aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/serial/mux.c
blob: ccb8fa1800a58e0b8a9f1fdf1b32b40d1e225831 (plain) (blame)
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
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
/*
** mux.c:
**	serial driver for the Mux console found in some PA-RISC servers.
**
**	(c) Copyright 2002 Ryan Bradetich
**	(c) Copyright 2002 Hewlett-Packard Company
**
** 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.
**
** This Driver currently only supports the console (port 0) on the MUX.
** Additional work will be needed on this driver to enable the full
** functionality of the MUX.
**
*/

#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/slab.h>
#include <linux/delay.h> /* for udelay */
#include <linux/device.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/parisc-device.h>

#ifdef CONFIG_MAGIC_SYSRQ
#include <linux/sysrq.h>
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>

#define MUX_OFFSET 0x800
#define MUX_LINE_OFFSET 0x80

#define MUX_FIFO_SIZE 255
#define MUX_POLL_DELAY (30 * HZ / 1000)

#define IO_DATA_REG_OFFSET 0x3c
#define IO_DCOUNT_REG_OFFSET 0x40

#define MUX_EOFIFO(status) ((status & 0xF000) == 0xF000)
#define MUX_STATUS(status) ((status & 0xF000) == 0x8000)
#define MUX_BREAK(status) ((status & 0xF000) == 0x2000)

#define MUX_NR 256
static unsigned int port_cnt __read_mostly;
static struct uart_port mux_ports[MUX_NR];

static struct uart_driver mux_driver = {
	.owner = THIS_MODULE,
	.driver_name = "ttyB",
	.dev_name = "ttyB",
	.major = MUX_MAJOR,
	.minor = 0,
	.nr = MUX_NR,
};

static struct timer_list mux_timer;

#define UART_PUT_CHAR(p, c) __raw_writel((c), (p)->membase + IO_DATA_REG_OFFSET)
#define UART_GET_FIFO_CNT(p) __raw_readl((p)->membase + IO_DCOUNT_REG_OFFSET)
#define GET_MUX_PORTS(iodc_data) ((((iodc_data)[4] & 0xf0) >> 4) * 8) + 8

/**
 * mux_tx_empty - Check if the transmitter fifo is empty.
 * @port: Ptr to the uart_port.
 *
 * This function test if the transmitter fifo for the port
 * described by 'port' is empty.  If it is empty, this function
 * should return TIOCSER_TEMT, otherwise return 0.
 */
static unsigned int mux_tx_empty(struct uart_port *port)
{
	return UART_GET_FIFO_CNT(port) ? 0 : TIOCSER_TEMT;
} 

/**
 * mux_set_mctrl - Set the current state of the modem control inputs.
 * @ports: Ptr to the uart_port.
 * @mctrl: Modem control bits.
 *
 * The Serial MUX does not support CTS, DCD or DSR so this function
 * is ignored.
 */
static void mux_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}

/**
 * mux_get_mctrl - Returns the current state of modem control inputs.
 * @port: Ptr to the uart_port.
 *
 * The Serial MUX does not support CTS, DCD or DSR so these lines are
 * treated as permanently active.
 */
static unsigned int mux_get_mctrl(struct uart_port *port)
{ 
	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}

/**
 * mux_stop_tx - Stop transmitting characters.
 * @port: Ptr to the uart_port.
 *
 * The Serial MUX does not support this function.
 */
static void mux_stop_tx(struct uart_port *port)
{
}

/**
 * mux_start_tx - Start transmitting characters.
 * @port: Ptr to the uart_port.
 *
 * The Serial Mux does not support this function.
 */
static void mux_start_tx(struct uart_port *port)
{
}

/**
 * mux_stop_rx - Stop receiving characters.
 * @port: Ptr to the uart_port.
 *
 * The Serial Mux does not support this function.
 */
static void mux_stop_rx(struct uart_port *port)
{
}

/**
 * mux_enable_ms - Enable modum status interrupts.
 * @port: Ptr to the uart_port.
 *
 * The Serial Mux does not support this function.
 */
static void mux_enable_ms(struct uart_port *port)
{
}

