Merge branch 'depends/tty-omap-serial' into next/cleanup

This part of the tty tree (unfortunately with all the preceding patches
as well) is a dependency for some of the OMAP cleanups, so we've pulled
it in as a dependency based on agreement with Greg.

Signed-off-by: Olof Johansson <olof@lixom.net>

1 files changed, 86 insertions, 56 deletions

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index c43b683b6eb..3e210a430fb 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -108,7 +108,7 @@ struct gsm_mux_net {
  */
 
 struct gsm_msg {
-	struct gsm_msg *next;
+	struct list_head list;
 	u8 addr;		/* DLCI address + flags */
 	u8 ctrl;		/* Control byte + flags */
 	unsigned int len;	/* Length of data block (can be zero) */
@@ -245,8 +245,7 @@ struct gsm_mux {
 	unsigned int tx_bytes;		/* TX data outstanding */
 #define TX_THRESH_HI		8192
 #define TX_THRESH_LO		2048
-	struct gsm_msg *tx_head;	/* Pending data packets */
-	struct gsm_msg *tx_tail;
+	struct list_head tx_list;	/* Pending data packets */
 
 	/* Control messages */
 	struct timer_list t2_timer;	/* Retransmit timer for commands */
@@ -663,7 +662,7 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
 	m->len = len;
 	m->addr = addr;
 	m->ctrl = ctrl;
-	m->next = NULL;
+	INIT_LIST_HEAD(&m->list);
 	return m;
 }
 
@@ -673,22 +672,21 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
  *
  *	The tty device has called us to indicate that room has appeared in
  *	the transmit queue. Ram more data into the pipe if we have any
+ *	If we have been flow-stopped by a CMD_FCOFF, then we can only
+ *	send messages on DLCI0 until CMD_FCON
  *
  *	FIXME: lock against link layer control transmissions
  */
 
 static void gsm_data_kick(struct gsm_mux *gsm)
 {
-	struct gsm_msg *msg = gsm->tx_head;
+	struct gsm_msg *msg, *nmsg;
 	int len;
 	int skip_sof = 0;
 
-	/* FIXME: We need to apply this solely to data messages */
-	if (gsm->constipated)
-		return;
-
-	while (gsm->tx_head != NULL) {
-		msg = gsm->tx_head;
+	list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
+		if (gsm->constipated && msg->addr)
+			continue;
 		if (gsm->encoding != 0) {
 			gsm->txframe[0] = GSM1_SOF;
 			len = gsm_stuff_frame(msg->data,
@@ -711,14 +709,13 @@ static void gsm_data_kick(struct gsm_mux *gsm)
 						len - skip_sof) < 0)
 			break;
 		/* FIXME: Can eliminate one SOF in many more cases */
-		gsm->tx_head = msg->next;
-		if (gsm->tx_head == NULL)
-			gsm->tx_tail = NULL;
 		gsm->tx_bytes -= msg->len;
-		kfree(msg);
 		/* For a burst of frames skip the extra SOF within the
 		   burst */
 		skip_sof = 1;
+
+		list_del(&msg->list);
+		kfree(msg);
 	}
 }
 
@@ -768,11 +765,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
 	msg->data = dp;
 
 	/* Add to the actual output queue */
-	if (gsm->tx_tail)
-		gsm->tx_tail->next = msg;
-	else
-		gsm->tx_head = msg;
-	gsm->tx_tail = msg;
+	list_add_tail(&msg->list, &gsm->tx_list);
 	gsm->tx_bytes += msg->len;
 	gsm_data_kick(gsm);
 }
@@ -875,7 +868,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
 
 	/* dlci->skb is locked by tx_lock */
 	if (dlci->skb == NULL) {
-		dlci->skb = skb_dequeue(&dlci->skb_list);
+		dlci->skb = skb_dequeue_tail(&dlci->skb_list);
 		if (dlci->skb == NULL)
 			return 0;
 		first = 1;
@@ -886,7 +879,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
 	if (len > gsm->mtu) {
 		if (dlci->adaption == 3) {
 			/* Over long frame, bin it */
-			kfree_skb(dlci->skb);
+			dev_kfree_skb_any(dlci->skb);
 			dlci->skb = NULL;
 			return 0;
 		}
@@ -899,8 +892,11 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
 
