8250.c

the attached file is the driver of Uart

		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,
};

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 < UART_NR; 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++, 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;
		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 < UART_NR; i++) {
		struct uart_8250_port *up = &serial8250_ports[i];

		if (up->port.line == kgdb8250_ttyS)
			continue;

		up->port.dev = dev;
		uart_add_one_port(drv, &up->port);
	}
}

#ifdef CONFIG_SERIAL_8250_CONSOLE

#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

/*
 *	Wait for transmitter & holding register to empty
 */
static inline void wait_for_xmitr(struct uart_8250_port *up)
{
	unsigned int status, tmout = 10000;

	/* Wait up to 10ms for the character(s) to be sent. */
	do {
		status = serial_in(up, UART_LSR);

		if (status & UART_LSR_BI)
			up->lsr_break_flag = UART_LSR_BI;

		if (--tmout == 0)
			break;
		udelay(1);
	} while ((status & BOTH_EMPTY) != BOTH_EMPTY);

	/* Wait up to 1s for flow control if necessary */
	if (up->port.flags & UPF_CONS_FLOW) {
		tmout = 1000000;
		while (--tmout &&
		       ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
			udelay(1);
	}
}

/*
 *	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 int ier;
	int i;

	/*
	 *	First save the UER then disable the interrupts
	 */
	ier = serial_in(up, UART_IER);

	if (up->port.type == PORT_XSCALE)
		serial_out(up, UART_IER, UART_IER_UUE);
	else
		serial_out(up, UART_IER, 0);

	/*
	 *	Now, do each character
	 */
	for (i = 0; i < count; i++, s++) {
		wait_for_xmitr(up);

		/*
		 *	Send the character out.
		 *	If a LF, also do CR...
		 */
		serial_out(up, UART_TX, *s);
		if (*s == 10) {
			wait_for_xmitr(up);
			serial_out(up, UART_TX, 13);
		}
	}

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and restore the IER
	 */
	wait_for_xmitr(up);
	serial_out(up, UART_IER, ier);
}

static int 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 >= UART_NR)
		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 struct uart_driver serial8250_reg;
static struct console serial8250_console = {
	.name		= "ttyS",
	.write		= serial8250_console_write,
	.device		= uart_console_device,
	.setup		= serial8250_console_setup,
	.flags		= CON_PRINTBUFFER,
	.index		= -1,
	.data		= &serial8250_reg,
};

static int __init serial8250_console_init(void)
{
	serial8250_isa_init_ports();
	register_console(&serial8250_console);
	return 0;
}
console_initcall(serial8250_console_init);

static int __init serial8250_late_console_init(void)
{
	if (!(serial8250_console.flags & CON_ENABLED))
		register_console(&serial8250_console);
	return 0;
}
late_initcall(serial8250_late_console_init);

static int __init find_port(struct uart_port *p)
{
	int line;
	struct uart_port *port;

	for (line = 0; line < UART_NR; line++) {
		port = &serial8250_ports[line].port;
		if (p->iotype == port->iotype &&
		    p->iobase == port->iobase &&
		    p->membase == port->membase)
			return line;
	}
	return -ENODEV;
}

int __init serial8250_start_console(struct uart_port *port, char *options)
{
	int line;

	line = find_port(port);
	if (line < 0)
		return -ENODEV;

	add_preferred_console("ttyS", line, options);
	printk("Adding console on ttyS%d at %s 0x%lx (options '%s')\n",
		line, port->iotype == UPIO_MEM ? "MMIO" : "I/O port",
		port->iotype == UPIO_MEM ? (unsigned long) port->mapbase :
		    (unsigned long) port->iobase, options);
	if (!(serial8250_console.flags & CON_ENABLED)) {
		serial8250_console.flags &= ~CON_PRINTBUFFER;
		register_console(&serial8250_console);
	}
	return line;
}

