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linux/drivers/serial/8250.c

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/*
* linux/drivers/char/8250.c
*
* 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/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 <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;
}
/*
* 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 256
/*
* 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 uart_8250_port {
struct uart_port port;
struct timer_list timer; /* "no irq" timer */
struct list_head list; /* ports on this IRQ */
unsigned short capabilities; /* port capabilities */
unsigned short bugs; /* port bugs */
unsigned int tx_loadsz; /* transmit fifo load size */
unsigned char acr;
unsigned char ier;
unsigned char lcr;
unsigned char mcr;
unsigned char mcr_mask; /* mask of user bits */
unsigned char mcr_force; /* mask of forced bits */
/*
* Some bits in registers are cleared on a read, so they must
* be saved whenever the register is read but the bits will not
* be immediately processed.
*/
#define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
unsigned char lsr_saved_flags;
#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
unsigned char msr_saved_flags;
/*
* We provide a per-port pm hook.
*/
void (*pm)(struct uart_port *port,
unsigned int state, unsigned int old);
};
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,
.flags = UART_CAP_FIFO,
},
[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,
},
[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,
},
};
#if defined (CONFIG_SERIAL_8250_AU1X00)
/* 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);
}
#ifdef CONFIG_SERIAL_8250_AU1X00
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);
}
#endif
static unsigned int tsi_serial_in(struct uart_port *p, int offset)
{
unsigned int tmp;
offset = map_8250_in_reg(p, offset) << p->regshift;
if (offset == UART_IIR) {
tmp = readl(p->membase + (UART_IIR & ~3));
return (tmp >> 16) & 0xff; /* UART_IIR % 4 == 2 */
} else
return readb(p->membase + offset);
}
static void tsi_serial_out(struct uart_port *p, int offset, int value)
{
offset = map_8250_out_reg(p, offset) << p->regshift;
if (!((offset == UART_IER) && (value & UART_IER_UUE)))
writeb(value, p->membase + offset);
}
static void dwapb_serial_out(struct uart_port *p, int offset, int value)
{
int save_offset = offset;
offset = map_8250_out_reg(p, offset) << p->regshift;
/* Save the LCR value so it can be re-written when a
* Busy Detect interrupt occurs. */
if (save_offset == UART_LCR) {
struct uart_8250_port *up = (struct uart_8250_port *)p;
up->lcr = value;
}
writeb(value, p->membase + offset);
/* Read the IER to ensure any interrupt is cleared before
* returning from ISR. */
if (save_offset == UART_TX || save_offset == UART_IER)
value = p->serial_in(p, UART_IER);
}
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 void set_io_from_upio(struct uart_port *p)
{
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;
#ifdef CONFIG_SERIAL_8250_AU1X00
case UPIO_AU:
p->serial_in = au_serial_in;
p->serial_out = au_serial_out;
break;
#endif
case UPIO_TSI:
p->serial_in = tsi_serial_in;
p->serial_out = tsi_serial_out;
break;
case UPIO_DWAPB:
p->serial_in = mem_serial_in;
p->serial_out = dwapb_serial_out;
break;
default:
p->serial_in = io_serial_in;
p->serial_out = io_serial_out;
break;
}
}
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:
#ifdef CONFIG_SERIAL_8250_AU1X00
case UPIO_AU:
#endif
case UPIO_DWAPB:
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_SERIAL_8250_AU1X00)
/* 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, 0xBF);
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, 0xBF);
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_DLAB);
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_DLAB);
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_DLAB);
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, 0xBF);
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://www.exar.com/info.php?pdf=dan180_oct2004.pdf
*/
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;
/*
* Check for presence of the EFR when DLAB is set.
* Only ST16C650V1 UARTs pass this test.
*/
serial_outp(up, UART_LCR, UART_LCR_DLAB);
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, 0xBF);
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;
status1 = serial_in(up, 0x04); /* EXCR2 */
status1 &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
status1 |= 0x10; /* 1.625 divisor for baud_base --> 921600 */
serial_outp(up, 0x04, status1);
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_DLAB);
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(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_outp(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_outp(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;
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_outp(up, UART_IER, iersave);
}
/*
* 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 int probeflags)
{
unsigned char status1, scratch, scratch2, scratch3;
unsigned char save_lcr, save_mcr;
unsigned long flags;
if (!up->port.iobase && !up->port.mapbase && !up->port.membase)
return;
DEBUG_AUTOCONF("ttyS%d: autoconf (0x%04x, 0x%p): ",
serial_index(&up->port), up->port.iobase, up->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(&up->port.lock, flags);
up->capabilities = 0;
up->bugs = 0;
if (!(up->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_inp(up, UART_IER);
serial_outp(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_inp(up, UART_IER) & 0x0f;
serial_outp(up, UART_IER, 0x0F);
#ifdef __i386__
outb(0, 0x080);
#endif
scratch3 = serial_inp(up, UART_IER) & 0x0f;
serial_outp(up, UART_IER, scratch);
if (scratch2 != 0 || scratch3 != 0x0F) {
/*
* We failed; there's nothing here
*/
DEBUG_AUTOCONF("IER test failed (%02x, %02x) ",
scratch2, scratch3);
goto out;
}
}
save_mcr = serial_in(up, UART_MCR);
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 (!(up->port.flags & UPF_SKIP_TEST)) {
serial_outp(up, UART_MCR, UART_MCR_LOOP | 0x0A);
status1 = serial_inp(up, UART_MSR) & 0xF0;
serial_outp(up, UART_MCR, save_mcr);
if (status1 != 0x90) {
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_outp(up, UART_LCR, 0xBF);
serial_outp(up, UART_EFR, 0);
serial_outp(up, UART_LCR, 0);
serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
scratch = serial_in(up, UART_IIR) >> 6;
DEBUG_AUTOCONF("iir=%d ", scratch);
switch (scratch) {
case 0:
autoconfig_8250(up);
break;
case 1:
up->port.type = PORT_UNKNOWN;
break;
case 2:
up->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 (up->port.type == PORT_16550A && probeflags & PROBE_RSA) {
int i;
for (i = 0 ; i < probe_rsa_count; ++i) {
if (probe_rsa[i] == up->port.iobase &&
__enable_rsa(up)) {
up->port.type = PORT_RSA;
break;
}
}
}
#endif
#ifdef CONFIG_SERIAL_8250_AU1X00
/* if access method is AU, it is a 16550 with a quirk */
if (up->port.type == PORT_16550A && up->port.iotype == UPIO_AU)
up->bugs |= UART_BUG_NOMSR;
#endif
serial_outp(up, UART_LCR, save_lcr);
if (up->capabilities != uart_config[up->port.type].flags) {
printk(KERN_WARNING
"ttyS%d: detected caps %08x should be %08x\n",
serial_index(&up->port), up->capabilities,
uart_config[up->port.type].flags);
}
up->port.fifosize = uart_config[up->port.type].fifo_size;
up->capabilities = uart_config[up->port.type].flags;
up->tx_loadsz = uart_config[up->port.type].tx_loadsz;
if (up->port.type == PORT_UNKNOWN)
goto out;
/*
* Reset the UART.