 	/* FIXME: need a timer or something to kick this so it can't
 	   get stuck with no work outstanding and no buffer free */
-	if (msg == NULL)
+	if (msg == NULL) {
+		skb_queue_tail(&dlci->skb_list, dlci->skb);
+		dlci->skb = NULL;
 		return -ENOMEM;
+	}
 	dp = msg->data;
 
 	if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
@@ -912,7 +908,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
 	skb_pull(dlci->skb, len);
 	__gsm_data_queue(dlci, msg);
 	if (last) {
-		kfree_skb(dlci->skb);
+		dev_kfree_skb_any(dlci->skb);
 		dlci->skb = NULL;
 	}
 	return size;
@@ -971,16 +967,22 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
 static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
 {
 	unsigned long flags;
+	int sweep;
+
+	if (dlci->constipated) 
+		return;
 
 	spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
 	/* If we have nothing running then we need to fire up */
+	sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
 	if (dlci->gsm->tx_bytes == 0) {
 		if (dlci->net)
 			gsm_dlci_data_output_framed(dlci->gsm, dlci);
 		else
 			gsm_dlci_data_output(dlci->gsm, dlci);
-	} else if (dlci->gsm->tx_bytes < TX_THRESH_LO)
-		gsm_dlci_data_sweep(dlci->gsm);
+	}
+	if (sweep)
+ 		gsm_dlci_data_sweep(dlci->gsm);
 	spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
 }
 
@@ -1027,6 +1029,7 @@ static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
 {
 	int  mlines = 0;
 	u8 brk = 0;
+	int fc;
 
 	/* The modem status command can either contain one octet (v.24 signals)
 	   or two octets (v.24 signals + break signals). The length field will
@@ -1038,19 +1041,21 @@ static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
 	else {
 		brk = modem & 0x7f;
 		modem = (modem >> 7) & 0x7f;
-	};
+	}
 
 	/* Flow control/ready to communicate */
-	if (modem & MDM_FC) {
+	fc = (modem & MDM_FC) || !(modem & MDM_RTR);
+	if (fc && !dlci->constipated) {
 		/* Need to throttle our output on this device */
 		dlci->constipated = 1;
-	}
-	if (modem & MDM_RTC) {
-		mlines |= TIOCM_DSR | TIOCM_DTR;
+	} else if (!fc && dlci->constipated) {
 		dlci->constipated = 0;
 		gsm_dlci_data_kick(dlci);
 	}
+
 	/* Map modem bits */
+	if (modem & MDM_RTC)
+		mlines |= TIOCM_DSR | TIOCM_DTR;
 	if (modem & MDM_RTR)
 		mlines |= TIOCM_RTS | TIOCM_CTS;
 	if (modem & MDM_IC)
@@ -1061,7 +1066,7 @@ static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
 	/* Carrier drop -> hangup */
 	if (tty) {
 		if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
-			if (!(tty->termios->c_cflag & CLOCAL))
+			if (!(tty->termios.c_cflag & CLOCAL))
 				tty_hangup(tty);
 		if (brk & 0x01)
 			tty_insert_flip_char(tty, 0, TTY_BREAK);
@@ -1190,6 +1195,8 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
 							u8 *data, int clen)
 {
 	u8 buf[1];
+	unsigned long flags;
+
 	switch (command) {
 	case CMD_CLD: {
 		struct gsm_dlci *dlci = gsm->dlci[0];
@@ -1206,16 +1213,18 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
 		gsm_control_reply(gsm, CMD_TEST, data, clen);
 		break;
 	case CMD_FCON:
-		/* Modem wants us to STFU */
-		gsm->constipated = 1;
-		gsm_control_reply(gsm, CMD_FCON, NULL, 0);
-		break;
-	case CMD_FCOFF:
 		/* Modem can accept data again */
 		gsm->constipated = 0;
-		gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
+		gsm_control_reply(gsm, CMD_FCON, NULL, 0);
 		/* Kick the link in case it is idling */
+		spin_lock_irqsave(&gsm->tx_lock, flags);
 		gsm_data_kick(gsm);
+		spin_unlock_irqrestore(&gsm->tx_lock, flags);
+		break;
+	case CMD_FCOFF:
+		/* Modem wants us to STFU */
+		gsm->constipated = 1;
+		gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
 		break;
 	case CMD_MSC:
 		/* Out of band modem line change indicator for a DLCI */
@@ -1668,7 +1677,7 @@ static void gsm_dlci_free(struct kref *ref)
 	dlci->gsm->dlci[dlci->addr] = NULL;
 	kfifo_free(dlci->fifo);
 	while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
-		kfree_skb(dlci->skb);
+		dev_kfree_skb(dlci->skb);
 	kfree(dlci);
 }
 
@@ -2007,7 +2016,7 @@ void gsm_cleanup_mux(struct gsm_mux *gsm)
 {
 	int i;
 	struct gsm_dlci *dlci = gsm->dlci[0];
-	struct gsm_msg *txq;
+	struct gsm_msg *txq, *ntxq;
 	struct gsm_control *gc;
 
 	gsm->dead = 1;
@@ -2042,11 +2051,9 @@ void gsm_cleanup_mux(struct gsm_mux *gsm)
 		if (gsm->dlci[i])
 			gsm_dlci_release(gsm->dlci[i]);
 	/* Now wipe the queues */
-	for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
-		gsm->tx_head = txq->next;
+	list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
 		kfree(txq);
-	}
-	gsm->tx_tail = NULL;
+	INIT_LIST_HEAD(&gsm->tx_list);
 }
 EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
 
