Merge tag 'tty-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial updates from Greg KH:
 "Here is the big tty and serial pull request for 4.20-rc1

  Lots of little things here, including a merge from the SPI tree in
  order to keep things simpler for everyone to sync around for one
  platform.

  Major stuff is:

   - tty buffer clearing after use

   - atmel_serial fixes and additions

   - xilinx uart driver updates

  and of course, lots of tiny fixes and additions to individual serial
  drivers.

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

* tag 'tty-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (66 commits)
  of: base: Change logic in of_alias_get_alias_list()
  of: base: Fix english spelling in of_alias_get_alias_list()
  serial: sh-sci: do not warn if DMA transfers are not supported
  serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES
  tty: check name length in tty_find_polling_driver()
  serial: sh-sci: Add r8a77990 support
  tty: wipe buffer if not echoing data
  tty: wipe buffer.
  serial: fsl_lpuart: Remove the alias node dependence
  TTY: sn_console: Replace spin_is_locked() with spin_trylock()
  Revert "serial:serial_core: Allow use of CTS for PPS line discipline"
  serial: 8250_uniphier: add auto-flow-control support
  serial: 8250_uniphier: flatten probe function
  serial: 8250_uniphier: remove unused "fifo-size" property
  dt-bindings: serial: sh-sci: Document r8a7744 bindings
  serial: uartps: Fix missing unlock on error in cdns_get_id()
  tty/serial: atmel: add ISO7816 support
  tty/serial_core: add ISO7816 infrastructure
  serial:serial_core: Allow use of CTS for PPS line discipline
  serial: docs: Fix filename for serial reference implementation
  ...

43 files changed, 977 insertions, 380 deletions

diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
index eaca9da79d83..e52e16c6bc57 100644
--- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
+++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
@@ -14,6 +14,10 @@ Required properties:
     - "renesas,scifa-r8a7743" for R8A7743 (RZ/G1M) SCIFA compatible UART.
     - "renesas,scifb-r8a7743" for R8A7743 (RZ/G1M) SCIFB compatible UART.
     - "renesas,hscif-r8a7743" for R8A7743 (RZ/G1M) HSCIF compatible UART.
+    - "renesas,scif-r8a7744" for R8A7744 (RZ/G1N) SCIF compatible UART.
+    - "renesas,scifa-r8a7744" for R8A7744 (RZ/G1N) SCIFA compatible UART.
+    - "renesas,scifb-r8a7744" for R8A7744 (RZ/G1N) SCIFB compatible UART.
+    - "renesas,hscif-r8a7744" for R8A7744 (RZ/G1N) HSCIF compatible UART.
     - "renesas,scif-r8a7745" for R8A7745 (RZ/G1E) SCIF compatible UART.
     - "renesas,scifa-r8a7745" for R8A7745 (RZ/G1E) SCIFA compatible UART.
     - "renesas,scifb-r8a7745" for R8A7745 (RZ/G1E) SCIFB compatible UART.
@@ -50,6 +54,8 @@ Required properties:
     - "renesas,hscif-r8a77970" for R8A77970 (R-Car V3M) HSCIF compatible UART.
     - "renesas,scif-r8a77980" for R8A77980 (R-Car V3H) SCIF compatible UART.
     - "renesas,hscif-r8a77980" for R8A77980 (R-Car V3H) HSCIF compatible UART.
+    - "renesas,scif-r8a77990" for R8A77990 (R-Car E3) SCIF compatible UART.
+    - "renesas,hscif-r8a77990" for R8A77990 (R-Car E3) HSCIF compatible UART.
     - "renesas,scif-r8a77995" for R8A77995 (R-Car D3) SCIF compatible UART.
     - "renesas,hscif-r8a77995" for R8A77995 (R-Car D3) HSCIF compatible UART.
     - "renesas,scifa-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFA compatible UART.
diff --git a/Documentation/devicetree/bindings/serial/uniphier-uart.txt b/Documentation/devicetree/bindings/serial/uniphier-uart.txt
index 0b3892a7a528..7a1bf02bb869 100644
--- a/Documentation/devicetree/bindings/serial/uniphier-uart.txt
+++ b/Documentation/devicetree/bindings/serial/uniphier-uart.txt
@@ -7,7 +7,7 @@ Required properties:
 - clocks: phandle to the input clock.
 
