serial: group all the 8250 related code together

The drivers/tty/serial dir is already getting rather busy.
Relocate the 8250 related drivers to their own subdir to
reduce the clutter.

Note that sunsu.c is not included in this move -- it is
8250-like hardware, but it does not use any of the existing
infrastructure -- and does not depend on SERIAL_8250.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

22 files changed, 12216 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
new file mode 100644
index 000000000000..9f50c4e3c2be
--- /dev/null
+++ b/drivers/tty/serial/8250/8250.c
@@ -0,0 +1,3357 @@
+/*
+ *  Driver for 8250/16550-type serial ports
+ *
+ *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
+ *
+ *  Copyright (C) 2001 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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_reg.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/serial_8250.h>
+#include <linux/nmi.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include "8250.h"
+
+#ifdef CONFIG_SPARC
+#include "suncore.h"
+#endif
+
+/*
+ * Configuration:
+ *   share_irqs - whether we pass IRQF_SHARED to request_irq().  This option
+ *                is unsafe when used on edge-triggered interrupts.
+ */
+static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;
+
+static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;
+
+static struct uart_driver serial8250_reg;
+
+static int serial_index(struct uart_port *port)
+{
+	return (serial8250_reg.minor - 64) + port->line;
+}
+
+static unsigned int skip_txen_test; /* force skip of txen test at init time */
+
+/*
+ * Debugging.
+ */
+#if 0
+#define DEBUG_AUTOCONF(fmt...)	printk(fmt)
+#else
+#define DEBUG_AUTOCONF(fmt...)	do { } while (0)
+#endif
+
+#if 0
+#define DEBUG_INTR(fmt...)	printk(fmt)
+#else
+#define DEBUG_INTR(fmt...)	do { } while (0)
+#endif
+
+#define PASS_LIMIT	512
+
+#define BOTH_EMPTY 	(UART_LSR_TEMT | UART_LSR_THRE)
+
+
+/*
+ * We default to IRQ0 for the "no irq" hack.   Some
+ * machine types want others as well - they're free
+ * to redefine this in their header file.
+ */
+#define is_real_interrupt(irq)	((irq) != 0)
+
+#ifdef CONFIG_SERIAL_8250_DETECT_IRQ
+#define CONFIG_SERIAL_DETECT_IRQ 1
+#endif
+#ifdef CONFIG_SERIAL_8250_MANY_PORTS
+#define CONFIG_SERIAL_MANY_PORTS 1
+#endif
+
+/*
+ * HUB6 is always on.  This will be removed once the header
+ * files have been cleaned.
+ */
+#define CONFIG_HUB6 1
+
+#include <asm/serial.h>
+/*
+ * SERIAL_PORT_DFNS tells us about built-in ports that have no
+ * standard enumeration mechanism.   Platforms that can find all
+ * serial ports via mechanisms like ACPI or PCI need not supply it.
+ */
+#ifndef SERIAL_PORT_DFNS
+#define SERIAL_PORT_DFNS
+#endif
+
+static const struct old_serial_port old_serial_port[] = {
+	SERIAL_PORT_DFNS /* defined in asm/serial.h */
+};
+
+#define UART_NR	CONFIG_SERIAL_8250_NR_UARTS
+
+#ifdef CONFIG_SERIAL_8250_RSA
+
+#define PORT_RSA_MAX 4
+static unsigned long probe_rsa[PORT_RSA_MAX];
+static unsigned int probe_rsa_count;
+#endif /* CONFIG_SERIAL_8250_RSA  */
+
+struct irq_info {
+	struct			hlist_node node;
+	int			irq;
+	spinlock_t		lock;	/* Protects list not the hash */
+	struct list_head	*head;
+};
+
+#define NR_IRQ_HASH		32	/* Can be adjusted later */
+static struct hlist_head irq_lists[NR_IRQ_HASH];
+static DEFINE_MUTEX(hash_mutex);	/* Used to walk the hash */
+
+/*
+ * 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,
+		.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,
+		.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,
+		.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_10,
+		/* 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,
+		.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_RM9000] = {
+		.name		= "RM9000",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO,
+	},
+	[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,
+		.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,
+	},
+};
+
+#if defined(CONFIG_MIPS_ALCHEMY)
+
+/* Au1x00 UART hardware has a weird register layout */
