aboutsummaryrefslogtreecommitdiff
path: root/drivers/serial/altera_jtaguart.c
blob: f9b49b5ff5e1363acabf812f354fe24856152de6 (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
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
/*
 * altera_jtaguart.c -- Altera JTAG UART driver
 *
 * Based on mcf.c -- Freescale ColdFire UART driver
 *
 * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
 * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
 * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
 *
 * 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/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/altera_jtaguart.h>

#define DRV_NAME "altera_jtaguart"

/*
 * Altera JTAG UART register definitions according to the Altera JTAG UART
 * datasheet: http://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf
 */

#define ALTERA_JTAGUART_SIZE			8

#define ALTERA_JTAGUART_DATA_REG		0

#define ALTERA_JTAGUART_DATA_DATA_MSK		0x000000FF
#define ALTERA_JTAGUART_DATA_RVALID_MSK		0x00008000
#define ALTERA_JTAGUART_DATA_RAVAIL_MSK		0xFFFF0000
#define ALTERA_JTAGUART_DATA_RAVAIL_OFF		16

#define ALTERA_JTAGUART_CONTROL_REG		4

#define ALTERA_JTAGUART_CONTROL_RE_MSK		0x00000001
#define ALTERA_JTAGUART_CONTROL_WE_MSK		0x00000002
#define ALTERA_JTAGUART_CONTROL_RI_MSK		0x00000100
#define ALTERA_JTAGUART_CONTROL_RI_OFF		8
#define ALTERA_JTAGUART_CONTROL_WI_MSK		0x00000200
#define ALTERA_JTAGUART_CONTROL_AC_MSK		0x00000400
#define ALTERA_JTAGUART_CONTROL_WSPACE_MSK	0xFFFF0000
#define ALTERA_JTAGUART_CONTROL_WSPACE_OFF	16

/*
 * Local per-uart structure.
 */
struct altera_jtaguart {
	struct uart_port port;
	unsigned int sigs;	/* Local copy of line sigs */
	unsigned long imr;	/* Local IMR mirror */
};

static unsigned int altera_jtaguart_tx_empty(struct uart_port *port)
{
	return (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
		ALTERA_JTAGUART_CONTROL_WSPACE_MSK) ? TIOCSER_TEMT : 0;
}

static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port)
{
	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}

static void altera_jtaguart_set_mctrl(struct uart_port *port, unsigned int sigs)
{
}

static void altera_jtaguart_start_tx(struct uart_port *port)
{
	struct altera_jtaguart *pp =
	    container_of(port, struct altera_jtaguart, port);

	pp->imr |= ALTERA_JTAGUART_CONTROL_WE_MSK;
	writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
}

static void altera_jtaguart_stop_tx(struct uart_port *port)
{
	struct altera_jtaguart *pp =
	    container_of(port, struct altera_jtaguart, port);

	pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
	writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
}

static void altera_jtaguart_stop_rx(struct uart_port *port)
{
	struct altera_jtaguart *pp =
	    container_of(port, struct altera_jtaguart, port);

	pp->imr &= ~ALTERA_JTAGUART_CONTROL_RE_MSK;
	writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
}

static void altera_jtaguart_break_ctl(struct uart_port *port, int break_state)
{
}

static void altera_jtaguart_enable_ms(struct uart_port *port)
{
}

static void altera_jtaguart_set_termios(struct uart_port *port,
					struct ktermios *termios,
					struct ktermios *old)
{
	/* Just copy the old termios settings back */
	if (old)
		tty_termios_copy_hw(termios, old);
}

static void altera_jtaguart_rx_chars(struct altera_jtaguart *pp)
{
	struct uart_port *port = &pp->port;
	unsigned char ch, flag;
	unsigned long status;

	while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) &
	       ALTERA_JTAGUART_DATA_RVALID_MSK) {
		ch = status & ALTERA_JTAGUART_DATA_DATA_MSK;
		flag = TTY_NORMAL;
		port->icount.rx++;

		if (uart_handle_sysrq_char(port, ch))
			continue;
		uart_insert_char(port, 0, 0, ch, flag);
	}

	tty_flip_buffer_push(port->state->port.tty);
}

static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp)
{
	struct uart_port *port = &pp->port;
	struct circ_buf *xmit = &port->state->xmit;
	unsigned int pending, count;

	if (port->x_char) {
		/* Send special char - probably flow control */
		writel(port->x_char, port->membase + ALTERA_JTAGUART_DATA_REG);
		port->x_char = 0;
		port->icount.tx++;
		return;
	}

