X-Git-Url: http://rtime.felk.cvut.cz/gitweb/linux-lin.git/blobdiff_plain/aa1a6709bcec3aa70a1197cd314470d655068d4c..b56f1ea7a09bf50fc5f115a0c2e148e17d9e4799:/sllin/sllin.c

diff --git a/sllin/sllin.c b/sllin/sllin.c
index 91a18c7..cdc4327 100644
--- a/sllin/sllin.c
+++ b/sllin/sllin.c
@@ -72,6 +72,7 @@
 
 /* Should be in include/linux/tty.h */
 #define N_SLLIN			25
+#define N_SLLIN_SLAVE		26
 /* -------------------------------- */
 
 #ifdef SLLIN_LED_TRIGGER
@@ -104,11 +105,18 @@ MODULE_AUTHOR("Pavel Pisa <pisa@cmp.felk.cvut.cz>");
 
 static bool master = true;
 static int baudrate; /* Use LIN_DEFAULT_BAUDRATE when not set */
+#ifndef BREAK_BY_BAUD
+static bool break_by_baud = false;
+#else /*BREAK_BY_BAUD*/
+static bool break_by_baud = true;
+#endif /*BREAK_BY_BAUD*/
 
 module_param(master, bool, 0444);
 MODULE_PARM_DESC(master, "LIN interface is Master device");
 module_param(baudrate, int, 0444);
 MODULE_PARM_DESC(baudrate, "Baudrate of LIN interface");
+module_param(break_by_baud, bool, 0444);
+MODULE_PARM_DESC(break_by_baud, "Break is sent by temporal baudrate switching");
 
 static int maxdev = 10;		/* MAX number of SLLIN channels;
 				   This can be overridden with
@@ -164,6 +172,7 @@ struct sllin {
 	int			tx_lim;         /* actual limit of bytes to Tx */
 	int			tx_cnt;         /* number of already Tx bytes */
 	char			lin_master;	/* node is a master node */
+	bool			lin_break_by_baud; /* send break character by baudrate switching */
 	int			lin_baud;	/* LIN baudrate */
 	int			lin_state;	/* state */
 	char			id_to_send;	/* there is ID to be sent */
@@ -661,13 +670,14 @@ static void sllin_master_receive_buf(struct tty_struct *tty,
 			}
 		}
 
-#ifndef BREAK_BY_BAUD
-		/* We didn't receive Break character -- fake it! */
-		if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
-			netdev_dbg(sl->dev, "LIN_RX[%d]: 0x00\n", sl->rx_cnt);
-			sl->rx_buff[sl->rx_cnt++] = 0x00;
+		if (!sl->lin_break_by_baud ) {
+			/* We didn't receive Break character -- fake it! */
+			if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
+				netdev_dbg(sl->dev, "LIN_RX[%d]: 0x00\n",
+					sl->rx_cnt);
+				sl->rx_buff[sl->rx_cnt++] = 0x00;
+			}
 		}
-#endif /* BREAK_BY_BAUD */
 
 		if (sl->rx_cnt < SLLIN_BUFF_LEN) {
 			netdev_dbg(sl->dev, "LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
@@ -1025,14 +1035,14 @@ static int sllin_send_tx_buff(struct sllin *sl)
 		smp_mb__after_atomic();
 #endif
 
-#ifdef BREAK_BY_BAUD
-		if (sl->lin_state != SLSTATE_BREAK_SENT)
+		if (sl->lin_break_by_baud) {
+			if (sl->lin_state != SLSTATE_BREAK_SENT)
+				remains = sl->tx_lim - sl->tx_cnt;
+			else
+				remains = 1;
+		} else {
 			remains = sl->tx_lim - sl->tx_cnt;
-		else
-			remains = 1;
-#else
-		remains = sl->tx_lim - sl->tx_cnt;
-#endif
+		}
 
 		res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
 		if (res < 0)
@@ -1077,8 +1087,7 @@ error_in_write:
 
 }
 
-#ifdef BREAK_BY_BAUD
-static int sllin_send_break(struct sllin *sl)
+static int sllin_send_break_by_baud(struct sllin *sl)
 {
 	struct tty_struct *tty = sl->tty;
 	unsigned long break_baud;
@@ -1087,7 +1096,7 @@ static int sllin_send_break(struct sllin *sl)
 	break_baud = ((sl->lin_baud * 2) / 3);
 	sltty_change_speed(tty, break_baud);
 
-	if (tty != NULL && tty->ops != NULL && tty->ops->flush_buffer != NULL) {
+	if (tty->ops->flush_buffer != NULL) {
 		tty->ops->flush_buffer(tty);
 	} else {
 		netdev_dbg(sl->dev, "flush_buffer is not implemented.\n");
@@ -1105,9 +1114,8 @@ static int sllin_send_break(struct sllin *sl)
 
 	return 0;
 }
-#else /* BREAK_BY_BAUD */
 
-static int sllin_send_break(struct sllin *sl)
+static int sllin_send_break_by_usleep(struct sllin *sl)
 {
 	struct tty_struct *tty = sl->tty;
 	int retval;
@@ -1150,8 +1158,14 @@ static int sllin_send_break(struct sllin *sl)
 
 	return 0;
 }
-#endif /* BREAK_BY_BAUD */
 
+static int sllin_send_break(struct sllin *sl)
+{
+	if (sl->lin_break_by_baud)
+		return sllin_send_break_by_baud(sl);
+	else
+		return sllin_send_break_by_usleep(sl);
+}
 
 static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
 {
@@ -1331,12 +1345,12 @@ static int sllin_kwthread(void *ptr)
 			break;
 
 		case SLSTATE_BREAK_SENT:
-#ifdef BREAK_BY_BAUD
-			if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
-				continue;
+			if (sl->lin_break_by_baud) {
+				if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
+					continue;
 
