1/*
  2 *  Serial Port driver for Open Firmware platform devices
  3 *
  4 *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
  5 *
  6 *  This program is free software; you can redistribute it and/or
  7 *  modify it under the terms of the GNU General Public License
  8 *  as published by the Free Software Foundation; either version
  9 *  2 of the License, or (at your option) any later version.
 10 *
 11 */
 12#include <linux/init.h>
 13#include <linux/module.h>
 14#include <linux/slab.h>
 15#include <linux/serial_core.h>
 16#include <linux/serial_8250.h>
 17#include <linux/of_address.h>
 18#include <linux/of_irq.h>
 19#include <linux/of_platform.h>
 20#include <linux/nwpserial.h>
 21
 22struct of_serial_info {
 23	int type;
 24	int line;
 25};
 26
 27/*
 28 * Fill a struct uart_port for a given device node
 29 */
 30static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
 31					int type, struct uart_port *port)
 32{
 33	struct resource resource;
 34	struct device_node *np = ofdev->dev.of_node;
 35	u32 clk, spd, prop;
 36	int ret;
 37
 38	memset(port, 0, sizeof *port);
 39	if (of_property_read_u32(np, "clock-frequency", &clk)) {
 40		dev_warn(&ofdev->dev, "no clock-frequency property set\n");
 41		return -ENODEV;
 42	}
 43	/* If current-speed was set, then try not to change it. */
 44	if (of_property_read_u32(np, "current-speed", &spd) == 0)
 45		port->custom_divisor = clk / (16 * spd);
 46
 47	ret = of_address_to_resource(np, 0, &resource);
 48	if (ret) {
 49		dev_warn(&ofdev->dev, "invalid address\n");
 50		return ret;
 51	}
 52
 53	spin_lock_init(&port->lock);
 54	port->mapbase = resource.start;
 55
 56	/* Check for shifted address mapping */
 57	if (of_property_read_u32(np, "reg-offset", &prop) == 0)
 58		port->mapbase += prop;
 59
 60	/* Check for registers offset within the devices address range */
 61	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 62		port->regshift = prop;
 63
 64	port->irq = irq_of_parse_and_map(np, 0);
 65	port->iotype = UPIO_MEM;
 66	if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 67		switch (prop) {
 68		case 1:
 69			port->iotype = UPIO_MEM;
 70			break;
 71		case 4:
 72			port->iotype = UPIO_MEM32;
 73			break;
 74		default:
 75			dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 76				 prop);
 77			return -EINVAL;
 78		}
 79	}
 80
 81	port->type = type;
 82	port->uartclk = clk;
 83	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 84		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
 85	port->dev = &ofdev->dev;
 86
 87	return 0;
 88}
 89
 90/*
 91 * Try to register a serial port
 92 */
 93static struct of_device_id of_platform_serial_table[];
 94static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
 95{
 96	const struct of_device_id *match;
 97	struct of_serial_info *info;
 98	struct uart_port port;
 99	int port_type;
100	int ret;
101
102	match = of_match_device(of_platform_serial_table, &ofdev->dev);
103	if (!match)
104		return -EINVAL;
105
106	if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
107		return -EBUSY;
108
109	info = kmalloc(sizeof(*info), GFP_KERNEL);
110	if (info == NULL)
111		return -ENOMEM;
112
113	port_type = (unsigned long)match->data;
114	ret = of_platform_serial_setup(ofdev, port_type, &port);
115	if (ret)
116		goto out;
117
118	switch (port_type) {
119#ifdef CONFIG_SERIAL_8250
120	case PORT_8250 ... PORT_MAX_8250:
121		ret = serial8250_register_port(&port);
122		break;
123#endif
124#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
125	case PORT_NWPSERIAL:
126		ret = nwpserial_register_port(&port);
127		break;
128#endif
129	default:
130		/* need to add code for these */
131	case PORT_UNKNOWN:
132		dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
133		ret = -ENODEV;
134		break;
135	}
136	if (ret < 0)
137		goto out;
138
139	info->type = port_type;
140	info->line = ret;
141	dev_set_drvdata(&ofdev->dev, info);
142	return 0;
143out:
144	kfree(info);
145	irq_dispose_mapping(port.irq);
146	return ret;
147}
148
149/*
150 * Release a line
151 */
152static int of_platform_serial_remove(struct platform_device *ofdev)
153{
154	struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
155	switch (info->type) {
156#ifdef CONFIG_SERIAL_8250
157	case PORT_8250 ... PORT_MAX_8250:
158		serial8250_unregister_port(info->line);
159		break;
160#endif
161#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
162	case PORT_NWPSERIAL:
163		nwpserial_unregister_port(info->line);
164		break;
165#endif
166	default:
167		/* need to add code for these */
168		break;
169	}
170	kfree(info);
171	return 0;
172}
173
174/*
175 * A few common types, add more as needed.
176 */
177static struct of_device_id __devinitdata of_platform_serial_table[] = {
178	{ .compatible = "ns8250",   .data = (void *)PORT_8250, },
179	{ .compatible = "ns16450",  .data = (void *)PORT_16450, },
180	{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
181	{ .compatible = "ns16550",  .data = (void *)PORT_16550, },
182	{ .compatible = "ns16750",  .data = (void *)PORT_16750, },
183	{ .compatible = "ns16850",  .data = (void *)PORT_16850, },
184	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
185#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
186	{ .compatible = "ibm,qpace-nwp-serial",
187		.data = (void *)PORT_NWPSERIAL, },
188#endif
189	{ .type = "serial",         .data = (void *)PORT_UNKNOWN, },
190	{ /* end of list */ },
191};
192
193static struct platform_driver of_platform_serial_driver = {
194	.driver = {
195		.name = "of_serial",
196		.owner = THIS_MODULE,
197		.of_match_table = of_platform_serial_table,
198	},
199	.probe = of_platform_serial_probe,
200	.remove = of_platform_serial_remove,
201};
202
203static int __init of_platform_serial_init(void)
204{
205	return platform_driver_register(&of_platform_serial_driver);
206}
207module_init(of_platform_serial_init);
208
209static void __exit of_platform_serial_exit(void)
210{
211	return platform_driver_unregister(&of_platform_serial_driver);
212};
213module_exit(of_platform_serial_exit);
214
215MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
216MODULE_LICENSE("GPL");
217MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");