 Optional properties:
-- fifo-size: the RX/TX FIFO size.  Defaults to 64 if not specified.
+-auto-flow-control: enable automatic flow control support.
 
 Example:
 	aliases {
@@ -19,5 +19,4 @@ Example:
 		reg = <0x54006800 0x40>;
 		interrupts = <0 33 4>;
 		clocks = <&uart_clk>;
-		fifo-size = <64>;
 	};
diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index da193e092fc3..86e47c19a924 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -7,7 +7,7 @@ This document is meant as a brief overview of some aspects of the new serial
 driver.  It is not complete, any questions you have should be directed to
 <rmk@arm.linux.org.uk>
 
-The reference implementation is contained within amba_pl011.c.
+The reference implementation is contained within amba-pl011.c.
 
 
 
diff --git a/Documentation/serial/serial-iso7816.txt b/Documentation/serial/serial-iso7816.txt
new file mode 100644
index 000000000000..3193d24a2b0f
--- /dev/null
+++ b/Documentation/serial/serial-iso7816.txt
@@ -0,0 +1,83 @@
+                        ISO7816 SERIAL COMMUNICATIONS
+
+1. INTRODUCTION
+
+  ISO/IEC7816 is a series of standards specifying integrated circuit cards (ICC)
+  also known as smart cards.
+
+2. HARDWARE-RELATED CONSIDERATIONS
+
+  Some CPUs/UARTs (e.g., Microchip AT91) contain a built-in mode capable of
+  handling communication with a smart card.
+
+  For these microcontrollers, the Linux driver should be made capable of
+  working in both modes, and proper ioctls (see later) should be made
+  available at user-level to allow switching from one mode to the other, and
+  vice versa.
+
+3. DATA STRUCTURES ALREADY AVAILABLE IN THE KERNEL
+
+  The Linux kernel provides the serial_iso7816 structure (see [1]) to handle
+  ISO7816 communications. This data structure is used to set and configure
+  ISO7816 parameters in ioctls.
+
+  Any driver for devices capable of working both as RS232 and ISO7816 should
+  implement the iso7816_config callback in the uart_port structure. The
+  serial_core calls iso7816_config to do the device specific part in response
+  to TIOCGISO7816 and TIOCSISO7816 ioctls (see below). The iso7816_config
+  callback receives a pointer to struct serial_iso7816.
+
+4. USAGE FROM USER-LEVEL
+
+  From user-level, ISO7816 configuration can be get/set using the previous
+  ioctls. For instance, to set ISO7816 you can use the following code:
+
+	#include <linux/serial.h>
+
+	/* Include definition for ISO7816 ioctls: TIOCSISO7816 and TIOCGISO7816 */
+	#include <sys/ioctl.h>
+
+	/* Open your specific device (e.g., /dev/mydevice): */
+	int fd = open ("/dev/mydevice", O_RDWR);
+	if (fd < 0) {
+		/* Error handling. See errno. */
+	}
+
+	struct serial_iso7816 iso7816conf;
+
+	/* Reserved fields as to be zeroed */
+	memset(&iso7816conf, 0, sizeof(iso7816conf));
+
+	/* Enable ISO7816 mode: */
+	iso7816conf.flags |= SER_ISO7816_ENABLED;
+
+	/* Select the protocol: */
+	/* T=0 */
+	iso7816conf.flags |= SER_ISO7816_T(0);
+	/* or T=1 */
+	iso7816conf.flags |= SER_ISO7816_T(1);
+
+	/* Set the guard time: */
+	iso7816conf.tg = 2;
+
+	/* Set the clock frequency*/
+	iso7816conf.clk = 3571200;
+
+	/* Set transmission factors: */
+	iso7816conf.sc_fi = 372;
+	iso7816conf.sc_di = 1;
+
+	if (ioctl(fd_usart, TIOCSISO7816, &iso7816conf) < 0) {
+		/* Error handling. See errno. */
+	}
+
+	/* Use read() and write() syscalls here... */
+
+	/* Close the device when finished: */
+	if (close (fd) < 0) {
+		/* Error handling. See errno. */
+	}
+
+5. REFERENCES
+
+ [1]    include/uapi/linux/serial.h
diff --git a/arch/alpha/include/uapi/asm/ioctls.h b/arch/alpha/include/uapi/asm/ioctls.h
index 3729d92d3fa8..1e9121c9b3c7 100644
--- a/arch/alpha/include/uapi/asm/ioctls.h
+++ b/arch/alpha/include/uapi/asm/ioctls.h
@@ -102,6 +102,8 @@
 #define TIOCGPTLCK	_IOR('T', 0x39, int) /* Get Pty lock state */
 #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
 #define TIOCGPTPEER	_IO('T', 0x41) /* Safely open the slave */
+#define TIOCGISO7816	_IOR('T', 0x42, struct serial_iso7816)
+#define TIOCSISO7816	_IOWR('T', 0x43, struct serial_iso7816)
 
