uartlite.c

linux 内核源代码

	struct uart_port *port = &ulite_ports[co->index];
	unsigned long flags;
	unsigned int ier;
	int locked = 1;

	if (oops_in_progress) {
		locked = spin_trylock_irqsave(&port->lock, flags);
	} else
		spin_lock_irqsave(&port->lock, flags);

	/* save and disable interrupt */
	ier = readb(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
	writeb(0, port->membase + ULITE_CONTROL);

	uart_console_write(port, s, count, ulite_console_putchar);

	ulite_console_wait_tx(port);

	/* restore interrupt state */
	if (ier)
		writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);

	if (locked)
		spin_unlock_irqrestore(&port->lock, flags);
}

#if defined(CONFIG_OF)
static inline void __init ulite_console_of_find_device(int id)
{
	struct device_node *np;
	struct resource res;
	const unsigned int *of_id;
	int rc;

	for_each_compatible_node(np, NULL, "xilinx,uartlite") {
		of_id = of_get_property(np, "port-number", NULL);
		if ((!of_id) || (*of_id != id))
			continue;

		rc = of_address_to_resource(np, 0, &res);
		if (rc)
			continue;

		ulite_ports[id].mapbase = res.start;
		of_node_put(np);
		return;
	}
}
#else /* CONFIG_OF */
static inline void __init ulite_console_of_find_device(int id) { /* do nothing */ }
#endif /* CONFIG_OF */

static int __init ulite_console_setup(struct console *co, char *options)
{
	struct uart_port *port;
	int baud = 9600;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

	if (co->index < 0 || co->index >= ULITE_NR_UARTS)
		return -EINVAL;

	port = &ulite_ports[co->index];

	/* Check if it is an OF device */
	if (!port->mapbase)
		ulite_console_of_find_device(co->index);

	/* Do we have a device now? */
	if (!port->mapbase) {
		pr_debug("console on ttyUL%i not present\n", co->index);
		return -ENODEV;
	}

	/* not initialized yet? */
	if (!port->membase) {
		if (ulite_request_port(port))
			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 ulite_uart_driver;

static struct console ulite_console = {
	.name	= ULITE_NAME,
	.write	= ulite_console_write,
	.device	= uart_console_device,
	.setup	= ulite_console_setup,
	.flags	= CON_PRINTBUFFER,
	.index	= -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
	.data	= &ulite_uart_driver,
};

static int __init ulite_console_init(void)
{
	register_console(&ulite_console);
	return 0;
}

console_initcall(ulite_console_init);

#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */

static struct uart_driver ulite_uart_driver = {
	.owner		= THIS_MODULE,
	.driver_name	= "uartlite",
	.dev_name	= ULITE_NAME,
	.major		= ULITE_MAJOR,
	.minor		= ULITE_MINOR,
	.nr		= ULITE_NR_UARTS,
#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
	.cons		= &ulite_console,
#endif
};

/* ---------------------------------------------------------------------
 * Port assignment functions (mapping devices to uart_port structures)
 */

/** ulite_assign: register a uartlite device with the driver
 *
 * @dev: pointer to device structure
 * @id: requested id number.  Pass -1 for automatic port assignment
 * @base: base address of uartlite registers
 * @irq: irq number for uartlite
 *
 * Returns: 0 on success, <0 otherwise
 */
static int __devinit ulite_assign(struct device *dev, int id, u32 base, int irq)
{
	struct uart_port *port;
	int rc;

	/* if id = -1; then scan for a free id and use that */
	if (id < 0) {
		for (id = 0; id < ULITE_NR_UARTS; id++)
			if (ulite_ports[id].mapbase == 0)
				break;
	}
	if (id < 0 || id >= ULITE_NR_UARTS) {
		dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
		return -EINVAL;
	}

	if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
		dev_err(dev, "cannot assign to %s%i; it is already in use\n",
			ULITE_NAME, id);
		return -EBUSY;
	}

	port = &ulite_ports[id];

	spin_lock_init(&port->lock);
	port->fifosize = 16;
	port->regshift = 2;
	port->iotype = UPIO_MEM;
	port->iobase = 1; /* mark port in use */
	port->mapbase = base;
	port->membase = NULL;
	port->ops = &ulite_ops;
	port->irq = irq;
	port->flags = UPF_BOOT_AUTOCONF;
	port->dev = dev;
	port->type = PORT_UNKNOWN;
	port->line = id;

	dev_set_drvdata(dev, port);