+static const u8 au_io_in_map[] = {
+	[UART_RX]  = 0,
+	[UART_IER] = 2,
+	[UART_IIR] = 3,
+	[UART_LCR] = 5,
+	[UART_MCR] = 6,
+	[UART_LSR] = 7,
+	[UART_MSR] = 8,
+};
+
+static const u8 au_io_out_map[] = {
+	[UART_TX]  = 1,
+	[UART_IER] = 2,
+	[UART_FCR] = 4,
+	[UART_LCR] = 5,
+	[UART_MCR] = 6,
+};
+
+/* sane hardware needs no mapping */
+static inline int map_8250_in_reg(struct uart_port *p, int offset)
+{
+	if (p->iotype != UPIO_AU)
+		return offset;
+	return au_io_in_map[offset];
+}
+
+static inline int map_8250_out_reg(struct uart_port *p, int offset)
+{
+	if (p->iotype != UPIO_AU)
+		return offset;
+	return au_io_out_map[offset];
+}
+
+#elif defined(CONFIG_SERIAL_8250_RM9K)
+
+static const u8
+	regmap_in[8] = {
+		[UART_RX]	= 0x00,
+		[UART_IER]	= 0x0c,
+		[UART_IIR]	= 0x14,
+		[UART_LCR]	= 0x1c,
+		[UART_MCR]	= 0x20,
+		[UART_LSR]	= 0x24,
+		[UART_MSR]	= 0x28,
+		[UART_SCR]	= 0x2c
+	},
+	regmap_out[8] = {
+		[UART_TX] 	= 0x04,
+		[UART_IER]	= 0x0c,
+		[UART_FCR]	= 0x18,
+		[UART_LCR]	= 0x1c,
+		[UART_MCR]	= 0x20,
+		[UART_LSR]	= 0x24,
+		[UART_MSR]	= 0x28,
+		[UART_SCR]	= 0x2c
+	};
+
+static inline int map_8250_in_reg(struct uart_port *p, int offset)
+{
+	if (p->iotype != UPIO_RM9000)
+		return offset;
+	return regmap_in[offset];
+}
+
+static inline int map_8250_out_reg(struct uart_port *p, int offset)
+{
+	if (p->iotype != UPIO_RM9000)
+		return offset;
+	return regmap_out[offset];
+}
+
+#else
+
+/* sane hardware needs no mapping */
+#define map_8250_in_reg(up, offset) (offset)
+#define map_8250_out_reg(up, offset) (offset)
+
+#endif
+
+static unsigned int hub6_serial_in(struct uart_port *p, int offset)
+{
+	offset = map_8250_in_reg(p, 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 = map_8250_out_reg(p, 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 = map_8250_in_reg(p, offset) << p->regshift;
+	return readb(p->membase + offset);
+}
+
+static void mem_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = map_8250_out_reg(p, offset) << p->regshift;
+	writeb(value, p->membase + offset);
+}
+
+static void mem32_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = map_8250_out_reg(p, offset) << p->regshift;
+	writel(value, p->membase + offset);
+}
+
+static unsigned int mem32_serial_in(struct uart_port *p, int offset)
+{
+	offset = map_8250_in_reg(p, offset) << p->regshift;
+	return readl(p->membase + offset);
+}
+
+static unsigned int au_serial_in(struct uart_port *p, int offset)
+{
+	offset = map_8250_in_reg(p, offset) << p->regshift;
+	return __raw_readl(p->membase + offset);
+}
+
+static void au_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = map_8250_out_reg(p, offset) << p->regshift;
+	__raw_writel(value, p->membase + offset);
+}
+
+static unsigned int io_serial_in(struct uart_port *p, int offset)
+{
+	offset = map_8250_in_reg(p, offset) << p->regshift;
+	return inb(p->iobase + offset);
+}
+
+static void io_serial_out(struct uart_port *p, int offset, int value)
+{
+	offset = map_8250_out_reg(p, 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 =
+		container_of(p, struct uart_8250_port, port);
+	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_RM9000:
+	case UPIO_MEM32:
+		p->serial_in = mem32_serial_in;
+		p->serial_out = mem32_serial_out;
+		break;
+
+	case UPIO_AU:
+		p->serial_in = au_serial_in;
+		p->serial_out = au_serial_out;
+		break;
+
+	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_out_sync(struct uart_8250_port *up, int offset, int value)
+{
+	struct uart_port *p = &up->port;
+	switch (p->iotype) {
+	case UPIO_MEM:
+	case UPIO_MEM32:
+	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);
+	}
+}
+
+#define serial_in(up, offset)		\
+	(up->port.serial_in(&(up)->port, (offset)))
+#define serial_out(up, offset, value)	\
+	(up->port.serial_out(&(up)->port, (offset), (value)))
+/*
+ * We used to support using pause I/O for certain machines.  We
+ * haven't supported this for a while, but just in case it's badly
+ * needed for certain old 386 machines, I've left these #define's
+ * in....
