diff options
Diffstat (limited to 'drivers/char/n_hdlc.c')
| -rw-r--r-- | drivers/char/n_hdlc.c | 1007 |
1 files changed, 0 insertions, 1007 deletions
diff --git a/drivers/char/n_hdlc.c b/drivers/char/n_hdlc.c deleted file mode 100644 index 47d32281032c..000000000000 --- a/drivers/char/n_hdlc.c +++ /dev/null @@ -1,1007 +0,0 @@ -/* generic HDLC line discipline for Linux - * - * Written by Paul Fulghum paulkf@microgate.com - * for Microgate Corporation - * - * Microgate and SyncLink are registered trademarks of Microgate Corporation - * - * Adapted from ppp.c, written by Michael Callahan <callahan@maths.ox.ac.uk>, - * Al Longyear <longyear@netcom.com>, - * Paul Mackerras <Paul.Mackerras@cs.anu.edu.au> - * - * Original release 01/11/99 - * - * This code is released under the GNU General Public License (GPL) - * - * This module implements the tty line discipline N_HDLC for use with - * tty device drivers that support bit-synchronous HDLC communications. - * - * All HDLC data is frame oriented which means: - * - * 1. tty write calls represent one complete transmit frame of data - * The device driver should accept the complete frame or none of - * the frame (busy) in the write method. Each write call should have - * a byte count in the range of 2-65535 bytes (2 is min HDLC frame - * with 1 addr byte and 1 ctrl byte). The max byte count of 65535 - * should include any crc bytes required. For example, when using - * CCITT CRC32, 4 crc bytes are required, so the maximum size frame - * the application may transmit is limited to 65531 bytes. For CCITT - * CRC16, the maximum application frame size would be 65533. - * - * - * 2. receive callbacks from the device driver represents - * one received frame. The device driver should bypass - * the tty flip buffer and call the line discipline receive - * callback directly to avoid fragmenting or concatenating - * multiple frames into a single receive callback. - * - * The HDLC line discipline queues the receive frames in separate - * buffers so complete receive frames can be returned by the - * tty read calls. - * - * 3. tty read calls returns an entire frame of data or nothing. - * - * 4. all send and receive data is considered raw. No processing - * or translation is performed by the line discipline, regardless - * of the tty flags - * - * 5. When line discipline is queried for the amount of receive - * data available (FIOC), 0 is returned if no data available, - * otherwise the count of the next available frame is returned. - * (instead of the sum of all received frame counts). - * - * These conventions allow the standard tty programming interface - * to be used for synchronous HDLC applications when used with - * this line discipline (or another line discipline that is frame - * oriented such as N_PPP). - * - * The SyncLink driver (synclink.c) implements both asynchronous - * (using standard line discipline N_TTY) and synchronous HDLC - * (using N_HDLC) communications, with the latter using the above - * conventions. - * - * This implementation is very basic and does not maintain - * any statistics. The main point is to enforce the raw data - * and frame orientation of HDLC communications. - * - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED - * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, - * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES - * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR - * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, - * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED - * OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -#define HDLC_MAGIC 0x239e - -#include <linux/module.h> -#include <linux/init.h> -#include <linux/kernel.h> -#include <linux/sched.h> -#include <linux/types.h> -#include <linux/fcntl.h> -#include <linux/interrupt.h> -#include <linux/ptrace.h> - -#undef VERSION -#define VERSION(major,minor,patch) (((((major)<<8)+(minor))<<8)+(patch)) - -#include <linux/poll.h> -#include <linux/in.h> -#include <linux/ioctl.