 #define TIOCSERCONFIG	0x5453
 #define TIOCSERGWILD	0x5454
diff --git a/arch/mips/include/uapi/asm/ioctls.h b/arch/mips/include/uapi/asm/ioctls.h
index 890245a9f0c4..16aa8a766aec 100644
--- a/arch/mips/include/uapi/asm/ioctls.h
+++ b/arch/mips/include/uapi/asm/ioctls.h
@@ -93,6 +93,8 @@
 #define TIOCGPTLCK	_IOR('T', 0x39, int) /* Get Pty lock state */
 #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
 #define TIOCGPTPEER	_IO('T', 0x41) /* Safely open the slave */
+#define TIOCGISO7816	_IOR('T', 0x42, struct serial_iso7816)
+#define TIOCSISO7816	_IOWR('T', 0x43, struct serial_iso7816)
 
 /* I hope the range from 0x5480 on is free ... */
 #define TIOCSCTTY	0x5480		/* become controlling tty */
diff --git a/arch/parisc/include/uapi/asm/ioctls.h b/arch/parisc/include/uapi/asm/ioctls.h
index aafb1c0ca0af..82d1148c6379 100644
--- a/arch/parisc/include/uapi/asm/ioctls.h
+++ b/arch/parisc/include/uapi/asm/ioctls.h
@@ -62,6 +62,8 @@
 #define TIOCGPTLCK	_IOR('T', 0x39, int) /* Get Pty lock state */
 #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
 #define TIOCGPTPEER	_IO('T', 0x41) /* Safely open the slave */
+#define TIOCGISO7816	_IOR('T', 0x42, struct serial_iso7816)
+#define TIOCSISO7816	_IOWR('T', 0x43, struct serial_iso7816)
 
 #define FIONCLEX	0x5450  /* these numbers need to be adjusted. */
 #define FIOCLEX		0x5451
diff --git a/arch/powerpc/include/uapi/asm/ioctls.h b/arch/powerpc/include/uapi/asm/ioctls.h
index 41b1a5c15734..2c145da3b774 100644
--- a/arch/powerpc/include/uapi/asm/ioctls.h
+++ b/arch/powerpc/include/uapi/asm/ioctls.h
@@ -102,6 +102,8 @@
 #define TIOCGPTLCK	_IOR('T', 0x39, int) /* Get Pty lock state */
 #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
 #define TIOCGPTPEER	_IO('T', 0x41) /* Safely open the slave */
+#define TIOCGISO7816	_IOR('T', 0x42, struct serial_iso7816)
+#define TIOCSISO7816	_IOWR('T', 0x43, struct serial_iso7816)
 
