summaryrefslogtreecommitdiff
path: root/drivers/tty/serial/8250/8250_of.c
blob: f6687756ec5e1efd797ea7097facfb07a6466c20 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
// SPDX-License-Identifier: GPL-2.0+
/*
 *  Serial Port driver for Open Firmware platform devices
 *
 *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
 */
#include <linux/console.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/pm_runtime.h>
#include <linux/clk.h>
#include <linux/reset.h>

#include "8250.h"

struct of_serial_info {
	struct clk *clk;
	struct reset_control *rst;
	int type;
	int line;
};

#ifdef CONFIG_ARCH_TEGRA
static void tegra_serial_handle_break(struct uart_port *p)
{
	unsigned int status, tmout = 10000;

	do {
		status = p->serial_in(p, UART_LSR);
		if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
			status = p->serial_in(p, UART_RX);
		else
			break;
		if (--tmout == 0)
			break;
		udelay(1);
	} while (1);
}
#else
static inline void tegra_serial_handle_break(struct uart_port *port)
{
}
#endif

static int of_8250_rs485_config(struct uart_port *port,
				  struct serial_rs485 *rs485)
{
	struct uart_8250_port *up = up_to_u8250p(port);

	/* Clamp the delays to [0, 100ms] */
	rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
	rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);

	port->rs485 = *rs485;

	/*
	 * Both serial8250_em485_init and serial8250_em485_destroy
	 * are idempotent
	 */
	if (rs485->flags & SER_RS485_ENABLED) {
		int ret = serial8250_em485_init(up);

		if (ret) {
			rs485->flags &= ~SER_RS485_ENABLED;
			port->rs485.flags &= ~SER_RS485_ENABLED;
		}
		return ret;
	}

	serial8250_em485_destroy(up);

	return 0;
}

/*
 * Fill a struct uart_port for a given device node
 */
static int of_platform_serial_setup(struct platform_device *ofdev,
			int type, struct uart_port *port,
			struct of_serial_info *info)
{
	struct resource resource;
	struct device_node *np = ofdev->dev.of_node;
	u32 clk, spd, prop;
	int ret, irq;

	memset(port, 0, sizeof *port);

	pm_runtime_enable(&ofdev->dev);
	pm_runtime_get_sync(&ofdev->dev);

	if (of_property_read_u32(np, "clock-frequency", &clk)) {

		/* Get clk rate through clk driver if present */
		info->clk = devm_clk_get(&ofdev->dev, NULL);
		if (IS_ERR(info->clk)) {
			ret = PTR_ERR(info->clk);
			if (ret != -EPROBE_DEFER)
				dev_warn(&ofdev->dev,
					 "failed to get clock: %d\n", ret);
			goto err_pmruntime;
		}

		ret = clk_prepare_enable(info->clk);
		if (ret < 0)
			goto err_pmruntime;

		clk = clk_get_rate(info->clk);
	}
	/* If current-speed was set, then try not to change it. */
	if (of_property_read_u32(np, "current-speed", &spd) == 0)
		port->custom_divisor = clk / (16 * spd);

	ret = of_address_to_resource(np, 0, &resource);
	if (ret) {
		dev_warn(&ofdev->dev, "invalid address\n");
		goto err_unprepare;
	}

	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
				  UPF_FIXED_TYPE;
	spin_lock_init(&port->lock);

	if (resource_type(&resource) == IORESOURCE_IO) {
		port->iotype = UPIO_PORT;
		port->iobase = resource.start;
	} else {
		port->mapbase = resource.start;
		port->mapsize = resource_size(&resource);

		/* Check for shifted address mapping */
		if (of_property_read_u32(np, "reg-offset", &prop) == 0)
			port->mapbase += prop;

		port->iotype = UPIO_MEM;
		if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
			switch (prop) {
			case 1:
				port->iotype = UPIO_MEM;
				break;
			case 2:
				port->iotype = UPIO_MEM16;
				break;
			case 4:
				port->iotype = of_device_is_big_endian(np) ?
					       UPIO_MEM32BE : UPIO_MEM32;
				break;
			default:
				dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
					 prop);
				ret = -EINVAL;
				goto err_unprepare;
			}
		}
		port->flags |= UPF_IOREMAP;
	}

	/* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
	if (of_device_is_compatible(np, "mrvl,mmp-uart"))
		port->regshift = 2;

	/* Check for registers offset within the devices address range */
	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
		port->regshift = prop;

	/* Check for fifo size */
	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
		port->fifosize = prop;

	/* Check for a fixed line number */
	ret = of_alias_get_id(np, "serial");
	if (ret >= 0)
		port->line = ret;

	irq = of_irq_get(np, 0);
	if (irq < 0) {
		if (irq == -EPROBE_DEFER) {
			ret = -EPROBE_DEFER;
			goto err_unprepare;
		}
		/* IRQ support not mandatory */
		irq = 0;
	}

	port->irq = irq;

	info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
	if (IS_ERR(info->rst)) {
		ret = PTR_ERR(info->rst);
		goto err_unprepare;
	}

	ret = reset_control_deassert(info->rst);
	if (ret)
		goto err_unprepare;

	port->type = type;
	port->uartclk = clk;

	if (of_property_read_bool(np, "no-loopback-test"))
		port->flags |= UPF_SKIP_TEST;

	port->dev = &ofdev->dev;
	port->rs485_config = of_8250_rs485_config;

	switch (type) {
	case PORT_TEGRA:
		port->handle_break = tegra_serial_handle_break;
		break;

	case PORT_RT2880:
		port->iotype = UPIO_AU;
		break;
	}

	if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
	    (of_device_is_compatible(np, "fsl,ns16550") ||
	     of_device_is_compatible(np, "fsl,16550-FIFO64"))) {
		port->handle_irq = fsl8250_handle_irq;
		port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
	}

	return 0;
err_unprepare:
	clk_disable_unprepare(info->clk);
err_pmruntime:
	pm_runtime_put_sync(&ofdev->dev);
	pm_runtime_disable(&ofdev->dev);
	return ret;
}

