Merge tag 'tty-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver fixes from Greg KH:
 "Here are some small tty/serial/vt driver fixes for 6.0-rc4 that
  resolve a number of reported issues:

   - n_gsm fixups for previous changes that caused problems

   - much-reported serdev crash fix that showed up in 6.0-rc1

   - vt font selection bugfix

   - kerneldoc build warning fixes

   - other tiny serial core fixes

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'tty-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: n_gsm: avoid call of sleeping functions from atomic context
  tty: n_gsm: replace kicktimer with delayed_work
  tty: n_gsm: initialize more members at gsm_alloc_mux()
  tty: n_gsm: add sanity check for gsm->receive in gsm_receive_buf()
  tty: serial: atmel: Preserve previous USART mode if RS485 disabled
  tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete
  tty: Fix lookahead_buf crash with serdev
  serial: fsl_lpuart: RS485 RTS polariy is inverse
  vt: Clear selection before changing the font
  serial: document start_rx member at struct uart_ops

Author: torvalds

drivers/tty/n_gsm.c

@@ -248,15 +248,15 @@ struct gsm_mux {
 	bool constipated;		/* Asked by remote to shut up */
 	bool has_devices;		/* Devices were registered */
 
-	spinlock_t tx_lock;
+	struct mutex tx_mutex;
 	unsigned int tx_bytes;		/* TX data outstanding */
 #define TX_THRESH_HI		8192
 #define TX_THRESH_LO		2048
 	struct list_head tx_ctrl_list;	/* Pending control packets */
 	struct list_head tx_data_list;	/* Pending data packets */
 
 	/* Control messages */
-	struct timer_list kick_timer;	/* Kick TX queuing on timeout */
+	struct delayed_work kick_timeout;	/* Kick TX queuing on timeout */
 	struct timer_list t2_timer;	/* Retransmit timer for commands */
 	int cretries;			/* Command retry counter */
 	struct gsm_control *pending_cmd;/* Our current pending command */
@@ -680,7 +680,6 @@ static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
 	struct gsm_msg *msg;
 	u8 *dp;
 	int ocr;
-	unsigned long flags;
 
 	msg = gsm_data_alloc(gsm, addr, 0, control);
 	if (!msg)
@@ -702,10 +701,10 @@ static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
 
 	gsm_print_packet("Q->", addr, cr, control, NULL, 0);
 
-	spin_lock_irqsave(&gsm->tx_lock, flags);
+	mutex_lock(&gsm->tx_mutex);
 	list_add_tail(&msg->list, &gsm->tx_ctrl_list);
 	gsm->tx_bytes += msg->len;
-	spin_unlock_irqrestore(&gsm->tx_lock, flags);
+	mutex_unlock(&gsm->tx_mutex);
 	gsmld_write_trigger(gsm);
 
 	return 0;
@@ -730,15 +729,15 @@ static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci)
 	spin_unlock_irqrestore(&dlci->lock, flags);
 
 	/* Clear data packets in MUX write queue */
-	spin_lock_irqsave(&gsm->tx_lock, flags);
+	mutex_lock(&gsm->tx_mutex);
 	list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
 		if (msg->addr != addr)
 			continue;
 		gsm->tx_bytes -= msg->len;
 		list_del(&msg->list);
 		kfree(msg);
 	}
-	spin_unlock_irqrestore(&gsm->tx_lock, flags);
+	mutex_unlock(&gsm->tx_mutex);
 }
 
 /**
@@ -1009,7 +1008,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
 	gsm->tx_bytes += msg->len;
 
 	gsmld_write_trigger(gsm);
-	mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100);
+	schedule_delayed_work(&gsm->kick_timeout, 10 * gsm->t1 * HZ / 100);
 }
 
 /**
@@ -1024,10 +1023,9 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
 
 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
 {
-	unsigned long flags;
-	spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
+	mutex_lock(&dlci->gsm->tx_mutex);
 	__gsm_data_queue(dlci, msg);
-	spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
+	mutex_unlock(&dlci->gsm->tx_mutex);
 }
 
 /**
@@ -1039,7 +1037,7 @@ static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
  *	is data. Keep to the MRU of the mux. This path handles the usual tty
  *	interface which is a byte stream with optional modem data.
  *
- *	Caller must hold the tx_lock of the mux.
+ *	Caller must hold the tx_mutex of the mux.
  */
 
 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
@@ -1099,7 +1097,7 @@ static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
  *	is data. Keep to the MRU of the mux. This path handles framed data
  *	queued as skbuffs to the DLCI.
  *
- *	Caller must hold the tx_lock of the mux.
+ *	Caller must hold the tx_mutex of the mux.
  */
 
 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
@@ -1115,7 +1113,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
 	if (dlci->adaption == 4)
 		overhead = 1;
 