+ */
+#define serial_inp(up, offset)		serial_in(up, offset)
+#define serial_outp(up, offset, value)	serial_out(up, offset, value)
+
+/* Uart divisor latch read */
+static inline int _serial_dl_read(struct uart_8250_port *up)
+{
+	return serial_inp(up, UART_DLL) | serial_inp(up, UART_DLM) << 8;
+}
+
+/* Uart divisor latch write */
+static inline void _serial_dl_write(struct uart_8250_port *up, int value)
+{
+	serial_outp(up, UART_DLL, value & 0xff);
+	serial_outp(up, UART_DLM, value >> 8 & 0xff);
+}
+
+#if defined(CONFIG_MIPS_ALCHEMY)
+/* Au1x00 haven't got a standard divisor latch */
+static int serial_dl_read(struct uart_8250_port *up)
+{
+	if (up->port.iotype == UPIO_AU)
+		return __raw_readl(up->port.membase + 0x28);
+	else
+		return _serial_dl_read(up);
+}
+
+static void serial_dl_write(struct uart_8250_port *up, int value)
+{
+	if (up->port.iotype == UPIO_AU)
+		__raw_writel(value, up->port.membase + 0x28);
+	else
+		_serial_dl_write(up, value);
+}
+#elif defined(CONFIG_SERIAL_8250_RM9K)
+static int serial_dl_read(struct uart_8250_port *up)
+{
+	return	(up->port.iotype == UPIO_RM9000) ?
+		(((__raw_readl(up->port.membase + 0x10) << 8) |
+		(__raw_readl(up->port.membase + 0x08) & 0xff)) & 0xffff) :
+		_serial_dl_read(up);
+}
+
+static void serial_dl_write(struct uart_8250_port *up, int value)
+{
+	if (up->port.iotype == UPIO_RM9000) {
+		__raw_writel(value, up->port.membase + 0x08);
+		__raw_writel(value >> 8, up->port.membase + 0x10);
+	} else {
+		_serial_dl_write(up, value);
+	}
+}
+#else
+#define serial_dl_read(up) _serial_dl_read(up)
+#define serial_dl_write(up, value) _serial_dl_write(up, value)
+#endif
+
+/*
+ * 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_outp(p, UART_FCR, UART_FCR_ENABLE_FIFO);
+		serial_outp(p, UART_FCR, UART_FCR_ENABLE_FIFO |
+			       UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+		serial_outp(p, UART_FCR, 0);
+	}
+}
+
+/*
+ * 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)
+{
+	if (p->capabilities & UART_CAP_SLEEP) {
+		if (p->capabilities & UART_CAP_EFR) {
+			serial_outp(p, UART_LCR, UART_LCR_CONF_MODE_B);
+			serial_outp(p, UART_EFR, UART_EFR_ECB);
+			serial_outp(p, UART_LCR, 0);
+		}
+		serial_outp(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
+		if (p->capabilities & UART_CAP_EFR) {
+			serial_outp(p, UART_LCR, UART_LCR_CONF_MODE_B);
+			serial_outp(p, UART_EFR, 0);
+			serial_outp(p, UART_LCR, 0);
+		}
+	}
+}
+
+#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_inp(up, UART_RSA_MSR);
+	result = mode & UART_RSA_MSR_FIFO;
+
+	if (!result) {
+		serial_outp(up, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
+		mode = serial_inp(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_outp(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_inp(up, UART_RSA_MSR);
+		result = !(mode & UART_RSA_MSR_FIFO);
+
+		if (!result) {
+			serial_outp(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
+			mode = serial_inp(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_inp(up, UART_LCR);
+	serial_outp(up, UART_LCR, 0);
+	old_fcr = serial_inp(up, UART_FCR);
+	old_mcr = serial_inp(up, UART_MCR);
+	serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO |
+		    UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+	serial_outp(up, UART_MCR, UART_MCR_LOOP);
+	serial_outp(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	old_dl = serial_dl_read(up);
+	serial_dl_write(up, 0x0001);
