/**
* n_hdlc_tty_close - line discipline close
* @tty - pointer to tty info structure
*
* Called when the line discipline is changed to something
* else, the tty is closed, or the tty detects a hangup.
*/
static void n_hdlc_tty_close(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_close() called\n",__FILE__,__LINE__);
if (n_hdlc != NULL) {
if (n_hdlc->magic != HDLC_MAGIC) {
printk (KERN_WARNING"n_hdlc: trying to close unopened tty!\n");
return;
}
#if defined(TTY_NO_WRITE_SPLIT)
clear_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
#endif
tty->disc_data = NULL;
if (tty == n_hdlc->backup_tty)
n_hdlc->backup_tty = NULL;
if (tty != n_hdlc->tty)
return;
if (n_hdlc->backup_tty) {
n_hdlc->tty = n_hdlc->backup_tty;
} else {
n_hdlc_release (n_hdlc);
}
}
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_close() success\n",__FILE__,__LINE__);
} /* end of n_hdlc_tty_close() */
static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
poll_table *wait)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
unsigned int mask = 0;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_poll() called\n",__FILE__,__LINE__);
if (n_hdlc && n_hdlc->magic == HDLC_MAGIC && tty == n_hdlc->tty) {
poll_wait(filp, &tty->read_wait, wait);
poll_wait(filp, &tty->write_wait, wait);
if (n_hdlc->rx_buf_list.head)
mask |= POLLIN | POLLRDNORM;
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
mask |= POLLHUP;
if (tty_hung_up_p(filp))
mask |= POLLHUP;
if (!tty_is_writelocked(tty) &&
n_hdlc->tx_free_buf_list.head)
mask |= POLLOUT | POLLWRNORM;
}
return mask;
}
/**
* n_hdlc_tty_ioctl - process IOCTL system call for the tty device.
* @tty - pointer to tty instance data
* @file - pointer to open file object for device
* @cmd - IOCTL command code
* @arg - argument for IOCTL call (cmd dependent)
*
* Returns command dependent result.
*/
static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
int error = 0;
int count;
unsigned long flags;
struct n_hdlc_buf *buf = NULL;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_ioctl() called %d\n",
__FILE__,__LINE__,cmd);
/* Verify the status of the device */
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
return -EBADF;
switch (cmd) {
case FIONREAD:
/* report count of read data available */
/* in next available frame (if any) */
spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags);
buf = list_first_entry_or_null(&n_hdlc->rx_buf_list.list,
struct n_hdlc_buf, list_item);
if (buf)
count = buf->count;
else
count = 0;
spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags);
error = put_user(count, (int __user *)arg);
break;
case TIOCOUTQ:
/* get the pending tx byte count in the driver */
count = tty_chars_in_buffer(tty);
/* add size of next output frame in queue */
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags);
buf = list_first_entry_or_null(&n_hdlc->tx_buf_list.list,
struct n_hdlc_buf, list_item);
if (buf)
count += buf->count;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags);
error = put_user(count, (int __user *)arg);
break;
case TCFLSH:
switch (arg) {
case TCIOFLUSH:
case TCOFLUSH:
flush_tx_queue(tty);
}
/* fall through to default */
default:
error = n_tty_ioctl_helper(tty, file, cmd, arg);
break;
}
return error;
} /* end of n_hdlc_tty_ioctl() */
/**
* n_hdlc_tty_poll - TTY callback for poll system call
* @tty - pointer to tty instance data
* @filp - pointer to open file object for device
* @poll_table - wait queue for operations
*
* Determine which operations (read/write) will not block and return info
* to caller.
* Returns a bit mask containing info on which ops will not block.
*/
static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
poll_table *wait)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
unsigned int mask = 0;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_poll() called\n",__FILE__,__LINE__);
if (n_hdlc && n_hdlc->magic == HDLC_MAGIC && tty == n_hdlc->tty) {
/* queue current process into any wait queue that */
/* may awaken in the future (read and write) */
poll_wait(filp, &tty->read_wait, wait);
poll_wait(filp, &tty->write_wait, wait);
/* set bits for operations that won't block */
if (n_hdlc->rx_buf_list.head)
mask |= POLLIN | POLLRDNORM; /* readable */
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
mask |= POLLHUP;
if (tty_hung_up_p(filp))
mask |= POLLHUP;
if (!tty_is_writelocked(tty) &&
n_hdlc->tx_free_buf_list.head)
mask |= POLLOUT | POLLWRNORM; /* writable */
}
return mask;
} /* end of n_hdlc_tty_poll() */
static void flush_rx_queue(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
struct n_hdlc_buf *buf;
while ((buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)))
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, buf);
}
/* n_hdlc_tty_receive()
*
* Called by tty low level driver when receive data is
* available. Data is interpreted as one HDLC frame.
