serial_core.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,430 行 · 第 1/4 页

 *	uart_set_options - setup the serial console parameters
 *	@port: pointer to the serial ports uart_port structure
 *	@co: console pointer
 *	@baud: baud rate
 *	@parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
 *	@bits: number of data bits
 *	@flow: flow control character - 'r' (rts)
 */
int __init
uart_set_options(struct uart_port *port, struct console *co,
		 int baud, int parity, int bits, int flow)
{
	struct termios termios;
	int i;

	memset(&termios, 0, sizeof(struct termios));

	termios.c_cflag = CREAD | HUPCL | CLOCAL;

	/*
	 * Construct a cflag setting.
	 */
	for (i = 0; baud_rates[i].rate; i++)
		if (baud_rates[i].rate <= baud)
			break;

	termios.c_cflag |= baud_rates[i].cflag;

	if (bits == 7)
		termios.c_cflag |= CS7;
	else
		termios.c_cflag |= CS8;

	switch (parity) {
	case 'o': case 'O':
		termios.c_cflag |= PARODD;
		/*fall through*/
	case 'e': case 'E':
		termios.c_cflag |= PARENB;
		break;
	}

	if (flow == 'r')
		termios.c_cflag |= CRTSCTS;

	port->ops->set_termios(port, &termios, NULL);
	co->cflag = termios.c_cflag;

	return 0;
}
#endif /* CONFIG_SERIAL_CORE_CONSOLE */

static void uart_change_pm(struct uart_state *state, int pm_state)
{
	struct uart_port *port = state->port;
	if (port->ops->pm)
		port->ops->pm(port, pm_state, state->pm_state);
	state->pm_state = pm_state;
}

int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
{
	struct uart_state *state = drv->state + port->line;

	down(&state->sem);

	if (state->info && state->info->flags & UIF_INITIALIZED) {
		struct uart_ops *ops = port->ops;

		spin_lock_irq(&port->lock);
		ops->stop_tx(port, 0);
		ops->set_mctrl(port, 0);
		ops->stop_rx(port);
		spin_unlock_irq(&port->lock);

		/*
		 * Wait for the transmitter to empty.
		 */
		while (!ops->tx_empty(port)) {
			set_current_state(TASK_UNINTERRUPTIBLE);
			schedule_timeout(10*HZ/1000);
		}
		set_current_state(TASK_RUNNING);

		ops->shutdown(port);
	}

	/*
	 * Disable the console device before suspending.
	 */
	if (uart_console(port))
		console_stop(port->cons);

	uart_change_pm(state, 3);

	up(&state->sem);

	return 0;
}

int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
{
	struct uart_state *state = drv->state + port->line;

	down(&state->sem);

	uart_change_pm(state, 0);

	/*
	 * Re-enable the console device after suspending.
	 */
	if (uart_console(port)) {
		uart_change_speed(state, NULL);
		console_start(port->cons);
	}

	if (state->info && state->info->flags & UIF_INITIALIZED) {
		struct uart_ops *ops = port->ops;

		ops->set_mctrl(port, 0);
		ops->startup(port);
		uart_change_speed(state, NULL);
		spin_lock_irq(&port->lock);
		ops->set_mctrl(port, port->mctrl);
		ops->start_tx(port, 0);
		spin_unlock_irq(&port->lock);
	}

	up(&state->sem);

	return 0;
}

static inline void
uart_report_port(struct uart_driver *drv, struct uart_port *port)
{
	printk("%s%d", drv->dev_name, port->line);
	printk(" at ");
	switch (port->iotype) {
	case UPIO_PORT:
		printk("I/O 0x%x", port->iobase);
		break;
	case UPIO_HUB6:
		printk("I/O 0x%x offset 0x%x", port->iobase, port->hub6);
		break;
	case UPIO_MEM:
	case UPIO_MEM32:
		printk("MMIO 0x%lx", port->mapbase);
		break;
	}
	printk(" (irq = %d) is a %s\n", port->irq, uart_type(port));
}

static void
uart_configure_port(struct uart_driver *drv, struct uart_state *state,
		    struct uart_port *port)
{
	unsigned int flags;

