Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3381 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
new file mode 100644
index 000000000..5a2e67a8d
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -0,0 +1,3381 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Base port operations for 8250/16550-type serial ports
+ *
+ *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
+ *  Split from 8250_core.c, Copyright (C) 2001 Russell King.
+ *
+ * A note about mapbase / membase
+ *
+ *  mapbase is the physical address of the IO port.
+ *  membase is an 'ioremapped' cookie.
+ */
+
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/tty.h>
+#include <linux/ratelimit.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/serial_8250.h>
+#include <linux/nmi.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/pm_runtime.h>
+#include <linux/ktime.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include "8250.h"
+
+/*
+ * These are definitions for the Exar XR17V35X and XR17(C|D)15X
+ */
+#define UART_EXAR_INT0		0x80
+#define UART_EXAR_SLEEP		0x8b	/* Sleep mode */
+#define UART_EXAR_DVID		0x8d	/* Device identification */
+
+/* Nuvoton NPCM timeout register */
+#define UART_NPCM_TOR          7
+#define UART_NPCM_TOIE         BIT(7)  /* Timeout Interrupt Enable */
+
+/*
+ * Debugging.
+ */
+#if 0
+#define DEBUG_AUTOCONF(fmt...)	printk(fmt)
+#else
+#define DEBUG_AUTOCONF(fmt...)	do { } while (0)
+#endif
+
+#define BOTH_EMPTY	(UART_LSR_TEMT | UART_LSR_THRE)
+
+/*
+ * Here we define the default xmit fifo size used for each type of UART.
+ */
+static const struct serial8250_config uart_config[] = {
+	[PORT_UNKNOWN] = {
+		.name		= "unknown",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_8250] = {
+		.name		= "8250",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16450] = {
+		.name		= "16450",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16550] = {
+		.name		= "16550",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16550A] = {
+		.name		= "16550A",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.rxtrig_bytes	= {1, 4, 8, 14},
+		.flags		= UART_CAP_FIFO,
+	},
+	[PORT_CIRRUS] = {
+		.name		= "Cirrus",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16650] = {
+		.name		= "ST16650",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+		.flags		= UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+	},
+	[PORT_16650V2] = {
+		.name		= "ST16650V2",
+		.fifo_size	= 32,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
+				  UART_FCR_T_TRIG_00,
+		.rxtrig_bytes	= {8, 16, 24, 28},
+		.flags		= UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+	},
+	[PORT_16750] = {
+		.name		= "TI16750",
+		.fifo_size	= 64,
+		.tx_loadsz	= 64,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
+				  UART_FCR7_64BYTE,
+		.rxtrig_bytes	= {1, 16, 32, 56},
+		.flags		= UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE,
+	},
+	[PORT_STARTECH] = {
+		.name		= "Startech",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16C950] = {
+		.name		= "16C950/954",
+		.fifo_size	= 128,
+		.tx_loadsz	= 128,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01,
+		.rxtrig_bytes	= {16, 32, 112, 120},
+		/* UART_CAP_EFR breaks billionon CF bluetooth card. */
+		.flags		= UART_CAP_FIFO | UART_CAP_SLEEP,
+	},
+	[PORT_16654] = {
+		.name		= "ST16654",
+		.fifo_size	= 64,
+		.tx_loadsz	= 32,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
+				  UART_FCR_T_TRIG_10,
+		.rxtrig_bytes	= {8, 16, 56, 60},
+		.flags		= UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+	},
+	[PORT_16850] = {
+		.name		= "XR16850",
+		.fifo_size	= 128,
+		.tx_loadsz	= 128,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+	},
+	[PORT_RSA] = {
+		.name		= "RSA",
+		.fifo_size	= 2048,
+		.tx_loadsz	= 2048,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11,
+		.flags		= UART_CAP_FIFO,
+	},
+	[PORT_NS16550A] = {
+		.name		= "NS16550A",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO | UART_NATSEMI,
+	},
+	[PORT_XSCALE] = {
+		.name		= "XScale",
+		.fifo_size	= 32,
+		.tx_loadsz	= 32,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO | UART_CAP_UUE | UART_CAP_RTOIE,
+	},
+	[PORT_OCTEON] = {
+		.name		= "OCTEON",
+		.fifo_size	= 64,
+		.tx_loadsz	= 64,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO,
+	},
+	[PORT_AR7] = {
+		.name		= "AR7",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
+		.flags		= UART_CAP_FIFO /* | UART_CAP_AFE */,
+	},
+	[PORT_U6_16550A] = {
+		.name		= "U6_16550A",
+		.fifo_size	= 64,
+		.tx_loadsz	= 64,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE,
+	},
+	[PORT_TEGRA] = {
+		.name		= "Tegra",
+		.fifo_size	= 32,
+		.tx_loadsz	= 8,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
+				  UART_FCR_T_TRIG_01,
+		.rxtrig_bytes	= {1, 4, 8, 14},
+		.flags		= UART_CAP_FIFO | UART_CAP_RTOIE,
+	},
+	[PORT_XR17D15X] = {
+		.name		= "XR17D15X",
+		.fifo_size	= 64,
+		.tx_loadsz	= 64,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
+				  UART_CAP_SLEEP,
+	},
+	[PORT_XR17V35X] = {
+		.name		= "XR17V35X",
+		.fifo_size	= 256,
+		.tx_loadsz	= 256,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11 |
+				  UART_FCR_T_TRIG_11,
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
+				  UART_CAP_SLEEP,
+	},
+	[PORT_LPC3220] = {
+		.name		= "LPC3220",
+		.fifo_size	= 64,
+		.tx_loadsz	= 32,
+		.fcr		= UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
+				  UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00,
+		.flags		= UART_CAP_FIFO,
+	},
+	[PORT_BRCM_TRUMANAGE] = {
+		.name		= "TruManage",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1024,
+		.flags		= UART_CAP_HFIFO,
+	},
+	[PORT_8250_CIR] = {
+		.name		= "CIR port"
+	},
+	[PORT_ALTR_16550_F32] = {
+		.name		= "Altera 16550 FIFO32",
+		.fifo_size	= 32,
+		.tx_loadsz	= 32,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.rxtrig_bytes	= {1, 8, 16, 30},
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE,
+	},
+	[PORT_ALTR_16550_F64] = {
+		.name		= "Altera 16550 FIFO64",
+		.fifo_size	= 64,
+		.tx_loadsz	= 64,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.rxtrig_bytes	= {1, 16, 32, 62},
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE,
+	},
+	[PORT_ALTR_16550_F128] = {
+		.name		= "Altera 16550 FIFO128",
+		.fifo_size	= 128,
+		.tx_loadsz	= 128,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.rxtrig_bytes	= {1, 32, 64, 126},
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE,
+	},
+	/*
+	 * tx_loadsz is set to 63-bytes instead of 64-bytes to implement
+	 * workaround of errata A-008006 which states that tx_loadsz should
+	 * be configured less than Maximum supported fifo bytes.
+	 */
+	[PORT_16550A_FSL64] = {
+		.name		= "16550A_FSL64",
+		.fifo_size	= 64,
+		.tx_loadsz	= 63,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
+				  UART_FCR7_64BYTE,
+		.flags		= UART_CAP_FIFO,
+	},
+	[PORT_RT2880] = {
+		.name		= "Palmchip BK-3103",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.rxtrig_bytes	= {1, 4, 8, 14},
+		.flags		= UART_CAP_FIFO,
+	},
+	[PORT_DA830] = {
+		.name		= "TI DA8xx/66AK2x",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
+				  UART_FCR_R_TRIG_10,
+		.rxtrig_bytes	= {1, 4, 8, 14},
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE,
+	},
+	[PORT_MTK_BTIF] = {
+		.name		= "MediaTek BTIF",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO |
+				  UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
+		.flags		= UART_CAP_FIFO,
+	},
+	[PORT_NPCM] = {
+		.name		= "Nuvoton 16550",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
+				  UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
+		.rxtrig_bytes	= {1, 4, 8, 14},
+		.flags		= UART_CAP_FIFO,
+	},
+};
+
+/* Uart divisor latch read */
+static int default_serial_dl_read(struct uart_8250_port *up)
+{
+	/* Assign these in pieces to truncate any bits above 7.  */
+	unsigned char dll = serial_in(up, UART_DLL);
+	unsigned char dlm = serial_in(up, UART_DLM);
+
+	return dll | dlm << 8;
+}
+
+/* Uart divisor latch write */
+static void default_serial_dl_write(struct uart_8250_port *up, int value)
+{
+	serial_out(up, UART_DLL, value & 0xff);
+	serial_out(up, UART_DLM, value >> 8 & 0xff);
+}
+
+#ifdef CONFIG_SERIAL_8250_RT288X
+
+/* Au1x00/RT288x UART hardware has a weird register layout */
+static const s8 au_io_in_map[8] = {
+	 0,	/* UART_RX  */
+	 2,	/* UART_IER */
+	 3,	/* UART_IIR */
+	 5,	/* UART_LCR */
+	 6,	/* UART_MCR */
+	 7,	/* UART_LSR */
+	 8,	/* UART_MSR */
+	-1,	/* UART_SCR (unmapped) */
+};
+
+static const s8 au_io_out_map[8] = {
+	 1,	/* UART_TX  */
+	 2,	/* UART_IER */
+	 4,	/* UART_FCR */
+	 5,	/* UART_LCR */
+	 6,	/* UART_MCR */
+	-1,	/* UART_LSR (unmapped) */
+	-1,	/* UART_MSR (unmapped) */
+	-1,	/* UART_SCR (unmapped) */
+};
+
+unsigned int au_serial_in(struct uart_port *p, int offset)
+{
+	if (offset >= ARRAY_SIZE(au_io_in_map))
+		return UINT_MAX;
+	offset = au_io_in_map[offset];
+	if (offset < 0)
+		return UINT_MAX;
+	return __raw_readl(p->membase + (offset << p->regshift));
+}
+
+void au_serial_out(struct uart_port *p, int offset, int value)
+{
+	if (offset >= ARRAY_SIZE(au_io_out_map))
+		return;
+	offset = au_io_out_map[offset];
+	if (offset < 0)
+		return;
+	__raw_writel(value, p->membase + (offset << p->regshift));
+}
+
+/* Au1x00 haven't got a standard divisor latch */
+static int au_serial_dl_read(struct uart_8250_port *up)
+{
+	return __raw_readl(up->port.membase + 0x28);
+}
+
+static void au_serial_dl_write(struct uart_8250_port *up, int value)
+{
+	__raw_writel(value, up->port.membase + 0x28);
+}
+
+#endif
+
+static unsigned int hub6_serial_in(struct uart_port *p, int offset)
+{
+	offset = offset << p->regshift;
+	outb(p->hub6 - 1 + offset, p->iobase);
+	return inb(p->iobase + 1);
+}
+
+static void hub6_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = offset << p->regshift;
+	outb(p->hub6 - 1 + offset, p->iobase);
+	outb(value, p->iobase + 1);
+}
+
+static unsigned int mem_serial_in(struct uart_port *p, int offset)
+{
+	offset = offset << p->regshift;
+	return readb(p->membase + offset);
+}
+
+static void mem_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = offset << p->regshift;
+	writeb(value, p->membase + offset);
+}
+
+static void mem16_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = offset << p->regshift;
+	writew(value, p->membase + offset);
+}
+
+static unsigned int mem16_serial_in(struct uart_port *p, int offset)
+{
+	offset = offset << p->regshift;
+	return readw(p->membase + offset);
+}
+
+static void mem32_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = offset << p->regshift;
+	writel(value, p->membase + offset);
+}
+
+static unsigned int mem32_serial_in(struct uart_port *p, int offset)
+{
+	offset = offset << p->regshift;
+	return readl(p->membase + offset);
+}
+
+static void mem32be_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = offset << p->regshift;
+	iowrite32be(value, p->membase + offset);
+}
+
+static unsigned int mem32be_serial_in(struct uart_port *p, int offset)
+{
+	offset = offset << p->regshift;
+	return ioread32be(p->membase + offset);
+}
+
+static unsigned int io_serial_in(struct uart_port *p, int offset)
+{
+	offset = offset << p->regshift;
+	return inb(p->iobase + offset);
+}
+
+static void io_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = offset << p->regshift;
+	outb(value, p->iobase + offset);
+}
+
+static int serial8250_default_handle_irq(struct uart_port *port);
+
+static void set_io_from_upio(struct uart_port *p)
+{
+	struct uart_8250_port *up = up_to_u8250p(p);
+
+	up->dl_read = default_serial_dl_read;
+	up->dl_write = default_serial_dl_write;
+
+	switch (p->iotype) {
+	case UPIO_HUB6:
+		p->serial_in = hub6_serial_in;
+		p->serial_out = hub6_serial_out;
+		break;
+
+	case UPIO_MEM:
+		p->serial_in = mem_serial_in;
+		p->serial_out = mem_serial_out;
+		break;
+
+	case UPIO_MEM16:
+		p->serial_in = mem16_serial_in;
+		p->serial_out = mem16_serial_out;
+		break;
+
+	case UPIO_MEM32:
+		p->serial_in = mem32_serial_in;
+		p->serial_out = mem32_serial_out;
+		break;
+
+	case UPIO_MEM32BE:
+		p->serial_in = mem32be_serial_in;
+		p->serial_out = mem32be_serial_out;
+		break;
+
+#ifdef CONFIG_SERIAL_8250_RT288X
+	case UPIO_AU:
+		p->serial_in = au_serial_in;
+		p->serial_out = au_serial_out;
+		up->dl_read = au_serial_dl_read;
+		up->dl_write = au_serial_dl_write;
+		break;
+#endif
+
+	default:
+		p->serial_in = io_serial_in;
+		p->serial_out = io_serial_out;
+		break;
+	}
+	/* Remember loaded iotype */
+	up->cur_iotype = p->iotype;
+	p->handle_irq = serial8250_default_handle_irq;
+}
+
+static void
+serial_port_out_sync(struct uart_port *p, int offset, int value)
+{
+	switch (p->iotype) {
+	case UPIO_MEM:
+	case UPIO_MEM16:
+	case UPIO_MEM32:
+	case UPIO_MEM32BE:
+	case UPIO_AU:
+		p->serial_out(p, offset, value);
+		p->serial_in(p, UART_LCR);	/* safe, no side-effects */
+		break;
+	default:
+		p->serial_out(p, offset, value);
+	}
+}
+
+/*
+ * For the 16C950
+ */
+static void serial_icr_write(struct uart_8250_port *up, int offset, int value)
+{
+	serial_out(up, UART_SCR, offset);
+	serial_out(up, UART_ICR, value);
+}
+
+static unsigned int serial_icr_read(struct uart_8250_port *up, int offset)
+{
+	unsigned int value;
+
+	serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD);
+	serial_out(up, UART_SCR, offset);
+	value = serial_in(up, UART_ICR);
+	serial_icr_write(up, UART_ACR, up->acr);
+
+	return value;
+}
+
+/*
+ * FIFO support.