-			res = sltty_change_speed(tty, sl->lin_baud);
-#endif
+				sltty_change_speed(tty, sl->lin_baud);
+			}
 
 			sl->lin_state = SLSTATE_ID_SENT;
 			sllin_send_tx_buff(sl);
@@ -1584,7 +1598,7 @@ static struct sllin *sll_alloc(dev_t line)
  * Called in process context serialized from other ldisc calls.
  */
 
-static int sllin_open(struct tty_struct *tty)
+static int sllin_open_common(struct tty_struct *tty, bool setup_master)
 {
 	struct sllin *sl;
 	int err;
@@ -1625,8 +1639,8 @@ static int sllin_open(struct tty_struct *tty)
 
 	if (!test_bit(SLF_INUSE, &sl->flags)) {
 		/* Perform the low-level SLLIN initialization. */
-		sl->lin_master = master;
-		if (master)
+		sl->lin_master = setup_master;
+		if (sl->lin_master)
 			pr_debug("sllin: Configured as MASTER\n");
 		else
 			pr_debug("sllin: Configured as SLAVE\n");
@@ -1636,6 +1650,13 @@ static int sllin_open(struct tty_struct *tty)
 		sl->lin_baud = (baudrate == 0) ? LIN_DEFAULT_BAUDRATE : baudrate;
 		pr_debug("sllin: Baudrate set to %u\n", sl->lin_baud);
 
+		sl->lin_break_by_baud = break_by_baud;
+
+		if (tty->ops->break_ctl == NULL && !sl->lin_break_by_baud) {
+			sl->lin_break_by_baud = true;
+			pr_notice ("sllin: break_ctl, switching to break_by_baud\n");
+		}
+
 		sl->lin_state = SLSTATE_IDLE;
 
 		hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
@@ -1684,6 +1705,43 @@ err_exit:
 	return err;
 }
 
+/*
+ * Open the high-level part of the SLLIN channel.
+ * This function is called by the TTY module when the
+ * SLLIN line discipline is called for.  Because we are
+ * sure the tty line exists, we only have to link it to
+ * a free SLLIN channel...
+ *
+ * Called in process context serialized from other ldisc calls.
+ *
+ * This call variant preserves original functionality where
+ * slave/master can be selected by module parameter.
+ * Default is the master.
+ */
+
+static int sllin_open(struct tty_struct *tty)
+{
+	return sllin_open_common(tty, master);
+}
+
+/*
+ * Open the high-level part of the SLLIN channel.
+ * This function is called by the TTY module when the
+ * SLLIN line discipline is called for.  Because we are
+ * sure the tty line exists, we only have to link it to
+ * a free SLLIN channel...
+ *
+ * Called in process context serialized from other ldisc calls.
+ *
+ * This call variant enforces slave/LIN device functionality.
+ */
+
+static int sllin_open_slave(struct tty_struct *tty)
+{
+	return sllin_open_common(tty, false);
+}
+
+
 /*
  * Close down a SLLIN channel.
  * This means flushing out any pending queues, and then returning. This
@@ -1755,6 +1813,18 @@ static struct tty_ldisc_ops sll_ldisc = {
 	.write_wakeup	= sllin_write_wakeup,
 };
 
+static struct tty_ldisc_ops sll_slave_ldisc = {
+	.owner		= THIS_MODULE,
+	.magic		= TTY_LDISC_MAGIC,
+	.name		= "sllin-slave",
+	.open		= sllin_open_slave,
+	.close		= sllin_close,
+	.hangup		= sllin_hangup,
+	.ioctl		= sllin_ioctl,
+	.receive_buf	= sllin_receive_buf,
+	.write_wakeup	= sllin_write_wakeup,
+};
+
 static int __init sllin_init(void)
 {
 	int status;
@@ -1782,13 +1852,20 @@ static int __init sllin_init(void)
 	if (status)  {
 		pr_err("sllin: can't register line discipline\n");
 		kfree(sllin_devs);
+	} else {
+		status = tty_register_ldisc(N_SLLIN_SLAVE, &sll_slave_ldisc);
+		if (status)  {
+			tty_unregister_ldisc(N_SLLIN);
+			pr_err("sllin: can't register slave line discipline\n");
+			kfree(sllin_devs);
+		}
 	}
 
-#ifdef BREAK_BY_BAUD
-	pr_debug("sllin: Break is generated by baud-rate change.");
-#else
-	pr_debug("sllin: Break is generated manually with tiny sleep.");
-#endif
+
+	if (break_by_baud)
+		pr_debug("sllin: Break is generated by baud-rate change.");
+	else
+		pr_debug("sllin: Break is generated manually with tiny sleep.");
 
 	return status;
 }
@@ -1855,6 +1932,11 @@ static void __exit sllin_exit(void)
 	if (i)
 		pr_err("sllin: can't unregister ldisc (err %d)\n", i);
 
+	i = tty_unregister_ldisc(N_SLLIN_SLAVE);
+	if (i)
+		pr_err("sllin: can't unregister slave ldisc (err %d)\n", i);
+
+
 #ifdef SLLIN_LED_TRIGGER
 	unregister_netdevice_notifier(&sllin_netdev_notifier);
 #endif