*
* Arguments: tty pointer to tty isntance data
* data pointer to received data
* flags pointer to flags for data
* count count of received data in bytes
*
* Return Value: None
*/
static void n_hdlc_tty_receive(struct tty_struct *tty,
const __u8 * data, char *flags, int count)
{
register struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
register N_HDLC_BUF *buf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_receive() called count=%d\n",
__FILE__,__LINE__, count);
/* This can happen if stuff comes in on the backup tty */
if (n_hdlc == 0 || tty != n_hdlc->tty)
return;
/* verify line is using HDLC discipline */
if (n_hdlc->magic != HDLC_MAGIC) {
printk("%s(%d) line not using HDLC discipline\n",
__FILE__,__LINE__);
return;
}
if ( count>maxframe ) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) rx count>maxframesize, data discarded\n",
__FILE__,__LINE__);
return;
}
/* get a free HDLC buffer */
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (!buf) {
/* no buffers in free list, attempt to allocate another rx buffer */
/* unless the maximum count has been reached */
if (n_hdlc->rx_buf_list.count < MAX_RX_BUF_COUNT)
buf = (N_HDLC_BUF*)kmalloc(N_HDLC_BUF_SIZE,GFP_ATOMIC);
}
if (!buf) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) no more rx buffers, data discarded\n",
__FILE__,__LINE__);
return;
}
/* copy received data to HDLC buffer */
memcpy(buf->buf,data,count);
buf->count=count;
/* add HDLC buffer to list of received frames */
n_hdlc_buf_put(&n_hdlc->rx_buf_list,buf);
/* wake up any blocked reads and perform async signalling */
wake_up_interruptible (&n_hdlc->read_wait);
wake_up_interruptible (&n_hdlc->poll_wait);
if (n_hdlc->tty->fasync != NULL)
kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN);
} /* end of n_hdlc_tty_receive() */
static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
char *flags, int count)
{
register struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
register struct n_hdlc_buf *buf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_receive() called count=%d\n",
__FILE__,__LINE__, count);
if (!n_hdlc || tty != n_hdlc->tty)
return;
if (n_hdlc->magic != HDLC_MAGIC) {
printk("%s(%d) line not using HDLC discipline\n",
__FILE__,__LINE__);
return;
}
if ( count>maxframe ) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) rx count>maxframesize, data discarded\n",
__FILE__,__LINE__);
return;
}
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (!buf) {
if (n_hdlc->rx_buf_list.count < MAX_RX_BUF_COUNT)
buf = kmalloc(N_HDLC_BUF_SIZE, GFP_ATOMIC);
}
if (!buf) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d) no more rx buffers, data discarded\n",
__FILE__,__LINE__);
return;
}
memcpy(buf->buf,data,count);
buf->count=count;
n_hdlc_buf_put(&n_hdlc->rx_buf_list, buf);
wake_up_interruptible (&tty->read_wait);
if (n_hdlc->tty->fasync != NULL)
kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN);
}
static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
int error = 0;
int count;
unsigned long flags;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_ioctl() called %d\n",
__FILE__,__LINE__,cmd);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
return -EBADF;
switch (cmd) {
case FIONREAD:
spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags);
if (n_hdlc->rx_buf_list.head)
count = n_hdlc->rx_buf_list.head->count;
else
count = 0;
spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags);
error = put_user(count, (int __user *)arg);
break;
case TIOCOUTQ:
count = tty_chars_in_buffer(tty);
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags);
if (n_hdlc->tx_buf_list.head)
count += n_hdlc->tx_buf_list.head->count;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags);
error = put_user(count, (int __user *)arg);
break;
case TCFLSH:
switch (arg) {
case TCIOFLUSH:
case TCOFLUSH:
flush_tx_queue(tty);
}
default:
error = n_tty_ioctl_helper(tty, file, cmd, arg);
break;
}
return error;
}
static void flush_tx_queue(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
struct n_hdlc_buf *buf;
unsigned long flags;
while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list)))
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf);
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->tbuf) {
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf);
n_hdlc->tbuf = NULL;
}
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
}
/* n_hdlc_tty_ioctl()
*
* Process IOCTL system call for the tty device.