 #define TIOCSERCONFIG	0x5453
 #define TIOCSERGWILD	0x5454
diff --git a/arch/sh/include/uapi/asm/ioctls.h b/arch/sh/include/uapi/asm/ioctls.h
index cc62f6f98103..11866d4f60e1 100644
--- a/arch/sh/include/uapi/asm/ioctls.h
+++ b/arch/sh/include/uapi/asm/ioctls.h
@@ -95,6 +95,8 @@
 #define TIOCGPTLCK	_IOR('T', 0x39, int) /* Get Pty lock state */
 #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
 #define TIOCGPTPEER	_IO('T', 0x41) /* Safely open the slave */
+#define TIOCGISO7816	_IOR('T', 0x42, struct serial_iso7816)
+#define TIOCSISO7816	_IOWR('T', 0x43, struct serial_iso7816)
 
 #define TIOCSERCONFIG	_IO('T', 83) /* 0x5453 */
 #define TIOCSERGWILD	_IOR('T', 84,  int) /* 0x5454 */
diff --git a/arch/sparc/include/uapi/asm/ioctls.h b/arch/sparc/include/uapi/asm/ioctls.h
index 2df52711e170..7fd2f5873c9e 100644
--- a/arch/sparc/include/uapi/asm/ioctls.h
+++ b/arch/sparc/include/uapi/asm/ioctls.h
@@ -27,6 +27,8 @@
 #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
 #define TIOCGRS485	_IOR('T', 0x41, struct serial_rs485)
 #define TIOCSRS485	_IOWR('T', 0x42, struct serial_rs485)
+#define TIOCGISO7816	_IOR('T', 0x43, struct serial_iso7816)
+#define TIOCSISO7816	_IOWR('T', 0x44, struct serial_iso7816)
 
 /* Note that all the ioctls that are not available in Linux have a
  * double underscore on the front to: a) avoid some programs to
diff --git a/arch/xtensa/include/uapi/asm/ioctls.h b/arch/xtensa/include/uapi/asm/ioctls.h
index ec43609cbfc5..6d4a87296c95 100644
--- a/arch/xtensa/include/uapi/asm/ioctls.h
+++ b/arch/xtensa/include/uapi/asm/ioctls.h
@@ -107,6 +107,8 @@
 #define TIOCGPTLCK	_IOR('T', 0x39, int) /* Get Pty lock state */
 #define TIOCGEXCL	_IOR('T', 0x40, int) /* Get exclusive mode state */
 #define TIOCGPTPEER	_IO('T', 0x41) /* Safely open the slave */
+#define TIOCGISO7816	_IOR('T', 0x42, struct serial_iso7816)
+#define TIOCSISO7816	_IOWR('T', 0x43, struct serial_iso7816)
 
 #define TIOCSERCONFIG	_IO('T', 83)
 #define TIOCSERGWILD	_IOR('T', 84,  int)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 13ebb16be64e..d023cf303d56 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -16,6 +16,7 @@
 
 #define pr_fmt(fmt)	"OF: " fmt
 
+#include <linux/bitmap.h>
 #include <linux/console.h>
 #include <linux/ctype.h>
 #include <linux/cpu.h>
@@ -1986,6 +1987,59 @@ int of_alias_get_id(struct device_node *np, const char *stem)
 EXPORT_SYMBOL_GPL(of_alias_get_id);
 