*/
#ifdef CONFIG_SERIAL_8250_RSA
if (up->port.type == PORT_RSA)
serial_outp(up, UART_RSA_FRR, 0);
#endif
serial_outp(up, UART_MCR, save_mcr);
serial8250_clear_fifos(up);
serial_in(up, UART_RX);
if (up->capabilities & UART_CAP_UUE)
serial_outp(up, UART_IER, UART_IER_UUE);
else
serial_outp(up, UART_IER, 0);
out:
spin_unlock_irqrestore(&up->port.lock, flags);
DEBUG_AUTOCONF("type=%s\n", uart_config[up->port.type].name);
}
static void autoconfig_irq(struct uart_8250_port *up)
{
unsigned char save_mcr, save_ier;
unsigned char save_ICP = 0;
unsigned int ICP = 0;
unsigned long irqs;
int irq;
if (up->port.flags & UPF_FOURPORT) {
ICP = (up->port.iobase & 0xfe0) | 0x1f;
save_ICP = inb_p(ICP);
outb_p(0x80, ICP);
(void) inb_p(ICP);
}
/* forget possible initially masked and pending IRQ */
probe_irq_off(probe_irq_on());
save_mcr = serial_inp(up, UART_MCR);
save_ier = serial_inp(up, UART_IER);
serial_outp(up, UART_MCR, UART_MCR_OUT1 | UART_MCR_OUT2);
irqs = probe_irq_on();
serial_outp(up, UART_MCR, 0);
udelay(10);
if (up->port.flags & UPF_FOURPORT) {
serial_outp(up, UART_MCR,
UART_MCR_DTR | UART_MCR_RTS);
} else {
serial_outp(up, UART_MCR,
UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2);
}
serial_outp(up, UART_IER, 0x0f); /* enable all intrs */
(void)serial_inp(up, UART_LSR);
(void)serial_inp(up, UART_RX);
(void)serial_inp(up, UART_IIR);
(void)serial_inp(up, UART_MSR);
serial_outp(up, UART_TX, 0xFF);
udelay(20);
irq = probe_irq_off(irqs);
serial_outp(up, UART_MCR, save_mcr);
serial_outp(up, UART_IER, save_ier);
if (up->port.flags & UPF_FOURPORT)
outb_p(save_ICP, ICP);
up->port.irq = (irq > 0) ? irq : 0;
}
static inline void __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);
}
}
static void serial8250_stop_tx(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
__stop_tx(up);
/*
* We really want to stop the transmitter from sending.
*/
if (up->port.type == PORT_16C950) {
up->acr |= UART_ACR_TXDIS;
serial_icr_write(up, UART_ACR, up->acr);
}
}
static void transmit_chars(struct uart_8250_port *up);
static void serial8250_start_tx(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
if (!(up->ier & UART_IER_THRI)) {
up->ier |= UART_IER_THRI;
serial_out(up, UART_IER, up->ier);
if (up->bugs & UART_BUG_TXEN) {
unsigned char lsr, iir;
lsr = serial_in(up, UART_LSR);
up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
iir = serial_in(up, UART_IIR) & 0x0f;
if ((up->port.type == PORT_RM9000) ?
(lsr & UART_LSR_THRE &&
(iir == UART_IIR_NO_INT || iir == UART_IIR_THRI)) :
(lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT))
transmit_chars(up);
}
}
/*
* Re-enable the transmitter if we disabled it.
*/
if (up->port.type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
up->acr &= ~UART_ACR_TXDIS;
serial_icr_write(up, UART_ACR, up->acr);
}
}
static void serial8250_stop_rx(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
up->ier &= ~UART_IER_RLSI;
up->port.read_status_mask &= ~UART_LSR_DR;
serial_out(up, UART_IER, up->ier);
}
static void serial8250_enable_ms(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
/* no MSR capabilities */
if (up->bugs & UART_BUG_NOMSR)
return;
up->ier |= UART_IER_MSI;
serial_out(up, UART_IER, up->ier);
}
static void
receive_chars(struct uart_8250_port *up, unsigned int *status)
{
struct tty_struct *tty = up->port.info->port.tty;
unsigned char ch, lsr = *status;
int max_count = 256;
char flag;
do {
if (likely(lsr & UART_LSR_DR))
ch = serial_inp(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;
flag = TTY_NORMAL;
up->port.icount.rx++;
lsr |= up->lsr_saved_flags;
up->lsr_saved_flags = 0;
if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
/*
* For statistics only
*/
if (lsr & UART_LSR_BI) {
lsr &= ~(UART_LSR_FE | UART_LSR_PE);
up->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(&up->port))
goto ignore_char;
} else if (lsr & UART_LSR_PE)
up->port.icount.parity++;
else if (lsr & UART_LSR_FE)
up->port.icount.frame++;
if (lsr & UART_LSR_OE)
up->port.icount.overrun++;
/*
* Mask off conditions which should be ignored.
*/
lsr &= up->port.read_status_mask;
if (lsr & UART_LSR_BI) {
DEBUG_INTR("handling break....");
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(&up->port, ch))
goto ignore_char;
uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
ignore_char:
lsr = serial_inp(up, UART_LSR);
} while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (max_count-- > 0));
spin_unlock(&up->port.lock);
tty_flip_buffer_push(tty);
spin_lock(&up->port.lock);
*status = lsr;
}
static void transmit_chars(struct uart_8250_port *up)
{
struct circ_buf *xmit = &up->port.info->xmit;
int count;
if (up->port.x_char) {
serial_outp(up, UART_TX, up->port.x_char);
up->port.icount.tx++;
up->port.x_char = 0;
return;
}
if (uart_tx_stopped(&up->port)) {
serial8250_stop_tx(&up->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);
up->port.icount.tx++;
if (uart_circ_empty(xmit))
break;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&up->port);
DEBUG_INTR("THRE...");
if (uart_circ_empty(xmit))
__stop_tx(up);
}
static unsigned int check_modem_status(struct uart_8250_port *up)
{
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 &&
up->port.info != NULL) {
if (status & UART_MSR_TERI)
up->port.icount.rng++;
if (status & UART_MSR_DDSR)
up->port.icount.dsr++;
if (status & UART_MSR_DDCD)
uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
if (status & UART_MSR_DCTS)
uart_handle_cts_change(&up->port, status & UART_MSR_CTS);
wake_up_interruptible(&up->port.info->delta_msr_wait);
}
return status;
}
/*
* This handles the interrupt from one port.