*
* Arguments:
*
* tty pointer to tty instance data
* file pointer to open file object for device
* cmd IOCTL command code
* arg argument for IOCTL call (cmd dependent)
*
* Return Value: Command dependent
*/
static int n_hdlc_tty_ioctl (struct tty_struct *tty, struct file * file,
unsigned int cmd, unsigned long arg)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
int error = 0;
int count;
unsigned long flags;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_ioctl() called %d\n",
__FILE__,__LINE__,cmd);
/* Verify the status of the device */
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
return -EBADF;
switch (cmd) {
case FIONREAD:
/* report count of read data available */
/* in next available frame (if any) */
spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags);
if (n_hdlc->rx_buf_list.head)
count = n_hdlc->rx_buf_list.head->count;
else
count = 0;
spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags);
PUT_USER (error, count, (int *) arg);
break;
case TIOCOUTQ:
/* get the pending tx byte count in the driver */
count = tty->driver.chars_in_buffer ?
tty->driver.chars_in_buffer(tty) : 0;
/* add size of next output frame in queue */
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags);
if (n_hdlc->tx_buf_list.head)
count += n_hdlc->tx_buf_list.head->count;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags);
PUT_USER (error, count, (int*)arg);
break;
default:
error = n_tty_ioctl (tty, file, cmd, arg);
break;
}
return error;
} /* end of n_hdlc_tty_ioctl() */
/* n_hdlc_tty_open
*
* called when line discipline changed to n_hdlc
*
* Arguments: tty pointer to tty info structure
* Return Value: 0 if success, otherwise error code
*/
static int n_hdlc_tty_open (struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() called (major=%u,minor=%u)\n",
__FILE__,__LINE__,
MAJOR(tty->device), MINOR(tty->device));
/* There should not be an existing table for this slot. */
if (n_hdlc) {
printk (KERN_ERR"n_hdlc_tty_open:tty already associated!\n" );
return -EEXIST;
}
n_hdlc = n_hdlc_alloc();
if (!n_hdlc) {
printk (KERN_ERR "n_hdlc_alloc failed\n");
return -ENFILE;
}
tty->disc_data = n_hdlc;
n_hdlc->tty = tty;
MOD_INC_USE_COUNT;
#if defined(TTY_NO_WRITE_SPLIT)
/* change tty_io write() to not split large writes into 8K chunks */
set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
#endif
/* Flush any pending characters in the driver and discipline. */
if (tty->ldisc.flush_buffer)
tty->ldisc.flush_buffer (tty);
if (tty->driver.flush_buffer)
tty->driver.flush_buffer (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() success\n",__FILE__,__LINE__);
return 0;
} /* end of n_tty_hdlc_open() */
/**
* n_hdlc_tty_wakeup - Callback for transmit wakeup
* @tty - pointer to associated tty instance data
*
* Called when low level device driver can accept more send data.
*/
static void n_hdlc_tty_wakeup(struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_wakeup() called\n",__FILE__,__LINE__);
if (!n_hdlc)
return;
if (tty != n_hdlc->tty) {
tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
return;
}
n_hdlc_send_frames (n_hdlc, tty);
} /* end of n_hdlc_tty_wakeup() */
/**
* n_hdlc_tty_open - called when line discipline changed to n_hdlc
* @tty - pointer to tty info structure
*
* Returns 0 if success, otherwise error code
*/
static int n_hdlc_tty_open (struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() called (device=%s)\n",
__FILE__,__LINE__,
tty->name);
/* There should not be an existing table for this slot. */
if (n_hdlc) {
printk (KERN_ERR"n_hdlc_tty_open:tty already associated!\n" );
return -EEXIST;
}
n_hdlc = n_hdlc_alloc();
if (!n_hdlc) {
printk (KERN_ERR "n_hdlc_alloc failed\n");
return -ENFILE;
}
tty->disc_data = n_hdlc;
n_hdlc->tty = tty;
tty->receive_room = 65536;
#if defined(TTY_NO_WRITE_SPLIT)
/* change tty_io write() to not split large writes into 8K chunks */
set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
#endif
/* flush receive data from driver */
tty_driver_flush_buffer(tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() success\n",__FILE__,__LINE__);
return 0;
} /* end of n_tty_hdlc_open() */
static int n_hdlc_tty_open (struct tty_struct *tty)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() called (device=%s)\n",
__FILE__,__LINE__,
tty->name);
if (n_hdlc) {
printk (KERN_ERR"n_hdlc_tty_open:tty already associated!\n" );
return -EEXIST;
}
n_hdlc = n_hdlc_alloc();
if (!n_hdlc) {
printk (KERN_ERR "n_hdlc_alloc failed\n");
return -ENFILE;
}
tty->disc_data = n_hdlc;
n_hdlc->tty = tty;
tty->receive_room = 65536;
#if defined(TTY_NO_WRITE_SPLIT)
set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
#endif
tty_driver_flush_buffer(tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_open() success\n",__FILE__,__LINE__);
return 0;
}
/**
* n_hdlc_tty_read - Called to retrieve one frame of data (if available)
* @tty - pointer to tty instance data
* @file - pointer to open file object
* @buf - pointer to returned data buffer
* @nr - size of returned data buffer
*
* Returns the number of bytes returned or error code.
*/
static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
__u8 __user *buf, size_t nr)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
int ret;
struct n_hdlc_buf *rbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__);
/* Validate the pointers */
if (!n_hdlc)
return -EIO;
/* verify user access to buffer */
if (!access_ok(VERIFY_WRITE, buf, nr)) {
printk(KERN_WARNING "%s(%d) n_hdlc_tty_read() can't verify user "
"buffer\n", __FILE__, __LINE__);
return -EFAULT;
}
tty_lock();
for (;;) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
tty_unlock();
return -EIO;
}
n_hdlc = tty2n_hdlc (tty);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
tty != n_hdlc->tty) {
tty_unlock();
return 0;
}
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (rbuf)
break;
/* no data */
if (file->f_flags & O_NONBLOCK) {
tty_unlock();
return -EAGAIN;
}
interruptible_sleep_on (&tty->read_wait);
if (signal_pending(current)) {
tty_unlock();
return -EINTR;
}
}
if (rbuf->count > nr)
/* frame too large for caller's buffer (discard frame) */
ret = -EOVERFLOW;
else {
/* Copy the data to the caller's buffer */
if (copy_to_user(buf, rbuf->buf, rbuf->count))
ret = -EFAULT;
else
ret = rbuf->count;
}
/* return HDLC buffer to free list unless the free list */
/* count has exceeded the default value, in which case the */
/* buffer is freed back to the OS to conserve memory */
if (n_hdlc->rx_free_buf_list.count > DEFAULT_RX_BUF_COUNT)
kfree(rbuf);
else
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,rbuf);
tty_unlock();
return ret;
} /* end of n_hdlc_tty_read() */
/**
* n_hdlc_tty_write - write a single frame of data to device
* @tty - pointer to associated tty device instance data
* @file - pointer to file object data
* @data - pointer to transmit data (one frame)
* @count - size of transmit frame in bytes
*
* Returns the number of bytes written (or error code).
*/
static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
const unsigned char *data, size_t count)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
int error = 0;
DECLARE_WAITQUEUE(wait, current);
struct n_hdlc_buf *tbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_write() called count=%Zd\n",
__FILE__,__LINE__,count);
/* Verify pointers */
if (!n_hdlc)
return -EIO;
if (n_hdlc->magic != HDLC_MAGIC)
return -EIO;
/* verify frame size */
if (count > maxframe ) {
if (debuglevel & DEBUG_LEVEL_INFO)
printk (KERN_WARNING
"n_hdlc_tty_write: truncating user packet "
"from %lu to %d\n", (unsigned long) count,
maxframe );
count = maxframe;
}
add_wait_queue(&tty->write_wait, &wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
if (tbuf)
break;
if (file->f_flags & O_NONBLOCK) {
error = -EAGAIN;
break;
}
schedule();
n_hdlc = tty2n_hdlc (tty);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
tty != n_hdlc->tty) {
printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc);
error = -EIO;
break;
}
if (signal_pending(current)) {
error = -EINTR;
break;
}
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&tty->write_wait, &wait);
if (!error) {
/* Retrieve the user's buffer */
memcpy(tbuf->buf, data, count);
/* Send the data */
tbuf->count = error = count;
n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf);
n_hdlc_send_frames(n_hdlc,tty);
}
return error;
} /* end of n_hdlc_tty_write() */
/**
* n_hdlc_tty_read - Called to retrieve one frame of data (if available)
* @tty - pointer to tty instance data
* @file - pointer to open file object
* @buf - pointer to returned data buffer
* @nr - size of returned data buffer
*
* Returns the number of bytes returned or error code.