+ */
+static void serial8250_clear_fifos(struct uart_8250_port *p)
+{
+	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);
+	}
+}
+
+static inline void serial8250_em485_rts_after_send(struct uart_8250_port *p)
+{
+	unsigned char mcr = serial8250_in_MCR(p);
+
+	if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
+		mcr |= UART_MCR_RTS;
+	else
+		mcr &= ~UART_MCR_RTS;
+	serial8250_out_MCR(p, mcr);
+}
+
+static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t);
+static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t);
+
+void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
+{
+	serial8250_clear_fifos(p);
+	serial_out(p, UART_FCR, p->fcr);
+}
+EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
+
+void serial8250_rpm_get(struct uart_8250_port *p)
+{
+	if (!(p->capabilities & UART_CAP_RPM))
+		return;
+	pm_runtime_get_sync(p->port.dev);
+}
+EXPORT_SYMBOL_GPL(serial8250_rpm_get);
+
+void serial8250_rpm_put(struct uart_8250_port *p)
+{
+	if (!(p->capabilities & UART_CAP_RPM))
+		return;
+	pm_runtime_mark_last_busy(p->port.dev);
+	pm_runtime_put_autosuspend(p->port.dev);
+}
+EXPORT_SYMBOL_GPL(serial8250_rpm_put);
+
+/**
+ *	serial8250_em485_init() - put uart_8250_port into rs485 emulating
+ *	@p:	uart_8250_port port instance
+ *
+ *	The function is used to start rs485 software emulating on the
+ *	&struct uart_8250_port* @p. Namely, RTS is switched before/after
+ *	transmission. The function is idempotent, so it is safe to call it
+ *	multiple times.
+ *
+ *	The caller MUST enable interrupt on empty shift register before
+ *	calling serial8250_em485_init(). This interrupt is not a part of
+ *	8250 standard, but implementation defined.
+ *
+ *	The function is supposed to be called from .rs485_config callback
+ *	or from any other callback protected with p->port.lock spinlock.
+ *
+ *	See also serial8250_em485_destroy()
+ *
+ *	Return 0 - success, -errno - otherwise
+ */
+int serial8250_em485_init(struct uart_8250_port *p)
+{
+	if (p->em485)
+		return 0;
+
+	p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC);
+	if (!p->em485)
+		return -ENOMEM;
+
+	hrtimer_init(&p->em485->stop_tx_timer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_REL);
+	hrtimer_init(&p->em485->start_tx_timer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_REL);
+	p->em485->stop_tx_timer.function = &serial8250_em485_handle_stop_tx;
+	p->em485->start_tx_timer.function = &serial8250_em485_handle_start_tx;
+	p->em485->port = p;
+	p->em485->active_timer = NULL;
+	serial8250_em485_rts_after_send(p);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(serial8250_em485_init);
+
+/**
+ *	serial8250_em485_destroy() - put uart_8250_port into normal state
+ *	@p:	uart_8250_port port instance
+ *
+ *	The function is used to stop rs485 software emulating on the
+ *	&struct uart_8250_port* @p. The function is idempotent, so it is safe to
+ *	call it multiple times.
+ *
+ *	The function is supposed to be called from .rs485_config callback
+ *	or from any other callback protected with p->port.lock spinlock.
+ *
+ *	See also serial8250_em485_init()
+ */
+void serial8250_em485_destroy(struct uart_8250_port *p)
+{
+	if (!p->em485)
+		return;
+
+	hrtimer_cancel(&p->em485->start_tx_timer);
+	hrtimer_cancel(&p->em485->stop_tx_timer);
+
+	kfree(p->em485);
+	p->em485 = NULL;
+}
+EXPORT_SYMBOL_GPL(serial8250_em485_destroy);
+
+/*
+ * These two wrappers ensure that enable_runtime_pm_tx() can be called more than
+ * once and disable_runtime_pm_tx() will still disable RPM because the fifo is
+ * empty and the HW can idle again.
+ */
+void serial8250_rpm_get_tx(struct uart_8250_port *p)
+{
+	unsigned char rpm_active;
+
+	if (!(p->capabilities & UART_CAP_RPM))
+		return;
+
+	rpm_active = xchg(&p->rpm_tx_active, 1);
+	if (rpm_active)
+		return;
+	pm_runtime_get_sync(p->port.dev);
+}
+EXPORT_SYMBOL_GPL(serial8250_rpm_get_tx);
+
+void serial8250_rpm_put_tx(struct uart_8250_port *p)
+{
+	unsigned char rpm_active;
+
+	if (!(p->capabilities & UART_CAP_RPM))
+		return;
+
+	rpm_active = xchg(&p->rpm_tx_active, 0);
+	if (!rpm_active)
+		return;
+	pm_runtime_mark_last_busy(p->port.dev);
+	pm_runtime_put_autosuspend(p->port.dev);
+}
+EXPORT_SYMBOL_GPL(serial8250_rpm_put_tx);
+
+/*
+ * IER sleep support.  UARTs which have EFRs need the "extended
+ * capability" bit enabled.  Note that on XR16C850s, we need to
+ * reset LCR to write to IER.
+ */
+static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
+{
+	unsigned char lcr = 0, efr = 0;
+	/*
+	 * Exar UARTs have a SLEEP register that enables or disables
+	 * each UART to enter sleep mode separately.  On the XR17V35x the
+	 * register is accessible to each UART at the UART_EXAR_SLEEP
+	 * offset but the UART channel may only write to the corresponding
+	 * bit.
+	 */
+	serial8250_rpm_get(p);
+	if ((p->port.type == PORT_XR17V35X) ||
+	   (p->port.type == PORT_XR17D15X)) {
+		serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0);
+		goto out;
+	}
+
+	if (p->capabilities & UART_CAP_SLEEP) {
+		if (p->capabilities & UART_CAP_EFR) {
+			lcr = serial_in(p, UART_LCR);
+			efr = serial_in(p, UART_EFR);
+			serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
+			serial_out(p, UART_EFR, UART_EFR_ECB);
+			serial_out(p, UART_LCR, 0);
+		}
+		serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
+		if (p->capabilities & UART_CAP_EFR) {
+			serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
+			serial_out(p, UART_EFR, efr);
+			serial_out(p, UART_LCR, lcr);
+		}
+	}
+out:
+	serial8250_rpm_put(p);
+}
+
+#ifdef CONFIG_SERIAL_8250_RSA
+/*
+ * Attempts to turn on the RSA FIFO.  Returns zero on failure.
+ * We set the port uart clock rate if we succeed.
+ */
+static int __enable_rsa(struct uart_8250_port *up)
+{
+	unsigned char mode;
+	int result;
+
+	mode = serial_in(up, UART_RSA_MSR);
+	result = mode & UART_RSA_MSR_FIFO;
+
+	if (!result) {
+		serial_out(up, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
+		mode = serial_in(up, UART_RSA_MSR);
+		result = mode & UART_RSA_MSR_FIFO;
+	}
+
+	if (result)
+		up->port.uartclk = SERIAL_RSA_BAUD_BASE * 16;
+
+	return result;
+}
+
+static void enable_rsa(struct uart_8250_port *up)
+{
+	if (up->port.type == PORT_RSA) {
+		if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
+			spin_lock_irq(&up->port.lock);
+			__enable_rsa(up);
+			spin_unlock_irq(&up->port.lock);
+		}
+		if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
+			serial_out(up, UART_RSA_FRR, 0);
+	}
+}
+
+/*
+ * Attempts to turn off the RSA FIFO.  Returns zero on failure.
+ * It is unknown why interrupts were disabled in here.  However,
+ * the caller is expected to preserve this behaviour by grabbing
+ * the spinlock before calling this function.
+ */
+static void disable_rsa(struct uart_8250_port *up)
+{
+	unsigned char mode;
+	int result;
+
+	if (up->port.type == PORT_RSA &&
+	    up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
+		spin_lock_irq(&up->port.lock);
+
+		mode = serial_in(up, UART_RSA_MSR);
+		result = !(mode & UART_RSA_MSR_FIFO);
+
+		if (!result) {
+			serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
+			mode = serial_in(up, UART_RSA_MSR);
+			result = !(mode & UART_RSA_MSR_FIFO);
+		}
+
+		if (result)
+			up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
+		spin_unlock_irq(&up->port.lock);
+	}
+}
+#endif /* CONFIG_SERIAL_8250_RSA */
+
+/*
+ * This is a quickie test to see how big the FIFO is.
+ * It doesn't work at all the time, more's the pity.
+ */
+static int size_fifo(struct uart_8250_port *up)
+{
+	unsigned char old_fcr, old_mcr, old_lcr;
+	unsigned short old_dl;
+	int count;
+
+	old_lcr = serial_in(up, UART_LCR);
+	serial_out(up, UART_LCR, 0);
+	old_fcr = serial_in(up, UART_FCR);
+	old_mcr = serial8250_in_MCR(up);
+	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
+		    UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+	serial8250_out_MCR(up, UART_MCR_LOOP);
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	old_dl = serial_dl_read(up);
+	serial_dl_write(up, 0x0001);
+	serial_out(up, UART_LCR, 0x03);
+	for (count = 0; count < 256; count++)
+		serial_out(up, UART_TX, count);
+	mdelay(20);/* FIXME - schedule_timeout */
+	for (count = 0; (serial_in(up, UART_LSR) & UART_LSR_DR) &&
+	     (count < 256); count++)
+		serial_in(up, UART_RX);
+	serial_out(up, UART_FCR, old_fcr);
+	serial8250_out_MCR(up, old_mcr);
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	serial_dl_write(up, old_dl);
+	serial_out(up, UART_LCR, old_lcr);
+
+	return count;
+}
+
+/*
+ * Read UART ID using the divisor method - set DLL and DLM to zero
+ * and the revision will be in DLL and device type in DLM.  We
+ * preserve the device state across this.
+ */
+static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
+{
+	unsigned char old_lcr;
+	unsigned int id, old_dl;
+
+	old_lcr = serial_in(p, UART_LCR);
+	serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
+	old_dl = serial_dl_read(p);
+	serial_dl_write(p, 0);
+	id = serial_dl_read(p);
+	serial_dl_write(p, old_dl);
+
+	serial_out(p, UART_LCR, old_lcr);
+
+	return id;
+}
+
+/*
+ * This is a helper routine to autodetect StarTech/Exar/Oxsemi UART's.
+ * When this function is called we know it is at least a StarTech
+ * 16650 V2, but it might be one of several StarTech UARTs, or one of
+ * its clones.  (We treat the broken original StarTech 16650 V1 as a
+ * 16550, and why not?  Startech doesn't seem to even acknowledge its
+ * existence.)
+ *
+ * What evil have men's minds wrought...
+ */
+static void autoconfig_has_efr(struct uart_8250_port *up)
+{
+	unsigned int id1, id2, id3, rev;
+
+	/*
+	 * Everything with an EFR has SLEEP
+	 */
+	up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
+
+	/*
+	 * First we check to see if it's an Oxford Semiconductor UART.
