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/console.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/delay.h>
16#include <linux/serial_core.h>
17#include <linux/serial_reg.h>
18#include <linux/of_address.h>
19#include <linux/of_irq.h>
20#include <linux/of_platform.h>
21#include <linux/nwpserial.h>
22#include <linux/clk.h>
23
24#include "8250/8250.h"
25
26struct of_serial_info {
27	struct clk *clk;
28	int type;
29	int line;
30};
31
32#ifdef CONFIG_ARCH_TEGRA
33void tegra_serial_handle_break(struct uart_port *p)
34{
35	unsigned int status, tmout = 10000;
36
37	do {
38		status = p->serial_in(p, UART_LSR);
39		if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
40			status = p->serial_in(p, UART_RX);
41		else
42			break;
43		if (--tmout == 0)
44			break;
45		udelay(1);
46	} while (1);
47}
48#else
49static inline void tegra_serial_handle_break(struct uart_port *port)
50{
51}
52#endif
53
54/*
55 * Fill a struct uart_port for a given device node
56 */
57static int of_platform_serial_setup(struct platform_device *ofdev,
58			int type, struct uart_port *port,
59			struct of_serial_info *info)
60{
61	struct resource resource;
62	struct device_node *np = ofdev->dev.of_node;
63	u32 clk, spd, prop;
64	int ret;
65
66	memset(port, 0, sizeof *port);
67	if (of_property_read_u32(np, "clock-frequency", &clk)) {
68
69		/* Get clk rate through clk driver if present */
70		info->clk = clk_get(&ofdev->dev, NULL);
71		if (IS_ERR(info->clk)) {
72			dev_warn(&ofdev->dev,
73				"clk or clock-frequency not defined\n");
74			return PTR_ERR(info->clk);
75		}
76
77		clk_prepare_enable(info->clk);
78		clk = clk_get_rate(info->clk);
79	}
80	/* If current-speed was set, then try not to change it. */
81	if (of_property_read_u32(np, "current-speed", &spd) == 0)
82		port->custom_divisor = clk / (16 * spd);
83
84	ret = of_address_to_resource(np, 0, &resource);
85	if (ret) {
86		dev_warn(&ofdev->dev, "invalid address\n");
87		goto out;
88	}
89
90	spin_lock_init(&port->lock);
91	port->mapbase = resource.start;
92	port->mapsize = resource_size(&resource);
93
94	/* Check for shifted address mapping */
95	if (of_property_read_u32(np, "reg-offset", &prop) == 0)
96		port->mapbase += prop;
97
98	/* Check for registers offset within the devices address range */
99	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
100		port->regshift = prop;
101
102	/* Check for fifo size */
103	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
104		port->fifosize = prop;
105
106	/* Check for a fixed line number */
107	ret = of_alias_get_id(np, "serial");
108	if (ret >= 0)
109		port->line = ret;
110
111	port->irq = irq_of_parse_and_map(np, 0);
112	port->iotype = UPIO_MEM;
113	if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
114		switch (prop) {
115		case 1:
116			port->iotype = UPIO_MEM;
117			break;
118		case 4:
119			port->iotype = of_device_is_big_endian(np) ?
120				       UPIO_MEM32BE : UPIO_MEM32;
121			break;
122		default:
123			dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
124				 prop);
125			ret = -EINVAL;
126			goto out;
127		}
128	}
129
130	port->type = type;
131	port->uartclk = clk;
132	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
133		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
134
135	if (of_find_property(np, "no-loopback-test", NULL))
136		port->flags |= UPF_SKIP_TEST;
137
138	port->dev = &ofdev->dev;
139
140	switch (type) {
141	case PORT_TEGRA:
142		port->handle_break = tegra_serial_handle_break;
143		break;
144
145	case PORT_RT2880:
146		port->iotype = UPIO_AU;
147		break;
148	}
149
150	return 0;
151out:
152	if (info->clk)
153		clk_disable_unprepare(info->clk);
154	return ret;
155}
156
157/*
158 * Try to register a serial port
159 */
160static const struct of_device_id of_platform_serial_table[];
161static int of_platform_serial_probe(struct platform_device *ofdev)
162{
163	const struct of_device_id *match;
164	struct of_serial_info *info;
165	struct uart_port port;
166	int port_type;
167	int ret;
168
169	match = of_match_device(of_platform_serial_table, &ofdev->dev);
170	if (!match)
171		return -EINVAL;
172
173	if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
174		return -EBUSY;
175
176	info = kzalloc(sizeof(*info), GFP_KERNEL);
177	if (info == NULL)
178		return -ENOMEM;
179
180	port_type = (unsigned long)match->data;
181	ret = of_platform_serial_setup(ofdev, port_type, &port, info);
182	if (ret)
183		goto out;
184
185	switch (port_type) {
186#ifdef CONFIG_SERIAL_8250
187	case PORT_8250 ... PORT_MAX_8250:
188	{
189		struct uart_8250_port port8250;
190		memset(&port8250, 0, sizeof(port8250));
191		port.type = port_type;
192		port8250.port = port;
193
194		if (port.fifosize)
195			port8250.capabilities = UART_CAP_FIFO;