/*
 * Try to register a serial port
 */
static int of_platform_serial_probe(struct platform_device *ofdev)
{
	struct of_serial_info *info;
	struct uart_8250_port port8250;
	unsigned int port_type;
	u32 tx_threshold;
	int ret;

	port_type = (unsigned long)of_device_get_match_data(&ofdev->dev);
	if (port_type == PORT_UNKNOWN)
		return -EINVAL;

	if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
		return -EBUSY;

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (info == NULL)
		return -ENOMEM;

	memset(&port8250, 0, sizeof(port8250));
	ret = of_platform_serial_setup(ofdev, port_type, &port8250.port, info);
	if (ret)
		goto err_free;

	if (port8250.port.fifosize)
		port8250.capabilities = UART_CAP_FIFO;

	/* Check for TX FIFO threshold & set tx_loadsz */
	if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
				  &tx_threshold) == 0) &&
	    (tx_threshold < port8250.port.fifosize))
		port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;

	if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
		port8250.capabilities |= UART_CAP_AFE;

	if (of_property_read_u32(ofdev->dev.of_node,
			"overrun-throttle-ms",
			&port8250.overrun_backoff_time_ms) != 0)
		port8250.overrun_backoff_time_ms = 0;

	ret = serial8250_register_8250_port(&port8250);
	if (ret < 0)
		goto err_dispose;

	info->type = port_type;
	info->line = ret;
	platform_set_drvdata(ofdev, info);
	return 0;
err_dispose:
	irq_dispose_mapping(port8250.port.irq);
	pm_runtime_put_sync(&ofdev->dev);
	pm_runtime_disable(&ofdev->dev);
	clk_disable_unprepare(info->clk);
err_free:
	kfree(info);
	return ret;
}

/*
 * Release a line
 */
static int of_platform_serial_remove(struct platform_device *ofdev)
{
	struct of_serial_info *info = platform_get_drvdata(ofdev);

	serial8250_unregister_port(info->line);

	reset_control_assert(info->rst);
	pm_runtime_put_sync(&ofdev->dev);
	pm_runtime_disable(&ofdev->dev);
	clk_disable_unprepare(info->clk);
	kfree(info);
	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int of_serial_suspend(struct device *dev)
{
	struct of_serial_info *info = dev_get_drvdata(dev);
	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
	struct uart_port *port = &port8250->port;

	serial8250_suspend_port(info->line);

	if (!uart_console(port) || console_suspend_enabled) {
		pm_runtime_put_sync(dev);
		clk_disable_unprepare(info->clk);
	}
	return 0;
}

static int of_serial_resume(struct device *dev)
{
	struct of_serial_info *info = dev_get_drvdata(dev);
	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
	struct uart_port *port = &port8250->port;

	if (!uart_console(port) || console_suspend_enabled) {
		pm_runtime_get_sync(dev);
		clk_prepare_enable(info->clk);
	}

	serial8250_resume_port(info->line);

	return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);

/*
 * A few common types, add more as needed.
 */
static const struct of_device_id of_platform_serial_table[] = {
	{ .compatible = "ns8250",   .data = (void *)PORT_8250, },
	{ .compatible = "ns16450",  .data = (void *)PORT_16450, },
	{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
	{ .compatible = "ns16550",  .data = (void *)PORT_16550, },
	{ .compatible = "ns16750",  .data = (void *)PORT_16750, },
	{ .compatible = "ns16850",  .data = (void *)PORT_16850, },
	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
	{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
	{ .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
	{ .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
	{ .compatible = "altr,16550-FIFO32",
		.data = (void *)PORT_ALTR_16550_F32, },
	{ .compatible = "altr,16550-FIFO64",
		.data = (void *)PORT_ALTR_16550_F64, },
	{ .compatible = "altr,16550-FIFO128",
		.data = (void *)PORT_ALTR_16550_F128, },
	{ .compatible = "mediatek,mtk-btif",
		.data = (void *)PORT_MTK_BTIF, },
	{ .compatible = "mrvl,mmp-uart",
		.data = (void *)PORT_XSCALE, },
	{ .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
	{ .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
	{ /* end of list */ },
};
MODULE_DEVICE_TABLE(of, of_platform_serial_table);

static struct platform_driver of_platform_serial_driver = {
	.driver = {
		.name = "of_serial",
		.of_match_table = of_platform_serial_table,
		.pm = &of_serial_pm_ops,
	},
	.probe = of_platform_serial_probe,
	.remove = of_platform_serial_remove,
};

module_platform_driver(of_platform_serial_driver);

MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");