+	 *
+	 * If we have to do this here because some non-National
+	 * Semiconductor clone chips lock up if you try writing to the
+	 * LSR register (which serial_icr_read does)
+	 */
+
+	/*
+	 * Check for Oxford Semiconductor 16C950.
+	 *
+	 * EFR [4] must be set else this test fails.
+	 *
+	 * This shouldn't be necessary, but Mike Hudson (Exoray@isys.ca)
+	 * claims that it's needed for 952 dual UART's (which are not
+	 * recommended for new designs).
+	 */
+	up->acr = 0;
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	serial_out(up, UART_EFR, UART_EFR_ECB);
+	serial_out(up, UART_LCR, 0x00);
+	id1 = serial_icr_read(up, UART_ID1);
+	id2 = serial_icr_read(up, UART_ID2);
+	id3 = serial_icr_read(up, UART_ID3);
+	rev = serial_icr_read(up, UART_REV);
+
+	DEBUG_AUTOCONF("950id=%02x:%02x:%02x:%02x ", id1, id2, id3, rev);
+
+	if (id1 == 0x16 && id2 == 0xC9 &&
+	    (id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) {
+		up->port.type = PORT_16C950;
+
+		/*
+		 * Enable work around for the Oxford Semiconductor 952 rev B
+		 * chip which causes it to seriously miscalculate baud rates
+		 * when DLL is 0.
+		 */
+		if (id3 == 0x52 && rev == 0x01)
+			up->bugs |= UART_BUG_QUOT;
+		return;
+	}
+
+	/*
+	 * We check for a XR16C850 by setting DLL and DLM to 0, and then
+	 * reading back DLL and DLM.  The chip type depends on the DLM
+	 * value read back:
+	 *  0x10 - XR16C850 and the DLL contains the chip revision.
+	 *  0x12 - XR16C2850.
+	 *  0x14 - XR16C854.
+	 */
+	id1 = autoconfig_read_divisor_id(up);
+	DEBUG_AUTOCONF("850id=%04x ", id1);
+
+	id2 = id1 >> 8;
+	if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) {
+		up->port.type = PORT_16850;
+		return;
+	}
+
+	/*
+	 * It wasn't an XR16C850.
+	 *
+	 * We distinguish between the '654 and the '650 by counting
+	 * how many bytes are in the FIFO.  I'm using this for now,
+	 * since that's the technique that was sent to me in the
+	 * serial driver update, but I'm not convinced this works.
+	 * I've had problems doing this in the past.  -TYT
+	 */
+	if (size_fifo(up) == 64)
+		up->port.type = PORT_16654;
+	else
+		up->port.type = PORT_16650V2;
+}
+
+/*
+ * We detected a chip without a FIFO.  Only two fall into
+ * this category - the original 8250 and the 16450.  The
+ * 16450 has a scratch register (accessible with LCR=0)
+ */
+static void autoconfig_8250(struct uart_8250_port *up)
+{
+	unsigned char scratch, status1, status2;
+
+	up->port.type = PORT_8250;
+
+	scratch = serial_in(up, UART_SCR);
+	serial_out(up, UART_SCR, 0xa5);
+	status1 = serial_in(up, UART_SCR);
+	serial_out(up, UART_SCR, 0x5a);
+	status2 = serial_in(up, UART_SCR);
+	serial_out(up, UART_SCR, scratch);
+
+	if (status1 == 0xa5 && status2 == 0x5a)
+		up->port.type = PORT_16450;
+}
+
+static int broken_efr(struct uart_8250_port *up)
+{
+	/*
+	 * Exar ST16C2550 "A2" devices incorrectly detect as
+	 * having an EFR, and report an ID of 0x0201.  See
+	 * http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-11/4812.html
+	 */
+	if (autoconfig_read_divisor_id(up) == 0x0201 && size_fifo(up) == 16)
+		return 1;
+
+	return 0;
+}
+
+/*
+ * We know that the chip has FIFOs.  Does it have an EFR?  The
+ * EFR is located in the same register position as the IIR and
+ * we know the top two bits of the IIR are currently set.  The
+ * EFR should contain zero.  Try to read the EFR.
+ */
+static void autoconfig_16550a(struct uart_8250_port *up)
+{
+	unsigned char status1, status2;
+	unsigned int iersave;
+
+	up->port.type = PORT_16550A;
+	up->capabilities |= UART_CAP_FIFO;
+
+	/*
+	 * XR17V35x UARTs have an extra divisor register, DLD
+	 * that gets enabled with when DLAB is set which will
+	 * cause the device to incorrectly match and assign
+	 * port type to PORT_16650.  The EFR for this UART is
+	 * found at offset 0x09. Instead check the Deice ID (DVID)
+	 * register for a 2, 4 or 8 port UART.
+	 */
+	if (up->port.flags & UPF_EXAR_EFR) {
+		status1 = serial_in(up, UART_EXAR_DVID);
+		if (status1 == 0x82 || status1 == 0x84 || status1 == 0x88) {
+			DEBUG_AUTOCONF("Exar XR17V35x ");
+			up->port.type = PORT_XR17V35X;
+			up->capabilities |= UART_CAP_AFE | UART_CAP_EFR |
+						UART_CAP_SLEEP;
+
+			return;
+		}
+
+	}
+
+	/*
+	 * Check for presence of the EFR when DLAB is set.
+	 * Only ST16C650V1 UARTs pass this test.
+	 */
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	if (serial_in(up, UART_EFR) == 0) {
+		serial_out(up, UART_EFR, 0xA8);
+		if (serial_in(up, UART_EFR) != 0) {
+			DEBUG_AUTOCONF("EFRv1 ");
+			up->port.type = PORT_16650;
+			up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
+		} else {
+			serial_out(up, UART_LCR, 0);
+			serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
+				   UART_FCR7_64BYTE);
+			status1 = serial_in(up, UART_IIR) >> 5;
+			serial_out(up, UART_FCR, 0);
+			serial_out(up, UART_LCR, 0);
+
+			if (status1 == 7)
+				up->port.type = PORT_16550A_FSL64;
+			else
+				DEBUG_AUTOCONF("Motorola 8xxx DUART ");
+		}
+		serial_out(up, UART_EFR, 0);
+		return;
+	}
+
+	/*
+	 * Maybe it requires 0xbf to be written to the LCR.
+	 * (other ST16C650V2 UARTs, TI16C752A, etc)
+	 */
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	if (serial_in(up, UART_EFR) == 0 && !broken_efr(up)) {
+		DEBUG_AUTOCONF("EFRv2 ");
+		autoconfig_has_efr(up);
+		return;
+	}
+
+	/*
+	 * Check for a National Semiconductor SuperIO chip.
+	 * Attempt to switch to bank 2, read the value of the LOOP bit
+	 * from EXCR1. Switch back to bank 0, change it in MCR. Then
+	 * switch back to bank 2, read it from EXCR1 again and check
+	 * it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2
+	 */
+	serial_out(up, UART_LCR, 0);
+	status1 = serial8250_in_MCR(up);
+	serial_out(up, UART_LCR, 0xE0);
+	status2 = serial_in(up, 0x02); /* EXCR1 */
+
+	if (!((status2 ^ status1) & UART_MCR_LOOP)) {
+		serial_out(up, UART_LCR, 0);
+		serial8250_out_MCR(up, status1 ^ UART_MCR_LOOP);
+		serial_out(up, UART_LCR, 0xE0);
+		status2 = serial_in(up, 0x02); /* EXCR1 */
+		serial_out(up, UART_LCR, 0);
+		serial8250_out_MCR(up, status1);
+
+		if ((status2 ^ status1) & UART_MCR_LOOP) {
+			unsigned short quot;
+
+			serial_out(up, UART_LCR, 0xE0);
+
+			quot = serial_dl_read(up);
+			quot <<= 3;
+
+			if (ns16550a_goto_highspeed(up))
+				serial_dl_write(up, quot);
+
+			serial_out(up, UART_LCR, 0);
+
+			up->port.uartclk = 921600*16;
+			up->port.type = PORT_NS16550A;
+			up->capabilities |= UART_NATSEMI;
+			return;
+		}
+	}
+
+	/*
+	 * No EFR.  Try to detect a TI16750, which only sets bit 5 of
+	 * the IIR when 64 byte FIFO mode is enabled when DLAB is set.
+	 * Try setting it with and without DLAB set.  Cheap clones
+	 * set bit 5 without DLAB set.
+	 */
+	serial_out(up, UART_LCR, 0);
+	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
+	status1 = serial_in(up, UART_IIR) >> 5;
+	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
+	status2 = serial_in(up, UART_IIR) >> 5;
+	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+	serial_out(up, UART_LCR, 0);
+
+	DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
+
+	if (status1 == 6 && status2 == 7) {
+		up->port.type = PORT_16750;
+		up->capabilities |= UART_CAP_AFE | UART_CAP_SLEEP;
+		return;
+	}
+
+	/*
+	 * Try writing and reading the UART_IER_UUE bit (b6).
+	 * If it works, this is probably one of the Xscale platform's
+	 * internal UARTs.
+	 * We're going to explicitly set the UUE bit to 0 before
+	 * trying to write and read a 1 just to make sure it's not
+	 * already a 1 and maybe locked there before we even start start.
+	 */
+	iersave = serial_in(up, UART_IER);
+	serial_out(up, UART_IER, iersave & ~UART_IER_UUE);
+	if (!(serial_in(up, UART_IER) & UART_IER_UUE)) {
+		/*
+		 * OK it's in a known zero state, try writing and reading
+		 * without disturbing the current state of the other bits.
+		 */
+		serial_out(up, UART_IER, iersave | UART_IER_UUE);
+		if (serial_in(up, UART_IER) & UART_IER_UUE) {
+			/*
+			 * It's an Xscale.
+			 * We'll leave the UART_IER_UUE bit set to 1 (enabled).
+			 */
+			DEBUG_AUTOCONF("Xscale ");
+			up->port.type = PORT_XSCALE;
+			up->capabilities |= UART_CAP_UUE | UART_CAP_RTOIE;
+			return;
+		}
+	} else {
+		/*
+		 * If we got here we couldn't force the IER_UUE bit to 0.
+		 * Log it and continue.
+		 */
+		DEBUG_AUTOCONF("Couldn't force IER_UUE to 0 ");
+	}
+	serial_out(up, UART_IER, iersave);
+
+	/*
+	 * Exar uarts have EFR in a weird location
+	 */
+	if (up->port.flags & UPF_EXAR_EFR) {
+		DEBUG_AUTOCONF("Exar XR17D15x ");
+		up->port.type = PORT_XR17D15X;
+		up->capabilities |= UART_CAP_AFE | UART_CAP_EFR |
+				    UART_CAP_SLEEP;
+
+		return;
+	}
+
+	/*
+	 * We distinguish between 16550A and U6 16550A by counting
+	 * how many bytes are in the FIFO.
+	 */
+	if (up->port.type == PORT_16550A && size_fifo(up) == 64) {
+		up->port.type = PORT_U6_16550A;
+		up->capabilities |= UART_CAP_AFE;
+	}
+}
+
+/*
+ * This routine is called by rs_init() to initialize a specific serial
+ * port.  It determines what type of UART chip this serial port is
+ * using: 8250, 16450, 16550, 16550A.  The important question is
+ * whether or not this UART is a 16550A or not, since this will
+ * determine whether or not we can use its FIFO features or not.
+ */
+static void autoconfig(struct uart_8250_port *up)
+{
+	unsigned char status1, scratch, scratch2, scratch3;
+	unsigned char save_lcr, save_mcr;
+	struct uart_port *port = &up->port;
+	unsigned long flags;
+	unsigned int old_capabilities;
+
+	if (!port->iobase && !port->mapbase && !port->membase)
+		return;
+
+	DEBUG_AUTOCONF("%s: autoconf (0x%04lx, 0x%p): ",
+		       port->name, port->iobase, port->membase);
+
+	/*
+	 * We really do need global IRQs disabled here - we're going to
+	 * be frobbing the chips IRQ enable register to see if it exists.
+	 */
+	spin_lock_irqsave(&port->lock, flags);
+
+	up->capabilities = 0;
+	up->bugs = 0;
+
+	if (!(port->flags & UPF_BUGGY_UART)) {
+		/*
+		 * Do a simple existence test first; if we fail this,
+		 * there's no point trying anything else.
+		 *
+		 * 0x80 is used as a nonsense port to prevent against
+		 * false positives due to ISA bus float.  The
+		 * assumption is that 0x80 is a non-existent port;
+		 * which should be safe since include/asm/io.h also
+		 * makes this assumption.
+		 *
+		 * Note: this is safe as long as MCR bit 4 is clear
+		 * and the device is in "PC" mode.
+		 */
+		scratch = serial_in(up, UART_IER);
+		serial_out(up, UART_IER, 0);
+#ifdef __i386__
+		outb(0xff, 0x080);
+#endif
+		/*
+		 * Mask out IER[7:4] bits for test as some UARTs (e.g. TL
+		 * 16C754B) allow only to modify them if an EFR bit is set.
+		 */
+		scratch2 = serial_in(up, UART_IER) & 0x0f;
+		serial_out(up, UART_IER, 0x0F);
+#ifdef __i386__
+		outb(0, 0x080);
+#endif
+		scratch3 = serial_in(up, UART_IER) & 0x0f;
+		serial_out(up, UART_IER, scratch);
+		if (scratch2 != 0 || scratch3 != 0x0F) {
+			/*
+			 * We failed; there's nothing here
+			 */
+			spin_unlock_irqrestore(&port->lock, flags);
+			DEBUG_AUTOCONF("IER test failed (%02x, %02x) ",
+				       scratch2, scratch3);
+			goto out;
+		}
+	}
+
+	save_mcr = serial8250_in_MCR(up);
+	save_lcr = serial_in(up, UART_LCR);
+
+	/*
+	 * Check to see if a UART is really there.  Certain broken
+	 * internal modems based on the Rockwell chipset fail this
+	 * test, because they apparently don't implement the loopback
+	 * test mode.  So this test is skipped on the COM 1 through
+	 * COM 4 ports.  This *should* be safe, since no board
+	 * manufacturer would be stupid enough to design a board
+	 * that conflicts with COM 1-4 --- we hope!
+	 */
+	if (!(port->flags & UPF_SKIP_TEST)) {
+		serial8250_out_MCR(up, UART_MCR_LOOP | 0x0A);
+		status1 = serial_in(up, UART_MSR) & 0xF0;
+		serial8250_out_MCR(up, save_mcr);
+		if (status1 != 0x90) {
+			spin_unlock_irqrestore(&port->lock, flags);
+			DEBUG_AUTOCONF("LOOP test failed (%02x) ",
+				       status1);
+			goto out;
+		}
+	}
+
+	/*
+	 * We're pretty sure there's a port here.  Lets find out what
+	 * type of port it is.  The IIR top two bits allows us to find
+	 * out if it's 8250 or 16450, 16550, 16550A or later.  This
+	 * determines what we test for next.
+	 *
+	 * We also initialise the EFR (if any) to zero for later.  The
+	 * EFR occupies the same register location as the FCR and IIR.
+	 */
+	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+	serial_out(up, UART_EFR, 0);
+	serial_out(up, UART_LCR, 0);
+
+	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+
+	/* Assign this as it is to truncate any bits above 7.  */
+	scratch = serial_in(up, UART_IIR);
+
+	switch (scratch >> 6) {
+	case 0:
+		autoconfig_8250(up);
+		break;
+	case 1:
+		port->type = PORT_UNKNOWN;
+		break;
+	case 2:
+		port->type = PORT_16550;
+		break;
+	case 3:
+		autoconfig_16550a(up);
+		break;
+	}
+
+#ifdef CONFIG_SERIAL_8250_RSA
+	/*
+	 * Only probe for RSA ports if we got the region.
+	 */
+	if (port->type == PORT_16550A && up->probe & UART_PROBE_RSA &&
+	    __enable_rsa(up))
+		port->type = PORT_RSA;
+#endif
+
+	serial_out(up, UART_LCR, save_lcr);
+
+	port->fifosize = uart_config[up->port.type].fifo_size;
+	old_capabilities = up->capabilities;
+	up->capabilities = uart_config[port->type].flags;
+	up->tx_loadsz = uart_config[port->type].tx_loadsz;
+
+	if (port->type == PORT_UNKNOWN)
+		goto out_lock;
+
+	/*
+	 * Reset the UART.
+	 */
+#ifdef CONFIG_SERIAL_8250_RSA
+	if (port->type == PORT_RSA)
+		serial_out(up, UART_RSA_FRR, 0);
+#endif
+	serial8250_out_MCR(up, save_mcr);
+	serial8250_clear_fifos(up);
+	serial_in(up, UART_RX);
+	if (up->capabilities & UART_CAP_UUE)
+		serial_out(up, UART_IER, UART_IER_UUE);
+	else
+		serial_out(up, UART_IER, 0);
+
+out_lock:
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	/*
+	 * Check if the device is a Fintek F81216A
+	 */
+	if (port->type == PORT_16550A && port->iotype == UPIO_PORT)
+		fintek_8250_probe(up);
+
+	if (up->capabilities != old_capabilities) {
+		pr_warn("%s: detected caps %08x should be %08x\n",
+			port->name, old_capabilities, up->capabilities);
+	}
+out:
+	DEBUG_AUTOCONF("iir=%d ", scratch);
+	DEBUG_AUTOCONF("type=%s\n", uart_config[port->type].name);
+}
+
+static void autoconfig_irq(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+	unsigned char save_mcr, save_ier;
+	unsigned char save_ICP = 0;
+	unsigned int ICP = 0;
+	unsigned long irqs;
+	int irq;
+
+	if (port->flags & UPF_FOURPORT) {
+		ICP = (port->iobase & 0xfe0) | 0x1f;
+		save_ICP = inb_p(ICP);
+		outb_p(0x80, ICP);
+		inb_p(ICP);
+	}
+
+	if (uart_console(port))
+		console_lock();
+
+	/* forget possible initially masked and pending IRQ */
+	probe_irq_off(probe_irq_on());
+	save_mcr = serial8250_in_MCR(up);
+	save_ier = serial_in(up, UART_IER);
+	serial8250_out_MCR(up, UART_MCR_OUT1 | UART_MCR_OUT2);
+
+	irqs = probe_irq_on();
+	serial8250_out_MCR(up, 0);
+	udelay(10);
+	if (port->flags & UPF_FOURPORT) {
+		serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
+	} else {
+		serial8250_out_MCR(up,
+			UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2);
+	}
+	serial_out(up, UART_IER, 0x0f);	/* enable all intrs */
+	serial_in(up, UART_LSR);
+	serial_in(up, UART_RX);
+	serial_in(up, UART_IIR);
+	serial_in(up, UART_MSR);
+	serial_out(up, UART_TX, 0xFF);
+	udelay(20);
+	irq = probe_irq_off(irqs);
+
+	serial8250_out_MCR(up, save_mcr);
+	serial_out(up, UART_IER, save_ier);
+
+	if (port->flags & UPF_FOURPORT)
+		outb_p(save_ICP, ICP);
+
+	if (uart_console(port))
+		console_unlock();
+
+	port->irq = (irq > 0) ? irq : 0;
+}
+
+static void serial8250_stop_rx(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	serial8250_rpm_get(up);
+
+	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
+	up->port.read_status_mask &= ~UART_LSR_DR;
+	serial_port_out(port, UART_IER, up->ier);
+
+	serial8250_rpm_put(up);
+}
+
+static void __do_stop_tx_rs485(struct uart_8250_port *p)
+{
+	serial8250_em485_rts_after_send(p);
+
+	/*
+	 * Empty the RX FIFO, we are not interested in anything
+	 * received during the half-duplex transmission.
+	 * Enable previously disabled RX interrupts.
+	 */
+	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
+		serial8250_clear_and_reinit_fifos(p);
+
+		p->ier |= UART_IER_RLSI | UART_IER_RDI;
+		serial_port_out(&p->port, UART_IER, p->ier);
+	}
+}
+static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
+{
+	struct uart_8250_em485 *em485;
+	struct uart_8250_port *p;
+	unsigned long flags;
+
+	em485 = container_of(t, struct uart_8250_em485, stop_tx_timer);
+	p = em485->port;
+
+	serial8250_rpm_get(p);
+	spin_lock_irqsave(&p->port.lock, flags);
+	if (em485->active_timer == &em485->stop_tx_timer) {
+		__do_stop_tx_rs485(p);
+		em485->active_timer = NULL;
+	}
+	spin_unlock_irqrestore(&p->port.lock, flags);
+	serial8250_rpm_put(p);
+	return HRTIMER_NORESTART;
+}
+
+static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
+{
+	long sec = msec / 1000;
+	long nsec = (msec % 1000) * 1000000;
+	ktime_t t = ktime_set(sec, nsec);
+
+	hrtimer_start(hrt, t, HRTIMER_MODE_REL);
+}
+
+static void __stop_tx_rs485(struct uart_8250_port *p)
+{
+	struct uart_8250_em485 *em485 = p->em485;
+
+	/*
+	 * __do_stop_tx_rs485 is going to set RTS according to config
+	 * AND flush RX FIFO if required.
+	 */
+	if (p->port.rs485.delay_rts_after_send > 0) {
+		em485->active_timer = &em485->stop_tx_timer;
+		start_hrtimer_ms(&em485->stop_tx_timer,
+				   p->port.rs485.delay_rts_after_send);
+	} else {
+		__do_stop_tx_rs485(p);
+	}
+}
+
+static inline void __do_stop_tx(struct uart_8250_port *p)
+{
+	if (p->ier & UART_IER_THRI) {
+		p->ier &= ~UART_IER_THRI;
+		serial_out(p, UART_IER, p->ier);
+		serial8250_rpm_put_tx(p);
+	}
+}
+
+static inline void __stop_tx(struct uart_8250_port *p)
+{
+	struct uart_8250_em485 *em485 = p->em485;
+
+	if (em485) {
+		unsigned char lsr = serial_in(p, UART_LSR);
+		p->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+
+		/*
+		 * To provide required timeing and allow FIFO transfer,
+		 * __stop_tx_rs485() must be called only when both FIFO and
+		 * shift register are empty. It is for device driver to enable
+		 * interrupt on TEMT.
+		 */
+		if ((lsr & BOTH_EMPTY) != BOTH_EMPTY)
+			return;
+
+		em485->active_timer = NULL;
+
+		__stop_tx_rs485(p);
+	}
+	__do_stop_tx(p);
+}
+
+static void serial8250_stop_tx(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	serial8250_rpm_get(up);
+	__stop_tx(up);
+
+	/*
+	 * We really want to stop the transmitter from sending.
+	 */
+	if (port->type == PORT_16C950) {
+		up->acr |= UART_ACR_TXDIS;
+		serial_icr_write(up, UART_ACR, up->acr);
+	}
+	serial8250_rpm_put(up);
+}
+
+static inline void __start_tx(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	if (up->dma && !up->dma->tx_dma(up))
+		return;
+
+	if (!(up->ier & UART_IER_THRI)) {
+		up->ier |= UART_IER_THRI;
+		serial_port_out(port, UART_IER, up->ier);
+
+		if (up->bugs & UART_BUG_TXEN) {
+			unsigned char lsr;
+
+			lsr = serial_in(up, UART_LSR);
+			up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+			if (lsr & UART_LSR_THRE)
+				serial8250_tx_chars(up);
+		}
+	}
+
+	/*
+	 * Re-enable the transmitter if we disabled it.
+	 */
+	if (port->type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
+		up->acr &= ~UART_ACR_TXDIS;
+		serial_icr_write(up, UART_ACR, up->acr);
+	}
+}
+
+static inline void start_tx_rs485(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct uart_8250_em485 *em485 = up->em485;
+	unsigned char mcr;
+
+	if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
+		serial8250_stop_rx(&up->port);
+
+	/*
+	 * While serial8250_em485_handle_stop_tx() is a noop if
+	 * em485->active_timer != &em485->stop_tx_timer, it might happen that
+	 * the timer is still armed and triggers only after the current bunch of
+	 * chars is send and em485->active_timer == &em485->stop_tx_timer again.
+	 * So cancel the timer. There is still a theoretical race condition if
+	 * the timer is already running and only comes around to check for
+	 * em485->active_timer when &em485->stop_tx_timer is armed again.
