/* n_hdlc_release()
*
* release an n_hdlc per device line discipline info structure
*
*/
static void n_hdlc_release (struct n_hdlc *n_hdlc)
{
struct tty_struct *tty = n_hdlc2tty (n_hdlc);
N_HDLC_BUF *buf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_release() called\n",__FILE__,__LINE__);
/* Ensure that the n_hdlcd process is not hanging on select()/poll() */
wake_up_interruptible (&n_hdlc->read_wait);
wake_up_interruptible (&n_hdlc->poll_wait);
wake_up_interruptible (&n_hdlc->write_wait);
if (tty != NULL && tty->disc_data == n_hdlc)
tty->disc_data = NULL; /* Break the tty->n_hdlc link */
/* Release transmit and receive buffers */
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
kfree(n_hdlc);
} /* end of n_hdlc_release() */
static void n_hdlc_release(struct n_hdlc *n_hdlc)
{
struct tty_struct *tty = n_hdlc2tty (n_hdlc);
struct n_hdlc_buf *buf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_release() called\n",__FILE__,__LINE__);
wake_up_interruptible (&tty->read_wait);
wake_up_interruptible (&tty->write_wait);
if (tty->disc_data == n_hdlc)
tty->disc_data = NULL;
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
kfree(n_hdlc->tbuf);
kfree(n_hdlc);
}
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 size_t vs_sdlc_kernel_write(void *context, const void *buf, size_t count)
{
struct vl_sync_port *port = (struct vl_sync_port *)context;
struct vl_sync_port *paired_port = NULL;
struct n_hdlc *n_hdlc = NULL;
struct n_hdlc_buf *tbuf;
//unsigned long flags;
/* Validate the pointers */
if(!port || !IS_OPEN(port))
return -ENODEV;
paired_port = port->paired_port;
if (!paired_port || !IS_OPEN(paired_port))
return -EINVAL;
// Write into paired_port receive buffer, if available
n_hdlc = paired_port->n_hdlc;
if (!n_hdlc)
return -EIO;
/* Verify frame size */
if (count > MAX_HDLC_FRAME_SIZE) {
pr_debug("vs_sdlc_kernel_write: truncating user packet from %lu to %d\n",
(unsigned long) count, MAX_HDLC_FRAME_SIZE);
count = MAX_HDLC_FRAME_SIZE;
}
// Lock paired_port
//spin_lock_irqsave(&paired_port->ctrl_lock, flags);
/* Allocate transmit buffer */
if (!(tbuf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list))) {
//spin_unlock_irqrestore(&paired_port->ctrl_lock, flags);
return -EAGAIN;
}
/* Copy the user's buffer */
memcpy(tbuf->buf, buf, count);
pr_debug("vs_sdlc_kernel_write: %d bytes: %02x\n", count, tbuf->buf[0]);
/* Send the data */
tbuf->count = count;
n_hdlc_buf_put(&n_hdlc->rx_buf_list,tbuf);
//spin_unlock_irqrestore(&paired_port->ctrl_lock, flags);
/* Wake up any blocked reads on paired port and perform async signalling */
wake_up_interruptible (&paired_port->read_wait);
if (paired_port->fasync_queue != NULL)
kill_fasync (&paired_port->fasync_queue, SIGIO, POLL_IN);
return count;
}
static void n_hdlc_release(struct n_hdlc *n_hdlc)
{
struct n_hdlc_buf *buf;
/* Release transmit and receive buffers */
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
for(;;) {
buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
if (buf) {
kfree(buf);
} else
break;
}
kfree(n_hdlc->tbuf);
kfree(n_hdlc);
} /* end of n_hdlc_release() */
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);
}
static int vs_sdlc_kernel_read( void *context, void *buf, size_t count)
{
struct vl_sync_port *port = (struct vl_sync_port *)context;
struct n_hdlc *n_hdlc = port->n_hdlc;
struct n_hdlc_buf *rbuf;
pr_debug("%s(%d)vs_sdlc_kernel_read() called\n",__FILE__,__LINE__);
/* Validate the pointers */
if(!port || !IS_OPEN(port) || !n_hdlc)
return -EBADF;
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (!rbuf) {
/* no data */
return 0;
}
/* Copy the data to the caller's buffer */
if (count > rbuf->count)
count = rbuf->count;
memcpy(buf, rbuf->buf, count);
pr_debug("vs_sdlc_kernel_read: %d bytes: %02x\n", count, rbuf->buf[0]);
/* 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);
// Wake up paired_port write wait queue
if (port->paired_port && IS_OPEN(port->paired_port))
/* wake up sleeping writers */
wake_up_interruptible(&port->paired_port->write_wait);
return count;
}
/**
* 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_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 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_send_frames - send frames on pending send buffer list
* @n_hdlc - pointer to ldisc instance data
* @tty - pointer to tty instance data
*
* Send frames on pending send buffer list until the driver does not accept a
* frame (busy) this function is called after adding a frame to the send buffer
* list and by the tty wakeup callback.