	pending = uart_circ_chars_pending(xmit);
	if (pending > 0) {
		count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
				ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >>
			ALTERA_JTAGUART_CONTROL_WSPACE_OFF;
		if (count > pending)
			count = pending;
		if (count > 0) {
			pending -= count;
			while (count--) {
				writel(xmit->buf[xmit->tail],
				       port->membase + ALTERA_JTAGUART_DATA_REG);
				xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
				port->icount.tx++;
			}
			if (pending < WAKEUP_CHARS)
				uart_write_wakeup(port);
		}
	}

	if (pending == 0) {
		pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
		writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
	}
}

static irqreturn_t altera_jtaguart_interrupt(int irq, void *data)
{
	struct uart_port *port = data;
	struct altera_jtaguart *pp =
	    container_of(port, struct altera_jtaguart, port);
	unsigned int isr;

	isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >>
	       ALTERA_JTAGUART_CONTROL_RI_OFF) & pp->imr;

	spin_lock(&port->lock);

	if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK)
		altera_jtaguart_rx_chars(pp);
	if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK)
		altera_jtaguart_tx_chars(pp);

	spin_unlock(&port->lock);

	return IRQ_RETVAL(isr);
}

static void altera_jtaguart_config_port(struct uart_port *port, int flags)
{
	port->type = PORT_ALTERA_JTAGUART;

	/* Clear mask, so no surprise interrupts. */
	writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG);
}

static int altera_jtaguart_startup(struct uart_port *port)
{
	struct altera_jtaguart *pp =
	    container_of(port, struct altera_jtaguart, port);
	unsigned long flags;
	int ret;

	ret = request_irq(port->irq, altera_jtaguart_interrupt, IRQF_DISABLED,
			DRV_NAME, port);
	if (ret) {
		pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d "
		       "interrupt vector=%d\n", port->line, port->irq);
		return ret;
	}

	spin_lock_irqsave(&port->lock, flags);

	/* Enable RX interrupts now */
	pp->imr = ALTERA_JTAGUART_CONTROL_RE_MSK;
	writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);

	spin_unlock_irqrestore(&port->lock, flags);

	return 0;
}

static void altera_jtaguart_shutdown(struct uart_port *port)
{
	struct altera_jtaguart *pp =
	    container_of(port, struct altera_jtaguart, port);
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);

	/* Disable all interrupts now */
	pp->imr = 0;
	writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);

	spin_unlock_irqrestore(&port->lock, flags);

	free_irq(port->irq, port);
}

static const char *altera_jtaguart_type(struct uart_port *port)
{
	return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL;
}

static int altera_jtaguart_request_port(struct uart_port *port)
{
	/* UARTs always present */
	return 0;
}

static void altera_jtaguart_release_port(struct uart_port *port)
{
	/* Nothing to release... */
}

static int altera_jtaguart_verify_port(struct uart_port *port,
				       struct serial_struct *ser)
{
	if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART)
		return -EINVAL;
	return 0;
}

/*
 *	Define the basic serial functions we support.
 */
static struct uart_ops altera_jtaguart_ops = {
	.tx_empty	= altera_jtaguart_tx_empty,
	.get_mctrl	= altera_jtaguart_get_mctrl,
	.set_mctrl	= altera_jtaguart_set_mctrl,
	.start_tx	= altera_jtaguart_start_tx,
	.stop_tx	= altera_jtaguart_stop_tx,
	.stop_rx	= altera_jtaguart_stop_rx,
	.enable_ms	= altera_jtaguart_enable_ms,
	.break_ctl	= altera_jtaguart_break_ctl,
	.startup	= altera_jtaguart_startup,
	.shutdown	= altera_jtaguart_shutdown,
	.set_termios	= altera_jtaguart_set_termios,
	.type		= altera_jtaguart_type,
	.request_port	= altera_jtaguart_request_port,
	.release_port	= altera_jtaguart_release_port,
	.config_port	= altera_jtaguart_config_port,
	.verify_port	= altera_jtaguart_verify_port,
};

#define ALTERA_JTAGUART_MAXPORTS 1
static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS];

#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)

int __init early_altera_jtaguart_setup(struct altera_jtaguart_platform_uart
				       *platp)
{
	struct uart_port *port;
	int i;

	for (i = 0; i < ALTERA_JTAGUART_MAXPORTS && platp[i].mapbase; i++) {
		port = &altera_jtaguart_ports[i].port;

		port->line = i;
		port->type = PORT_ALTERA_JTAGUART;
		port->mapbase = platp[i].mapbase;
		port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE);
		port->iotype = SERIAL_IO_MEM;
		port->irq = platp[i].irq;
		port->flags = ASYNC_BOOT_AUTOCONF;
		port->ops = &altera_jtaguart_ops;
	}