+	 */
+	if (em485->active_timer == &em485->stop_tx_timer)
+		hrtimer_try_to_cancel(&em485->stop_tx_timer);
+
+	em485->active_timer = NULL;
+
+	mcr = serial8250_in_MCR(up);
+	if (!!(up->port.rs485.flags & SER_RS485_RTS_ON_SEND) !=
+	    !!(mcr & UART_MCR_RTS)) {
+		if (up->port.rs485.flags & SER_RS485_RTS_ON_SEND)
+			mcr |= UART_MCR_RTS;
+		else
+			mcr &= ~UART_MCR_RTS;
+		serial8250_out_MCR(up, mcr);
+
+		if (up->port.rs485.delay_rts_before_send > 0) {
+			em485->active_timer = &em485->start_tx_timer;
+			start_hrtimer_ms(&em485->start_tx_timer,
+					 up->port.rs485.delay_rts_before_send);
+			return;
+		}
+	}
+
+	__start_tx(port);
+}
+
+static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
+{
+	struct uart_8250_em485 *em485;
+	struct uart_8250_port *p;
+	unsigned long flags;
+
+	em485 = container_of(t, struct uart_8250_em485, start_tx_timer);
+	p = em485->port;
+
+	spin_lock_irqsave(&p->port.lock, flags);
+	if (em485->active_timer == &em485->start_tx_timer) {
+		__start_tx(&p->port);
+		em485->active_timer = NULL;
+	}
+	spin_unlock_irqrestore(&p->port.lock, flags);
+	return HRTIMER_NORESTART;
+}
+
+static void serial8250_start_tx(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct uart_8250_em485 *em485 = up->em485;
+
+	serial8250_rpm_get_tx(up);
+
+	if (em485 &&
+	    em485->active_timer == &em485->start_tx_timer)
+		return;
+
+	if (em485)
+		start_tx_rs485(port);
+	else
+		__start_tx(port);
+}
+
+static void serial8250_throttle(struct uart_port *port)
+{
+	port->throttle(port);
+}
+
+static void serial8250_unthrottle(struct uart_port *port)
+{
+	port->unthrottle(port);
+}
+
+static void serial8250_disable_ms(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	/* no MSR capabilities */
+	if (up->bugs & UART_BUG_NOMSR)
+		return;
+
+	up->ier &= ~UART_IER_MSI;
+	serial_port_out(port, UART_IER, up->ier);
+}
+
+static void serial8250_enable_ms(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	/* no MSR capabilities */
+	if (up->bugs & UART_BUG_NOMSR)
+		return;
+
+	up->ier |= UART_IER_MSI;
+
+	serial8250_rpm_get(up);
+	serial_port_out(port, UART_IER, up->ier);
+	serial8250_rpm_put(up);
+}
+
+void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
+{
+	struct uart_port *port = &up->port;
+	unsigned char ch;
+	char flag = TTY_NORMAL;
+
+	if (likely(lsr & UART_LSR_DR))
+		ch = serial_in(up, UART_RX);
+	else
+		/*
+		 * Intel 82571 has a Serial Over Lan device that will
+		 * set UART_LSR_BI without setting UART_LSR_DR when
+		 * it receives a break. To avoid reading from the
+		 * receive buffer without UART_LSR_DR bit set, we
+		 * just force the read character to be 0
+		 */
+		ch = 0;
+
+	port->icount.rx++;
+
+	lsr |= up->lsr_saved_flags;
+	up->lsr_saved_flags = 0;
+
+	if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
+		if (lsr & UART_LSR_BI) {
+			lsr &= ~(UART_LSR_FE | UART_LSR_PE);
+			port->icount.brk++;
+			/*
+			 * We do the SysRQ and SAK checking
+			 * here because otherwise the break
+			 * may get masked by ignore_status_mask
+			 * or read_status_mask.
+			 */
+			if (uart_handle_break(port))
+				return;
+		} else if (lsr & UART_LSR_PE)
+			port->icount.parity++;
+		else if (lsr & UART_LSR_FE)
+			port->icount.frame++;
+		if (lsr & UART_LSR_OE)
+			port->icount.overrun++;
+
+		/*
+		 * Mask off conditions which should be ignored.
+		 */
+		lsr &= port->read_status_mask;
+
+		if (lsr & UART_LSR_BI) {
+			pr_debug("%s: handling break\n", __func__);
+			flag = TTY_BREAK;
+		} else if (lsr & UART_LSR_PE)
+			flag = TTY_PARITY;
+		else if (lsr & UART_LSR_FE)
+			flag = TTY_FRAME;
+	}
+	if (uart_handle_sysrq_char(port, ch))
+		return;
+
+	uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
+}
+EXPORT_SYMBOL_GPL(serial8250_read_char);
+
+/*
+ * serial8250_rx_chars: processes according to the passed in LSR
+ * value, and returns the remaining LSR bits not handled
+ * by this Rx routine.
+ */
+unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
+{
+	struct uart_port *port = &up->port;
+	int max_count = 256;
+
+	do {
+		serial8250_read_char(up, lsr);
+		if (--max_count == 0)
+			break;
+		lsr = serial_in(up, UART_LSR);
+	} while (lsr & (UART_LSR_DR | UART_LSR_BI));
+
+	tty_flip_buffer_push(&port->state->port);
+	return lsr;
+}
+EXPORT_SYMBOL_GPL(serial8250_rx_chars);
+
+void serial8250_tx_chars(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+	struct circ_buf *xmit = &port->state->xmit;
+	int count;
+
+	if (port->x_char) {
+		serial_out(up, UART_TX, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+	if (uart_tx_stopped(port)) {
+		serial8250_stop_tx(port);
+		return;
+	}
+	if (uart_circ_empty(xmit)) {
+		__stop_tx(up);
+		return;
+	}
+
+	count = up->tx_loadsz;
+	do {
+		serial_out(up, UART_TX, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+		if ((up->capabilities & UART_CAP_HFIFO) &&
+		    (serial_in(up, UART_LSR) & BOTH_EMPTY) != BOTH_EMPTY)
+			break;
+		/* The BCM2835 MINI UART THRE bit is really a not-full bit. */
+		if ((up->capabilities & UART_CAP_MINI) &&
+		    !(serial_in(up, UART_LSR) & UART_LSR_THRE))
+			break;
+	} while (--count > 0);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	/*
+	 * With RPM enabled, we have to wait until the FIFO is empty before the
+	 * HW can go idle. So we get here once again with empty FIFO and disable
+	 * the interrupt and RPM in __stop_tx()
+	 */
+	if (uart_circ_empty(xmit) && !(up->capabilities & UART_CAP_RPM))
+		__stop_tx(up);
+}
+EXPORT_SYMBOL_GPL(serial8250_tx_chars);
+
+/* Caller holds uart port lock */
+unsigned int serial8250_modem_status(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+	unsigned int status = serial_in(up, UART_MSR);
+
+	status |= up->msr_saved_flags;
+	up->msr_saved_flags = 0;
+	if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
+	    port->state != NULL) {
+		if (status & UART_MSR_TERI)
+			port->icount.rng++;
+		if (status & UART_MSR_DDSR)
+			port->icount.dsr++;
+		if (status & UART_MSR_DDCD)
+			uart_handle_dcd_change(port, status & UART_MSR_DCD);
+		if (status & UART_MSR_DCTS)
+			uart_handle_cts_change(port, status & UART_MSR_CTS);
+
+		wake_up_interruptible(&port->state->port.delta_msr_wait);
+	}
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(serial8250_modem_status);
+
+static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
+{
+	switch (iir & 0x3f) {
+	case UART_IIR_RX_TIMEOUT:
+		serial8250_rx_dma_flush(up);
+		/* fall-through */
+	case UART_IIR_RLSI:
+		return true;
+	}
+	return up->dma->rx_dma(up);
+}
+
+/*
+ * This handles the interrupt from one port.
+ */
+int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
+{
+	unsigned char status;
+	unsigned long flags;
+	struct uart_8250_port *up = up_to_u8250p(port);
+	bool skip_rx = false;
+
+	if (iir & UART_IIR_NO_INT)
+		return 0;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	status = serial_port_in(port, UART_LSR);
+
+	/*
+	 * If port is stopped and there are no error conditions in the
+	 * FIFO, then don't drain the FIFO, as this may lead to TTY buffer
+	 * overflow. Not servicing, RX FIFO would trigger auto HW flow
+	 * control when FIFO occupancy reaches preset threshold, thus
+	 * halting RX. This only works when auto HW flow control is
+	 * available.
+	 */
+	if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) &&
+	    (port->status & (UPSTAT_AUTOCTS | UPSTAT_AUTORTS)) &&
+	    !(port->read_status_mask & UART_LSR_DR))
+		skip_rx = true;
+
+	if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) {
+		if (!up->dma || handle_rx_dma(up, iir))
+			status = serial8250_rx_chars(up, status);
+	}
+	serial8250_modem_status(up);
+	if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE) &&
+		(up->ier & UART_IER_THRI))
+		serial8250_tx_chars(up);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(serial8250_handle_irq);
+
+static int serial8250_default_handle_irq(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned int iir;
+	int ret;
+
+	serial8250_rpm_get(up);
+
+	iir = serial_port_in(port, UART_IIR);
+	ret = serial8250_handle_irq(port, iir);
+
+	serial8250_rpm_put(up);
+	return ret;
+}
+
+/*
+ * Newer 16550 compatible parts such as the SC16C650 & Altera 16550 Soft IP
+ * have a programmable TX threshold that triggers the THRE interrupt in
+ * the IIR register. In this case, the THRE interrupt indicates the FIFO
+ * has space available. Load it up with tx_loadsz bytes.
+ */
+static int serial8250_tx_threshold_handle_irq(struct uart_port *port)
+{
+	unsigned long flags;
+	unsigned int iir = serial_port_in(port, UART_IIR);
+
+	/* TX Threshold IRQ triggered so load up FIFO */
+	if ((iir & UART_IIR_ID) == UART_IIR_THRI) {
+		struct uart_8250_port *up = up_to_u8250p(port);
+
+		spin_lock_irqsave(&port->lock, flags);
+		serial8250_tx_chars(up);
+		spin_unlock_irqrestore(&port->lock, flags);
+	}
+
+	iir = serial_port_in(port, UART_IIR);
+	return serial8250_handle_irq(port, iir);
+}
+
+static unsigned int serial8250_tx_empty(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned long flags;
+	unsigned int lsr;
+
+	serial8250_rpm_get(up);
+
+	spin_lock_irqsave(&port->lock, flags);
+	lsr = serial_port_in(port, UART_LSR);
+	up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	serial8250_rpm_put(up);
+
+	return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0;
+}
+
+unsigned int serial8250_do_get_mctrl(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned int status;
+	unsigned int ret;
+
+	serial8250_rpm_get(up);
+	status = serial8250_modem_status(up);
+	serial8250_rpm_put(up);
+
+	ret = 0;
+	if (status & UART_MSR_DCD)
+		ret |= TIOCM_CAR;
+	if (status & UART_MSR_RI)
+		ret |= TIOCM_RNG;
+	if (status & UART_MSR_DSR)
+		ret |= TIOCM_DSR;
+	if (status & UART_MSR_CTS)
+		ret |= TIOCM_CTS;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl);
+
+static unsigned int serial8250_get_mctrl(struct uart_port *port)
+{
+	if (port->get_mctrl)
+		return port->get_mctrl(port);
+	return serial8250_do_get_mctrl(port);
+}
+
+void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned char mcr = 0;
+
+	if (mctrl & TIOCM_RTS)
+		mcr |= UART_MCR_RTS;
+	if (mctrl & TIOCM_DTR)
+		mcr |= UART_MCR_DTR;
+	if (mctrl & TIOCM_OUT1)
+		mcr |= UART_MCR_OUT1;
+	if (mctrl & TIOCM_OUT2)
+		mcr |= UART_MCR_OUT2;
+	if (mctrl & TIOCM_LOOP)
+		mcr |= UART_MCR_LOOP;
+
+	mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr;
+
+	serial8250_out_MCR(up, mcr);
+}
+EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl);
+
+static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	if (port->set_mctrl)
+		port->set_mctrl(port, mctrl);
+	else
+		serial8250_do_set_mctrl(port, mctrl);
+}
+
+static void serial8250_break_ctl(struct uart_port *port, int break_state)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned long flags;
+
+	serial8250_rpm_get(up);
+	spin_lock_irqsave(&port->lock, flags);
+	if (break_state == -1)
+		up->lcr |= UART_LCR_SBC;
+	else
+		up->lcr &= ~UART_LCR_SBC;
+	serial_port_out(port, UART_LCR, up->lcr);
+	spin_unlock_irqrestore(&port->lock, flags);
+	serial8250_rpm_put(up);
+}
+
+/*
+ *	Wait for transmitter & holding register to empty
+ */
+static void wait_for_xmitr(struct uart_8250_port *up, int bits)
+{
+	unsigned int status, tmout = 10000;
+
+	/* Wait up to 10ms for the character(s) to be sent. */
+	for (;;) {
+		status = serial_in(up, UART_LSR);
+
+		up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
+
+		if ((status & bits) == bits)
+			break;
+		if (--tmout == 0)
+			break;
+		udelay(1);
+		touch_nmi_watchdog();
+	}
+
+	/* Wait up to 1s for flow control if necessary */
+	if (up->port.flags & UPF_CONS_FLOW) {
+		for (tmout = 1000000; tmout; tmout--) {
+			unsigned int msr = serial_in(up, UART_MSR);
+			up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
+			if (msr & UART_MSR_CTS)
+				break;
+			udelay(1);
+			touch_nmi_watchdog();
+		}
+	}
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+/*
+ * Console polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+static int serial8250_get_poll_char(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned char lsr;
+	int status;
+
+	serial8250_rpm_get(up);
+
+	lsr = serial_port_in(port, UART_LSR);
+
+	if (!(lsr & UART_LSR_DR)) {
+		status = NO_POLL_CHAR;
+		goto out;
+	}
+
+	status = serial_port_in(port, UART_RX);
+out:
+	serial8250_rpm_put(up);
+	return status;
+}
+
+
+static void serial8250_put_poll_char(struct uart_port *port,
+			 unsigned char c)
+{
+	unsigned int ier;
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	serial8250_rpm_get(up);
+	/*
+	 *	First save the IER then disable the interrupts
+	 */
+	ier = serial_port_in(port, UART_IER);
+	if (up->capabilities & UART_CAP_UUE)
+		serial_port_out(port, UART_IER, UART_IER_UUE);
+	else
+		serial_port_out(port, UART_IER, 0);
+
+	wait_for_xmitr(up, BOTH_EMPTY);
+	/*
+	 *	Send the character out.