*/
static void serial8250_handle_port(struct uart_8250_port *up)
{
unsigned int status;
unsigned long flags;
spin_lock_irqsave(&up->port.lock, flags);
status = serial_inp(up, UART_LSR);
DEBUG_INTR("status = %x...", status);
if (status & (UART_LSR_DR | UART_LSR_BI))
receive_chars(up, &status);
check_modem_status(up);
if (status & UART_LSR_THRE)
transmit_chars(up);
spin_unlock_irqrestore(&up->port.lock, flags);
}
/*
* This is the serial driver's interrupt routine.
*
* Arjan thinks the old way was overly complex, so it got simplified.
* Alan disagrees, saying that need the complexity to handle the weird
* nature of ISA shared interrupts. (This is a special exception.)
*
* In order to handle ISA shared interrupts properly, we need to check
* that all ports have been serviced, and therefore the ISA interrupt
* line has been de-asserted.
*
* This means we need to loop through all ports. checking that they
* don't have an interrupt pending.
*/
static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
{
struct irq_info *i = dev_id;
struct list_head *l, *end = NULL;
int pass_counter = 0, handled = 0;
DEBUG_INTR("serial8250_interrupt(%d)...", irq);
spin_lock(&i->lock);
l = i->head;
do {
struct uart_8250_port *up;
unsigned int iir;
up = list_entry(l, struct uart_8250_port, list);
iir = serial_in(up, UART_IIR);
if (!(iir & UART_IIR_NO_INT)) {
serial8250_handle_port(up);
handled = 1;
end = NULL;
} else if (up->port.iotype == UPIO_DWAPB &&
(iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
/* The DesignWare APB UART has an Busy Detect (0x07)
* interrupt meaning an LCR write attempt occured while the
* UART was busy. The interrupt must be cleared by reading
* the UART status register (USR) and the LCR re-written. */
unsigned int status;
status = *(volatile u32 *)up->port.private_data;
serial_out(up, UART_LCR, up->lcr);
handled = 1;
end = NULL;
} else if (end == NULL)
end = l;
l = l->next;
if (l == i->head && pass_counter++ > PASS_LIMIT) {
/* If we hit this, we're dead. */
printk(KERN_ERR "serial8250: too much work for "
"irq%d\n", irq);
break;
}
} while (l != end);
spin_unlock(&i->lock);
DEBUG_INTR("end.\n");
return IRQ_RETVAL(handled);
}
/*
* To support ISA shared interrupts, we need to have one interrupt
* handler that ensures that the IRQ line has been deasserted
* before returning. Failing to do this will result in the IRQ
* line being stuck active, and, since ISA irqs are edge triggered,
* no more IRQs will be seen.
*/
static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
{
spin_lock_irq(&i->lock);
if (!list_empty(i->head)) {
if (i->head == &up->list)
i->head = i->head->next;
list_del(&up->list);
} else {
BUG_ON(i->head != &up->list);
i->head = NULL;
}
spin_unlock_irq(&i->lock);
/* List empty so throw away the hash node */
if (i->head == NULL) {
hlist_del(&i->node);
kfree(i);
}
}
static int serial_link_irq_chain(struct uart_8250_port *up)
{
struct hlist_head *h;
struct hlist_node *n;
struct irq_info *i;
int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ? IRQF_SHARED : 0;
mutex_lock(&hash_mutex);
h = &irq_lists[up->port.irq % NR_IRQ_HASH];
hlist_for_each(n, h) {
i = hlist_entry(n, struct irq_info, node);
if (i->irq == up->port.irq)
break;
}
if (n == NULL) {
i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
if (i == NULL) {
mutex_unlock(&hash_mutex);
return -ENOMEM;
}
spin_lock_init(&i->lock);
i->irq = up->port.irq;
hlist_add_head(&i->node, h);
}
mutex_unlock(&hash_mutex);
spin_lock_irq(&i->lock);
if (i->head) {
list_add(&up->list, i->head);
spin_unlock_irq(&i->lock);
ret = 0;
} else {
INIT_LIST_HEAD(&up->list);
i->head = &up->list;
spin_unlock_irq(&i->lock);
ret = request_irq(up->port.irq, serial8250_interrupt,
irq_flags, "serial", i);
if (ret < 0)
serial_do_unlink(i, up);
}
return ret;
}
static void serial_unlink_irq_chain(struct uart_8250_port *up)
{
struct irq_info *i;
struct hlist_node *n;
struct hlist_head *h;
mutex_lock(&hash_mutex);
h = &irq_lists[up->port.irq % NR_IRQ_HASH];
hlist_for_each(n, h) {
i = hlist_entry(n, struct irq_info, node);
if (i->irq == up->port.irq)
break;
}
BUG_ON(n == NULL);
BUG_ON(i->head == NULL);
if (list_empty(i->head))
free_irq(up->port.irq, i);
serial_do_unlink(i, up);
mutex_unlock(&hash_mutex);
}
/* Base timer interval for polling */
static inline int poll_timeout(int timeout)
{
return timeout > 6 ? (timeout / 2 - 2) : 1;
}
/*
* This function is used to handle ports that do not have an
* interrupt. This doesn't work very well for 16450's, but gives
* barely passable results for a 16550A. (Although at the expense
* of much CPU overhead).
*/
static void serial8250_timeout(unsigned long data)
{
struct uart_8250_port *up = (struct uart_8250_port *)data;
unsigned int iir;
iir = serial_in(up, UART_IIR);
if (!(iir & UART_IIR_NO_INT))
serial8250_handle_port(up);
mod_timer(&up->timer, jiffies + poll_timeout(up->port.timeout));
}
static void serial8250_backup_timeout(unsigned long data)
{
struct uart_8250_port *up = (struct uart_8250_port *)data;
unsigned int iir, ier = 0, lsr;
unsigned long flags;
/*
* Must disable interrupts or else we risk racing with the interrupt
* based handler.
