* Paul Mackerras <Paul.Mackerras@cs.anu.edu.au>
*
* Original release 01/11/99
- * $Id: n_hdlc.c,v 4.8 2003/05/06 21:18:51 paulkf Exp $
*
* This code is released under the GNU General Public License (GPL)
*
*/
#define HDLC_MAGIC 0x239e
-#define HDLC_VERSION "$Revision: 4.8 $"
-#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
+#include <linux/smp_lock.h>
#include <linux/string.h> /* used in new tty drivers */
#include <linux/signal.h> /* used in new tty drivers */
#include <linux/if.h>
#define MAX_HDLC_FRAME_SIZE 65535
#define DEFAULT_RX_BUF_COUNT 10
#define MAX_RX_BUF_COUNT 60
-#define DEFAULT_TX_BUF_COUNT 1
+#define DEFAULT_TX_BUF_COUNT 3
struct n_hdlc_buf {
struct n_hdlc_buf *link;
poll_table *wait);
static int n_hdlc_tty_open(struct tty_struct *tty);
static void n_hdlc_tty_close(struct tty_struct *tty);
-static int n_hdlc_tty_room(struct tty_struct *tty);
static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *cp,
char *fp, int count);
static void n_hdlc_tty_wakeup(struct tty_struct *tty);
#define tty2n_hdlc(tty) ((struct n_hdlc *) ((tty)->disc_data))
#define n_hdlc2tty(n_hdlc) ((n_hdlc)->tty)
-static struct tty_ldisc n_hdlc_ldisc = {
+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);
+}
+
+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 struct tty_ldisc_ops n_hdlc_ldisc = {
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
.name = "hdlc",
.ioctl = n_hdlc_tty_ioctl,
.poll = n_hdlc_tty_poll,
.receive_buf = n_hdlc_tty_receive,
- .receive_room = n_hdlc_tty_room,
.write_wakeup = n_hdlc_tty_wakeup,
+ .flush_buffer = flush_rx_queue,
};
/**
wake_up_interruptible (&tty->read_wait);
wake_up_interruptible (&tty->write_wait);
- if (tty != NULL && tty->disc_data == n_hdlc)
+ if (tty->disc_data == n_hdlc)
tty->disc_data = NULL; /* Break the tty->n_hdlc link */
/* Release transmit and receive buffers */
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 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);
+ /* 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__);
/* Send the next block of data to device */
tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
- actual = tty->driver->write(tty, tbuf->buf, tbuf->count);
-
+ 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)
} /* end of n_hdlc_tty_wakeup() */
/**
- * n_hdlc_tty_room - Return the amount of space left in the receiver's buffer
- * @tty - pointer to associated tty instance data
- *
- * Callback function from tty driver. Return the amount of space left in the
- * receiver's buffer to decide if remote transmitter is to be throttled.
- */
-static int n_hdlc_tty_room(struct tty_struct *tty)
-{
- if (debuglevel >= DEBUG_LEVEL_INFO)
- printk("%s(%d)n_hdlc_tty_room() called\n",__FILE__,__LINE__);
- /* always return a larger number to prevent */
- /* throttling of remote transmitter. */
- return 65536;
-} /* end of n_hdlc_tty_root() */
-
-/**
* n_hdlc_tty_receive - Called by tty driver when receive data is available
* @tty - pointer to tty instance data
* @data - pointer to received data
__FILE__,__LINE__, count);
/* This can happen if stuff comes in on the backup tty */
- if (n_hdlc == 0 || tty != n_hdlc->tty)
+ if (!n_hdlc || tty != n_hdlc->tty)
return;
/* verify line is using HDLC discipline */
} /* end of n_hdlc_tty_receive() */
/**
- * n_hdlc_tty_read - Called to retreive one frame of data (if available)
+ * 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
return -EFAULT;
}
+ lock_kernel();
+
for (;;) {
- if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
+ if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
+ unlock_kernel();
return -EIO;
+ }
n_hdlc = tty2n_hdlc (tty);
if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
- tty != n_hdlc->tty)
+ tty != n_hdlc->tty) {
+ unlock_kernel();
return 0;
+ }
rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
if (rbuf)
break;
/* no data */
- if (file->f_flags & O_NONBLOCK)
+ if (file->f_flags & O_NONBLOCK) {
+ unlock_kernel();
return -EAGAIN;
+ }
interruptible_sleep_on (&tty->read_wait);
- if (signal_pending(current))
+ if (signal_pending(current)) {
+ unlock_kernel();
return -EINTR;
+ }
}
if (rbuf->count > nr)
kfree(rbuf);
else
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,rbuf);
-
+ unlock_kernel();
return ret;
} /* end of n_hdlc_tty_read() */
count = maxframe;
}
+ lock_kernel();
+
add_wait_queue(&tty->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))) {
+ if (file->f_flags & O_NONBLOCK) {
+ error = -EAGAIN;
+ break;
+ }
schedule();
n_hdlc = tty2n_hdlc (tty);
n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf);
n_hdlc_send_frames(n_hdlc,tty);
}
-
+ unlock_kernel();
return error;
} /* end of n_hdlc_tty_write() */
case TIOCOUTQ:
/* get the pending tx byte count in the driver */
- count = tty->driver->chars_in_buffer ?
- tty->driver->chars_in_buffer(tty) : 0;
+ count = tty_chars_in_buffer(tty);
/* 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)
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 (tty, file, cmd, arg);
+ error = n_tty_ioctl_helper(tty, file, cmd, arg);
break;
}
return error;
poll_wait(filp, &tty->write_wait, wait);
/* set bits for operations that won't block */
- if(n_hdlc->rx_buf_list.head)
+ 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))
+ if (tty_hung_up_p(filp))
mask |= POLLHUP;
- if(n_hdlc->tx_free_buf_list.head)
+ if (!tty_is_writelocked(tty) &&
+ n_hdlc->tx_free_buf_list.head)
mask |= POLLOUT | POLLWRNORM; /* writable */
}
return mask;
spin_lock_irqsave(&list->spinlock,flags);
buf->link=NULL;
- if(list->tail)
+ if (list->tail)
list->tail->link = buf;
else
list->head = buf;
} /* end of n_hdlc_buf_get() */
static char hdlc_banner[] __initdata =
- KERN_INFO "HDLC line discipline: version " HDLC_VERSION
- ", maxframe=%u\n";
+ KERN_INFO "HDLC line discipline maxframe=%u\n";
static char hdlc_register_ok[] __initdata =
KERN_INFO "N_HDLC line discipline registered.\n";
static char hdlc_register_fail[] __initdata =
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff