Merge tag 'tty-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are some small tty and serial driver fixes for 5.1-rc3.

  Nothing major here, just a number of potential problems fixes for
  error handling paths, as well as some other minor bugfixes for
  reported issues with 5.1-rc1.

  All of these have been in linux-next with no reported issues"

* tag 'tty-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: fix NULL pointer issue when tty_port ops is not set
  Disable kgdboc failed by echo space to /sys/module/kgdboc/parameters/kgdboc
  dt-bindings: serial: Add compatible for Mediatek MT8183
  tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped
  tty/serial: atmel: Add is_half_duplex helper
  serial: sh-sci: Fix setting SCSCR_TIE while transferring data
  serial: ar933x_uart: Fix build failure with disabled console
  tty: serial: qcom_geni_serial: Initialize baud in qcom_geni_console_setup
  sc16is7xx: missing unregister/delete driver on error in sc16is7xx_init()
  tty: mxs-auart: fix a potential NULL pointer dereference
  tty: atmel_serial: fix a potential NULL pointer dereference
  serial: max310x: Fix to avoid potential NULL pointer dereference
  serial: mvebu-uart: Fix to avoid a potential NULL pointer dereference

10 files changed, 74 insertions, 51 deletions

diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
index db5df3d54818..3bdd56a1021b 100644
--- a/drivers/tty/serial/ar933x_uart.c
+++ b/drivers/tty/serial/ar933x_uart.c
@@ -49,11 +49,6 @@ struct ar933x_uart_port {
 	struct clk		*clk;
 };
 
-static inline bool ar933x_uart_console_enabled(void)
-{
-	return IS_ENABLED(CONFIG_SERIAL_AR933X_CONSOLE);
-}
-
 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
 					    int offset)
 {
@@ -508,6 +503,7 @@ static const struct uart_ops ar933x_uart_ops = {
 	.verify_port	= ar933x_uart_verify_port,
 };
 
+#ifdef CONFIG_SERIAL_AR933X_CONSOLE
 static struct ar933x_uart_port *
 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
 
@@ -604,14 +600,7 @@ static struct console ar933x_uart_console = {
 	.index		= -1,
 	.data		= &ar933x_uart_driver,
 };
-
-static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
-{
-	if (!ar933x_uart_console_enabled())
-		return;
-
-	ar933x_console_ports[up->port.line] = up;
-}
+#endif /* CONFIG_SERIAL_AR933X_CONSOLE */
 
 static struct uart_driver ar933x_uart_driver = {
 	.owner		= THIS_MODULE,
@@ -700,7 +689,9 @@ static int ar933x_uart_probe(struct platform_device *pdev)
 	baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
 	up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
 
-	ar933x_uart_add_console_port(up);
+#ifdef CONFIG_SERIAL_AR933X_CONSOLE
+	ar933x_console_ports[up->port.line] = up;
+#endif
 
 	ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
 	if (ret)
@@ -749,8 +740,9 @@ static int __init ar933x_uart_init(void)
 {
 	int ret;
 
-	if (ar933x_uart_console_enabled())
-		ar933x_uart_driver.cons = &ar933x_uart_console;
+#ifdef CONFIG_SERIAL_AR933X_CONSOLE
+	ar933x_uart_driver.cons = &ar933x_uart_console;
+#endif
 
 	ret = uart_register_driver(&ar933x_uart_driver);
 	if (ret)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..0b4f36905321 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -166,6 +166,8 @@ struct atmel_uart_port {
 	unsigned int		pending_status;
 	spinlock_t		lock_suspended;
 
+	bool			hd_start_rx;	/* can start RX during half-duplex operation */
+
 	/* ISO7816 */
 	unsigned int		fidi_min;
 	unsigned int		fidi_max;
@@ -231,6 +233,13 @@ static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
 	__raw_writeb(value, port->membase + ATMEL_US_THR);
 }
 
+static inline int atmel_uart_is_half_duplex(struct uart_port *port)
+{
+	return ((port->rs485.flags & SER_RS485_ENABLED) &&
+		!(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
+		(port->iso7816.flags & SER_ISO7816_ENABLED);
+}
+
 #ifdef CONFIG_SERIAL_ATMEL_PDC
 static bool atmel_use_pdc_rx(struct uart_port *port)
 {
@@ -608,10 +617,9 @@ static void atmel_stop_tx(struct uart_port *port)
 	/* Disable interrupts */
 	atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
 