*/
if (is_real_interrupt(up->port.irq)) {
ier = serial_in(up, UART_IER);
serial_out(up, UART_IER, 0);
}
iir = serial_in(up, UART_IIR);
/*
* This should be a safe test for anyone who doesn't trust the
* IIR bits on their UART, but it's specifically designed for
* the "Diva" UART used on the management processor on many HP
* ia64 and parisc boxes.
*/
spin_lock_irqsave(&up->port.lock, flags);
lsr = serial_in(up, UART_LSR);
up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
spin_unlock_irqrestore(&up->port.lock, flags);
if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
(!uart_circ_empty(&up->port.info->xmit) || up->port.x_char) &&
(lsr & UART_LSR_THRE)) {
iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
iir |= UART_IIR_THRI;
}
if (!(iir & UART_IIR_NO_INT))
serial8250_handle_port(up);
if (is_real_interrupt(up->port.irq))
serial_out(up, UART_IER, ier);
/* Standard timer interval plus 0.2s to keep the port running */
mod_timer(&up->timer,
jiffies + poll_timeout(up->port.timeout) + HZ / 5);
}
static unsigned int serial8250_tx_empty(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
unsigned long flags;
unsigned int lsr;
spin_lock_irqsave(&up->port.lock, flags);
lsr = serial_in(up, UART_LSR);
up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
spin_unlock_irqrestore(&up->port.lock, flags);
return lsr & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
}
static unsigned int serial8250_get_mctrl(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
unsigned int status;
unsigned int ret;
status = check_modem_status(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;
}
static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct uart_8250_port *up = (struct uart_8250_port *)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;
serial_out(up, UART_MCR, mcr);
}
static void serial8250_break_ctl(struct uart_port *port, int break_state)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
unsigned long flags;
spin_lock_irqsave(&up->port.lock, flags);
if (break_state == -1)
up->lcr |= UART_LCR_SBC;
else
up->lcr &= ~UART_LCR_SBC;
serial_out(up, UART_LCR, up->lcr);
spin_unlock_irqrestore(&up->port.lock, flags);
}
#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
/*
* 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. */
do {
status = serial_in(up, UART_LSR);
up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
if (--tmout == 0)
break;
udelay(1);
} while ((status & bits) != bits);
/* Wait up to 1s for flow control if necessary */
if (up->port.flags & UPF_CONS_FLOW) {
unsigned int tmout;
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 = (struct uart_8250_port *)port;
unsigned char lsr = serial_inp(up, UART_LSR);
while (!(lsr & UART_LSR_DR))
lsr = serial_inp(up, UART_LSR);
return serial_inp(up, UART_RX);
}
static void serial8250_put_poll_char(struct uart_port *port,
unsigned char c)
{
unsigned int ier;
struct uart_8250_port *up = (struct uart_8250_port *)port;
/*
* First save the IER then disable the interrupts
*/
ier = serial_in(up, UART_IER);
if (up->capabilities & UART_CAP_UUE)
serial_out(up, UART_IER, UART_IER_UUE);
else
serial_out(up, UART_IER, 0);
wait_for_xmitr(up, BOTH_EMPTY);
/*
* Send the character out.
* If a LF, also do CR...
*/
serial_out(up, UART_TX, c);
if (c == 10) {
wait_for_xmitr(up, BOTH_EMPTY);
serial_out(up, UART_TX, 13);
}
/*
* Finally, wait for transmitter to become empty
* and restore the IER
*/
wait_for_xmitr(up, BOTH_EMPTY);
serial_out(up, UART_IER, ier);
}
#endif /* CONFIG_CONSOLE_POLL */
static int serial8250_startup(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
unsigned long flags;
unsigned char lsr, iir;
int retval;
up->capabilities = uart_config[up->port.type].flags;
up->mcr = 0;
if (up->port.type == PORT_16C950) {
/* Wake up and initialize UART */
up->acr = 0;
serial_outp(up, UART_LCR, 0xBF);
serial_outp(up, UART_EFR, UART_EFR_ECB);
serial_outp(up, UART_IER, 0);
serial_outp(up, UART_LCR, 0);
serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
serial_outp(up, UART_LCR, 0xBF);
serial_outp(up, UART_EFR, UART_EFR_ECB);
serial_outp(up, UART_LCR, 0);
}
#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
/*
* Clear the FIFO buffers and disable them.
* (they will be reenabled in set_termios())
*/
serial8250_clear_fifos(up);
/*
* Clear the interrupt registers.
*/
(void) serial_inp(up, UART_LSR);
(void) serial_inp(up, UART_RX);
(void) serial_inp(up, UART_IIR);
(void) serial_inp(up, UART_MSR);
/*
* 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 (!(up->port.flags & UPF_BUGGY_UART) &&
(serial_inp(up, UART_LSR) == 0xff)) {
printk(KERN_INFO "ttyS%d: LSR safety check engaged!\n",
serial_index(&up->port));
return -ENODEV;
}
/*
* For a XR16C850, we need to set the trigger levels
*/
if (up->port.type == PORT_16850) {
unsigned char fctr;
serial_outp(up, UART_LCR, 0xbf);
fctr = serial_inp(up, UART_FCTR) & ~(UART_FCTR_RX|UART_FCTR_TX);
serial_outp(up, UART_FCTR, fctr | UART_FCTR_TRGD | UART_FCTR_RX);
serial_outp(up, UART_TRG, UART_TRG_96);
serial_outp(up, UART_FCTR, fctr | UART_FCTR_TRGD | UART_FCTR_TX);
serial_outp(up, UART_TRG, UART_TRG_96);
serial_outp(up, UART_LCR, 0);
}
if (is_real_interrupt(up->port.irq)) {
unsigned char iir1;
/*
* 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(&up->port.lock, flags);
if (up->port.flags & UPF_SHARE_IRQ)
disable_irq_nosync(up->port.irq);
wait_for_xmitr(up, UART_LSR_THRE);
serial_out_sync(up, UART_IER, UART_IER_THRI);
udelay(1); /* allow THRE to set */
iir1 = serial_in(up, UART_IIR);
serial_out(up, UART_IER, 0);
serial_out_sync(up, UART_IER, UART_IER_THRI);
udelay(1); /* allow a working UART time to re-assert THRE */
iir = serial_in(up, UART_IIR);
serial_out(up, UART_IER, 0);
if (up->port.flags & UPF_SHARE_IRQ)
enable_irq(up->port.irq);
spin_unlock_irqrestore(&up->port.lock, flags);
/*
* If the interrupt is not reasserted, setup a timer to
* kick the UART on a regular basis.
