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/module.h>
 13#include <linux/slab.h>
 14#include <linux/delay.h>
 15#include <linux/serial_core.h>
 16#include <linux/serial_reg.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#include <linux/clk.h>
 22
 23#include "8250/8250.h"
 24
 25struct of_serial_info {
 26	struct clk *clk;
 27	int type;
 28	int line;
 29};
 30
 31#ifdef CONFIG_ARCH_TEGRA
 32void tegra_serial_handle_break(struct uart_port *p)
 33{
 34	unsigned int status, tmout = 10000;
 35
 36	do {
 37		status = p->serial_in(p, UART_LSR);
 38		if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
 39			status = p->serial_in(p, UART_RX);
 40		else
 41			break;
 42		if (--tmout == 0)
 43			break;
 44		udelay(1);
 45	} while (1);
 46}
 47#else
 48static inline void tegra_serial_handle_break(struct uart_port *port)
 49{
 50}
 51#endif
 52
 53/*
 54 * Fill a struct uart_port for a given device node
 55 */
 56static int of_platform_serial_setup(struct platform_device *ofdev,
 57			int type, struct uart_port *port,
 58			struct of_serial_info *info)
 59{
 60	struct resource resource;
 61	struct device_node *np = ofdev->dev.of_node;
 62	u32 clk, spd, prop;
 63	int ret;
 64
 65	memset(port, 0, sizeof *port);
 66	if (of_property_read_u32(np, "clock-frequency", &clk)) {
 67
 68		/* Get clk rate through clk driver if present */
 69		info->clk = clk_get(&ofdev->dev, NULL);
 70		if (IS_ERR(info->clk)) {
 71			dev_warn(&ofdev->dev,
 72				"clk or clock-frequency not defined\n");
 73			return PTR_ERR(info->clk);
 74		}
 75
 76		clk_prepare_enable(info->clk);
 77		clk = clk_get_rate(info->clk);
 78	}
 79	/* If current-speed was set, then try not to change it. */
 80	if (of_property_read_u32(np, "current-speed", &spd) == 0)
 81		port->custom_divisor = clk / (16 * spd);
 82
 83	ret = of_address_to_resource(np, 0, &resource);
 84	if (ret) {
 85		dev_warn(&ofdev->dev, "invalid address\n");
 86		goto out;
 87	}
 88
 89	spin_lock_init(&port->lock);
 90	port->mapbase = resource.start;
 91
 92	/* Check for shifted address mapping */
 93	if (of_property_read_u32(np, "reg-offset", &prop) == 0)
 94		port->mapbase += prop;
 95
 96	/* Check for registers offset within the devices address range */
 97	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 98		port->regshift = prop;
 99
100	/* Check for fifo size */
101	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
102		port->fifosize = prop;
103
104	port->irq = irq_of_parse_and_map(np, 0);
105	port->iotype = UPIO_MEM;
106	if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
107		switch (prop) {
108		case 1:
109			port->iotype = UPIO_MEM;
110			break;
111		case 4:
112			port->iotype = UPIO_MEM32;
113			break;
114		default:
115			dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
116				 prop);
117			ret = -EINVAL;
118			goto out;
119		}
120	}
121
122	port->type = type;
123	port->uartclk = clk;
124	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
125		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
126
127	if (of_find_property(np, "no-loopback-test", NULL))
128		port->flags |= UPF_SKIP_TEST;
129
130	port->dev = &ofdev->dev;
131
132	if (type == PORT_TEGRA)
133		port->handle_break = tegra_serial_handle_break;
134
135	return 0;
136out:
137	if (info->clk)
138		clk_disable_unprepare(info->clk);
139	return ret;
140}
141
142/*
143 * Try to register a serial port
144 */
145static struct of_device_id of_platform_serial_table[];
146static int of_platform_serial_probe(struct platform_device *ofdev)
147{
148	const struct of_device_id *match;
149	struct of_serial_info *info;
150	struct uart_port port;
151	int port_type;
152	int ret;
153
154	match = of_match_device(of_platform_serial_table, &ofdev->dev);
