diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index cc57a3a6b02b348df95c827fd2c770e59ffca155..396344cb011fd1fafab05c3ddeeff1841e13e055 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -162,6 +162,17 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
 	return put_user(x, ptr);
 }
 
+static inline int tty_copy_to_user(struct tty_struct *tty,
+					void __user *to,
+					const void *from,
+					unsigned long n)
+{
+	struct n_tty_data *ldata = tty->disc_data;
+
+	tty_audit_add_data(tty, to, n, ldata->icanon);
+	return copy_to_user(to, from, n);
+}
+
 /**
  *	n_tty_kick_worker - start input worker (if required)
  *	@tty: terminal
@@ -2070,8 +2081,8 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
 
 	size = N_TTY_BUF_SIZE - tail;
 	n = eol - tail;
-	if (n > 4096)
-		n += 4096;
+	if (n > N_TTY_BUF_SIZE)
+		n += N_TTY_BUF_SIZE;
 	n += found;
 	c = n;
 
@@ -2084,12 +2095,12 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
 		    __func__, eol, found, n, c, size, more);
 
 	if (n > size) {
-		ret = copy_to_user(*b, read_buf_addr(ldata, tail), size);
+		ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), size);
 		if (ret)
 			return -EFAULT;
-		ret = copy_to_user(*b + size, ldata->read_buf, n - size);
+		ret = tty_copy_to_user(tty, *b + size, ldata->read_buf, n - size);
 	} else
-		ret = copy_to_user(*b, read_buf_addr(ldata, tail), n);
+		ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), n);
 
 	if (ret)
 		return -EFAULT;
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 9289999cb7c62bb05b2a4b758fa76d5ce9413316..dce1a23706e86531d3caa86ba4b03c36b03bf3cf 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -562,12 +562,36 @@ static irqreturn_t omap_wake_irq(int irq, void *dev_id)
 	return IRQ_NONE;
 }
 
+#ifdef CONFIG_SERIAL_8250_DMA
+static int omap_8250_dma_handle_irq(struct uart_port *port);
+#endif
+
+static irqreturn_t omap8250_irq(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned int iir;
+	int ret;
+
+#ifdef CONFIG_SERIAL_8250_DMA
+	if (up->dma) {
+		ret = omap_8250_dma_handle_irq(port);
+		return IRQ_RETVAL(ret);
+	}
+#endif
+
+	serial8250_rpm_get(up);
+	iir = serial_port_in(port, UART_IIR);
+	ret = serial8250_handle_irq(port, iir);
+	serial8250_rpm_put(up);
+
+	return IRQ_RETVAL(ret);
+}
+
 static int omap_8250_startup(struct uart_port *port)
 {
-	struct uart_8250_port *up =
-		container_of(port, struct uart_8250_port, port);
+	struct uart_8250_port *up = up_to_u8250p(port);
 	struct omap8250_priv *priv = port->private_data;
-
 	int ret;
 
 	if (priv->wakeirq) {
@@ -580,10 +604,31 @@ static int omap_8250_startup(struct uart_port *port)
 
 	pm_runtime_get_sync(port->dev);
 
-	ret = serial8250_do_startup(port);
-	if (ret)
+	up->mcr = 0;
+	serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+
+	serial_out(up, UART_LCR, UART_LCR_WLEN8);
+
+	up->lsr_saved_flags = 0;
+	up->msr_saved_flags = 0;
+
+	if (up->dma) {
+		ret = serial8250_request_dma(up);
+		if (ret) {
+			dev_warn_ratelimited(port->dev,
+					     "failed to request DMA\n");
+			up->dma = NULL;
+		}
+	}
+
+	ret = request_irq(port->irq, omap8250_irq, IRQF_SHARED,
+			  dev_name(port->dev), port);
+	if (ret < 0)
 		goto err;
 