 /**
+ * of_alias_get_alias_list - Get alias list for the given device driver
+ * @matches:	Array of OF device match structures to search in
+ * @stem:	Alias stem of the given device_node
+ * @bitmap:	Bitmap field pointer
+ * @nbits:	Maximum number of alias IDs which can be recorded in bitmap
+ *
+ * The function travels the lookup table to record alias ids for the given
+ * device match structures and alias stem.
+ *
+ * Return:	0 or -ENOSYS when !CONFIG_OF or
+ *		-EOVERFLOW if alias ID is greater then allocated nbits
+ */
+int of_alias_get_alias_list(const struct of_device_id *matches,
+			     const char *stem, unsigned long *bitmap,
+			     unsigned int nbits)
+{
+	struct alias_prop *app;
+	int ret = 0;
+
+	/* Zero bitmap field to make sure that all the time it is clean */
+	bitmap_zero(bitmap, nbits);
+
+	mutex_lock(&of_mutex);
+	pr_debug("%s: Looking for stem: %s\n", __func__, stem);
+	list_for_each_entry(app, &aliases_lookup, link) {
+		pr_debug("%s: stem: %s, id: %d\n",
+			 __func__, app->stem, app->id);
+
+		if (strcmp(app->stem, stem) != 0) {
+			pr_debug("%s: stem comparison didn't pass %s\n",
+				 __func__, app->stem);
+			continue;
+		}
+
+		if (of_match_node(matches, app->np)) {
+			pr_debug("%s: Allocated ID %d\n", __func__, app->id);
+
+			if (app->id >= nbits) {
+				pr_warn("%s: ID %d >= than bitmap field %d\n",
+					__func__, app->id, nbits);
+				ret = -EOVERFLOW;
+			} else {
+				set_bit(app->id, bitmap);
+			}
+		}
+	}
+	mutex_unlock(&of_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_alias_get_alias_list);
+
+/**
  * of_alias_get_highest_id - Get highest alias id for the given stem
  * @stem:	Alias stem to be examined
  *
diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index eea4049b5dcc..769e0a5d1dfc 100644
--- a/drivers/tty/ehv_bytechan.c
+++ b/drivers/tty/ehv_bytechan.c
@@ -128,8 +128,8 @@ static int find_console_handle(void)
 	 */
 	iprop = of_get_property(np, "hv-handle", NULL);
 	if (!iprop) {
-		pr_err("ehv-bc: no 'hv-handle' property in %s node\n",
-		       np->name);
+		pr_err("ehv-bc: no 'hv-handle' property in %pOFn node\n",
+		       np);
 		return 0;
 	}
 	stdout_bc = be32_to_cpu(*iprop);
@@ -661,8 +661,8 @@ static int ehv_bc_tty_probe(struct platform_device *pdev)
 
 	iprop = of_get_property(np, "hv-handle", NULL);
 	if (!iprop) {
-		dev_err(&pdev->dev, "no 'hv-handle' property in %s node\n",
-			np->name);
+		dev_err(&pdev->dev, "no 'hv-handle' property in %pOFn node\n",
+			np);
 		return -ENODEV;
 	}
 
@@ -682,8 +682,8 @@ static int ehv_bc_tty_probe(struct platform_device *pdev)
 	bc->rx_irq = irq_of_parse_and_map(np, 0);
 	bc->tx_irq = irq_of_parse_and_map(np, 1);
 	if ((bc->rx_irq == NO_IRQ) || (bc->tx_irq == NO_IRQ)) {
-		dev_err(&pdev->dev, "no 'interrupts' property in %s node\n",
-			np->name);
+		dev_err(&pdev->dev, "no 'interrupts' property in %pOFn node\n",
+			np);
 		ret = -ENODEV;
 		goto error;
 	}
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 431742201709..3ad460219fd6 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -152,17 +152,28 @@ static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
 	return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
 }
 
+/* If we are not echoing the data, perhaps this is a secret so erase it */
+static void zero_buffer(struct tty_struct *tty, u8 *buffer, int size)
+{
+	bool icanon = !!L_ICANON(tty);
+	bool no_echo = !L_ECHO(tty);
+
+	if (icanon && no_echo)
+		memset(buffer, 0x00, size);
+}
+
 static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
 			    size_t tail, size_t n)
 {
 	struct n_tty_data *ldata = tty->disc_data;
 	size_t size = N_TTY_BUF_SIZE - tail;
-	const void *from = read_buf_addr(ldata, tail);
+	void *from = read_buf_addr(ldata, tail);
 	int uncopied;
 
 	if (n > size) {
 		tty_audit_add_data(tty, from, size);
 		uncopied = copy_to_user(to, from, size);
+		zero_buffer(tty, from, size - uncopied);
 		if (uncopied)
 			return uncopied;
 		to += size;
@@ -171,7 +182,9 @@ static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
 	}
 
 	tty_audit_add_data(tty, from, n);
-	return copy_to_user(to, from, n);
+	uncopied = copy_to_user(to, from, n);
+	zero_buffer(tty, from, n - uncopied);
+	return uncopied;
 }
 