-	if (((port->rs485.flags & SER_RS485_ENABLED) &&
-	     !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-	    port->iso7816.flags & SER_ISO7816_ENABLED)
+	if (atmel_uart_is_half_duplex(port))
 		atmel_start_rx(port);
+
 }
 
 /*
@@ -628,9 +636,7 @@ static void atmel_start_tx(struct uart_port *port)
 		return;
 
 	if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
-		if (((port->rs485.flags & SER_RS485_ENABLED) &&
-		     !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-		    port->iso7816.flags & SER_ISO7816_ENABLED)
+		if (atmel_uart_is_half_duplex(port))
 			atmel_stop_rx(port);
 
 	if (atmel_use_pdc_tx(port))
@@ -928,11 +934,14 @@ static void atmel_complete_tx_dma(void *arg)
 	 */
 	if (!uart_circ_empty(xmit))
 		atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
-	else if (((port->rs485.flags & SER_RS485_ENABLED) &&
-		  !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-		 port->iso7816.flags & SER_ISO7816_ENABLED) {
-		/* DMA done, stop TX, start RX for RS485 */
-		atmel_start_rx(port);
+	else if (atmel_uart_is_half_duplex(port)) {
+		/*
+		 * DMA done, re-enable TXEMPTY and signal that we can stop
+		 * TX and start RX for RS485
+		 */
+		atmel_port->hd_start_rx = true;
+		atmel_uart_writel(port, ATMEL_US_IER,
+				  atmel_port->tx_done_mask);
 	}
 
 	spin_unlock_irqrestore(&port->lock, flags);
@@ -1288,6 +1297,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 					 sg_dma_len(&atmel_port->sg_rx)/2,
 					 DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(port->dev, "Preparing DMA cyclic failed\n");
+		goto chan_err;
+	}
 	desc->callback = atmel_complete_rx_dma;
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
@@ -1376,9 +1389,20 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending)
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
 	if (pending & atmel_port->tx_done_mask) {
-		/* Either PDC or interrupt transmission */
 		atmel_uart_writel(port, ATMEL_US_IDR,
 				  atmel_port->tx_done_mask);
+
+		/* Start RX if flag was set and FIFO is empty */
+		if (atmel_port->hd_start_rx) {
+			if (!(atmel_uart_readl(port, ATMEL_US_CSR)
+					& ATMEL_US_TXEMPTY))
+				dev_warn(port->dev, "Should start RX, but TX fifo is not empty\n");
+
+			atmel_port->hd_start_rx = false;
+			atmel_start_rx(port);
+			return;
+		}
+
 		atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
 	}
 }
@@ -1508,9 +1532,7 @@ static void atmel_tx_pdc(struct uart_port *port)
 		atmel_uart_writel(port, ATMEL_US_IER,
 				  atmel_port->tx_done_mask);
 	} else {
-		if (((port->rs485.flags & SER_RS485_ENABLED) &&
-		     !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
-		    port->iso7816.flags & SER_ISO7816_ENABLED) {
+		if (atmel_uart_is_half_duplex(port)) {
 			/* DMA done, stop TX, start RX for RS485 */
 			atmel_start_rx(port);
 		}
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index 6fb312e7af71..bfe5e9e034ec 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -148,8 +148,10 @@ static int configure_kgdboc(void)
 	char *cptr = config;
 	struct console *cons;
 
-	if (!strlen(config) || isspace(config[0]))
+	if (!strlen(config) || isspace(config[0])) {
+		err = 0;
 		goto noconfig;
+	}
 
 	kgdboc_io_ops.is_console = 0;
 	kgdb_tty_driver = NULL;
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index f5bdde405627..450ba6d7996c 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1415,6 +1415,8 @@ static int max310x_spi_probe(struct spi_device *spi)
 	if (spi->dev.of_node) {
 		const struct of_device_id *of_id =
 			of_match_device(max310x_dt_ids, &spi->dev);
+		if (!of_id)
+			return -ENODEV;
 
 		devtype = (struct max310x_devtype *)of_id->data;
 	} else {
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 231f751d1ef4..7e7b1559fa36 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -810,6 +810,9 @@ static int mvebu_uart_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	if (!match)
+		return -ENODEV;
+
 	/* Assume that all UART ports have a DT alias or none has */
 	id = of_alias_get_id(pdev->dev.of_node, "serial");
 	if (!pdev->dev.of_node || id < 0)
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 27235a526cce..4c188f4079b3 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1686,6 +1686,10 @@ static int mxs_auart_probe(struct platform_device *pdev)
 