*/
static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
{
register int actual;
unsigned long flags;
struct n_hdlc_buf *tbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_send_frames() called\n",__FILE__,__LINE__);
check_again:
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->tbusy) {
n_hdlc->woke_up = 1;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
return;
}
n_hdlc->tbusy = 1;
n_hdlc->woke_up = 0;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
/* get current transmit buffer or get new transmit */
/* buffer from list of pending transmit buffers */
tbuf = n_hdlc->tbuf;
if (!tbuf)
tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
while (tbuf) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)sending frame %p, count=%d\n",
__FILE__,__LINE__,tbuf,tbuf->count);
/* Send the next block of data to device */
tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
actual = tty->ops->write(tty, tbuf->buf, tbuf->count);
/* rollback was possible and has been done */
if (actual == -ERESTARTSYS) {
n_hdlc->tbuf = tbuf;
break;
}
/* if transmit error, throw frame away by */
/* pretending it was accepted by driver */
if (actual < 0)
actual = tbuf->count;
if (actual == tbuf->count) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)frame %p completed\n",
__FILE__,__LINE__,tbuf);
/* free current transmit buffer */
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf);
/* this tx buffer is done */
n_hdlc->tbuf = NULL;
/* wait up sleeping writers */
wake_up_interruptible(&tty->write_wait);
/* get next pending transmit buffer */
tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
} else {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)frame %p pending\n",
__FILE__,__LINE__,tbuf);
/* buffer not accepted by driver */
/* set this buffer as pending buffer */
n_hdlc->tbuf = tbuf;
break;
}
}
if (!tbuf)
tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
/* Clear the re-entry flag */
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
n_hdlc->tbusy = 0;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->woke_up)
goto check_again;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_send_frames() exit\n",__FILE__,__LINE__);
} /* end of n_hdlc_send_frames() */
/* 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() */
static ssize_t vl_sync_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos)
{
struct vl_sync_port *port = (struct vl_sync_port *)filp->private_data;
struct vl_sync_port *paired_port = port->paired_port;
register struct n_hdlc *n_hdlc = NULL;
register struct n_hdlc_buf *tbuf;
int error = 0;
DECLARE_WAITQUEUE(wait, current);
/* Verify pointers */
if (!port)
return -ENODEV;
if (!paired_port || !IS_OPEN(port))
return -EINVAL;
n_hdlc = paired_port->n_hdlc;
if ((!n_hdlc) || (n_hdlc->magic != HDLC_MAGIC))
return -EIO;
/* verify frame size */
if (count > MAX_HDLC_FRAME_SIZE ) {
pr_err("vl_sync_write: truncating user packet "
"from %lu to %d\n", (unsigned long) count,
MAX_HDLC_FRAME_SIZE );
count = MAX_HDLC_FRAME_SIZE;
}
add_wait_queue(&port->write_wait, &wait);
set_current_state(TASK_INTERRUPTIBLE);
//Write the data buffer into the receive buffer for the paired port
/* Allocate transmit buffer */
/* sleep until transmit buffer available */
while (!(tbuf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list))) {
if (filp->f_flags & O_NONBLOCK) {
error = -EAGAIN;
break;
}
schedule();
n_hdlc = paired_port->n_hdlc;
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ) {
pr_err("vl_sync_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(&port->write_wait, &wait);
if (!error) {
/* Retrieve the user's buffer */
if (copy_from_user(tbuf->buf, buf, count))
error = -EFAULT;
else {
/* Send the data */
tbuf->count = error = count;
n_hdlc_buf_put(&n_hdlc->rx_buf_list,tbuf);
/* Wake up any blocked reads on paired port and perform async signalling */
wake_up_interruptible (&paired_port->read_wait);
if (paired_port->fasync_queue != NULL)
kill_fasync (&paired_port->fasync_queue, SIGIO, POLL_IN);
}
}
return error;
}
static ssize_t vl_sync_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
struct vl_sync_port *port = (struct vl_sync_port *)filp->private_data;
struct n_hdlc *n_hdlc = port->n_hdlc;
int ret;
struct n_hdlc_buf *rbuf;
pr_debug("%s(%d)vl_sync_read() called\n",__FILE__,__LINE__);
/* Validate the pointers */
if (!n_hdlc)
return -EIO;
/* verify user access to buffer */
if (!access_ok(VERIFY_WRITE, buf, count)) {
pr_err("%s(%d) vl_sync_read() can't verify user buffer\n",
__FILE__, __LINE__);
return -EFAULT;
}
/*spin_lock_irqsave(&port->read_ctrl_lock, flags);*/
for (;;) {
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (rbuf)
break;
/* no data */
pr_debug("%s(%d): no data to read\n", __FILE__, __LINE__);
if (filp->f_flags & O_NONBLOCK) {
return -EAGAIN;
}
interruptible_sleep_on (&port->read_wait);
if (signal_pending(current)) {
return -EINTR;
}
}
if (rbuf->count > count)
/* 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);
// Wake up paired_port write wait queue
if (port->paired_port && IS_OPEN(port->paired_port))
/* wake up sleeping writers */
wake_up_interruptible(&port->paired_port->write_wait);
return ret;
}
static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
{
register int actual;
unsigned long flags;
struct n_hdlc_buf *tbuf;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_send_frames() called\n",__FILE__,__LINE__);
check_again:
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->tbusy) {
n_hdlc->woke_up = 1;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
return;
}
n_hdlc->tbusy = 1;
n_hdlc->woke_up = 0;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
tbuf = n_hdlc->tbuf;
if (!tbuf)
tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
while (tbuf) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)sending frame %p, count=%d\n",
__FILE__,__LINE__,tbuf,tbuf->count);
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
actual = tty->ops->write(tty, tbuf->buf, tbuf->count);
if (actual == -ERESTARTSYS) {
n_hdlc->tbuf = tbuf;
break;
}
if (actual < 0)
actual = tbuf->count;
if (actual == tbuf->count) {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)frame %p completed\n",
__FILE__,__LINE__,tbuf);
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf);
n_hdlc->tbuf = NULL;
wake_up_interruptible(&tty->write_wait);
tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
} else {
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)frame %p pending\n",
__FILE__,__LINE__,tbuf);
n_hdlc->tbuf = tbuf;
break;
}
}
if (!tbuf)
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
n_hdlc->tbusy = 0;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->woke_up)
goto check_again;
if (debuglevel >= DEBUG_LEVEL_INFO)
printk("%s(%d)n_hdlc_send_frames() exit\n",__FILE__,__LINE__);
}
/**
* 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() */