 /**
@@ -1960,11 +1973,12 @@ static int copy_from_read_buf(struct tty_struct *tty,
 	n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail);
 	n = min(*nr, n);
 	if (n) {
-		const unsigned char *from = read_buf_addr(ldata, tail);
+		unsigned char *from = read_buf_addr(ldata, tail);
 		retval = copy_to_user(*b, from, n);
 		n -= retval;
 		is_eof = n == 1 && *from == EOF_CHAR(tty);
 		tty_audit_add_data(tty, from, n);
+		zero_buffer(tty, from, n);
 		smp_store_release(&ldata->read_tail, ldata->read_tail + n);
 		/* Turn single EOF into zero-length read */
 		if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 8fe3d0ed229e..94f3e1c64490 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -130,12 +130,8 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
 
 		l = l->next;
 
-		if (l == i->head && pass_counter++ > PASS_LIMIT) {
-			/* If we hit this, we're dead. */
-			printk_ratelimited(KERN_ERR
-				"serial8250: too much work for irq%d\n", irq);
+		if (l == i->head && pass_counter++ > PASS_LIMIT)
 			break;
-		}
 	} while (l != end);
 
 	spin_unlock(&i->lock);
diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
index af8beefe9b5c..877fd7f8a8ed 100644
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -58,7 +58,7 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 	struct resource resource;
 	struct device_node *np = ofdev->dev.of_node;
 	u32 clk, spd, prop;
-	int ret;
+	int ret, irq;
 
 	memset(port, 0, sizeof *port);
 
@@ -143,21 +143,27 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 	if (ret >= 0)
 		port->line = ret;
 
-	port->irq = irq_of_parse_and_map(np, 0);
-	if (!port->irq) {
-		ret = -EPROBE_DEFER;
-		goto err_unprepare;
+	irq = of_irq_get(np, 0);
+	if (irq < 0) {
+		if (irq == -EPROBE_DEFER) {
+			ret = -EPROBE_DEFER;
+			goto err_unprepare;
+		}
+		/* IRQ support not mandatory */
+		irq = 0;
 	}
 
+	port->irq = irq;
+
 	info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
 	if (IS_ERR(info->rst)) {
 		ret = PTR_ERR(info->rst);
-		goto err_dispose;
+		goto err_unprepare;
 	}
 
 	ret = reset_control_deassert(info->rst);
 	if (ret)
-		goto err_dispose;
+		goto err_unprepare;
 
 	port->type = type;
 	port->uartclk = clk;
@@ -184,8 +190,6 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 		port->handle_irq = fsl8250_handle_irq;
 
 	return 0;
-err_dispose:
-	irq_dispose_mapping(port->irq);
 err_unprepare:
 	clk_disable_unprepare(info->clk);
 err_pmruntime:
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 3f779d25ec0c..f776b3eafb96 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -552,11 +552,30 @@ static unsigned int serial_icr_read(struct uart_8250_port *up, int offset)
  */
 static void serial8250_clear_fifos(struct uart_8250_port *p)
 {
+	unsigned char fcr;
+	unsigned char clr_mask = UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT;
+
 	if (p->capabilities & UART_CAP_FIFO) {
-		serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO);
-		serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO |
-			       UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
-		serial_out(p, UART_FCR, 0);
+		/*
+		 * Make sure to avoid changing FCR[7:3] and ENABLE_FIFO bits.
+		 * In case ENABLE_FIFO is not set, there is nothing to flush
+		 * so just return. Furthermore, on certain implementations of
+		 * the 8250 core, the FCR[7:3] bits may only be changed under
+		 * specific conditions and changing them if those conditions
+		 * are not met can have nasty side effects. One such core is
+		 * the 8250-omap present in TI AM335x.
+		 */
+		fcr = serial_in(p, UART_FCR);
+
+		/* FIFO is not enabled, there's nothing to clear. */
+		if (!(fcr & UART_FCR_ENABLE_FIFO))
+			return;
+
+		fcr |= clr_mask;
+		serial_out(p, UART_FCR, fcr);
+
+		fcr &= ~clr_mask;
+		serial_out(p, UART_FCR, fcr);
 	}
 }
 
