdata->in_urbs[i]);
        free_page((unsigned long)portdata->in_buffer[i]);
    }
    for (i = 0; i < N_OUT_URB; i++) {
        usb_kill_urb(portdata->out_urbs[i]);
        usb_free_urb(portdata->out_urbs[i]);
        kfree(portdata->out_buffer[i]);
    }

    /* Now free port private data */
    kfree(portdata);
    return 0;
}
EXPORT_SYMBOL(usb_wwan_port_remove);

#ifdef CONFIG_PM
static void stop_read_write_urbs(struct usb_serial *serial)
{
    int i, j;
    struct usb_serial_port *port;
    struct usb_wwan_port_private *portdata;

    /* Stop reading/writing urbs */
    for (i = 0; i < serial->num_ports; ++i) {
        port = serial->port[i];
        portdata = usb_get_serial_port_data(port);
        if (!portdata)
            continue;
        for (j = 0; j < N_IN_URB; j++)
            usb_kill_urb(portdata->in_urbs[j]);
        for (j = 0; j < N_OUT_URB; j++)
            usb_kill_urb(portdata->out_urbs[j]);
    }
}

int usb_wwan_suspend(struct usb_serial *serial, pm_message_t message)
{
    struct usb_wwan_intf_private *intfdata = serial->private;
    int b;

    if (PMSG_IS_AUTO(message)) {
        spin_lock_irq(&intfdata->susp_lock);
        b = intfdata->in_flight;
        spin_unlock_irq(&intfdata->susp_lock);

        if (b)
            return -EBUSY;
    }

    spin_lock_irq(&intfdata->susp_lock);
    intfdata->suspended = 1;
    spin_unlock_irq(&intfdata->susp_lock);
    stop_read_write_urbs(serial);

    return 0;
}
EXPORT_SYMBOL(usb_wwan_suspend);

static void unbusy_queued_urb(struct urb *urb, struct usb_wwan_port_private *portdata)
{
    int i;

    for (i = 0; i < N_OUT_URB; i++) {
        if (urb == portdata->out_urbs[i]) {
            clear_bit(i, &portdata->out_busy);
            break;
        }
    }
}

static void play_delayed(struct usb_serial_port *port)
{
    struct usb_wwan_intf_private *data;
    struct usb_wwan_port_private *portdata;
    struct urb *urb;
    int err;

    portdata = usb_get_serial_port_data(port);
    data = port->serial->private;
    while ((urb = usb_get_from_anchor(&portdata->delayed))) {
        err = usb_submit_urb(urb, GFP_ATOMIC);
        if (!err) {
            data->in_flight++;
        } else {
            /* we have to throw away the rest */
            do {
                unbusy_queued_urb(urb, portdata);
                usb_autopm_put_interface_no_suspend(port->serial->interface);
            } while ((urb = usb_get_from_anchor(&portdata->delayed)));
            break;
        }
    }
}

int usb_wwan_resume(struct usb_serial *serial)
{
    int i, j;
    struct usb_serial_port *port;
    struct usb_wwan_intf_private *intfdata = serial->private;
    struct usb_wwan_port_private *portdata;
    struct urb *urb;
    int err = 0;

    /* get the interrupt URBs resubmitted unconditionally */
    for (i = 0; i < serial->num_ports; i++) {
        port = serial->port[i];
        if (!port->interrupt_in_urb) {
            dev_dbg(&port->dev, "%s: No interrupt URB for port\n", __func__);
            continue;
        }
        err = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
        dev_dbg(&port->dev, "Submitted interrupt URB for port (result %d)\n", err);
        if (err < 0) {
            dev_err(&port->dev, "%s: Error %d for interrupt URB\n",
                __func__, err);
            goto err_out;
        }
    }

    for (i = 0; i < serial->num_ports; i++) {
        /* walk all ports */
        port = serial->port[i];
        portdata = usb_get_serial_port_data(port);

        /* skip closed ports */
        spin_lock_irq(&intfdata->susp_lock);
        if (!portdata || !portdata->opened) {
            spin_unlock_irq(&intfdata->susp_lock);
            continue;
        }

        for (j = 0; j < N_IN_URB; j++) {
            urb = portdata->in_urbs[j];
            err = usb_submit_urb(urb, GFP_ATOMIC);
            if (err < 0) {
                dev_err(&port->dev, "%s: Error %d for bulk URB %d\n",
                    __func__, err, i);
                spin_unlock_irq(&intfdata->susp_lock);
                goto err_out;
            }
        }
        play_delayed(port);
        spin_unlock_irq(&intfdata->susp_lock);
    }
    spin_lock_irq(&intfdata->susp_lock);
    intfdata->suspended = 0;
    spin_unlock_irq(&intfdata->susp_lock);
err_out:
    return err;
}
EXPORT_SYMBOL(usb_wwan_resume);
#endif

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