*/
if (!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) {
up->bugs |= UART_BUG_THRE;
pr_debug("ttyS%d - using backup timer\n",
serial_index(port));
}
}
/*
* The above check will only give an accurate result the first time
* the port is opened so this value needs to be preserved.
*/
if (up->bugs & UART_BUG_THRE) {
up->timer.function = serial8250_backup_timeout;
up->timer.data = (unsigned long)up;
mod_timer(&up->timer, jiffies +
poll_timeout(up->port.timeout) + HZ / 5);
}
/*
* If the "interrupt" for this port doesn't correspond with any
* hardware interrupt, we use a timer-based system. The original
* driver used to do this with IRQ0.
*/
if (!is_real_interrupt(up->port.irq)) {
up->timer.data = (unsigned long)up;
mod_timer(&up->timer, jiffies + poll_timeout(up->port.timeout));
} else {
retval = serial_link_irq_chain(up);
if (retval)
return retval;
}
/*
* Now, initialize the UART
*/
serial_outp(up, UART_LCR, UART_LCR_WLEN8);
spin_lock_irqsave(&up->port.lock, flags);
if (up->port.flags & UPF_FOURPORT) {
if (!is_real_interrupt(up->port.irq))
up->port.mctrl |= TIOCM_OUT1;
} else
/*
* Most PC uarts need OUT2 raised to enable interrupts.
*/
if (is_real_interrupt(up->port.irq))
up->port.mctrl |= TIOCM_OUT2;
serial8250_set_mctrl(&up->port, up->port.mctrl);
/*
* Do a quick test to see if we receive an
* interrupt when we enable the TX irq.
*/
serial_outp(up, UART_IER, UART_IER_THRI);
lsr = serial_in(up, UART_LSR);
iir = serial_in(up, UART_IIR);
serial_outp(up, 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("ttyS%d - enabling bad tx status workarounds\n",
serial_index(port));
}
} else {
up->bugs &= ~UART_BUG_TXEN;
}
spin_unlock_irqrestore(&up->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_inp(up, UART_LSR);
serial_inp(up, UART_RX);
serial_inp(up, UART_IIR);
serial_inp(up, UART_MSR);
up->lsr_saved_flags = 0;
up->msr_saved_flags = 0;
/*
* Finally, enable interrupts. Note: Modem status interrupts
* are set via set_termios(), which will be occurring imminently
* anyway, so we don't enable them here.
*/
up->ier = UART_IER_RLSI | UART_IER_RDI;
serial_outp(up, UART_IER, up->ier);
if (up->port.flags & UPF_FOURPORT) {
unsigned int icp;
/*
* Enable interrupts on the AST Fourport board
*/
icp = (up->port.iobase & 0xfe0) | 0x01f;
outb_p(0x80, icp);
(void) inb_p(icp);
}
return 0;
}
static void serial8250_shutdown(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
unsigned long flags;
/*
* Disable interrupts from this port
*/
up->ier = 0;
serial_outp(up, UART_IER, 0);
spin_lock_irqsave(&up->port.lock, flags);
if (up->port.flags & UPF_FOURPORT) {
/* reset interrupts on the AST Fourport board */
inb((up->port.iobase & 0xfe0) | 0x1f);
up->port.mctrl |= TIOCM_OUT1;
} else
up->port.mctrl &= ~TIOCM_OUT2;
serial8250_set_mctrl(&up->port, up->port.mctrl);
spin_unlock_irqrestore(&up->port.lock, flags);
/*
* Disable break condition and FIFOs
*/
serial_out(up, UART_LCR, serial_inp(up, 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.
*/
(void) serial_in(up, UART_RX);
del_timer_sync(&up->timer);
up->timer.function = serial8250_timeout;
if (is_real_interrupt(up->port.irq))
serial_unlink_irq_chain(up);
}
static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int baud)
{
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
quot = uart_get_divisor(port, baud);
return quot;
}
static void
serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
unsigned char cval, fcr = 0;
unsigned long flags;
unsigned int baud, quot;
switch (termios->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 (termios->c_cflag & CSTOPB)
cval |= UART_LCR_STOP;
if (termios->c_cflag & PARENB)
cval |= UART_LCR_PARITY;
if (!(termios->c_cflag & PARODD))
cval |= UART_LCR_EPAR;
#ifdef CMSPAR
if (termios->c_cflag & CMSPAR)
cval |= UART_LCR_SPAR;
#endif
/*
* Ask the core to calculate the divisor for us.
*/
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
quot = serial8250_get_divisor(port, baud);
/*
* Oxford Semi 952 rev B workaround
*/
if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0)
quot++;
if (up->capabilities & UART_CAP_FIFO && up->port.fifosize > 1) {
if (baud < 2400)
fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
else
fcr = uart_config[up->port.type].fcr;
}
/*
* 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. In the case where
* the remote UART is not using CTS auto flow control, we must
* have sufficient FIFO entries for the latency of the remote
* UART to respond. IOW, at least 32 bytes of FIFO.
*/
if (up->capabilities & UART_CAP_AFE && up->port.fifosize >= 32) {
up->mcr &= ~UART_MCR_AFE;
if (termios->c_cflag & CRTSCTS)
up->mcr |= UART_MCR_AFE;
}
/*
* Ok, we're now changing the port state. Do it with
* interrupts disabled.