@@ -1448,7 +1467,7 @@ static void __do_stop_tx_rs485(struct uart_8250_port *p)
 	 * Enable previously disabled RX interrupts.
 	 */
 	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
-		serial8250_clear_and_reinit_fifos(p);
+		serial8250_clear_fifos(p);
 
 		p->ier |= UART_IER_RLSI | UART_IER_RDI;
 		serial_port_out(&p->port, UART_IER, p->ier);
diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c
index 28d88ccf5a0c..164ba133437a 100644
--- a/drivers/tty/serial/8250/8250_uniphier.c
+++ b/drivers/tty/serial/8250/8250_uniphier.c
@@ -12,9 +12,6 @@
 
 #include "8250.h"
 
-/* Most (but not all) of UniPhier UART devices have 64-depth FIFO. */
-#define UNIPHIER_UART_DEFAULT_FIFO_SIZE	64
-
 /*
  * This hardware is similar to 8250, but its register map is a bit different:
  *   - MMIO32 (regshift = 2)
@@ -158,42 +155,6 @@ static void uniphier_serial_dl_write(struct uart_8250_port *up, int value)
 	writel(value, up->port.membase + UNIPHIER_UART_DLR);
 }
 
-static int uniphier_of_serial_setup(struct device *dev, struct uart_port *port,
-				    struct uniphier8250_priv *priv)
-{
-	int ret;
-	u32 prop;
-	struct device_node *np = dev->of_node;
-
-	ret = of_alias_get_id(np, "serial");
-	if (ret < 0) {
-		dev_err(dev, "failed to get alias id\n");
-		return ret;
-	}
-	port->line = ret;
-
-	/* Get clk rate through clk driver */
-	priv->clk = devm_clk_get(dev, NULL);
-	if (IS_ERR(priv->clk)) {
-		dev_err(dev, "failed to get clock\n");
-		return PTR_ERR(priv->clk);
-	}
-
-	ret = clk_prepare_enable(priv->clk);
-	if (ret < 0)
-		return ret;
-
-	port->uartclk = clk_get_rate(priv->clk);
-
-	/* Check for fifo size */
-	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
-		port->fifosize = prop;
-	else
-		port->fifosize = UNIPHIER_UART_DEFAULT_FIFO_SIZE;
-
-	return 0;
-}
-
 static int uniphier_uart_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -226,10 +187,25 @@ static int uniphier_uart_probe(struct platform_device *pdev)
 
 	memset(&up, 0, sizeof(up));
 
-	ret = uniphier_of_serial_setup(dev, &up.port, priv);
-	if (ret < 0)
+	ret = of_alias_get_id(dev->of_node, "serial");
+	if (ret < 0) {
+		dev_err(dev, "failed to get alias id\n");
+		return ret;
+	}
+	up.port.line = ret;
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
 		return ret;
 
+	up.port.uartclk = clk_get_rate(priv->clk);
+
 	spin_lock_init(&priv->atomic_write_lock);
 
 	up.port.dev = dev;
@@ -241,10 +217,14 @@ static int uniphier_uart_probe(struct platform_device *pdev)
 
 	up.port.type = PORT_16550A;
 	up.port.iotype = UPIO_MEM32;
+	up.port.fifosize = 64;
 	up.port.regshift = UNIPHIER_UART_REGSHIFT;
 	up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE;
 	up.capabilities = UART_CAP_FIFO;
 
+	if (of_property_read_bool(dev->of_node, "auto-flow-control"))
+		up.capabilities |= UART_CAP_AFE;
+
 	up.port.serial_in = uniphier_serial_in;
 	up.port.serial_out = uniphier_serial_out;
 	up.dl_read = uniphier_serial_dl_read;
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index f005eaf8bc57..15c2c5463835 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -375,7 +375,7 @@ config SERIAL_8250_RT288X
 
 config SERIAL_8250_OMAP
 	tristate "Support for OMAP internal UART (8250 based driver)"
-	depends on SERIAL_8250 &&