* 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 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
* 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
/*
* Buffers for individual HDLC frames
*/
-#define MAX_HDLC_FRAME_SIZE 65535
+#define MAX_HDLC_FRAME_SIZE 65535
#define DEFAULT_RX_BUF_COUNT 10
#define MAX_RX_BUF_COUNT 60
#define DEFAULT_TX_BUF_COUNT 3
pr_err("%s: tty already associated!\n", __func__);
return -EEXIST;
}
-
+
n_hdlc = n_hdlc_alloc();
if (!n_hdlc) {
pr_err("%s: n_hdlc_alloc failed\n", __func__);
return -ENFILE;
}
-
+
tty->disc_data = n_hdlc;
tty->receive_room = 65536;
-
+
/* change tty_io write() to not split large writes into 8K chunks */
set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
-
+
/* flush receive data from driver */
tty_driver_flush_buffer(tty);
return 0;
-
+
} /* end of n_tty_hdlc_open() */
/**
unsigned long flags;
struct n_hdlc_buf *tbuf;
- check_again:
-
- spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
+check_again:
+
+ spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
if (n_hdlc->tbusy) {
n_hdlc->woke_up = true;
spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
/* pretending it was accepted by driver */
if (actual < 0)
actual = tbuf->count;
-
+
if (actual == tbuf->count) {
pr_debug("%s(%d)frame %p completed\n",
__FILE__, __LINE__, tbuf);
/* 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 {
break;
}
}
-
+
if (!tbuf)
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
-
+
/* Clear the re-entry flag */
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
n_hdlc->tbusy = false;
- spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
-
- if (n_hdlc->woke_up)
- goto check_again;
+ spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
+
+ if (n_hdlc->woke_up)
+ goto check_again;
} /* end of n_hdlc_send_frames() */
/**
__FILE__, __LINE__);
return;
}
-
+
if ( count>maxframe ) {
pr_debug("%s(%d) rx count>maxframesize, data discarded\n",
__FILE__, __LINE__);
return;
}
- /* get a free HDLC buffer */
+ /* 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 */
buf = kmalloc(struct_size(buf, buf, maxframe),
GFP_ATOMIC);
}
-
+
if (!buf) {
pr_debug("%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 (tty->fasync != NULL)
* @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,
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf);
break;
}
-
+
/* no data */
if (tty_io_nonblock(tty, file)) {
ret = -EAGAIN;
__set_current_state(TASK_RUNNING);
return ret;
-
+
} /* end of n_hdlc_tty_read() */
/**
* @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,
__func__, 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;
__set_current_state(TASK_RUNNING);
remove_wait_queue(&tty->write_wait, &wait);
- if (!error) {
+ if (!error) {
/* Retrieve the user's buffer */
memcpy(tbuf->buf, data, count);
}
return error;
-
+
} /* end of n_hdlc_tty_write() */
/**
break;
}
return error;
-
+
} /* end of n_hdlc_tty_ioctl() */
/**
* @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.
n_hdlc->magic = HDLC_MAGIC;
return n_hdlc;
-
+
} /* end of n_hdlc_alloc() */
/**
/**
* n_hdlc_buf_get - remove and return an HDLC buffer from list
* @buf_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.
status);
return status;
-
+
} /* end of init_module() */
static void __exit n_hdlc_exit(void)