155	if (!match)
156		return -EINVAL;
157
158	if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
159		return -EBUSY;
160
161	info = kmalloc(sizeof(*info), GFP_KERNEL);
162	if (info == NULL)
163		return -ENOMEM;
164
165	port_type = (unsigned long)match->data;
166	ret = of_platform_serial_setup(ofdev, port_type, &port, info);
167	if (ret)
168		goto out;
169
170	switch (port_type) {
171#ifdef CONFIG_SERIAL_8250
172	case PORT_8250 ... PORT_MAX_8250:
173	{
174		struct uart_8250_port port8250;
175		memset(&port8250, 0, sizeof(port8250));
176		port8250.port = port;
177
178		if (port.fifosize)
179			port8250.capabilities = UART_CAP_FIFO;
180
181		if (of_property_read_bool(ofdev->dev.of_node,
182					  "auto-flow-control"))
183			port8250.capabilities |= UART_CAP_AFE;
184
185		ret = serial8250_register_8250_port(&port8250);
186		break;
187	}
188#endif
189#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
190	case PORT_NWPSERIAL:
191		ret = nwpserial_register_port(&port);
192		break;
193#endif
194	default:
195		/* need to add code for these */
196	case PORT_UNKNOWN:
197		dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
198		ret = -ENODEV;
199		break;
200	}
201	if (ret < 0)
202		goto out;
203
204	info->type = port_type;
205	info->line = ret;
206	platform_set_drvdata(ofdev, info);
207	return 0;
208out:
209	kfree(info);
210	irq_dispose_mapping(port.irq);
211	return ret;
212}
213
214/*
215 * Release a line
216 */
217static int of_platform_serial_remove(struct platform_device *ofdev)
218{
219	struct of_serial_info *info = platform_get_drvdata(ofdev);
220	switch (info->type) {
221#ifdef CONFIG_SERIAL_8250
222	case PORT_8250 ... PORT_MAX_8250:
223		serial8250_unregister_port(info->line);
224		break;
225#endif
226#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
227	case PORT_NWPSERIAL:
228		nwpserial_unregister_port(info->line);
229		break;
230#endif
231	default:
232		/* need to add code for these */
233		break;
234	}
235
236	if (info->clk)
237		clk_disable_unprepare(info->clk);
238	kfree(info);
239	return 0;
240}
241
242/*
243 * A few common types, add more as needed.
244 */
245static struct of_device_id of_platform_serial_table[] = {
246	{ .compatible = "ns8250",   .data = (void *)PORT_8250, },
247	{ .compatible = "ns16450",  .data = (void *)PORT_16450, },
248	{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
249	{ .compatible = "ns16550",  .data = (void *)PORT_16550, },
250	{ .compatible = "ns16750",  .data = (void *)PORT_16750, },
251	{ .compatible = "ns16850",  .data = (void *)PORT_16850, },
252	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
253	{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
254	{ .compatible = "altr,16550-FIFO32",
255		.data = (void *)PORT_ALTR_16550_F32, },
256	{ .compatible = "altr,16550-FIFO64",
257		.data = (void *)PORT_ALTR_16550_F64, },
258	{ .compatible = "altr,16550-FIFO128",
259		.data = (void *)PORT_ALTR_16550_F128, },
260#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
261	{ .compatible = "ibm,qpace-nwp-serial",
262		.data = (void *)PORT_NWPSERIAL, },
263#endif
264	{ .type = "serial",         .data = (void *)PORT_UNKNOWN, },
265	{ /* end of list */ },
266};
267
268static struct platform_driver of_platform_serial_driver = {
269	.driver = {
270		.name = "of_serial",
271		.owner = THIS_MODULE,
272		.of_match_table = of_platform_serial_table,
273	},
274	.probe = of_platform_serial_probe,
275	.remove = of_platform_serial_remove,
276};
277
278module_platform_driver(of_platform_serial_driver);
279
280MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
281MODULE_LICENSE("GPL");
282MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");