	/*
	 * If there isn't a port here, don't do anything further.
	 */
	if (!port->iobase && !port->mapbase && !port->membase)
		return;

	/*
	 * Now do the auto configuration stuff.  Note that config_port
	 * is expected to claim the resources and map the port for us.
	 */
	flags = UART_CONFIG_TYPE;
	if (port->flags & UPF_AUTO_IRQ)
		flags |= UART_CONFIG_IRQ;
	if (port->flags & UPF_BOOT_AUTOCONF) {
		port->type = PORT_UNKNOWN;
		port->ops->config_port(port, flags);
	}

	if (port->type != PORT_UNKNOWN) {
		unsigned long flags;

		uart_report_port(drv, port);

		/*
		 * Ensure that the modem control lines are de-activated.
		 * We probably don't need a spinlock around this, but
		 */
		spin_lock_irqsave(&port->lock, flags);
		port->ops->set_mctrl(port, 0);
		spin_unlock_irqrestore(&port->lock, flags);

		/*
		 * Power down all ports by default, except the
		 * console if we have one.
		 */
		if (!uart_console(port))
			uart_change_pm(state, 3);
	}
}

/*
 * This reverses the effects of uart_configure_port, hanging up the
 * port before removal.
 */
static void
uart_unconfigure_port(struct uart_driver *drv, struct uart_state *state)
{
	struct uart_port *port = state->port;
	struct uart_info *info = state->info;

	if (info && info->tty)
		tty_vhangup(info->tty);

	down(&state->sem);

	state->info = NULL;

	/*
	 * Free the port IO and memory resources, if any.
	 */
	if (port->type != PORT_UNKNOWN)
		port->ops->release_port(port);

	/*
	 * Indicate that there isn't a port here anymore.
	 */
	port->type = PORT_UNKNOWN;

	/*
	 * Kill the tasklet, and free resources.
	 */
	if (info) {
		tasklet_kill(&info->tlet);
		kfree(info);
	}

	up(&state->sem);
}

static struct tty_operations uart_ops = {
	.open		= uart_open,
	.close		= uart_close,
	.write		= uart_write,
	.put_char	= uart_put_char,
	.flush_chars	= uart_flush_chars,
	.write_room	= uart_write_room,
	.chars_in_buffer= uart_chars_in_buffer,
	.flush_buffer	= uart_flush_buffer,
	.ioctl		= uart_ioctl,
	.throttle	= uart_throttle,
	.unthrottle	= uart_unthrottle,
	.send_xchar	= uart_send_xchar,
	.set_termios	= uart_set_termios,
	.stop		= uart_stop,
	.start		= uart_start,
	.hangup		= uart_hangup,
	.break_ctl	= uart_break_ctl,
	.wait_until_sent= uart_wait_until_sent,
#ifdef CONFIG_PROC_FS
	.read_proc	= uart_read_proc,
#endif
	.tiocmget	= uart_tiocmget,
	.tiocmset	= uart_tiocmset,
};

/**
 *	uart_register_driver - register a driver with the uart core layer
 *	@drv: low level driver structure
 *
 *	Register a uart driver with the core driver.  We in turn register
 *	with the tty layer, and initialise the core driver per-port state.
 *
 *	We have a proc file in /proc/tty/driver which is named after the
 *	normal driver.
 *
 *	drv->port should be NULL, and the per-port structures should be
 *	registered using uart_add_one_port after this call has succeeded.
 */
int uart_register_driver(struct uart_driver *drv)
{
	struct tty_driver *normal = NULL;
	int i, retval;

	BUG_ON(drv->state);