	/* Register the port */
	rc = uart_add_one_port(&ulite_uart_driver, port);
	if (rc) {
		dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
		port->mapbase = 0;
		dev_set_drvdata(dev, NULL);
		return rc;
	}

	return 0;
}

/** ulite_release: register a uartlite device with the driver
 *
 * @dev: pointer to device structure
 */
static int __devinit ulite_release(struct device *dev)
{
	struct uart_port *port = dev_get_drvdata(dev);
	int rc = 0;

	if (port) {
		rc = uart_remove_one_port(&ulite_uart_driver, port);
		dev_set_drvdata(dev, NULL);
		port->mapbase = 0;
	}

	return rc;
}

/* ---------------------------------------------------------------------
 * Platform bus binding
 */

static int __devinit ulite_probe(struct platform_device *pdev)
{
	struct resource *res, *res2;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;

	res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!res2)
		return -ENODEV;

	return ulite_assign(&pdev->dev, pdev->id, res->start, res2->start);
}

static int ulite_remove(struct platform_device *pdev)
{
	return ulite_release(&pdev->dev);
}

static struct platform_driver ulite_platform_driver = {
	.probe	= ulite_probe,
	.remove	= ulite_remove,
	.driver	= {
		   .owner = THIS_MODULE,
		   .name  = "uartlite",
		   },
};

/* ---------------------------------------------------------------------
 * OF bus bindings
 */
#if defined(CONFIG_OF)
static int __devinit
ulite_of_probe(struct of_device *op, const struct of_device_id *match)
{
	struct resource res;
	const unsigned int *id;
	int irq, rc;

	dev_dbg(&op->dev, "%s(%p, %p)\n", __FUNCTION__, op, match);

	rc = of_address_to_resource(op->node, 0, &res);
	if (rc) {
		dev_err(&op->dev, "invalid address\n");
		return rc;
	}

	irq = irq_of_parse_and_map(op->node, 0);

	id = of_get_property(op->node, "port-number", NULL);

	return ulite_assign(&op->dev, id ? *id : -1, res.start+3, irq);
}

static int __devexit ulite_of_remove(struct of_device *op)
{
	return ulite_release(&op->dev);
}

/* Match table for of_platform binding */
static struct of_device_id __devinit ulite_of_match[] = {
	{ .type = "serial", .compatible = "xilinx,uartlite", },
	{},
};
MODULE_DEVICE_TABLE(of, ulite_of_match);

static struct of_platform_driver ulite_of_driver = {
	.owner = THIS_MODULE,
	.name = "uartlite",
	.match_table = ulite_of_match,
	.probe = ulite_of_probe,
	.remove = __devexit_p(ulite_of_remove),
	.driver = {
		.name = "uartlite",
	},
};

/* Registration helpers to keep the number of #ifdefs to a minimum */
static inline int __init ulite_of_register(void)
{
	pr_debug("uartlite: calling of_register_platform_driver()\n");
	return of_register_platform_driver(&ulite_of_driver);
}

static inline void __exit ulite_of_unregister(void)
{
	of_unregister_platform_driver(&ulite_of_driver);
}
#else /* CONFIG_OF */
/* CONFIG_OF not enabled; do nothing helpers */
static inline int __init ulite_of_register(void) { return 0; }
static inline void __exit ulite_of_unregister(void) { }
#endif /* CONFIG_OF */

/* ---------------------------------------------------------------------
 * Module setup/teardown
 */

int __init ulite_init(void)
{
	int ret;

	pr_debug("uartlite: calling uart_register_driver()\n");
	ret = uart_register_driver(&ulite_uart_driver);
	if (ret)
		goto err_uart;

	ret = ulite_of_register();
	if (ret)
		goto err_of;

	pr_debug("uartlite: calling platform_driver_register()\n");
	ret = platform_driver_register(&ulite_platform_driver);
	if (ret)
		goto err_plat;

	return 0;

err_plat:
	ulite_of_unregister();
err_of:
	uart_unregister_driver(&ulite_uart_driver);
err_uart:
	printk(KERN_ERR "registering uartlite driver failed: err=%i", ret);
	return ret;
}

void __exit ulite_exit(void)
{
	platform_driver_unregister(&ulite_platform_driver);
	ulite_of_unregister();
	uart_unregister_driver(&ulite_uart_driver);
}

module_init(ulite_init);
module_exit(ulite_exit);

MODULE_AUTHOR("Peter Korsgaard <[e-mail]>");
MODULE_DESCRIPTION("Xilinx uartlite serial driver");
MODULE_LICENSE("GPL");