+	serial_outp(up, UART_LCR, 0x03);
+	for (count = 0; count < 256; count++)
+		serial_outp(up, UART_TX, count);
+	mdelay(20);/* FIXME - schedule_timeout */
+	for (count = 0; (serial_inp(up, UART_LSR) & UART_LSR_DR) &&
+	     (count < 256); count++)
+		serial_inp(up, UART_RX);
+	serial_outp(up, UART_FCR, old_fcr);
+	serial_outp(up, UART_MCR, old_mcr);
+	serial_outp(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	serial_dl_write(up, old_dl);
+	serial_outp(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_dll, old_dlm, old_lcr;
+	unsigned int id;
+
+	old_lcr = serial_inp(p, UART_LCR);
+	serial_outp(p, UART_LCR, UART_LCR_CONF_MODE_A);
+
+	old_dll = serial_inp(p, UART_DLL);
+	old_dlm = serial_inp(p, UART_DLM);
+
+	serial_outp(p, UART_DLL, 0);
+	serial_outp(p, UART_DLM, 0);
+
+	id = serial_inp(p, UART_DLL) | serial_inp(p, UART_DLM) << 8;
+
+	serial_outp(p, UART_DLL, old_dll);
+	serial_outp(p, UART_DLM, old_dlm);
+	serial_outp(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_outp(up, UART_SCR, 0xa5);
+	status1 = serial_in(up, UART_SCR);
+	serial_outp(up, UART_SCR, 0x5a);
+	status2 = serial_in(up, UART_SCR);
+	serial_outp(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;
+}
+
+static inline int ns16550a_goto_highspeed(struct uart_8250_port *up)
+{
+	unsigned char status;
+
+	status = serial_in(up, 0x04); /* EXCR2 */
+#define PRESL(x) ((x) & 0x30)
+	if (PRESL(status) == 0x10) {
+		/* already in high speed mode */
+		return 0;
+	} else {
+		status &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
+		status |= 0x10;  /* 1.625 divisor for baud_base --> 921600 */
+		serial_outp(up, 0x04, status);
+	}
+	return 1;
+}
+
+/*
+ * 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;
+
+	/*
+	 * Check for presence of the EFR when DLAB is set.
+	 * Only ST16C650V1 UARTs pass this test.
+	 */
+	serial_outp(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	if (serial_in(up, UART_EFR) == 0) {
+		serial_outp(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 {
+			DEBUG_AUTOCONF("Motorola 8xxx DUART ");
+		}
+		serial_outp(up, UART_EFR, 0);
+		return;
+	}
+
+	/*
+	 * Maybe it requires 0xbf to be written to the LCR.
+	 * (other ST16C650V2 UARTs, TI16C752A, etc)
+	 */
+	serial_outp(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_outp(up, UART_LCR, 0);
+	status1 = serial_in(up, UART_MCR);
+	serial_outp(up, UART_LCR, 0xE0);
+	status2 = serial_in(up, 0x02); /* EXCR1 */
+
+	if (!((status2 ^ status1) & UART_MCR_LOOP)) {
+		serial_outp(up, UART_LCR, 0);
+		serial_outp(up, UART_MCR, status1 ^ UART_MCR_LOOP);
+		serial_outp(up, UART_LCR, 0xE0);
+		status2 = serial_in(up, 0x02); /* EXCR1 */
+		serial_outp(up, UART_LCR, 0);
+		serial_outp(up, UART_MCR, status1);
+
+		if ((status2 ^ status1) & UART_MCR_LOOP) {
+			unsigned short quot;
+
+			serial_outp(up, UART_LCR, 0xE0);
+
+			quot = serial_dl_read(up);
+			quot <<= 3;
+
+			if (ns16550a_goto_highspeed(up))
+				serial_dl_write(up, quot);
+
+			serial_outp(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_outp(up, UART_LCR, 0);
+	serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
+	status1 = serial_in(up, UART_IIR) >> 5;
+	serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+	serial_outp(up, UART_LCR, UART_LCR_CONF_MODE_A);
+	serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
+	status2 = serial_in(up, UART_IIR) >> 5;
+	serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+	serial_outp