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> -#include <linux/bitops.h> - -#include <asm/system.h> -#include <asm/termios.h> -#include <asm/uaccess.h> - -/* - * Buffers for individual HDLC frames - */ -#define MAX_HDLC_FRAME_SIZE 65535 -#define DEFAULT_RX_BUF_COUNT 10 -#define MAX_RX_BUF_COUNT 60 -#define DEFAULT_TX_BUF_COUNT 3 - -struct n_hdlc_buf { - struct n_hdlc_buf *link; - int count; - char buf[1]; -}; - -#define N_HDLC_BUF_SIZE (sizeof(struct n_hdlc_buf) + maxframe) - -struct n_hdlc_buf_list { - struct n_hdlc_buf *head; - struct n_hdlc_buf *tail; - int count; - spinlock_t spinlock; -}; - -/** - * struct n_hdlc - per device instance data structure - * @magic - magic value for structure - * @flags - miscellaneous control flags - * @tty - ptr to TTY structure - * @backup_tty - TTY to use if tty gets closed - * @tbusy - reentrancy flag for tx wakeup code - * @woke_up - FIXME: describe this field - * @tbuf - currently transmitting tx buffer - * @tx_buf_list - list of pending transmit frame buffers - * @rx_buf_list - list of received frame buffers - * @tx_free_buf_list - list unused transmit frame buffers - * @rx_free_buf_list - list unused received frame buffers - */ -struct n_hdlc { - int magic; - __u32 flags; - struct tty_struct *tty; - struct tty_struct *backup_tty; - int tbusy; - int woke_up; - struct n_hdlc_buf *tbuf; - struct n_hdlc_buf_list tx_buf_list; - struct n_hdlc_buf_list rx_buf_list; - struct n_hdlc_buf_list tx_free_buf_list; - struct n_hdlc_buf_list rx_free_buf_list; -}; - -/* - * HDLC buffer list manipulation functions - */ -static void n_hdlc_buf_list_init(struct n_hdlc_buf_list *list); -static void n_hdlc_buf_put(struct n_hdlc_buf_list *list, - struct n_hdlc_buf *buf); -static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *list); - -/* Local functions */ - -static struct n_hdlc *n_hdlc_alloc (void); - -/* debug level can be set by insmod for debugging purposes */ -#define DEBUG_LEVEL_INFO 1 -static int debuglevel; - -/* max frame size for memory allocations */ -static int maxframe = 4096; - -/* TTY callbacks */ - -static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, - __u8 __user *buf, size_t nr); -static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, - const unsigned char *buf, size_t nr); -static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file, - unsigned int cmd, unsigned long arg); -static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, - poll_table *wait); -static int n_hdlc_tty_open(struct tty_struct *tty); -static void n_hdlc_tty_close(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 bset(p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f))) - -#define tty2n_hdlc(tty) ((struct n_hdlc *) ((tty)->disc_data)) -#define n_hdlc2tty(n_hdlc) ((n_hdlc)->tty) - -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", - .open = n_hdlc_tty_open, - .close = n_hdlc_tty_close, - .read = n_hdlc_tty_read, - .write = n_hdlc_tty_write, - .ioctl = n_hdlc_tty_ioctl, - .poll = n_hdlc_tty_poll, - .receive_buf = n_hdlc_tty_receive, - .write_wakeup = n_hdlc_tty_wakeup, - .flush_buffer = flush_rx_queue, -}; - -/** - * n_hdlc_release - release an n_hdlc per device line discipline info structure - * @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); - struct 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 (&tty->read_wait); - wake_up_interruptible (&tty->write_wait); - - if (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->tbuf); - kfree(n_hdlc); - -} /* end of n_hdlc_release() */ - -/** - * 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() */ - -/** - * 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() */ - -/** - * 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_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_receive - Called by tty driver when receive data is available - * @tty - pointer to tty instance data - * @data - pointer to received data - * @flags - pointer to flags for data - * @count - count of received data in bytes - * - * Called by tty low level driver when receive data is available. Data is - * interpreted as one HDLC frame. - */ -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); - - /* This can happen if stuff comes in on the backup tty */ - if (!n_hdlc || 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 = 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 (&tty->read_wait); - if (n_hdlc->tty->fasync != NULL) - kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN); - -} /* end of n_hdlc_tty_receive() */ - -/** - * 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; - } - - tty_lock(); - - 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); - 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); - } - tty_unlock(); - return error; - -} /* end of n_hdlc_tty_write() */ - -/** - * 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; - - 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); - 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); - 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); - } - /* 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() */ - -/** - * n_hdlc_alloc - allocate an n_hdlc instance data structure - * - * Returns a pointer to newly created structure if success, otherwise %NULL - */ -static struct n_hdlc *n_hdlc_alloc(void) -{ - struct n_hdlc_buf *buf; - int i; - struct n_hdlc *n_hdlc = kmalloc(sizeof(*n_hdlc), GFP_KERNEL); - - if (!n_hdlc) - return NULL; - - memset(n_hdlc, 0, sizeof(*n_hdlc)); - - n_hdlc_buf_list_init(&n_hdlc->rx_free_buf_list); - n_hdlc_buf_list_init(&n_hdlc->tx_free_buf_list); - n_hdlc_buf_list_init(&n_hdlc->rx_buf_list); - n_hdlc_buf_list_init(&n_hdlc->tx_buf_list); - - /* allocate free rx buffer list */ - for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) { - buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL); - if (buf) - n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,buf); - else if (debuglevel >= DEBUG_LEVEL_INFO) - printk("%s(%d)n_hdlc_alloc(), kalloc() failed for rx buffer %d\n",__FILE__,__LINE__, i); - } - - /* allocate free tx buffer list */ - for(i=0;i<DEFAULT_TX_BUF_COUNT;i++) { - buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL); - if (buf) - n_hdlc_buf_put(&n_hdlc->tx_free_buf_list,buf); - else if (debuglevel >= DEBUG_LEVEL_INFO) - printk("%s(%d)n_hdlc_alloc(), kalloc() failed for tx buffer %d\n",__FILE__,__LINE__, i); - } - - /* Initialize the control block */ - n_hdlc->magic = HDLC_MAGIC; - n_hdlc->flags = 0; - - return n_hdlc; - -} /* end of n_hdlc_alloc() */ - -/** - * n_hdlc_buf_list_init - initialize specified HDLC buffer list - * @list - pointer to buffer list - */ -static void n_hdlc_buf_list_init(struct n_hdlc_buf_list *list) -{ - memset(list, 0, sizeof(*list)); - spin_lock_init(&list->spinlock); -} /* end of n_hdlc_buf_list_init() */ - -/** - * n_hdlc_buf_put - add specified HDLC buffer to tail of specified list - * @list - pointer to buffer list - * @buf - pointer to buffer - */ -static void n_hdlc_buf_put(struct n_hdlc_buf_list *list, - struct n_hdlc_buf *buf) -{ - unsigned long flags; - spin_lock_irqsave(&list->spinlock,flags); - - buf->link=NULL; - if (list->tail) - list->tail->link = buf; - else - list->head = buf; - list->tail = buf; - (list->count)++; - - spin_unlock_irqrestore(&list->spinlock,flags); - -} /* end of n_hdlc_buf_put() */ - -/** - * n_hdlc_buf_get - remove and return an HDLC buffer from list - * @list - pointer to HDLC buffer list - * - * Remove and return an HDLC buffer from the head of the specified HDLC buffer - * list. - * Returns a pointer to HDLC buffer if available, otherwise %NULL. - */ -static struct n_hdlc_buf* n_hdlc_buf_get(struct n_hdlc_buf_list *list) -{ - unsigned long flags; - struct n_hdlc_buf *buf; - spin_lock_irqsave(&list->spinlock,flags); - - buf = list->head; - if (buf) { - list->head = buf->link; - (list->count)--; - } - if (!list->head) - list->tail = NULL; - - spin_unlock_irqrestore(&list->spinlock,flags); - return buf; - -} /* end of n_hdlc_buf_get() */ - -static char hdlc_banner[] __initdata = - 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 = - KERN_ERR "error registering line discipline: %d\n"; -static char hdlc_init_fail[] __initdata = - KERN_INFO "N_HDLC: init failure %d\n"; - -static int __init n_hdlc_init(void) -{ - int status; - - /* range check maxframe arg */ - if (maxframe < 4096) - maxframe = 4096; - else if (maxframe > 65535) - maxframe = 65535; - - printk(hdlc_banner, maxframe); - - status = tty_register_ldisc(N_HDLC, &n_hdlc_ldisc); - if (!status) - printk(hdlc_register_ok); - else - printk(hdlc_register_fail, status); - - if (status) - printk(hdlc_init_fail, status); - return status; - -} /* end of init_module() */ - -static char hdlc_unregister_ok[] __exitdata = - KERN_INFO "N_HDLC: line discipline unregistered\n"; -static char hdlc_unregister_fail[] __exitdata = - KERN_ERR "N_HDLC: can't unregister line discipline (err = %d)\n"; - -static void __exit n_hdlc_exit(void) -{ - /* Release tty registration of line discipline */ - int status = tty_unregister_ldisc(N_HDLC); - - if (status) - printk(hdlc_unregister_fail, status); - else - printk(hdlc_unregister_ok); -} - -module_init(n_hdlc_init); -module_exit(n_hdlc_exit); - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Paul Fulghum paulkf@microgate.com"); -module_param(debuglevel, int, 0); -module_param(maxframe, int, 0); -MODULE_ALIAS_LDISC(N_HDLC); |