/**
* 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_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_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() */