text: /*
   *  Serial Port driver for Open Firmware platform devices
   *
   *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
   *
   *  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.
   *
   */
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/serial_core.h>
  #include <linux/serial_8250.h>
  #include <linux/of_platform.h>
  #include <linux/nwpserial.h>
  
  #include <asm/prom.h>
  
  struct of_serial_info {
  	int type;
  	int line;
  };
  
  /*
   * Fill a struct uart_port for a given device node
   */
  static int __devinit of_platform_serial_setup(struct of_device *ofdev,
  					int type, struct uart_port *port)
  {
  	struct resource resource;
  	struct device_node *np = ofdev->node;
  	const unsigned int *clk, *spd;
  	const u32 *prop;
  	int ret, prop_size;
  
  	memset(port, 0, sizeof *port);
  	spd = of_get_property(np, "current-speed", NULL);
  	clk = of_get_property(np, "clock-frequency", NULL);
  	if (!clk) {
  		dev_warn(&ofdev->dev, "no clock-frequency property set\n");
  		return -ENODEV;
  	}
  
  	ret = of_address_to_resource(np, 0, &resource);
  	if (ret) {
  		dev_warn(&ofdev->dev, "invalid address\n");
  		return ret;
  	}
  
  	spin_lock_init(&port->lock);
  	port->mapbase = resource.start;
  
  	/* Check for shifted address mapping */
  	prop = of_get_property(np, "reg-offset", &prop_size);
  	if (prop && (prop_size == sizeof(u32)))
  		port->mapbase += *prop;
  
  	/* Check for registers offset within the devices address range */
  	prop = of_get_property(np, "reg-shift", &prop_size);
  	if (prop && (prop_size == sizeof(u32)))
  		port->regshift = *prop;
  
  	port->irq = irq_of_parse_and_map(np, 0);
  	port->iotype = UPIO_MEM;
  	port->type = type;
  	port->uartclk = *clk;
  	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
  		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
  	port->dev = &ofdev->dev;
  	/* If current-speed was set, then try not to change it. */
  	if (spd)
  		port->custom_divisor = *clk / (16 * (*spd));
  
  	return 0;
  }
  
  /*
   * Try to register a serial port
   */
  static int __devinit of_platform_serial_probe(struct of_device *ofdev,
  						const struct of_device_id *id)
  {
  	struct of_serial_info *info;
  	struct uart_port port;
  	int port_type;
  	int ret;
  
  	if (of_find_property(ofdev->node, "used-by-rtas", NULL))
  		return -EBUSY;
  
  	info = kmalloc(sizeof(*info), GFP_KERNEL);
  	if (info == NULL)
  		return -ENOMEM;
  
  	port_type = (unsigned long)id->data;
  	ret = of_platform_serial_setup(ofdev, port_type, &port);
  	if (ret)
  		goto out;
  
  	switch (port_type) {
  #ifdef CONFIG_SERIAL_8250
  	case PORT_8250 ... PORT_MAX_8250:
  		ret = serial8250_register_port(&port);
  		break;
  #endif
  #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
  	case PORT_NWPSERIAL:
  		ret = nwpserial_register_port(&port);
  		break;
  #endif
  	default:
  		/* need to add code for these */
  	case PORT_UNKNOWN:
  		dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
  		ret = -ENODEV;
  		break;
  	}
  	if (ret < 0)
  		goto out;
  
  	info->type = port_type;
  	info->line = ret;
  	dev_set_drvdata(&ofdev->dev, info);
  	return 0;
  out:
  	kfree(info);
  	irq_dispose_mapping(port.irq);
  	return ret;
  }
  
  /*
   * Release a line
   */
  static int of_platform_serial_remove(struct of_device *ofdev)
  {
  	struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
  	switch (info->type) {
  #ifdef CONFIG_SERIAL_8250
  	case PORT_8250 ... PORT_MAX_8250:
  		serial8250_unregister_port(info->line);
  		break;
  #endif
  #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
  	case PORT_NWPSERIAL:
  		nwpserial_unregister_port(info->line);
  		break;
  #endif
  	default:
  		/* need to add code for these */
  		break;
  	}
  	kfree(info);
  	return 0;
  }
  
  /*
   * A few common types, add more as needed.
   */
  static struct of_device_id __devinitdata of_platform_serial_table[] = {
  	{ .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
  	{ .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
  	{ .type = "serial", .compatible = "ns16550a", .data = (void *)PORT_16550A, },
  	{ .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
  	{ .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
  	{ .type = "serial", .compatible = "ns16850",  .data = (void *)PORT_16850, },
  #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
  	{ .type = "serial", .compatible = "ibm,qpace-nwp-serial",
  					.data = (void *)PORT_NWPSERIAL, },
  #endif
  	{ .type = "serial",			      .data = (void *)PORT_UNKNOWN, },
  	{ /* end of list */ },
  };
  
  static struct of_platform_driver of_platform_serial_driver = {
  	.owner = THIS_MODULE,
  	.name = "of_serial",
  	.probe = of_platform_serial_probe,
  	.remove = of_platform_serial_remove,
  	.match_table = of_platform_serial_table,
  };
  
  static int __init of_platform_serial_init(void)
  {
  	return of_register_platform_driver(&of_platform_serial_driver);
  }
  module_init(of_platform_serial_init);
  
  static void __exit of_platform_serial_exit(void)
  {
  	return of_unregister_platform_driver(&of_platform_serial_driver);
  };
  module_exit(of_platform_serial_exit);
  
  MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
  