196
197		if (of_property_read_bool(ofdev->dev.of_node,
198					  "auto-flow-control"))
199			port8250.capabilities |= UART_CAP_AFE;
200
201		ret = serial8250_register_8250_port(&port8250);
202		break;
203	}
204#endif
205#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
206	case PORT_NWPSERIAL:
207		ret = nwpserial_register_port(&port);
208		break;
209#endif
210	default:
211		/* need to add code for these */
212	case PORT_UNKNOWN:
213		dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
214		ret = -ENODEV;
215		break;
216	}
217	if (ret < 0)
218		goto out;
219
220	info->type = port_type;
221	info->line = ret;
222	platform_set_drvdata(ofdev, info);
223	return 0;
224out:
225	kfree(info);
226	irq_dispose_mapping(port.irq);
227	return ret;
228}
229
230/*
231 * Release a line
232 */
233static int of_platform_serial_remove(struct platform_device *ofdev)
234{
235	struct of_serial_info *info = platform_get_drvdata(ofdev);
236	switch (info->type) {
237#ifdef CONFIG_SERIAL_8250
238	case PORT_8250 ... PORT_MAX_8250:
239		serial8250_unregister_port(info->line);
240		break;
241#endif
242#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
243	case PORT_NWPSERIAL:
244		nwpserial_unregister_port(info->line);
245		break;
246#endif
247	default:
248		/* need to add code for these */
249		break;
250	}
251
252	if (info->clk)
253		clk_disable_unprepare(info->clk);
254	kfree(info);
255	return 0;
256}
257
258#ifdef CONFIG_PM_SLEEP
259#ifdef CONFIG_SERIAL_8250
260static void of_serial_suspend_8250(struct of_serial_info *info)
261{
262	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
263	struct uart_port *port = &port8250->port;
264
265	serial8250_suspend_port(info->line);
266	if (info->clk && (!uart_console(port) || console_suspend_enabled))
267		clk_disable_unprepare(info->clk);
268}
269
270static void of_serial_resume_8250(struct of_serial_info *info)
271{
272	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
273	struct uart_port *port = &port8250->port;
274
275	if (info->clk && (!uart_console(port) || console_suspend_enabled))
276		clk_prepare_enable(info->clk);
277
278	serial8250_resume_port(info->line);
279}
280#else
281static inline void of_serial_suspend_8250(struct of_serial_info *info)
282{
283}
284
285static inline void of_serial_resume_8250(struct of_serial_info *info)
286{
287}
288#endif
289
290static int of_serial_suspend(struct device *dev)
291{
292	struct of_serial_info *info = dev_get_drvdata(dev);
293
294	switch (info->type) {
295	case PORT_8250 ... PORT_MAX_8250:
296		of_serial_suspend_8250(info);
297		break;
298	default:
299		break;
300	}
301
302	return 0;
303}
304
305static int of_serial_resume(struct device *dev)
306{
307	struct of_serial_info *info = dev_get_drvdata(dev);
308
309	switch (info->type) {
310	case PORT_8250 ... PORT_MAX_8250:
311		of_serial_resume_8250(info);
312		break;
313	default:
314		break;
315	}
316
317	return 0;
318}
319#endif
320static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
321
322/*
323 * A few common types, add more as needed.
324 */
325static const struct of_device_id of_platform_serial_table[] = {
326	{ .compatible = "ns8250",   .data = (void *)PORT_8250, },
327	{ .compatible = "ns16450",  .data = (void *)PORT_16450, },
328	{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
329	{ .compatible = "ns16550",  .data = (void *)PORT_16550, },
330	{ .compatible = "ns16750",  .data = (void *)PORT_16750, },
331	{ .compatible = "ns16850",  .data = (void *)PORT_16850, },
332	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
333	{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
334	{ .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
335	{ .compatible = "altr,16550-FIFO32",
336		.data = (void *)PORT_ALTR_16550_F32, },
337	{ .compatible = "altr,16550-FIFO64",
338		.data = (void *)PORT_ALTR_16550_F64, },
339	{ .compatible = "altr,16550-FIFO128",
340		.data = (void *)PORT_ALTR_16550_F128, },
341	{ .compatible = "mrvl,mmp-uart",
342		.data = (void *)PORT_XSCALE, },
343	{ .compatible = "mrvl,pxa-uart",
344		.data = (void *)PORT_XSCALE, },
345#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
346	{ .compatible = "ibm,qpace-nwp-serial",
347		.data = (void *)PORT_NWPSERIAL, },
348#endif
349	{ /* end of list */ },
350};
351
352static struct platform_driver of_platform_serial_driver = {
353	.driver = {
354		.name = "of_serial",
355		.of_match_table = of_platform_serial_table,
356	},
357	.probe = of_platform_serial_probe,
358	.remove = of_platform_serial_remove,
359};
360
361module_platform_driver(of_platform_serial_driver);
362
363MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
364MODULE_LICENSE("GPL");
365MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
366