+	 */
+	serial_port_out(port, UART_TX, c);
+
+	/*
+	 *	Finally, wait for transmitter to become empty
+	 *	and restore the IER
+	 */
+	wait_for_xmitr(up, BOTH_EMPTY);
+	serial_port_out(port, UART_IER, ier);
+	serial8250_rpm_put(up);
+}
+
+#endif /* CONFIG_CONSOLE_POLL */
+
+int serial8250_do_startup(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned long flags;
+	unsigned char lsr, iir;
+	int retval;
+
+	if (!port->fifosize)
+		port->fifosize = uart_config[port->type].fifo_size;
+	if (!up->tx_loadsz)
+		up->tx_loadsz = uart_config[port->type].tx_loadsz;
+	if (!up->capabilities)
+		up->capabilities = uart_config[port->type].flags;
+	up->mcr = 0;
+
+	if (port->iotype != up->cur_iotype)
+		set_io_from_upio(port);
+
+	serial8250_rpm_get(up);
+	if (port->type == PORT_16C950) {
+		/* Wake up and initialize UART */
+		up->acr = 0;
+		serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
+		serial_port_out(port, UART_EFR, UART_EFR_ECB);
+		serial_port_out(port, UART_IER, 0);
+		serial_port_out(port, UART_LCR, 0);
+		serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
+		serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
+		serial_port_out(port, UART_EFR, UART_EFR_ECB);
+		serial_port_out(port, UART_LCR, 0);
+	}
+
+	if (port->type == PORT_DA830) {
+		/* Reset the port */
+		serial_port_out(port, UART_IER, 0);
+		serial_port_out(port, UART_DA830_PWREMU_MGMT, 0);
+		mdelay(10);
+
+		/* Enable Tx, Rx and free run mode */
+		serial_port_out(port, UART_DA830_PWREMU_MGMT,
+				UART_DA830_PWREMU_MGMT_UTRST |
+				UART_DA830_PWREMU_MGMT_URRST |
+				UART_DA830_PWREMU_MGMT_FREE);
+	}
+
+	if (port->type == PORT_NPCM) {
+		/*
+		 * Nuvoton calls the scratch register 'UART_TOR' (timeout
+		 * register). Enable it, and set TIOC (timeout interrupt
+		 * comparator) to be 0x20 for correct operation.
+		 */
+		serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);
+	}
+
+#ifdef CONFIG_SERIAL_8250_RSA
+	/*
+	 * If this is an RSA port, see if we can kick it up to the
+	 * higher speed clock.
+	 */
+	enable_rsa(up);
+#endif
+
+	if (port->type == PORT_XR17V35X) {
+		/*
+		 * First enable access to IER [7:5], ISR [5:4], FCR [5:4],
+		 * MCR [7:5] and MSR [7:0]
+		 */
+		serial_port_out(port, UART_XR_EFR, UART_EFR_ECB);
+
+		/*
+		 * Make sure all interrups are masked until initialization is
+		 * complete and the FIFOs are cleared
+		 */
+		serial_port_out(port, UART_IER, 0);
+	}
+
+	/*
+	 * Clear the FIFO buffers and disable them.
+	 * (they will be reenabled in set_termios())
+	 */
+	serial8250_clear_fifos(up);
+
+	/*
+	 * Clear the interrupt registers.
+	 */
+	serial_port_in(port, UART_LSR);
+	serial_port_in(port, UART_RX);
+	serial_port_in(port, UART_IIR);
+	serial_port_in(port, UART_MSR);
+	if ((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X))
+		serial_port_in(port, UART_EXAR_INT0);
+
+	/*
+	 * At this point, there's no way the LSR could still be 0xff;
+	 * if it is, then bail out, because there's likely no UART
+	 * here.
+	 */
+	if (!(port->flags & UPF_BUGGY_UART) &&
+	    (serial_port_in(port, UART_LSR) == 0xff)) {
+		pr_info_ratelimited("%s: LSR safety check engaged!\n", port->name);
+		retval = -ENODEV;
+		goto out;
+	}
+
+	/*
+	 * For a XR16C850, we need to set the trigger levels
+	 */
+	if (port->type == PORT_16850) {
+		unsigned char fctr;
+
+		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
+		fctr = serial_in(up, UART_FCTR) & ~(UART_FCTR_RX|UART_FCTR_TX);
+		serial_port_out(port, UART_FCTR,
+				fctr | UART_FCTR_TRGD | UART_FCTR_RX);
+		serial_port_out(port, UART_TRG, UART_TRG_96);
+		serial_port_out(port, UART_FCTR,
+				fctr | UART_FCTR_TRGD | UART_FCTR_TX);
+		serial_port_out(port, UART_TRG, UART_TRG_96);
+
+		serial_port_out(port, UART_LCR, 0);
+	}
+
+	/*
+	 * For the Altera 16550 variants, set TX threshold trigger level.
+	 */
+	if (((port->type == PORT_ALTR_16550_F32) ||
+	     (port->type == PORT_ALTR_16550_F64) ||
+	     (port->type == PORT_ALTR_16550_F128)) && (port->fifosize > 1)) {
+		/* Bounds checking of TX threshold (valid 0 to fifosize-2) */
+		if ((up->tx_loadsz < 2) || (up->tx_loadsz > port->fifosize)) {
+			pr_err("%s TX FIFO Threshold errors, skipping\n",
+			       port->name);
+		} else {
+			serial_port_out(port, UART_ALTR_AFR,
+					UART_ALTR_EN_TXFIFO_LW);
+			serial_port_out(port, UART_ALTR_TX_LOW,
+					port->fifosize - up->tx_loadsz);
+			port->handle_irq = serial8250_tx_threshold_handle_irq;
+		}
+	}
+
+	/* Check if we need to have shared IRQs */
+	if (port->irq && (up->port.flags & UPF_SHARE_IRQ))
+		up->port.irqflags |= IRQF_SHARED;
+
+	if (port->irq && !(up->port.flags & UPF_NO_THRE_TEST)) {
+		unsigned char iir1;
+
+		if (port->irqflags & IRQF_SHARED)
+			disable_irq_nosync(port->irq);
+
+		/*
+		 * Test for UARTs that do not reassert THRE when the
+		 * transmitter is idle and the interrupt has already
+		 * been cleared.  Real 16550s should always reassert
+		 * this interrupt whenever the transmitter is idle and
+		 * the interrupt is enabled.  Delays are necessary to
+		 * allow register changes to become visible.
+		 */
+		spin_lock_irqsave(&port->lock, flags);
+
+		wait_for_xmitr(up, UART_LSR_THRE);
+		serial_port_out_sync(port, UART_IER, UART_IER_THRI);
+		udelay(1); /* allow THRE to set */
+		iir1 = serial_port_in(port, UART_IIR);
+		serial_port_out(port, UART_IER, 0);
+		serial_port_out_sync(port, UART_IER, UART_IER_THRI);
+		udelay(1); /* allow a working UART time to re-assert THRE */
+		iir = serial_port_in(port, UART_IIR);
+		serial_port_out(port, UART_IER, 0);
+
+		spin_unlock_irqrestore(&port->lock, flags);
+
+		if (port->irqflags & IRQF_SHARED)
+			enable_irq(port->irq);
+
+		/*
+		 * If the interrupt is not reasserted, or we otherwise
+		 * don't trust the iir, setup a timer to kick the UART
+		 * on a regular basis.
+		 */
+		if ((!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) ||
+		    up->port.flags & UPF_BUG_THRE) {
+			up->bugs |= UART_BUG_THRE;
+		}
+	}
+
+	retval = up->ops->setup_irq(up);
+	if (retval)
+		goto out;
+
+	/*
+	 * Now, initialize the UART
+	 */
+	serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
+
+	spin_lock_irqsave(&port->lock, flags);
+	if (up->port.flags & UPF_FOURPORT) {
+		if (!up->port.irq)
+			up->port.mctrl |= TIOCM_OUT1;
+	} else
+		/*
+		 * Most PC uarts need OUT2 raised to enable interrupts.
+		 */
+		if (port->irq)
+			up->port.mctrl |= TIOCM_OUT2;
+
+	serial8250_set_mctrl(port, port->mctrl);
+
+	/*
+	 * Serial over Lan (SoL) hack:
+	 * Intel 8257x Gigabit ethernet chips have a 16550 emulation, to be
+	 * used for Serial Over Lan.  Those chips take a longer time than a
+	 * normal serial device to signalize that a transmission data was
+	 * queued. Due to that, the above test generally fails. One solution
+	 * would be to delay the reading of iir. However, this is not
+	 * reliable, since the timeout is variable. So, let's just don't
+	 * test if we receive TX irq.  This way, we'll never enable
+	 * UART_BUG_TXEN.
+	 */
+	if (up->port.quirks & UPQ_NO_TXEN_TEST)
+		goto dont_test_tx_en;
+
+	/*
+	 * Do a quick test to see if we receive an interrupt when we enable
+	 * the TX irq.
+	 */
+	serial_port_out(port, UART_IER, UART_IER_THRI);
+	lsr = serial_port_in(port, UART_LSR);
+	iir = serial_port_in(port, UART_IIR);
+	serial_port_out(port, UART_IER, 0);
+
+	if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) {
+		if (!(up->bugs & UART_BUG_TXEN)) {
+			up->bugs |= UART_BUG_TXEN;
+			pr_debug("%s - enabling bad tx status workarounds\n",
+				 port->name);
+		}
+	} else {
+		up->bugs &= ~UART_BUG_TXEN;
+	}
+
+dont_test_tx_en:
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	/*
+	 * Clear the interrupt registers again for luck, and clear the
+	 * saved flags to avoid getting false values from polling
+	 * routines or the previous session.
+	 */
+	serial_port_in(port, UART_LSR);
+	serial_port_in(port, UART_RX);
+	serial_port_in(port, UART_IIR);
+	serial_port_in(port, UART_MSR);
+	if ((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X))
+		serial_port_in(port, UART_EXAR_INT0);
+	up->lsr_saved_flags = 0;
+	up->msr_saved_flags = 0;
+
+	/*
+	 * Request DMA channels for both RX and TX.
+	 */
+	if (up->dma) {
+		retval = serial8250_request_dma(up);
+		if (retval) {
+			pr_warn_ratelimited("%s - failed to request DMA\n",
+					    port->name);
+			up->dma = NULL;
+		}
+	}
+
+	/*
+	 * Set the IER shadow for rx interrupts but defer actual interrupt
+	 * enable until after the FIFOs are enabled; otherwise, an already-
+	 * active sender can swamp the interrupt handler with "too much work".
+	 */
+	up->ier = UART_IER_RLSI | UART_IER_RDI;
+
+	if (port->flags & UPF_FOURPORT) {
+		unsigned int icp;
+		/*
+		 * Enable interrupts on the AST Fourport board
+		 */
+		icp = (port->iobase & 0xfe0) | 0x01f;
+		outb_p(0x80, icp);
+		inb_p(icp);
+	}
+	retval = 0;
+out:
+	serial8250_rpm_put(up);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(serial8250_do_startup);
+
+static int serial8250_startup(struct uart_port *port)
+{
+	if (port->startup)
+		return port->startup(port);
+	return serial8250_do_startup(port);
+}
+
+void serial8250_do_shutdown(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned long flags;
+
+	serial8250_rpm_get(up);
+	/*
+	 * Disable interrupts from this port
+	 */
+	spin_lock_irqsave(&port->lock, flags);
+	up->ier = 0;
+	serial_port_out(port, UART_IER, 0);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	synchronize_irq(port->irq);
+
+	if (up->dma)
+		serial8250_release_dma(up);
+
+	spin_lock_irqsave(&port->lock, flags);
+	if (port->flags & UPF_FOURPORT) {
+		/* reset interrupts on the AST Fourport board */
+		inb((port->iobase & 0xfe0) | 0x1f);
+		port->mctrl |= TIOCM_OUT1;
+	} else
+		port->mctrl &= ~TIOCM_OUT2;
+
+	serial8250_set_mctrl(port, port->mctrl);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	/*
+	 * Disable break condition and FIFOs
+	 */
+	serial_port_out(port, UART_LCR,
+			serial_port_in(port, UART_LCR) & ~UART_LCR_SBC);
+	serial8250_clear_fifos(up);
+
+#ifdef CONFIG_SERIAL_8250_RSA
+	/*
+	 * Reset the RSA board back to 115kbps compat mode.
+	 */
+	disable_rsa(up);
+#endif
+
+	/*
+	 * Read data port to reset things, and then unlink from
+	 * the IRQ chain.