*/
spin_lock_irqsave(&up->port.lock, flags);
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
if (termios->c_iflag & INPCK)
up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
if (termios->c_iflag & (BRKINT | PARMRK))
up->port.read_status_mask |= UART_LSR_BI;
/*
* Characteres to ignore
*/
up->port.ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
if (termios->c_iflag & IGNBRK) {
up->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)
up->port.ignore_status_mask |= UART_LSR_OE;
}
/*
* ignore all characters if CREAD is not set
*/
if ((termios->c_cflag & CREAD) == 0)
up->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 | UART_IER_RTOIE;
serial_out(up, 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_outp(up, UART_LCR, 0xBF);
serial_outp(up, UART_EFR, efr);
}
#ifdef CONFIG_ARCH_OMAP
/* Workaround to enable 115200 baud on OMAP1510 internal ports */
if (cpu_is_omap1510() && is_omap_port(up)) {
if (baud == 115200) {
quot = 1;
serial_out(up, UART_OMAP_OSC_12M_SEL, 1);
} else
serial_out(up, UART_OMAP_OSC_12M_SEL, 0);
}
#endif
if (up->capabilities & UART_NATSEMI) {
/* Switch to bank 2 not bank 1, to avoid resetting EXCR2 */
serial_outp(up, UART_LCR, 0xe0);
} else {
serial_outp(up, UART_LCR, cval | UART_LCR_DLAB);/* set DLAB */
}
serial_dl_write(up, quot);
/*
* 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 (up->port.type == PORT_16750)
serial_outp(up, UART_FCR, fcr);
serial_outp(up, UART_LCR, cval); /* reset DLAB */
up->lcr = cval; /* Save LCR */
if (up->port.type != PORT_16750) {
if (fcr & UART_FCR_ENABLE_FIFO) {
/* emulated UARTs (Lucent Venus 167x) need two steps */
serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
}
serial_outp(up, UART_FCR, fcr); /* set fcr */
}
serial8250_set_mctrl(&up->port, up->port.mctrl);
spin_unlock_irqrestore(&up->port.lock, flags);
/* Don't rewrite B0 */
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
}
static void
serial8250_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
struct uart_8250_port *p = (struct uart_8250_port *)port;
serial8250_set_sleep(p, state != 0);
if (p->pm)
p->pm(port, state, oldstate);
}
static unsigned int serial8250_port_size(struct uart_8250_port *pt)
{
if (pt->port.iotype == UPIO_AU)
return 0x100000;
#ifdef CONFIG_ARCH_OMAP
if (is_omap_port(pt))
return 0x16 << pt->port.regshift;
#endif
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);
int ret = 0;
switch (up->port.iotype) {
case UPIO_AU:
case UPIO_TSI:
case UPIO_MEM32:
case UPIO_MEM:
case UPIO_DWAPB:
if (!up->port.mapbase)
break;
if (!request_mem_region(up->port.mapbase, size, "serial")) {
ret = -EBUSY;
break;
}
if (up->port.flags & UPF_IOREMAP) {
up->port.membase = ioremap_nocache(up->port.mapbase,
size);
if (!up->port.membase) {
release_mem_region(up->port.mapbase, size);
ret = -ENOMEM;
}
}
break;
case UPIO_HUB6:
case UPIO_PORT:
if (!request_region(up->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);
switch (up->port.iotype) {
case UPIO_AU:
case UPIO_TSI:
case UPIO_MEM32:
case UPIO_MEM:
case UPIO_DWAPB:
if (!up->port.mapbase)
break;
if (up->port.flags & UPF_IOREMAP) {
iounmap(up->port.membase);
up->port.membase = NULL;
}
release_mem_region(up->port.mapbase, size);
break;
case UPIO_HUB6:
case UPIO_PORT:
release_region(up->port.iobase, size);
break;
}
}
static int serial8250_request_rsa_resource(struct uart_8250_port *up)
{
unsigned long start = UART_RSA_BASE << up->port.regshift;
unsigned int size = 8 << up->port.regshift;
int ret = -EINVAL;
switch (up->port.iotype) {
case UPIO_HUB6:
case UPIO_PORT:
start += up->port.iobase;
if (request_region(start, size, "serial-rsa"))
ret = 0;
else
ret = -EBUSY;
break;
}
return ret;
}
static void serial8250_release_rsa_resource(struct uart_8250_port *up)
{
unsigned long offset = UART_RSA_BASE << up->port.regshift;
unsigned int size = 8 << up->port.regshift;
switch (up->port.iotype) {
case UPIO_HUB6:
case UPIO_PORT:
release_region(up->port.iobase + offset, size);
break;
}
}
static void serial8250_release_port(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
serial8250_release_std_resource(up);
if (up->port.type == PORT_RSA)
serial8250_release_rsa_resource(up);
}
static int serial8250_request_port(struct uart_port *port)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
int ret = 0;
ret = serial8250_request_std_resource(up);
if (ret == 0 && up->port.type == PORT_RSA) {
ret = serial8250_request_rsa_resource(up);
if (ret < 0)
serial8250_release_std_resource(up);
}
return ret;
}
static void serial8250_config_port(struct uart_port *port, int flags)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
int probeflags = PROBE_ANY;
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;
ret = serial8250_request_rsa_resource(up);
if (ret < 0)
probeflags &= ~PROBE_RSA;
if (flags & UART_CONFIG_TYPE)
autoconfig(up, probeflags);
if (up->port.type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
autoconfig_irq(up);
if (up->port.type != PORT_RSA && probeflags & PROBE_RSA)
serial8250_release_rsa_resource(up);
if (up->port.type == PORT_UNKNOWN)
serial8250_release_std_resource(up);
}
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 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,
.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,
.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
};
static struct uart_8250_port serial8250_ports[UART_NR];
static void __init serial8250_isa_init_ports(void)
{
struct uart_8250_port *up;
static int first = 1;
int i;
if (!first)
return;
first = 0;
for (i = 0; i < nr_uarts; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
up->port.line = i;
spin_lock_init(&up->port.lock);
init_timer(&up->timer);
up->timer.function = serial8250_timeout;
/*
* ALPHA_KLUDGE_MCR needs to be killed.
*/
up->mcr_mask = ~ALPHA_KLUDGE_MCR;
up->mcr_force = ALPHA_KLUDGE_MCR;
up->port.ops = &serial8250_pops;
}
for (i = 0, up = serial8250_ports;
i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
i++, up++) {
up->port.iobase = old_serial_port[i].port;
up->port.irq = irq_canonicalize(old_serial_port[i].irq);
up->port.uartclk = old_serial_port[i].baud_base * 16;
up->port.flags = old_serial_port[i].flags;
up->port.hub6 = old_serial_port[i].hub6;
up->port.membase = old_serial_port[i].iomem_base;
up->port.iotype = old_serial_port[i].io_type;
up->port.regshift = old_serial_port[i].iomem_reg_shift;
set_io_from_upio(&up->port);
if (share_irqs)
up->port.flags |= UPF_SHARE_IRQ;
}
}
static void __init
serial8250_register_ports(struct uart_driver *drv, struct device *dev)
{
int i;
serial8250_isa_init_ports();
for (i = 0; i < nr_uarts; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
up->port.dev = dev;
uart_add_one_port(drv, &up->port);
}
}
#ifdef CONFIG_SERIAL_8250_CONSOLE
static void serial8250_console_putchar(struct uart_port *port, int ch)
{
struct uart_8250_port *up = (struct uart_8250_port *)port;
wait_for_xmitr(up, UART_LSR_THRE);
serial_out(up, UART_TX, ch);
}
/*
* 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.