@@ -2157,6 +2164,7 @@ struct gsm_mux *gsm_alloc_mux(void)
 	}
 	spin_lock_init(&gsm->lock);
 	kref_init(&gsm->ref);
+	INIT_LIST_HEAD(&gsm->tx_list);
 
 	gsm->t1 = T1;
 	gsm->t2 = T2;
@@ -2273,7 +2281,7 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 			gsm->error(gsm, *dp, flags);
 			break;
 		default:
-			WARN_ONCE("%s: unknown flag %d\n",
+			WARN_ONCE(1, "%s: unknown flag %d\n",
 			       tty_name(tty, buf), flags);
 			break;
 		}
@@ -2377,12 +2385,12 @@ static void gsmld_write_wakeup(struct tty_struct *tty)
 
 	/* Queue poll */
 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+	spin_lock_irqsave(&gsm->tx_lock, flags);
 	gsm_data_kick(gsm);
 	if (gsm->tx_bytes < TX_THRESH_LO) {
-		spin_lock_irqsave(&gsm->tx_lock, flags);
 		gsm_dlci_data_sweep(gsm);
-		spin_unlock_irqrestore(&gsm->tx_lock, flags);
 	}
+	spin_unlock_irqrestore(&gsm->tx_lock, flags);
 }
 
 /**
@@ -2868,14 +2876,14 @@ static const struct tty_port_operations gsm_port_ops = {
 	.dtr_rts = gsm_dtr_rts,
 };
 
-
-static int gsmtty_open(struct tty_struct *tty, struct file *filp)
+static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
 {
 	struct gsm_mux *gsm;
 	struct gsm_dlci *dlci;
-	struct tty_port *port;
 	unsigned int line = tty->index;
 	unsigned int mux = line >> 6;
+	bool alloc = false;
+	int ret;
 
 	line = line & 0x3F;
 
@@ -2889,14 +2897,35 @@ static int gsmtty_open(struct tty_struct *tty, struct file *filp)
 	gsm = gsm_mux[mux];
 	if (gsm->dead)
 		return -EL2HLT;
+	/* If DLCI 0 is not yet fully open return an error. This is ok from a locking
+	   perspective as we don't have to worry about this if DLCI0 is lost */
+	if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) 
+		return -EL2NSYNC;
 	dlci = gsm->dlci[line];
-	if (dlci == NULL)
+	if (dlci == NULL) {
+		alloc = true;
 		dlci = gsm_dlci_alloc(gsm, line);
+	}
 	if (dlci == NULL)
 		return -ENOMEM;
-	port = &dlci->port;
-	port->count++;
+	ret = tty_port_install(&dlci->port, driver, tty);
+	if (ret) {
+		if (alloc)
+			dlci_put(dlci);
+		return ret;
+	}
+
 	tty->driver_data = dlci;
+
+	return 0;
+}
+
+static int gsmtty_open(struct tty_struct *tty, struct file *filp)
+{
+	struct gsm_dlci *dlci = tty->driver_data;
+	struct tty_port *port = &dlci->port;
+
+	port->count++;
 	dlci_get(dlci);
 	dlci_get(dlci->gsm->dlci[0]);
 	mux_get(dlci->gsm);
@@ -3043,13 +3072,13 @@ static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
 	   the RPN control message. This however rapidly gets nasty as we
 	   then have to remap modem signals each way according to whether
 	   our virtual cable is null modem etc .. */
-	tty_termios_copy_hw(tty->termios, old);
+	tty_termios_copy_hw(&tty->termios, old);
 }
 
 static void gsmtty_throttle(struct tty_struct *tty)
 {
 	struct gsm_dlci *dlci = tty->driver_data;
-	if (tty->termios->c_cflag & CRTSCTS)
+	if (tty->termios.c_cflag & CRTSCTS)
 		dlci->modem_tx &= ~TIOCM_DTR;
 	dlci->throttled = 1;
 	/* Send an MSC with DTR cleared */
@@ -3059,7 +3088,7 @@ static void gsmtty_throttle(struct tty_struct *tty)
 static void gsmtty_unthrottle(struct tty_struct *tty)
 {
 	struct gsm_dlci *dlci = tty->driver_data;
-	if (tty->termios->c_cflag & CRTSCTS)
+	if (tty->termios.c_cflag & CRTSCTS)
 		dlci->modem_tx |= TIOCM_DTR;
 	dlci->throttled = 0;
 	/* Send an MSC with DTR set */
@@ -3085,6 +3114,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state)
 
 /* Virtual ttys for the demux */
 static const struct tty_operations gsmtty_ops = {
+	.install		= gsmtty_install,
 	.open			= gsmtty_open,
 	.close			= gsmtty_close,
 	.write			= gsmtty_write,