+	 */
+	serial_port_in(port, UART_RX);
+	serial8250_rpm_put(up);
+
+	up->ops->release_irq(up);
+}
+EXPORT_SYMBOL_GPL(serial8250_do_shutdown);
+
+static void serial8250_shutdown(struct uart_port *port)
+{
+	if (port->shutdown)
+		port->shutdown(port);
+	else
+		serial8250_do_shutdown(port);
+}
+
+/*
+ * XR17V35x UARTs have an extra fractional divisor register (DLD)
+ * Calculate divisor with extra 4-bit fractional portion
+ */
+static unsigned int xr17v35x_get_divisor(struct uart_8250_port *up,
+					 unsigned int baud,
+					 unsigned int *frac)
+{
+	struct uart_port *port = &up->port;
+	unsigned int quot_16;
+
+	quot_16 = DIV_ROUND_CLOSEST(port->uartclk, baud);
+	*frac = quot_16 & 0x0f;
+
+	return quot_16 >> 4;
+}
+
+/* Nuvoton NPCM UARTs have a custom divisor calculation */
+static unsigned int npcm_get_divisor(struct uart_8250_port *up,
+		unsigned int baud)
+{
+	struct uart_port *port = &up->port;
+
+	return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
+}
+
+static unsigned int serial8250_do_get_divisor(struct uart_port *port,
+					      unsigned int baud,
+					      unsigned int *frac)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned int quot;
+
+	/*
+	 * Handle magic divisors for baud rates above baud_base on
+	 * SMSC SuperIO chips.
+	 *
+	 */
+	if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
+	    baud == (port->uartclk/4))
+		quot = 0x8001;
+	else if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
+		 baud == (port->uartclk/8))
+		quot = 0x8002;
+	else if (up->port.type == PORT_XR17V35X)
+		quot = xr17v35x_get_divisor(up, baud, frac);
+	else if (up->port.type == PORT_NPCM)
+		quot = npcm_get_divisor(up, baud);
+	else
+		quot = uart_get_divisor(port, baud);
+
+	/*
+	 * Oxford Semi 952 rev B workaround
+	 */
+	if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0)
+		quot++;
+
+	return quot;
+}
+
+static unsigned int serial8250_get_divisor(struct uart_port *port,
+					   unsigned int baud,
+					   unsigned int *frac)
+{
+	if (port->get_divisor)
+		return port->get_divisor(port, baud, frac);
+
+	return serial8250_do_get_divisor(port, baud, frac);
+}
+
+static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
+					    tcflag_t c_cflag)
+{
+	unsigned char cval;
+
+	switch (c_cflag & CSIZE) {
+	case CS5:
+		cval = UART_LCR_WLEN5;
+		break;
+	case CS6:
+		cval = UART_LCR_WLEN6;
+		break;
+	case CS7:
+		cval = UART_LCR_WLEN7;
+		break;
+	default:
+	case CS8:
+		cval = UART_LCR_WLEN8;
+		break;
+	}
+
+	if (c_cflag & CSTOPB)
+		cval |= UART_LCR_STOP;
+	if (c_cflag & PARENB) {
+		cval |= UART_LCR_PARITY;
+		if (up->bugs & UART_BUG_PARITY)
+			up->fifo_bug = true;
+	}
+	if (!(c_cflag & PARODD))
+		cval |= UART_LCR_EPAR;
+#ifdef CMSPAR
+	if (c_cflag & CMSPAR)
+		cval |= UART_LCR_SPAR;
+#endif
+
+	return cval;
+}
+
+void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
+			       unsigned int quot, unsigned int quot_frac)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	/* Workaround to enable 115200 baud on OMAP1510 internal ports */
+	if (is_omap1510_8250(up)) {
+		if (baud == 115200) {
+			quot = 1;
+			serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1);
+		} else
+			serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0);
+	}
+
+	/*
+	 * For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2,
+	 * otherwise just set DLAB
+	 */
+	if (up->capabilities & UART_NATSEMI)
+		serial_port_out(port, UART_LCR, 0xe0);
+	else
+		serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
+
+	serial_dl_write(up, quot);
+
+	/* XR17V35x UARTs have an extra fractional divisor register (DLD) */
+	if (up->port.type == PORT_XR17V35X) {
+		/* Preserve bits not related to baudrate; DLD[7:4]. */
+		quot_frac |= serial_port_in(port, 0x2) & 0xf0;
+		serial_port_out(port, 0x2, quot_frac);
+	}
+}
+EXPORT_SYMBOL_GPL(serial8250_do_set_divisor);
+
+static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
+				   unsigned int quot, unsigned int quot_frac)
+{
+	if (port->set_divisor)
+		port->set_divisor(port, baud, quot, quot_frac);
+	else
+		serial8250_do_set_divisor(port, baud, quot, quot_frac);
+}
+
+static unsigned int serial8250_get_baud_rate(struct uart_port *port,
+					     struct ktermios *termios,
+					     struct ktermios *old)
+{
+	unsigned int tolerance = port->uartclk / 100;
+	unsigned int min;
+	unsigned int max;
+
+	/*
+	 * Handle magic divisors for baud rates above baud_base on SMSC
+	 * Super I/O chips.  Enable custom rates of clk/4 and clk/8, but
+	 * disable divisor values beyond 32767, which are unavailable.
+	 */
+	if (port->flags & UPF_MAGIC_MULTIPLIER) {
+		min = port->uartclk / 16 / UART_DIV_MAX >> 1;
+		max = (port->uartclk + tolerance) / 4;
+	} else {
+		min = port->uartclk / 16 / UART_DIV_MAX;
+		max = (port->uartclk + tolerance) / 16;
+	}
+
+	/*
+	 * Ask the core to calculate the divisor for us.
+	 * Allow 1% tolerance at the upper limit so uart clks marginally
+	 * slower than nominal still match standard baud rates without
+	 * causing transmission errors.
+	 */
+	return uart_get_baud_rate(port, termios, old, min, max);
+}
+
+void
+serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
+			  struct ktermios *old)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned char cval;
+	unsigned long flags;
+	unsigned int baud, quot, frac = 0;
+
+	if (up->capabilities & UART_CAP_MINI) {
+		termios->c_cflag &= ~(CSTOPB | PARENB | PARODD | CMSPAR);
+		if ((termios->c_cflag & CSIZE) == CS5 ||
+		    (termios->c_cflag & CSIZE) == CS6)
+			termios->c_cflag = (termios->c_cflag & ~CSIZE) | CS7;
+	}
+	cval = serial8250_compute_lcr(up, termios->c_cflag);
+
+	baud = serial8250_get_baud_rate(port, termios, old);
+	quot = serial8250_get_divisor(port, baud, &frac);
+
+	/*
+	 * Ok, we're now changing the port state.  Do it with
+	 * interrupts disabled.
+	 */
+	serial8250_rpm_get(up);
+	spin_lock_irqsave(&port->lock, flags);
+
+	up->lcr = cval;					/* Save computed LCR */
+
+	if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
+		/* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
+		if ((baud < 2400 && !up->dma) || up->fifo_bug) {
+			up->fcr &= ~UART_FCR_TRIGGER_MASK;
+			up->fcr |= UART_FCR_TRIGGER_1;
+		}
+	}
+
+	/*
+	 * MCR-based auto flow control.  When AFE is enabled, RTS will be
+	 * deasserted when the receive FIFO contains more characters than
+	 * the trigger, or the MCR RTS bit is cleared.
+	 */
+	if (up->capabilities & UART_CAP_AFE) {
+		up->mcr &= ~UART_MCR_AFE;
+		if (termios->c_cflag & CRTSCTS)
+			up->mcr |= UART_MCR_AFE;
+	}
+
+	/*
+	 * Update the per-port timeout.
+	 */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
+	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
+		port->read_status_mask |= UART_LSR_BI;
+
+	/*
+	 * Characteres to ignore
+	 */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= UART_LSR_BI;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= UART_LSR_OE;
+	}
+
+	/*
+	 * ignore all characters if CREAD is not set
+	 */
+	if ((termios->c_cflag & CREAD) == 0)
+		port->ignore_status_mask |= UART_LSR_DR;
+
+	/*
+	 * CTS flow control flag and modem status interrupts
+	 */
+	up->ier &= ~UART_IER_MSI;
+	if (!(up->bugs & UART_BUG_NOMSR) &&
+			UART_ENABLE_MS(&up->port, termios->c_cflag))
+		up->ier |= UART_IER_MSI;
+	if (up->capabilities & UART_CAP_UUE)
+		up->ier |= UART_IER_UUE;
+	if (up->capabilities & UART_CAP_RTOIE)
+		up->ier |= UART_IER_RTOIE;
+
+	serial_port_out(port, UART_IER, up->ier);
+
+	if (up->capabilities & UART_CAP_EFR) {
+		unsigned char efr = 0;
+		/*
+		 * TI16C752/Startech hardware flow control.  FIXME:
+		 * - TI16C752 requires control thresholds to be set.
+		 * - UART_MCR_RTS is ineffective if auto-RTS mode is enabled.
+		 */
+		if (termios->c_cflag & CRTSCTS)
+			efr |= UART_EFR_CTS;
+
+		serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
+		if (port->flags & UPF_EXAR_EFR)
+			serial_port_out(port, UART_XR_EFR, efr);
+		else
+			serial_port_out(port, UART_EFR, efr);
+	}
+
+	serial8250_set_divisor(port, baud, quot, frac);
+
+	/*
+	 * LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
+	 * is written without DLAB set, this mode will be disabled.
+	 */
+	if (port->type == PORT_16750)
+		serial_port_out(port, UART_FCR, up->fcr);
+
+	serial_port_out(port, UART_LCR, up->lcr);	/* reset DLAB */
+	if (port->type != PORT_16750) {
+		/* emulated UARTs (Lucent Venus 167x) need two steps */
+		if (up->fcr & UART_FCR_ENABLE_FIFO)
+			serial_port_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
+		serial_port_out(port, UART_FCR, up->fcr);	/* set fcr */
+	}
+	serial8250_set_mctrl(port, port->mctrl);
+	spin_unlock_irqrestore(&port->lock, flags);
+	serial8250_rpm_put(up);
+
+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+}
+EXPORT_SYMBOL(serial8250_do_set_termios);
+
+static void
+serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
+		       struct ktermios *old)
+{
+	if (port->set_termios)
+		port->set_termios(port, termios, old);
+	else
+		serial8250_do_set_termios(port, termios, old);
+}
+
+void serial8250_do_set_ldisc(struct uart_port *port, struct ktermios *termios)
+{
+	if (termios->c_line == N_PPS) {
+		port->flags |= UPF_HARDPPS_CD;
+		spin_lock_irq(&port->lock);
+		serial8250_enable_ms(port);
+		spin_unlock_irq(&port->lock);
+	} else {
+		port->flags &= ~UPF_HARDPPS_CD;
+		if (!UART_ENABLE_MS(port, termios->c_cflag)) {
+			spin_lock_irq(&port->lock);
+			serial8250_disable_ms(port);
+			spin_unlock_irq(&port->lock);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(serial8250_do_set_ldisc);
+
+static void
+serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
+{
+	if (port->set_ldisc)
+		port->set_ldisc(port, termios);
+	else
+		serial8250_do_set_ldisc(port, termios);
+}
+
+void serial8250_do_pm(struct uart_port *port, unsigned int state,
+		      unsigned int oldstate)
+{
+	struct uart_8250_port *p = up_to_u8250p(port);
+
+	serial8250_set_sleep(p, state != 0);
+}
+EXPORT_SYMBOL(serial8250_do_pm);
+
+static void
+serial8250_pm(struct uart_port *port, unsigned int state,
+	      unsigned int oldstate)
+{
+	if (port->pm)
+		port->pm(port, state, oldstate);
+	else
+		serial8250_do_pm(port, state, oldstate);
+}
+
+static unsigned int serial8250_port_size(struct uart_8250_port *pt)
+{
+	if (pt->port.mapsize)
+		return pt->port.mapsize;
+	if (pt->port.iotype == UPIO_AU) {
+		if (pt->port.type == PORT_RT2880)
+			return 0x100;
+		return 0x1000;
+	}
+	if (is_omap1_8250(pt))
+		return 0x16 << pt->port.regshift;
+
+	return 8 << pt->port.regshift;
+}
+
+/*
+ * Resource handling.