*/
static void
serial8250_console_write(struct console *co, const char *s, unsigned int count)
{
struct uart_8250_port *up = &serial8250_ports[co->index];
unsigned long flags;
unsigned int ier;
int locked = 1;
touch_nmi_watchdog();
local_irq_save(flags);
if (up->port.sysrq) {
/* serial8250_handle_port() already took the lock */
locked = 0;
} else if (oops_in_progress) {
locked = spin_trylock(&up->port.lock);
} else
spin_lock(&up->port.lock);
/*
* First save the IER then disable the interrupts
*/
ier = serial_in(up, UART_IER);
if (up->capabilities & UART_CAP_UUE)
serial_out(up, UART_IER, UART_IER_UUE);
else
serial_out(up, UART_IER, 0);
uart_console_write(&up->port, s, count, serial8250_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the IER
*/
wait_for_xmitr(up, BOTH_EMPTY);
serial_out(up, 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)
check_modem_status(up);
if (locked)
spin_unlock(&up->port.lock);
local_irq_restore(flags);
}
static int __init serial8250_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
/*
* Check whether an invalid uart number has been specified, and
* if so, search for the first available port that does have
* console support.
*/
if (co->index >= nr_uarts)
co->index = 0;
port = &serial8250_ports[co->index].port;
if (!port->iobase && !port->membase)
return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static int serial8250_console_early_setup(void)
{
return serial8250_find_port_for_earlycon();
}
static struct console serial8250_console = {
.name = "ttyS",
.write = serial8250_console_write,
.device = uart_console_device,
.setup = serial8250_console_setup,
.early_setup = serial8250_console_early_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &serial8250_reg,
};
static int __init serial8250_console_init(void)
{
if (nr_uarts > UART_NR)
nr_uarts = UART_NR;
serial8250_isa_init_ports();
register_console(&serial8250_console);
return 0;
}
console_initcall(serial8250_console_init);
int serial8250_find_port(struct uart_port *p)
{
int line;
struct uart_port *port;
for (line = 0; line < nr_uarts; line++) {
port = &serial8250_ports[line].port;
if (uart_match_port(p, port))
return line;
}
return -ENODEV;
}
#define SERIAL8250_CONSOLE &serial8250_console
#else
#define SERIAL8250_CONSOLE NULL
#endif
static struct uart_driver serial8250_reg = {
.owner = THIS_MODULE,
.driver_name = "serial",
.dev_name = "ttyS",
.major = TTY_MAJOR,
.minor = 64,
.cons = SERIAL8250_CONSOLE,
};
/*
* early_serial_setup - early registration for 8250 ports
*
* Setup an 8250 port structure prior to console initialisation. Use
* after console initialisation will cause undefined behaviour.
*/
int __init early_serial_setup(struct uart_port *port)
{
struct uart_port *p;
if (port->line >= ARRAY_SIZE(serial8250_ports))
return -ENODEV;
serial8250_isa_init_ports();
p = &serial8250_ports[port->line].port;
p->iobase = port->iobase;
p->membase = port->membase;
p->irq = port->irq;
p->uartclk = port->uartclk;
p->fifosize = port->fifosize;
p->regshift = port->regshift;
p->iotype = port->iotype;
p->flags = port->flags;
p->mapbase = port->mapbase;
p->private_data = port->private_data;
set_io_from_upio(p);
if (port->serial_in)
p->serial_in = port->serial_in;
if (port->serial_out)
p->serial_out = port->serial_out;
return 0;
}
/**
* serial8250_suspend_port - suspend one serial port
* @line: serial line number
*
* Suspend one serial port.
*/
void serial8250_suspend_port(int line)
{
uart_suspend_port(&serial8250_reg, &serial8250_ports[line].port);
}
/**
* serial8250_resume_port - resume one serial port
* @line: serial line number
*
* Resume one serial port.
*/
void serial8250_resume_port(int line)
{
struct uart_8250_port *up = &serial8250_ports[line];
if (up->capabilities & UART_NATSEMI) {
unsigned char tmp;
/* Ensure it's still in high speed mode */
serial_outp(up, UART_LCR, 0xE0);
tmp = serial_in(up, 0x04); /* EXCR2 */
tmp &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
tmp |= 0x10; /* 1.625 divisor for baud_base --> 921600 */
serial_outp(up, 0x04, tmp);
serial_outp(up, UART_LCR, 0);
}
uart_resume_port(&serial8250_reg, &up->port);
}
/*
* Register a set of serial devices attached to a platform device. The
* list is terminated with a zero flags entry, which means we expect
* all entries to have at least UPF_BOOT_AUTOCONF set.
*/
static int __devinit serial8250_probe(struct platform_device *dev)
{
struct plat_serial8250_port *p = dev->dev.platform_data;
struct uart_port port;
int ret, i;
memset(&port, 0, sizeof(struct uart_port));
for (i = 0; p && p->flags != 0; p++, i++) {
port.iobase = p->iobase;
port.membase = p->membase;
port.irq = p->irq;
port.uartclk = p->uartclk;
port.regshift = p->regshift;
port.iotype = p->iotype;
port.flags = p->flags;
port.mapbase = p->mapbase;
port.hub6 = p->hub6;
port.private_data = p->private_data;
port.type = p->type;
port.serial_in = p->serial_in;
port.serial_out = p->serial_out;
port.dev = &dev->dev;
if (share_irqs)
port.flags |= UPF_SHARE_IRQ;
ret = serial8250_register_port(&port);
if (ret < 0) {
dev_err(&dev->dev, "unable to register port at index %d "
"(IO%lx MEM%llx IRQ%d): %d\n", i,
p->iobase, (unsigned long long)p->mapbase,
p->irq, ret);
}
}
return 0;
}
/*
* Remove serial ports registered against a platform device.
*/
static int __devexit serial8250_remove(struct platform_device *dev)
{
int i;
for (i = 0; i < nr_uarts; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
if (up->port.dev == &dev->dev)
serial8250_unregister_port(i);
}
return 0;
}
static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
{
int i;
for (i = 0; i < UART_NR; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
uart_suspend_port(&serial8250_reg, &up->port);
}
return 0;
}
static int serial8250_resume(struct platform_device *dev)
{
int i;
for (i = 0; i < UART_NR; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
serial8250_resume_port(i);
}
return 0;
}
static struct platform_driver serial8250_isa_driver = {
.probe = serial8250_probe,
.remove = __devexit_p(serial8250_remove),
.suspend = serial8250_suspend,
.resume = serial8250_resume,
.driver = {
.name = "serial8250",
.owner = THIS_MODULE,
},
};
/*
* This "device" covers _all_ ISA 8250-compatible serial devices listed
* in the table in include/asm/serial.h
*/
static struct platform_device *serial8250_isa_devs;
/*
* serial8250_register_port and serial8250_unregister_port allows for
* 16x50 serial ports to be configured at run-time, to support PCMCIA
* modems and PCI multiport cards.