	/*
	 * Maybe we should be using a slab cache for this, especially if
	 * we have a large number of ports to handle.
	 */
	drv->state = kmalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);
	retval = -ENOMEM;
	if (!drv->state)
		goto out;

	memset(drv->state, 0, sizeof(struct uart_state) * drv->nr);

	normal  = alloc_tty_driver(drv->nr);
	if (!normal)
		goto out;

	drv->tty_driver = normal;

	normal->owner		= drv->owner;
	normal->driver_name	= drv->driver_name;
	normal->devfs_name	= drv->devfs_name;
	normal->name		= drv->dev_name;
	normal->major		= drv->major;
	normal->minor_start	= drv->minor;
	normal->type		= TTY_DRIVER_TYPE_SERIAL;
	normal->subtype		= SERIAL_TYPE_NORMAL;
	normal->init_termios	= tty_std_termios;
	normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
	normal->flags		= TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
	normal->driver_state    = drv;
	tty_set_operations(normal, &uart_ops);

	/*
	 * Initialise the UART state(s).
	 */
	for (i = 0; i < drv->nr; i++) {
		struct uart_state *state = drv->state + i;

		state->close_delay     = 5 * HZ / 10;
		state->closing_wait    = 30 * HZ;

		init_MUTEX(&state->sem);
	}

	retval = tty_register_driver(normal);
 out:
	if (retval < 0) {
		put_tty_driver(normal);
		kfree(drv->state);
	}
	return retval;
}

/**
 *	uart_unregister_driver - remove a driver from the uart core layer
 *	@drv: low level driver structure
 *
 *	Remove all references to a driver from the core driver.  The low
 *	level driver must have removed all its ports via the
 *	uart_remove_one_port() if it registered them with uart_add_one_port().
 *	(ie, drv->port == NULL)
 */
void uart_unregister_driver(struct uart_driver *drv)
{
	struct tty_driver *p = drv->tty_driver;
	tty_unregister_driver(p);
	put_tty_driver(p);
	kfree(drv->state);
	drv->tty_driver = NULL;
}

struct tty_driver *uart_console_device(struct console *co, int *index)
{
	struct uart_driver *p = co->data;
	*index = co->index;
	return p->tty_driver;
}

/**
 *	uart_add_one_port - attach a driver-defined port structure
 *	@drv: pointer to the uart low level driver structure for this port
 *	@port: uart port structure to use for this port.
 *
 *	This allows the driver to register its own uart_port structure
 *	with the core driver.  The main purpose is to allow the low
 *	level uart drivers to expand uart_port, rather than having yet
 *	more levels of structures.
 */
int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
{
	struct uart_state *state;
	int ret = 0;

	BUG_ON(in_interrupt());

	if (port->line >= drv->nr)
		return -EINVAL;

	state = drv->state + port->line;

	down(&port_sem);
	if (state->port) {
		ret = -EINVAL;
		goto out;
	}

	state->port = port;

	spin_lock_init(&port->lock);
	port->cons = drv->cons;
	port->info = state->info;

	uart_configure_port(drv, state, port);

	/*
	 * Register the port whether it's detected or not.  This allows
	 * setserial to be used to alter this ports parameters.
	 */
	tty_register_device(drv->tty_driver, port->line, port->dev);

 out:
	up(&port_sem);

	return ret;
}

/**
 *	uart_remove_one_port - detach a driver defined port structure
 *	@drv: pointer to the uart low level driver structure for this port
 *	@port: uart port structure for this port
 *
 *	This unhooks (and hangs up) the specified port structure from the
 *	core driver.  No further calls will be made to the low-level code
 *	for this port.
 */
int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
{
	struct uart_state *state = drv->state + port->line;

	BUG_ON(in_interrupt());

	if (state->port != port)
		printk(KERN_ALERT "Removing wrong port: %p != %p\n",
			state->port, port);

	down(&port_sem);

	/*
	 * Remove the devices from devfs
	 */
	tty_unregister_device(drv->tty_driver, port->line);

	uart_unconfigure_port(drv, state);
	state->port = NULL;
	up(&port_sem);

	return 0;
}

/*
 *	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;
}

/*
 *	Try to find an unused uart_state slot for a port.
 */
static struct uart_state *
uart_find_match_or_unused(struct uart_driver *drv, struct uart_port *port)
{
	int i;