 	s->port.mapbase = r->start;
 	s->port.membase = ioremap(r->start, resource_size(r));
+	if (!s->port.membase) {
+		ret = -ENOMEM;
+		goto out_disable_clks;
+	}
 	s->port.ops = &mxs_auart_ops;
 	s->port.iotype = UPIO_MEM;
 	s->port.fifosize = MXS_AUART_FIFO_SIZE;
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 3bcec1c20219..35e5f9c5d5be 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -1050,7 +1050,7 @@ static int __init qcom_geni_console_setup(struct console *co, char *options)
 {
 	struct uart_port *uport;
 	struct qcom_geni_serial_port *port;
-	int baud;
+	int baud = 9600;
 	int bits = 8;
 	int parity = 'n';
 	int flow = 'n';
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 635178cf3eed..09a183dfc526 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1507,7 +1507,7 @@ static int __init sc16is7xx_init(void)
 	ret = i2c_add_driver(&sc16is7xx_i2c_uart_driver);
 	if (ret < 0) {
 		pr_err("failed to init sc16is7xx i2c --> %d\n", ret);
-		return ret;
+		goto err_i2c;
 	}
 #endif
 
@@ -1515,10 +1515,18 @@ static int __init sc16is7xx_init(void)
 	ret = spi_register_driver(&sc16is7xx_spi_uart_driver);
 	if (ret < 0) {
 		pr_err("failed to init sc16is7xx spi --> %d\n", ret);
-		return ret;
+		goto err_spi;
 	}
 #endif
 	return ret;
+
+err_spi:
+#ifdef CONFIG_SERIAL_SC16IS7XX_I2C
+	i2c_del_driver(&sc16is7xx_i2c_uart_driver);
+#endif
+err_i2c:
+	uart_unregister_driver(&sc16is7xx_uart);
+	return ret;
 }
 module_init(sc16is7xx_init);
 
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 060fcd42b6d5..2d1c626312cd 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -838,19 +838,9 @@ static void sci_transmit_chars(struct uart_port *port)
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
-	if (uart_circ_empty(xmit)) {
+	if (uart_circ_empty(xmit))
 		sci_stop_tx(port);
-	} else {
-		ctrl = serial_port_in(port, SCSCR);
-
-		if (port->type != PORT_SCI) {
-			serial_port_in(port, SCxSR); /* Dummy read */
-			sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));
-		}
 
-		ctrl |= SCSCR_TIE;
-		serial_port_out(port, SCSCR, ctrl);
-	}
 }
 
 /* On SH3, SCIF may read end-of-break as a space->mark char */
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 044c3cbdcfa4..a9e12b3bc31d 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -325,7 +325,7 @@ static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
 		if (tty && C_HUPCL(tty))
 			tty_port_lower_dtr_rts(port);
 
-		if (port->ops->shutdown)
+		if (port->ops && port->ops->shutdown)
 			port->ops->shutdown(port);
 	}
 out:
@@ -398,7 +398,7 @@ EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
  */
 int tty_port_carrier_raised(struct tty_port *port)
 {
-	if (port->ops->carrier_raised == NULL)
+	if (!port->ops || !port->ops->carrier_raised)
 		return 1;
 	return port->ops->carrier_raised(port);
 }
@@ -414,7 +414,7 @@ EXPORT_SYMBOL(tty_port_carrier_raised);
  */
 void tty_port_raise_dtr_rts(struct tty_port *port)
 {
-	if (port->ops->dtr_rts)
+	if (port->ops && port->ops->dtr_rts)
 		port->ops->dtr_rts(port, 1);
 }
 EXPORT_SYMBOL(tty_port_raise_dtr_rts);
@@ -429,7 +429,7 @@ EXPORT_SYMBOL(tty_port_raise_dtr_rts);
  */
 void tty_port_lower_dtr_rts(struct tty_port *port)
 {
-	if (port->ops->dtr_rts)
+	if (port->ops && port->ops->dtr_rts)
 		port->ops->dtr_rts(port, 0);
 }
 EXPORT_SYMBOL(tty_port_lower_dtr_rts);
@@ -684,7 +684,7 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty,
 
 	if (!tty_port_initialized(port)) {
 		clear_bit(TTY_IO_ERROR, &tty->flags);
-		if (port->ops->activate) {
+		if (port->ops && port->ops->activate) {
 			int retval = port->ops->activate(port, tty);
 			if (retval) {
 				mutex_unlock(&port->mutex);