*/
static DEFINE_MUTEX(serial_mutex);
static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *port)
{
int i;
/*
* First, find a port entry which matches.
*/
for (i = 0; i < nr_uarts; i++)
if (uart_match_port(&serial8250_ports[i].port, port))
return &serial8250_ports[i];
/*
* We didn't find a matching entry, so look for the first
* free entry. We look for one which hasn't been previously
* used (indicated by zero iobase).
*/
for (i = 0; i < nr_uarts; i++)
if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
serial8250_ports[i].port.iobase == 0)
return &serial8250_ports[i];
/*
* That also failed. Last resort is to find any entry which
* doesn't have a real port associated with it.
*/
for (i = 0; i < nr_uarts; i++)
if (serial8250_ports[i].port.type == PORT_UNKNOWN)
return &serial8250_ports[i];
return NULL;
}
/**
* serial8250_register_port - register a serial port
* @port: serial port template
*
* Configure the serial port specified by the request. If the
* port exists and is in use, it is hung up and unregistered
* first.
*
* The port is then probed and if necessary the IRQ is autodetected
* If this fails an error is returned.
*
* On success the port is ready to use and the line number is returned.
*/
int serial8250_register_port(struct uart_port *port)
{
struct uart_8250_port *uart;
int ret = -ENOSPC;
if (port->uartclk == 0)
return -EINVAL;
mutex_lock(&serial_mutex);
uart = serial8250_find_match_or_unused(port);
if (uart) {
uart_remove_one_port(&serial8250_reg, &uart->port);
uart->port.iobase = port->iobase;
uart->port.membase = port->membase;
uart->port.irq = port->irq;
uart->port.uartclk = port->uartclk;
uart->port.fifosize = port->fifosize;
uart->port.regshift = port->regshift;
uart->port.iotype = port->iotype;
uart->port.flags = port->flags | UPF_BOOT_AUTOCONF;
uart->port.mapbase = port->mapbase;
uart->port.private_data = port->private_data;
if (port->dev)
uart->port.dev = port->dev;
if (port->flags & UPF_FIXED_TYPE) {
uart->port.type = port->type;
uart->port.fifosize = uart_config[port->type].fifo_size;
uart->capabilities = uart_config[port->type].flags;
uart->tx_loadsz = uart_config[port->type].tx_loadsz;
}
set_io_from_upio(&uart->port);
/* Possibly override default I/O functions. */
if (port->serial_in)
uart->port.serial_in = port->serial_in;
if (port->serial_out)
uart->port.serial_out = port->serial_out;
ret = uart_add_one_port(&serial8250_reg, &uart->port);
if (ret == 0)
ret = uart->port.line;
}
mutex_unlock(&serial_mutex);
return ret;
}
EXPORT_SYMBOL(serial8250_register_port);
/**
* serial8250_unregister_port - remove a 16x50 serial port at runtime
* @line: serial line number
*
* Remove one serial port. This may not be called from interrupt
* context. We hand the port back to the our control.
*/
void serial8250_unregister_port(int line)
{
struct uart_8250_port *uart = &serial8250_ports[line];
mutex_lock(&serial_mutex);
uart_remove_one_port(&serial8250_reg, &uart->port);
if (serial8250_isa_devs) {
uart->port.flags &= ~UPF_BOOT_AUTOCONF;
uart->port.type = PORT_UNKNOWN;
uart->port.dev = &serial8250_isa_devs->dev;
uart_add_one_port(&serial8250_reg, &uart->port);
} else {
uart->port.dev = NULL;
}
mutex_unlock(&serial_mutex);
}
EXPORT_SYMBOL(serial8250_unregister_port);
static int __init serial8250_init(void)
{
int ret;
if (nr_uarts > UART_NR)
nr_uarts = UART_NR;
printk(KERN_INFO "Serial: 8250/16550 driver"
"%d ports, IRQ sharing %sabled\n", nr_uarts,
share_irqs ? "en" : "dis");
#ifdef CONFIG_SPARC
ret = sunserial_register_minors(&serial8250_reg, UART_NR);
#else
serial8250_reg.nr = UART_NR;
ret = uart_register_driver(&serial8250_reg);
#endif
if (ret)
goto out;
serial8250_isa_devs = platform_device_alloc("serial8250",
PLAT8250_DEV_LEGACY);
if (!serial8250_isa_devs) {
ret = -ENOMEM;
goto unreg_uart_drv;
}
ret = platform_device_add(serial8250_isa_devs);
if (ret)
goto put_dev;
serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
ret = platform_driver_register(&serial8250_isa_driver);
if (ret == 0)
goto out;
platform_device_del(serial8250_isa_devs);
put_dev:
platform_device_put(serial8250_isa_devs);
unreg_uart_drv:
#ifdef CONFIG_SPARC
sunserial_unregister_minors(&serial8250_reg, UART_NR);
#else
uart_unregister_driver(&serial8250_reg);
#endif
out:
return ret;
}
static void __exit serial8250_exit(void)
{
struct platform_device *isa_dev = serial8250_isa_devs;
/*
* This tells serial8250_unregister_port() not to re-register
* the ports (thereby making serial8250_isa_driver permanently
* in use.)
*/
serial8250_isa_devs = NULL;
platform_driver_unregister(&serial8250_isa_driver);
platform_device_unregister(isa_dev);
#ifdef CONFIG_SPARC
sunserial_unregister_minors(&serial8250_reg, UART_NR);
#else
uart_unregister_driver(&serial8250_reg);
#endif
}
module_init(serial8250_init);
module_exit(serial8250_exit);
EXPORT_SYMBOL(serial8250_suspend_port);
EXPORT_SYMBOL(serial8250_resume_port);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
module_param(share_irqs, uint, 0644);
MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices"
" (unsafe)");
module_param(nr_uarts, uint, 0644);
MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
#ifdef CONFIG_SERIAL_8250_RSA
module_param_array(probe_rsa, ulong, &probe_rsa_count, 0444);
MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
#endif
MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
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