*/
static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
__u8 __user *buf, size_t nr)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
int ret = 0;
struct n_hdlc_buf *rbuf;
DECLARE_WAITQUEUE(wait, current);
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__);
/* Validate the pointers */
if (!n_hdlc)
return -EIO;
/* verify user access to buffer */
if (!access_ok(VERIFY_WRITE, buf, nr)) {
printk(KERN_WARNING "%s(%d) n_hdlc_tty_read() can't verify user "
"buffer\n", __FILE__, __LINE__);
return -EFAULT;
}
add_wait_queue(&tty->read_wait, &wait);
for (;;) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
ret = -EIO;
break;
}
if (tty_hung_up_p(file))
break;
set_current_state(TASK_INTERRUPTIBLE);
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (rbuf) {
if (rbuf->count > nr) {
/* too large for caller's buffer */
ret = -EOVERFLOW;
} else {
if (copy_to_user(buf, rbuf->buf, rbuf->count))
ret = -EFAULT;
else
ret = rbuf->count;
}
if (n_hdlc->rx_free_buf_list.count >
DEFAULT_RX_BUF_COUNT)
kfree(rbuf);
else
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf);
break;
}
/* no data */
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
schedule();
if (signal_pending(current)) {
ret = -EINTR;
break;
}
}
remove_wait_queue(&tty->read_wait, &wait);
__set_current_state(TASK_RUNNING);
return ret;
} /* end of n_hdlc_tty_read() */
/* n_hdlc_tty_read()
*
* Called to retreive one frame of data (if available)
*
* Arguments:
*
* tty pointer to tty instance data
* file pointer to open file object
* buf pointer to returned data buffer
* nr size of returned data buffer
*
* Return Value:
*
* Number of bytes returned or error code
*/
static rw_ret_t n_hdlc_tty_read (struct tty_struct *tty,
struct file *file, __u8 * buf, rw_count_t nr)
{
struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
int error;
rw_ret_t ret;
N_HDLC_BUF *rbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__);
/* Validate the pointers */
if (!n_hdlc)
return -EIO;
/* verify user access to buffer */
error = verify_area (VERIFY_WRITE, buf, nr);
if (error != 0) {
printk(KERN_WARNING"%s(%d) n_hdlc_tty_read() can't verify user "
"buffer\n",__FILE__,__LINE__);
return (error);
}
for (;;) {
n_hdlc = tty2n_hdlc (tty);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
tty != n_hdlc->tty)
return 0;
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (rbuf)
break;
/* no data */
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
interruptible_sleep_on (&n_hdlc->read_wait);
if (signal_pending(current))
return -EINTR;
}
if (rbuf->count > nr) {
/* frame too large for caller's buffer (discard frame) */
ret = (rw_ret_t)-EOVERFLOW;
} else {
/* Copy the data to the caller's buffer */
COPY_TO_USER(error,buf,rbuf->buf,rbuf->count);
if (error)
ret = (rw_ret_t)error;
else
ret = (rw_ret_t)rbuf->count;
}
/* return HDLC buffer to free list unless the free list */
/* count has exceeded the default value, in which case the */
/* buffer is freed back to the OS to conserve memory */
if (n_hdlc->rx_free_buf_list.count > DEFAULT_RX_BUF_COUNT)
kfree(rbuf);
else
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,rbuf);
return ret;
} /* end of n_hdlc_tty_read() */
/* n_hdlc_tty_write()
*
* write a single frame of data to device
*
* Arguments: tty pointer to associated tty device instance data
* file pointer to file object data
* data pointer to transmit data (one frame)
* count size of transmit frame in bytes
*
* Return Value: number of bytes written (or error code)
*/
static rw_ret_t n_hdlc_tty_write (struct tty_struct *tty, struct file *file,
const __u8 * data, rw_count_t count)
{
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
int error = 0;
DECLARE_WAITQUEUE(wait, current);
N_HDLC_BUF *tbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_tty_write() called count=%d\n",
__FILE__,__LINE__,count);
/* Verify pointers */
if (!n_hdlc)
return -EIO;
if (n_hdlc->magic != HDLC_MAGIC)
return -EIO;
/* verify frame size */
if (count > maxframe ) {
if (debuglevel & DEBUG_LEVEL_INFO)
printk (KERN_WARNING
"n_hdlc_tty_write: truncating user packet "
"from %lu to %d\n", (unsigned long) count,
maxframe );
count = maxframe;
}
add_wait_queue(&n_hdlc->write_wait, &wait);
set_current_state(TASK_INTERRUPTIBLE);
/* Allocate transmit buffer */
/* sleep until transmit buffer available */
while (!(tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list))) {
schedule();
n_hdlc = tty2n_hdlc (tty);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
tty != n_hdlc->tty) {
printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc);
error = -EIO;
break;
}
if (signal_pending(current)) {
error = -EINTR;
break;
}
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&n_hdlc->write_wait, &wait);
if (!error) {
/* Retrieve the user's buffer */
COPY_FROM_USER (error, tbuf->buf, data, count);
if (error) {
/* return tx buffer to free list */
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list,tbuf);
} else {
/* Send the data */
tbuf->count = error = count;
n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf);
n_hdlc_send_frames(n_hdlc,tty);
}
}
return error;
} /* end of n_hdlc_tty_write() */