	/*
	 * First, find a port entry which matches.  Note: if we do
	 * find a matching entry, and it has a non-zero use count,
	 * then we can't register the port.
	 */
	for (i = 0; i < drv->nr; i++)
		if (uart_match_port(drv->state[i].port, port))
			return &drv->state[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 < drv->nr; i++)
		if (drv->state[i].port->type == PORT_UNKNOWN &&
		    drv->state[i].port->iobase == 0 &&
		    drv->state[i].count == 0)
			return &drv->state[i];

	/*
	 * That also failed.  Last resort is to find any currently
	 * entry which doesn't have a real port associated with it.
	 */
	for (i = 0; i < drv->nr; i++)
		if (drv->state[i].port->type == PORT_UNKNOWN &&
		    drv->state[i].count == 0)
			return &drv->state[i];

	return NULL;
}

/**
 *	uart_register_port: register uart settings with a port
 *	@drv: pointer to the uart low level driver structure for this port
 *	@port: uart port structure describing the port
 *
 *	Register UART settings with the specified low level driver.  Detect
 *	the type of the port if UPF_BOOT_AUTOCONF is set, and detect the
 *	IRQ if UPF_AUTO_IRQ is set.
 *
 *	We try to pick the same port for the same IO base address, so that
 *	when a modem is plugged in, unplugged and plugged back in, it gets
 *	allocated the same port.
 *
 *	Returns negative error, or positive line number.
 */
int uart_register_port(struct uart_driver *drv, struct uart_port *port)
{
	struct uart_state *state;
	int ret;

	down(&port_sem);

	state = uart_find_match_or_unused(drv, port);

	if (state) {
		/*
		 * Ok, we've found a line that we can use.
		 *
		 * If we find a port that matches this one, and it appears
		 * to be in-use (even if it doesn't have a type) we shouldn't
		 * alter it underneath itself - the port may be open and
		 * trying to do useful work.
		 */
		if (uart_users(state) != 0) {
			ret = -EBUSY;
			goto out;
		}

		/*
		 * If the port is already initialised, don't touch it.
		 */
		if (state->port->type == PORT_UNKNOWN) {
			state->port->type     = port->type;
			state->port->iobase   = port->iobase;
			state->port->membase  = port->membase;
			state->port->irq      = port->irq;
			state->port->uartclk  = port->uartclk;
			state->port->fifosize = port->fifosize;
			state->port->regshift = port->regshift;
			state->port->iotype   = port->iotype;
			state->port->flags    = port->flags;
			state->port->line     = state - drv->state;
			state->port->mapbase  = port->mapbase;

			uart_configure_port(drv, state, state->port);
		}

		ret = state->port->line;
	} else
		ret = -ENOSPC;
 out:
	up(&port_sem);
	return ret;
}

/**
 *	uart_unregister_port - de-allocate a port
 *	@drv: pointer to the uart low level driver structure for this port
 *	@line: line index previously returned from uart_register_port()
 *
 *	Hang up the specified line associated with the low level driver,
 *	and mark the port as unused.
 */
void uart_unregister_port(struct uart_driver *drv, int line)
{
	struct uart_state *state;

	if (line < 0 || line >= drv->nr) {
		printk(KERN_ERR "Attempt to unregister ");
		printk("%s%d", drv->dev_name, line);
		printk("\n");
		return;
	}

	state = drv->state + line;

	down(&port_sem);
	uart_unconfigure_port(drv, state);
	up(&port_sem);
}

EXPORT_SYMBOL(uart_write_wakeup);
EXPORT_SYMBOL(uart_register_driver);
EXPORT_SYMBOL(uart_unregister_driver);
EXPORT_SYMBOL(uart_suspend_port);
EXPORT_SYMBOL(uart_resume_port);
EXPORT_SYMBOL(uart_register_port);
EXPORT_SYMBOL(uart_unregister_port);
EXPORT_SYMBOL(uart_add_one_port);
EXPORT_SYMBOL(uart_remove_one_port);

MODULE_DESCRIPTION("Serial driver core");
MODULE_LICENSE("GPL");