-	/* dlci->skb is locked by tx_lock */
+	/* dlci->skb is locked by tx_mutex */
 	if (dlci->skb == NULL) {
 		dlci->skb = skb_dequeue_tail(&dlci->skb_list);
 		if (dlci->skb == NULL)
@@ -1169,7 +1167,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
  *	Push an empty frame in to the transmit queue to update the modem status
  *	bits and to transmit an optional break.
  *
- *	Caller must hold the tx_lock of the mux.
+ *	Caller must hold the tx_mutex of the mux.
  */
 
 static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
@@ -1283,13 +1281,12 @@ static int 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);
+	mutex_lock(&dlci->gsm->tx_mutex);
 	/* 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) {
@@ -1300,7 +1297,7 @@ static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
 	}
 	if (sweep)
 		gsm_dlci_data_sweep(dlci->gsm);
-	spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
+	mutex_unlock(&dlci->gsm->tx_mutex);
 }
 
 /*
@@ -1984,24 +1981,23 @@ static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
 }
 
 /**
- *	gsm_kick_timer	-	transmit if possible
- *	@t: timer contained in our gsm object
+ *	gsm_kick_timeout	-	transmit if possible
+ *	@work: work contained in our gsm object
  *
  *	Transmit data from DLCIs if the queue is empty. We can't rely on
  *	a tty wakeup except when we filled the pipe so we need to fire off
  *	new data ourselves in other cases.
  */
-static void gsm_kick_timer(struct timer_list *t)
+static void gsm_kick_timeout(struct work_struct *work)
 {
-	struct gsm_mux *gsm = from_timer(gsm, t, kick_timer);
-	unsigned long flags;
+	struct gsm_mux *gsm = container_of(work, struct gsm_mux, kick_timeout.work);
 	int sent = 0;
 
-	spin_lock_irqsave(&gsm->tx_lock, flags);
+	mutex_lock(&gsm->tx_mutex);
 	/* If we have nothing running then we need to fire up */
 	if (gsm->tx_bytes < TX_THRESH_LO)
 		sent = gsm_dlci_data_sweep(gsm);
-	spin_unlock_irqrestore(&gsm->tx_lock, flags);
+	mutex_unlock(&gsm->tx_mutex);
 
 	if (sent && debug & 4)
 		pr_info("%s TX queue stalled\n", __func__);
@@ -2458,7 +2454,7 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
 	}
 
 	/* Finish outstanding timers, making sure they are done */
-	del_timer_sync(&gsm->kick_timer);
+	cancel_delayed_work_sync(&gsm->kick_timeout);
 	del_timer_sync(&gsm->t2_timer);
 
 	/* Finish writing to ldisc */
@@ -2501,13 +2497,6 @@ static int gsm_activate_mux(struct gsm_mux *gsm)
 	if (dlci == NULL)
 		return -ENOMEM;
 
-	timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
-	timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
-	INIT_WORK(&gsm->tx_work, gsmld_write_task);
-	init_waitqueue_head(&gsm->event);
-	spin_lock_init(&gsm->control_lock);
-	spin_lock_init(&gsm->tx_lock);
-
 	if (gsm->encoding == 0)
 		gsm->receive = gsm0_receive;
 	else
@@ -2538,6 +2527,7 @@ static void gsm_free_mux(struct gsm_mux *gsm)
 			break;
 		}
 	}
+	mutex_destroy(&gsm->tx_mutex);
 	mutex_destroy(&gsm->mutex);
 	kfree(gsm->txframe);
 	kfree(gsm->buf);
@@ -2609,9 +2599,15 @@ static struct gsm_mux *gsm_alloc_mux(void)
 	}
 	spin_lock_init(&gsm->lock);
 	mutex_init(&gsm->mutex);
+	mutex_init(&gsm->tx_mutex);
 	kref_init(&gsm->ref);
 	INIT_LIST_HEAD(&gsm->tx_ctrl_list);
 	INIT_LIST_HEAD(&gsm->tx_data_list);
+	INIT_DELAYED_WORK(&gsm->kick_timeout, gsm_kick_timeout);
+	timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
+	INIT_WORK(&gsm->tx_work, gsmld_write_task);
+	init_waitqueue_head(&gsm->event);
+	spin_lock_init(&gsm->control_lock);
 
 	gsm->t1 = T1;
 	gsm->t2 = T2;
@@ -2636,6 +2632,7 @@ static struct gsm_mux *gsm_alloc_mux(void)
 	}
 	spin_unlock(&gsm_mux_lock);
 	if (i == MAX_MUX) {
+		mutex_destroy(&gsm->tx_mutex);
 		mutex_destroy(&gsm->mutex);
 		kfree(gsm->txframe);
 		kfree(gsm->buf);
@@ -2791,17 +2788,16 @@ static void gsmld_write_trigger(struct gsm_mux *gsm)
 static void gsmld_write_task(struct work_struct *work)
 {
 	struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work);
-	unsigned long flags;
 	int i, ret;
 