+	up->ier = UART_IER_RLSI | UART_IER_RDI;
+	serial_out(up, UART_IER, up->ier);
+
 #ifdef CONFIG_PM
 	up->capabilities |= UART_CAP_RPM;
 #endif
@@ -610,8 +655,7 @@ static int omap_8250_startup(struct uart_port *port)
 
 static void omap_8250_shutdown(struct uart_port *port)
 {
-	struct uart_8250_port *up =
-		container_of(port, struct uart_8250_port, port);
+	struct uart_8250_port *up = up_to_u8250p(port);
 	struct omap8250_priv *priv = port->private_data;
 
 	flush_work(&priv->qos_work);
@@ -621,11 +665,24 @@ static void omap_8250_shutdown(struct uart_port *port)
 	pm_runtime_get_sync(port->dev);
 
 	serial_out(up, UART_OMAP_WER, 0);
-	serial8250_do_shutdown(port);
+
+	up->ier = 0;
+	serial_out(up, UART_IER, 0);
+
+	if (up->dma)
+		serial8250_release_dma(up);
+
+	/*
+	 * Disable break condition and FIFOs
+	 */
+	if (up->lcr & UART_LCR_SBC)
+		serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC);
+	serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
 
 	pm_runtime_mark_last_busy(port->dev);
 	pm_runtime_put_autosuspend(port->dev);
 
+	free_irq(port->irq, port);
 	if (priv->wakeirq)
 		free_irq(priv->wakeirq, port);
 }
@@ -974,6 +1031,13 @@ static inline int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
 }
 #endif
 
+static int omap8250_no_handle_irq(struct uart_port *port)
+{
+	/* IRQ has not been requested but handling irq? */
+	WARN_ONCE(1, "Unexpected irq handling before port startup\n");
+	return 0;
+}
+
 static int omap8250_probe(struct platform_device *pdev)
 {
 	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1075,6 +1139,7 @@ static int omap8250_probe(struct platform_device *pdev)
 	pm_runtime_get_sync(&pdev->dev);
 
 	omap_serial_fill_features_erratas(&up, priv);
+	up.port.handle_irq = omap8250_no_handle_irq;
 #ifdef CONFIG_SERIAL_8250_DMA
 	if (pdev->dev.of_node) {
 		/*
@@ -1088,7 +1153,6 @@ static int omap8250_probe(struct platform_device *pdev)
 		ret = of_property_count_strings(pdev->dev.of_node, "dma-names");
 		if (ret == 2) {
 			up.dma = &priv->omap8250_dma;
-			up.port.handle_irq = omap_8250_dma_handle_irq;
 			priv->omap8250_dma.fn = the_no_dma_filter_fn;
 			priv->omap8250_dma.tx_dma = omap_8250_tx_dma;
 			priv->omap8250_dma.rx_dma = omap_8250_rx_dma;
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 6f5a0720a8c8eead6c23f37c359c516730013cef..763eb20fe3213b6cfda04dc2624bcd1b8638f324 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1249,20 +1249,19 @@ __acquires(&uap->port.lock)
 
 /*
  * Transmit a character
- * There must be at least one free entry in the TX FIFO to accept the char.
  *
- * Returns true if the FIFO might have space in it afterwards;
- * returns false if the FIFO definitely became full.
+ * Returns true if the character was successfully queued to the FIFO.
+ * Returns false otherwise.
  */
 static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c)
 {
+	if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
+		return false; /* unable to transmit character */
+
 	writew(c, uap->port.membase + UART01x_DR);
 	uap->port.icount.tx++;
 
-	if (likely(uap->tx_irq_seen > 1))
-		return true;
-
-	return !(readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF);
+	return true;
 }
 
 static bool pl011_tx_chars(struct uart_amba_port *uap)
@@ -1296,7 +1295,8 @@ static bool pl011_tx_chars(struct uart_amba_port *uap)
 		return false;
 
 	if (uap->port.x_char) {
-		pl011_tx_char(uap, uap->port.x_char);
+		if (!pl011_tx_char(uap, uap->port.x_char))
+			goto done;
 		uap->port.x_char = 0;
 		--count;
 	}
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index c8cfa06371280af6abfd63bd379ee5c121523ad7..88250395b0ce96486a2dac5e2e9162fb7f4eae43 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -911,6 +911,14 @@ static void dma_rx_callback(void *data)
 
 	status = dmaengine_tx_status(chan, (dma_cookie_t)0, &state);
 	count = RX_BUF_SIZE - state.residue;
+
+	if (readl(sport->port.membase + USR2) & USR2_IDLE) {
+		/* In condition [3] the SDMA counted up too early */
+		count--;
+
+		writel(USR2_IDLE, sport->port.membase + USR2);
+	}
+
 	dev_dbg(sport->port.dev, "We get %d bytes.\n", count);
 
 	if (count) {