+ */
+static int serial8250_request_std_resource(struct uart_8250_port *up)
+{
+	unsigned int size = serial8250_port_size(up);
+	struct uart_port *port = &up->port;
+	int ret = 0;
+
+	switch (port->iotype) {
+	case UPIO_AU:
+	case UPIO_TSI:
+	case UPIO_MEM32:
+	case UPIO_MEM32BE:
+	case UPIO_MEM16:
+	case UPIO_MEM:
+		if (!port->mapbase)
+			break;
+
+		if (!request_mem_region(port->mapbase, size, "serial")) {
+			ret = -EBUSY;
+			break;
+		}
+
+		if (port->flags & UPF_IOREMAP) {
+			port->membase = ioremap_nocache(port->mapbase, size);
+			if (!port->membase) {
+				release_mem_region(port->mapbase, size);
+				ret = -ENOMEM;
+			}
+		}
+		break;
+
+	case UPIO_HUB6:
+	case UPIO_PORT:
+		if (!request_region(port->iobase, size, "serial"))
+			ret = -EBUSY;
+		break;
+	}
+	return ret;
+}
+
+static void serial8250_release_std_resource(struct uart_8250_port *up)
+{
+	unsigned int size = serial8250_port_size(up);
+	struct uart_port *port = &up->port;
+
+	switch (port->iotype) {
+	case UPIO_AU:
+	case UPIO_TSI:
+	case UPIO_MEM32:
+	case UPIO_MEM32BE:
+	case UPIO_MEM16:
+	case UPIO_MEM:
+		if (!port->mapbase)
+			break;
+
+		if (port->flags & UPF_IOREMAP) {
+			iounmap(port->membase);
+			port->membase = NULL;
+		}
+
+		release_mem_region(port->mapbase, size);
+		break;
+
+	case UPIO_HUB6:
+	case UPIO_PORT:
+		release_region(port->iobase, size);
+		break;
+	}
+}
+
+static void serial8250_release_port(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	serial8250_release_std_resource(up);
+}
+
+static int serial8250_request_port(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	return serial8250_request_std_resource(up);
+}
+
+static int fcr_get_rxtrig_bytes(struct uart_8250_port *up)
+{
+	const struct serial8250_config *conf_type = &uart_config[up->port.type];
+	unsigned char bytes;
+
+	bytes = conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(up->fcr)];
+
+	return bytes ? bytes : -EOPNOTSUPP;
+}
+
+static int bytes_to_fcr_rxtrig(struct uart_8250_port *up, unsigned char bytes)
+{
+	const struct serial8250_config *conf_type = &uart_config[up->port.type];
+	int i;
+
+	if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)])
+		return -EOPNOTSUPP;
+
+	for (i = 1; i < UART_FCR_R_TRIG_MAX_STATE; i++) {
+		if (bytes < conf_type->rxtrig_bytes[i])
+			/* Use the nearest lower value */
+			return (--i) << UART_FCR_R_TRIG_SHIFT;
+	}
+
+	return UART_FCR_R_TRIG_11;
+}
+
+static int do_get_rxtrig(struct tty_port *port)
+{
+	struct uart_state *state = container_of(port, struct uart_state, port);
+	struct uart_port *uport = state->uart_port;
+	struct uart_8250_port *up = up_to_u8250p(uport);
+
+	if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1)
+		return -EINVAL;
+
+	return fcr_get_rxtrig_bytes(up);
+}
+
+static int do_serial8250_get_rxtrig(struct tty_port *port)
+{
+	int rxtrig_bytes;
+
+	mutex_lock(&port->mutex);
+	rxtrig_bytes = do_get_rxtrig(port);
+	mutex_unlock(&port->mutex);
+
+	return rxtrig_bytes;
+}
+
+static ssize_t serial8250_get_attr_rx_trig_bytes(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct tty_port *port = dev_get_drvdata(dev);
+	int rxtrig_bytes;
+
+	rxtrig_bytes = do_serial8250_get_rxtrig(port);
+	if (rxtrig_bytes < 0)
+		return rxtrig_bytes;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", rxtrig_bytes);
+}
+
+static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
+{
+	struct uart_state *state = container_of(port, struct uart_state, port);
+	struct uart_port *uport = state->uart_port;
+	struct uart_8250_port *up = up_to_u8250p(uport);
+	int rxtrig;
+
+	if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 ||
+	    up->fifo_bug)
+		return -EINVAL;
+
+	rxtrig = bytes_to_fcr_rxtrig(up, bytes);
+	if (rxtrig < 0)
+		return rxtrig;
+
+	serial8250_clear_fifos(up);
+	up->fcr &= ~UART_FCR_TRIGGER_MASK;
+	up->fcr |= (unsigned char)rxtrig;
+	serial_out(up, UART_FCR, up->fcr);
+	return 0;
+}
+
+static int do_serial8250_set_rxtrig(struct tty_port *port, unsigned char bytes)
+{
+	int ret;
+
+	mutex_lock(&port->mutex);
+	ret = do_set_rxtrig(port, bytes);
+	mutex_unlock(&port->mutex);
+
+	return ret;
+}
+
+static ssize_t serial8250_set_attr_rx_trig_bytes(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct tty_port *port = dev_get_drvdata(dev);
+	unsigned char bytes;
+	int ret;
+
+	if (!count)
+		return -EINVAL;
+
+	ret = kstrtou8(buf, 10, &bytes);
+	if (ret < 0)
+		return ret;
+
+	ret = do_serial8250_set_rxtrig(port, bytes);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR(rx_trig_bytes, S_IRUSR | S_IWUSR | S_IRGRP,
+		   serial8250_get_attr_rx_trig_bytes,
+		   serial8250_set_attr_rx_trig_bytes);
+
+static struct attribute *serial8250_dev_attrs[] = {
+	&dev_attr_rx_trig_bytes.attr,
+	NULL,
+	};
+
+static struct attribute_group serial8250_dev_attr_group = {
+	.attrs = serial8250_dev_attrs,
+	};
+
+static void register_dev_spec_attr_grp(struct uart_8250_port *up)
+{
+	const struct serial8250_config *conf_type = &uart_config[up->port.type];
+
+	if (conf_type->rxtrig_bytes[0])
+		up->port.attr_group = &serial8250_dev_attr_group;
+}
+
+static void serial8250_config_port(struct uart_port *port, int flags)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	int ret;
+
+	/*
+	 * Find the region that we can probe for.  This in turn
+	 * tells us whether we can probe for the type of port.
+	 */
+	ret = serial8250_request_std_resource(up);
+	if (ret < 0)
+		return;
+
+	if (port->iotype != up->cur_iotype)
+		set_io_from_upio(port);
+
+	if (flags & UART_CONFIG_TYPE)
+		autoconfig(up);
+
+	/* if access method is AU, it is a 16550 with a quirk */
+	if (port->type == PORT_16550A && port->iotype == UPIO_AU)
+		up->bugs |= UART_BUG_NOMSR;
+
+	/* HW bugs may trigger IRQ while IIR == NO_INT */
+	if (port->type == PORT_TEGRA)
+		up->bugs |= UART_BUG_NOMSR;
+
+	if (port->type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
+		autoconfig_irq(up);
+
+	if (port->type == PORT_UNKNOWN)
+		serial8250_release_std_resource(up);
+
+	register_dev_spec_attr_grp(up);
+	up->fcr = uart_config[up->port.type].fcr;
+}
+
+static int
+serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	if (ser->irq >= nr_irqs || ser->irq < 0 ||
+	    ser->baud_base < 9600 || ser->type < PORT_UNKNOWN ||
+	    ser->type >= ARRAY_SIZE(uart_config) || ser->type == PORT_CIRRUS ||
+	    ser->type == PORT_STARTECH)
+		return -EINVAL;
+	return 0;
+}
+
+static const char *serial8250_type(struct uart_port *port)
+{
+	int type = port->type;
+
+	if (type >= ARRAY_SIZE(uart_config))
+		type = 0;
+	return uart_config[type].name;
+}
+
+static const struct uart_ops serial8250_pops = {
+	.tx_empty	= serial8250_tx_empty,
+	.set_mctrl	= serial8250_set_mctrl,
+	.get_mctrl	= serial8250_get_mctrl,
+	.stop_tx	= serial8250_stop_tx,
+	.start_tx	= serial8250_start_tx,
+	.throttle	= serial8250_throttle,
+	.unthrottle	= serial8250_unthrottle,
+	.stop_rx	= serial8250_stop_rx,
+	.enable_ms	= serial8250_enable_ms,
+	.break_ctl	= serial8250_break_ctl,
+	.startup	= serial8250_startup,
+	.shutdown	= serial8250_shutdown,
+	.set_termios	= serial8250_set_termios,
+	.set_ldisc	= serial8250_set_ldisc,
+	.pm		= serial8250_pm,
+	.type		= serial8250_type,
+	.release_port	= serial8250_release_port,
+	.request_port	= serial8250_request_port,
+	.config_port	= serial8250_config_port,
+	.verify_port	= serial8250_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char = serial8250_get_poll_char,
+	.poll_put_char = serial8250_put_poll_char,
+#endif
+};
+
+void serial8250_init_port(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+
+	spin_lock_init(&port->lock);
+	port->ops = &serial8250_pops;
+
+	up->cur_iotype = 0xFF;
+}
+EXPORT_SYMBOL_GPL(serial8250_init_port);
+
+void serial8250_set_defaults(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+
+	if (up->port.flags & UPF_FIXED_TYPE) {
+		unsigned int type = up->port.type;
+
+		if (!up->port.fifosize)
+			up->port.fifosize = uart_config[type].fifo_size;
+		if (!up->tx_loadsz)
+			up->tx_loadsz = uart_config[type].tx_loadsz;
+		if (!up->capabilities)
+			up->capabilities = uart_config[type].flags;
+	}
+
+	set_io_from_upio(port);
+
+	/* default dma handlers */
+	if (up->dma) {
+		if (!up->dma->tx_dma)
+			up->dma->tx_dma = serial8250_tx_dma;
+		if (!up->dma->rx_dma)
+			up->dma->rx_dma = serial8250_rx_dma;
+	}
+}
+EXPORT_SYMBOL_GPL(serial8250_set_defaults);
+
+#ifdef CONFIG_SERIAL_8250_CONSOLE
+
+static void serial8250_console_putchar(struct uart_port *port, int ch)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	wait_for_xmitr(up, UART_LSR_THRE);
+	serial_port_out(port, UART_TX, ch);
+}
+
+/*
+ *	Restore serial console when h/w power-off detected
+ */
+static void serial8250_console_restore(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+	struct ktermios termios;
+	unsigned int baud, quot, frac = 0;
+
+	termios.c_cflag = port->cons->cflag;
+	if (port->state->port.tty && termios.c_cflag == 0)
+		termios.c_cflag = port->state->port.tty->termios.c_cflag;
+
+	baud = serial8250_get_baud_rate(port, &termios, NULL);
+	quot = serial8250_get_divisor(port, baud, &frac);
+
+	serial8250_set_divisor(port, baud, quot, frac);
+	serial_port_out(port, UART_LCR, up->lcr);
+	serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS);
+}
+
+/*
+ *	Print a string to the serial port trying not to disturb
+ *	any possible real use of the port...
+ *
+ *	The console_lock must be held when we get here.
+ */
+void serial8250_console_write(struct uart_8250_port *up, const char *s,
+			      unsigned int count)
+{
+	struct uart_port *port = &up->port;
+	unsigned long flags;
+	unsigned int ier;
+	int locked = 1;
+
+	touch_nmi_watchdog();
+
+	serial8250_rpm_get(up);
+
+	if (port->sysrq)
+		locked = 0;
+	else if (oops_in_progress)
+		locked = spin_trylock_irqsave(&port->lock, flags);
+	else
+		spin_lock_irqsave(&port->lock, flags);
+
+	/*
+	 *	First save the IER then disable the interrupts
+	 */
+	ier = serial_port_in(port, UART_IER);
+
+	if (up->capabilities & UART_CAP_UUE)
+		serial_port_out(port, UART_IER, UART_IER_UUE);
+	else
+		serial_port_out(port, UART_IER, 0);
+
+	/* check scratch reg to see if port powered off during system sleep */
+	if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
+		serial8250_console_restore(up);
+		up->canary = 0;
+	}
+
+	uart_console_write(port, s, count, serial8250_console_putchar);
+
+	/*
+	 *	Finally, wait for transmitter to become empty
+	 *	and restore the IER
+	 */
+	wait_for_xmitr(up, BOTH_EMPTY);
+	serial_port_out(port, UART_IER, ier);
+
+	/*
+	 *	The receive handling will happen properly because the
+	 *	receive ready bit will still be set; it is not cleared
+	 *	on read.  However, modem control will not, we must
+	 *	call it if we have saved something in the saved flags
+	 *	while processing with interrupts off.
+	 */
+	if (up->msr_saved_flags)
+		serial8250_modem_status(up);
+
+	if (locked)
+		spin_unlock_irqrestore(&port->lock, flags);
+	serial8250_rpm_put(up);
+}
+
+static unsigned int probe_baud(struct uart_port *port)
+{
+	unsigned char lcr, dll, dlm;
+	unsigned int quot;
+
+	lcr = serial_port_in(port, UART_LCR);
+	serial_port_out(port, UART_LCR, lcr | UART_LCR_DLAB);
+	dll = serial_port_in(port, UART_DLL);
+	dlm = serial_port_in(port, UART_DLM);
+	serial_port_out(port, UART_LCR, lcr);
+
+	quot = (dlm << 8) | dll;
+	return (port->uartclk / 16) / quot;
+}
+
+int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
+{
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (!port->iobase && !port->membase)
+		return -ENODEV;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else if (probe)
+		baud = probe_baud(port);
+
+	return uart_set_options(port, port->cons, baud, parity, bits, flow);
+}
+
+#endif /* CONFIG_SERIAL_8250_CONSOLE */
+
+MODULE_LICENSE("GPL");