	return 0;
}

#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
static void altera_jtaguart_console_putc(struct console *co, const char c)
{
	struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
	unsigned long status;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) &
		ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
		if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) {
			spin_unlock_irqrestore(&port->lock, flags);
			return;	/* no connection activity */
		}
		spin_unlock_irqrestore(&port->lock, flags);
		cpu_relax();
		spin_lock_irqsave(&port->lock, flags);
	}
	writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
	spin_unlock_irqrestore(&port->lock, flags);
}
#else
static void altera_jtaguart_console_putc(struct console *co, const char c)
{
	struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
		ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
		spin_unlock_irqrestore(&port->lock, flags);
		cpu_relax();
		spin_lock_irqsave(&port->lock, flags);
	}
	writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
	spin_unlock_irqrestore(&port->lock, flags);
}
#endif

static void altera_jtaguart_console_write(struct console *co, const char *s,
					  unsigned int count)
{
	for (; count; count--, s++) {
		altera_jtaguart_console_putc(co, *s);
		if (*s == '\n')
			altera_jtaguart_console_putc(co, '\r');
	}
}

static int __init altera_jtaguart_console_setup(struct console *co,
						char *options)
{
	struct uart_port *port;

	if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS)
		return -EINVAL;
	port = &altera_jtaguart_ports[co->index].port;
	if (port->membase == 0)
		return -ENODEV;
	return 0;
}

static struct uart_driver altera_jtaguart_driver;

static struct console altera_jtaguart_console = {
	.name	= "ttyJ",
	.write	= altera_jtaguart_console_write,
	.device	= uart_console_device,
	.setup	= altera_jtaguart_console_setup,
	.flags	= CON_PRINTBUFFER,
	.index	= -1,
	.data	= &altera_jtaguart_driver,
};

static int __init altera_jtaguart_console_init(void)
{
	register_console(&altera_jtaguart_console);
	return 0;
}

console_initcall(altera_jtaguart_console_init);

#define	ALTERA_JTAGUART_CONSOLE	(&altera_jtaguart_console)

#else

#define	ALTERA_JTAGUART_CONSOLE	NULL

#endif /* CONFIG_ALTERA_JTAGUART_CONSOLE */

static struct uart_driver altera_jtaguart_driver = {
	.owner		= THIS_MODULE,
	.driver_name	= "altera_jtaguart",
	.dev_name	= "ttyJ",
	.major		= ALTERA_JTAGUART_MAJOR,
	.minor		= ALTERA_JTAGUART_MINOR,
	.nr		= ALTERA_JTAGUART_MAXPORTS,
	.cons		= ALTERA_JTAGUART_CONSOLE,
};

static int __devinit altera_jtaguart_probe(struct platform_device *pdev)
{
	struct altera_jtaguart_platform_uart *platp = pdev->dev.platform_data;
	struct uart_port *port;
	int i;

	for (i = 0; i < ALTERA_JTAGUART_MAXPORTS && platp[i].mapbase; i++) {
		port = &altera_jtaguart_ports[i].port;

		port->line = i;
		port->type = PORT_ALTERA_JTAGUART;
		port->mapbase = platp[i].mapbase;
		port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE);
		port->iotype = SERIAL_IO_MEM;
		port->irq = platp[i].irq;
		port->ops = &altera_jtaguart_ops;
		port->flags = ASYNC_BOOT_AUTOCONF;

		uart_add_one_port(&altera_jtaguart_driver, port);
	}

	return 0;
}

static int __devexit altera_jtaguart_remove(struct platform_device *pdev)
{
	struct uart_port *port;
	int i;

	for (i = 0; i < ALTERA_JTAGUART_MAXPORTS; i++) {
		port = &altera_jtaguart_ports[i].port;
		if (port)
			uart_remove_one_port(&altera_jtaguart_driver, port);
	}

	return 0;
}

static struct platform_driver altera_jtaguart_platform_driver = {
	.probe	= altera_jtaguart_probe,
	.remove	= __devexit_p(altera_jtaguart_remove),
	.driver	= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init altera_jtaguart_init(void)
{
	int rc;

	rc = uart_register_driver(&altera_jtaguart_driver);
	if (rc)
		return rc;
	rc = platform_driver_register(&altera_jtaguart_platform_driver);
	if (rc) {
		uart_unregister_driver(&altera_jtaguart_driver);
		return rc;
	}
	return 0;
}

static void __exit altera_jtaguart_exit(void)
{
	platform_driver_unregister(&altera_jtaguart_platform_driver);
	uart_unregister_driver(&altera_jtaguart_driver);
}

module_init(altera_jtaguart_init);
module_exit(altera_jtaguart_exit);

MODULE_DESCRIPTION("Altera JTAG UART driver");
MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);