 	/* All outstanding control channel and control messages and one data
 	 * frame is sent.
 	 */
 	ret = -ENODEV;
-	spin_lock_irqsave(&gsm->tx_lock, flags);
+	mutex_lock(&gsm->tx_mutex);
 	if (gsm->tty)
 		ret = gsm_data_kick(gsm);
-	spin_unlock_irqrestore(&gsm->tx_lock, flags);
+	mutex_unlock(&gsm->tx_mutex);
 
 	if (ret >= 0)
 		for (i = 0; i < NUM_DLCI; i++)
@@ -2858,7 +2854,8 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 			flags = *fp++;
 		switch (flags) {
 		case TTY_NORMAL:
-			gsm->receive(gsm, *cp);
+			if (gsm->receive)
+				gsm->receive(gsm, *cp);
 			break;
 		case TTY_OVERRUN:
 		case TTY_BREAK:
@@ -2946,10 +2943,6 @@ static int gsmld_open(struct tty_struct *tty)
 
 	gsmld_attach_gsm(tty, gsm);
 
-	timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
-	timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
-	INIT_WORK(&gsm->tx_work, gsmld_write_task);
-
 	return 0;
 }
 
@@ -3012,21 +3005,20 @@ static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
 			   const unsigned char *buf, size_t nr)
 {
 	struct gsm_mux *gsm = tty->disc_data;
-	unsigned long flags;
 	int space;
 	int ret;
 
 	if (!gsm)
 		return -ENODEV;
 
 	ret = -ENOBUFS;
-	spin_lock_irqsave(&gsm->tx_lock, flags);
+	mutex_lock(&gsm->tx_mutex);
 	space = tty_write_room(tty);
 	if (space >= nr)
 		ret = tty->ops->write(tty, buf, nr);
 	else
 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
-	spin_unlock_irqrestore(&gsm->tx_lock, flags);
+	mutex_unlock(&gsm->tx_mutex);
 
 	return ret;
 }
@@ -3323,14 +3315,13 @@ static struct tty_ldisc_ops tty_ldisc_packet = {
 static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk)
 {
 	struct gsm_mux *gsm = dlci->gsm;
-	unsigned long flags;
 
 	if (dlci->state != DLCI_OPEN || dlci->adaption != 2)
 		return;
 
-	spin_lock_irqsave(&gsm->tx_lock, flags);
+	mutex_lock(&gsm->tx_mutex);
 	gsm_dlci_modem_output(gsm, dlci, brk);
-	spin_unlock_irqrestore(&gsm->tx_lock, flags);
+	mutex_unlock(&gsm->tx_mutex);
 }
 
 /**

drivers/tty/serial/atmel_serial.c

@@ -294,9 +294,6 @@ static int atmel_config_rs485(struct uart_port *port, struct ktermios *termios,
 
 	mode = atmel_uart_readl(port, ATMEL_US_MR);
 
-	/* Resetting serial mode to RS232 (0x0) */
-	mode &= ~ATMEL_US_USMODE;
-
 	if (rs485conf->flags & SER_RS485_ENABLED) {
 		dev_dbg(port->dev, "Setting UART to RS485\n");
 		if (rs485conf->flags & SER_RS485_RX_DURING_TX)
@@ -306,6 +303,7 @@ static int atmel_config_rs485(struct uart_port *port, struct ktermios *termios,
 
 		atmel_uart_writel(port, ATMEL_US_TTGR,
 				  rs485conf->delay_rts_after_send);
+		mode &= ~ATMEL_US_USMODE;
 		mode |= ATMEL_US_USMODE_RS485;
 	} else {
 		dev_dbg(port->dev, "Setting UART to RS232\n");

drivers/tty/serial/fsl_lpuart.c

@@ -1394,9 +1394,9 @@ static int lpuart_config_rs485(struct uart_port *port, struct ktermios *termios,
 		 * Note: UART is assumed to be active high.
 		 */
 		if (rs485->flags & SER_RS485_RTS_ON_SEND)
-			modem &= ~UARTMODEM_TXRTSPOL;
-		else if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
 			modem |= UARTMODEM_TXRTSPOL;
+		else if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
+			modem &= ~UARTMODEM_TXRTSPOL;
 	}
 
 	writeb(modem, sport->port.membase + UARTMODEM);
@@ -2191,6 +2191,7 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
 	uart_update_timeout(port, termios->c_cflag, baud);
 
 	/* wait transmit engin complete */
+	lpuart32_write(&sport->port, 0, UARTMODIR);
 	lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC);
 
 	/* disable transmit and receive */

drivers/tty/tty_buffer.c

@@ -470,7 +470,6 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
 
 	while (head) {
 		struct tty_buffer *next;
-		unsigned char *p, *f = NULL;
 		unsigned int count;
 
 		/*
@@ -489,11 +488,16 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
 			continue;
 		}
 
-		p = char_buf_ptr(head, head->lookahead);
-		if (~head->flags & TTYB_NORMAL)
-			f = flag_buf_ptr(head, head->lookahead);
+		if (port->client_ops->lookahead_buf) {
+			unsigned char *p, *f = NULL;
+
+			p = char_buf_ptr(head, head->lookahead);
+			if (~head->flags & TTYB_NORMAL)
+				f = flag_buf_ptr(head, head->lookahead);
+
+			port->client_ops->lookahead_buf(port, p, f, count);
+		}
 
-		port->client_ops->lookahead_buf(port, p, f, count);
 		head->lookahead += count;
 	}
 }