#define SERIAL8250_CONSOLE	&serial8250_console
#else
#define SERIAL8250_CONSOLE	NULL
#endif

static struct uart_driver serial8250_reg = {
	.owner			= THIS_MODULE,
	.driver_name		= "serial",
	.devfs_name		= "tts/",
	.dev_name		= "ttyS",
	.major			= TTY_MAJOR,
	.minor			= 64,
	.nr			= UART_NR,
	.cons			= SERIAL8250_CONSOLE,
};

int __init early_serial_setup(struct uart_port *port)
{
	if (port->line >= ARRAY_SIZE(serial8250_ports))
		return -ENODEV;

	serial8250_isa_init_ports();
	serial8250_ports[port->line].port	= *port;
	serial8250_ports[port->line].port.ops	= &serial8250_pops;
	spin_lock_init(&serial8250_ports[port->line].port.lock);
	return 0;
}

/**
 *	serial8250_suspend_port - suspend one serial port
 *	@line:  serial line number
 *      @level: the level of port suspension, as per uart_suspend_port
 *
 *	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
 *      @level: the level of port resumption, as per uart_resume_port
 *
 *	Resume one serial port.
 */
void serial8250_resume_port(int line)
{
	uart_resume_port(&serial8250_reg, &serial8250_ports[line].port);
}

static struct uart_8250_port *uart_8250_register_port(struct uart_port *port, int *line);

/*
 * 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 device *dev)
{
	struct plat_serial8250_port *p = dev->platform_data;
	struct uart_port port;
	struct uart_8250_port *uart;
	int line;

	memset(&port, 0, sizeof(struct uart_port));

	for (; p && p->flags != 0; p++) {
		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.line	= p->line;
		port.dev	= dev;
		if (share_irqs)
			port.flags |= UPF_SHARE_IRQ;

		uart = uart_8250_register_port(&port, &line);
		if (!IS_ERR(uart))
			uart->pm = p->pm;
	}
	return 0;
}

/*
 * Remove serial ports registered against a platform device.
 */
static int __devexit serial8250_remove(struct device *dev)
{
	int i;

	for (i = 0; i < UART_NR; i++) {
		struct uart_8250_port *up = &serial8250_ports[i];

		if (up->port.dev == dev)
			serial8250_unregister_port(i);
	}
	return 0;
}

static int serial8250_suspend(struct device *dev, u32 state, u32 level)
{
	int i;

	if (level != SUSPEND_DISABLE)
		return 0;

	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)
			uart_suspend_port(&serial8250_reg, &up->port);
	}

	return 0;
}

static int serial8250_resume(struct device *dev, u32 level)
{
	int i;

	if (level != RESUME_ENABLE)
		return 0;

	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)
			uart_resume_port(&serial8250_reg, &up->port);
	}

	return 0;
}

static struct device_driver serial8250_isa_driver = {
	.name		= "serial8250",
	.bus		= &platform_bus_type,
	.probe		= serial8250_probe,
	.remove		= __devexit_p(serial8250_remove),
	.suspend	= serial8250_suspend,
	.resume		= serial8250_resume,
};

/*
 * 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 DECLARE_MUTEX(serial_sem);

/*
 *	Are the two ports equivalent?
 */
static int uart_match_port(struct uart_port *port1, struct uart_port *port2)
{
	if (port1->iotype != port2->iotype)
		return 0;

	switch (port1->iotype) {
	case UPIO_PORT:
		return (port1->iobase == port2->iobase);
	case UPIO_HUB6:
		return (port1->iobase == port2->iobase) &&
		       (port1->hub6   == port2->hub6);
	case UPIO_MEM:
		return (port1->membase == port2->membase);
	}
	return 0;
}

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 < UART_NR; 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 < UART_NR; 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 < UART_NR; i++)
		if (serial8250_ports[i].port.type == PORT_UNKNOWN)
			return &serial8250_ports[i];

	return NULL;
}

/**
 *	uart_8250_register_port - register a serial port
 *	@port: serial port template
 *	@line: returned (on success) value of the line number
 *
 *	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 pointer to the 
 *	corresponding struct uart_8250_port is returned.
 */
static struct uart_8250_port *uart_8250_register_port(struct uart_port *port, int *line)
{
	struct uart_8250_port *uart;
	int ret = -ENOSPC;

	if (port->uartclk == 0)
		return ERR_PTR(-EINVAL);

	/* Avoid re-registering platform based ports if KGDB active */
	if (port->line