/**
 * mux_break_ctl - Control the transmitssion of a break signal.
 * @port: Ptr to the uart_port.
 * @break_state: Raise/Lower the break signal.
 *
 * The Serial Mux does not support this function.
 */
static void mux_break_ctl(struct uart_port *port, int break_state)
{
}

/**
 * mux_write - Write chars to the mux fifo.
 * @port: Ptr to the uart_port.
 *
 * This function writes all the data from the uart buffer to
 * the mux fifo.
 */
static void mux_write(struct uart_port *port)
{
	int count;
	struct circ_buf *xmit = &port->info->xmit;

	if(port->x_char) {
		UART_PUT_CHAR(port, port->x_char);
		port->icount.tx++;
		port->x_char = 0;
		return;
	}

	if(uart_circ_empty(xmit) || uart_tx_stopped(port)) {
		mux_stop_tx(port);
		return;
	}

	count = (port->fifosize) - UART_GET_FIFO_CNT(port);
	do {
		UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
		if(uart_circ_empty(xmit))
			break;

	} while(--count > 0);

	while(UART_GET_FIFO_CNT(port)) 
		udelay(1);

	if(uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

	if (uart_circ_empty(xmit))
		mux_stop_tx(port);
}

/**
 * mux_read - Read chars from the mux fifo.
 * @port: Ptr to the uart_port.
 *
 * This reads all available data from the mux's fifo and pushes
 * the data to the tty layer.
 */
static void mux_read(struct uart_port *port)
{
	int data;
	struct tty_struct *tty = port->info->tty;
	__u32 start_count = port->icount.rx;

	while(1) {
		data = __raw_readl(port->membase + IO_DATA_REG_OFFSET);

		if (MUX_STATUS(data))
			continue;

		if (MUX_EOFIFO(data))
			break;

		port->icount.rx++;

		if (MUX_BREAK(data)) {
			port->icount.brk++;
			if(uart_handle_break(port))
				continue;
		}

		if (uart_handle_sysrq_char(port, data & 0xffu))
			continue;

		tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
	}
	
	if (start_count != port->icount.rx) {
		tty_flip_buffer_push(tty);
	}
}

/**
 * mux_startup - Initialize the port.
 * @port: Ptr to the uart_port.
 *
 * Grab any resources needed for this port and start the
 * mux timer.
 */
static int mux_startup(struct uart_port *port)
{
	mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY);
	return 0;
}

/**
 * mux_shutdown - Disable the port.
 * @port: Ptr to the uart_port.
 *
 * Release any resources needed for the port.
 */
static void mux_shutdown(struct uart_port *port)
{
}

/**
 * mux_set_termios - Chane port parameters.
 * @port: Ptr to the uart_port.
 * @termios: new termios settings.
 * @old: old termios settings.
 *
 * The Serial Mux does not support this function.
 */
static void
mux_set_termios(struct uart_port *port, struct ktermios *termios,
	        struct ktermios *old)
{
}

/**
 * mux_type - Describe the port.
 * @port: Ptr to the uart_port.
 *
 * Return a pointer to a string constant describing the
 * specified port.
 */
static const char *mux_type(struct uart_port *port)
{
	return "Mux";
}

/**
 * mux_release_port - Release memory and IO regions.
 * @port: Ptr to the uart_port.
 * 
 * Release any memory and IO region resources currently in use by
 * the port.
 */
static void mux_release_port(struct uart_port *port)
{
}

/**
 * mux_request_port - Request memory and IO regions.
 * @port: Ptr to the uart_port.
 *
 * Request any memory and IO region resources required by the port.
 * If any fail, no resources should be registered when this function
 * returns, and it should return -EBUSY on failure.
 */
static int mux_request_port(struct uart_port *port)
{
	return 0;
}

/**
 * mux_config_port - Perform port autoconfiguration.
 * @port: Ptr to the uart_port.
 * @type: Bitmask of required configurations.
 *
 * Perform any autoconfiguration steps for the port.  This functino is
 * called if the UPF_BOOT_AUTOCONF flag is specified for the port.
 * [Note: This is required for now because of a bug in the Serial core.
 *  rmk has already submitted a patch to linus, should be available for
 *  2.5.47.]
 */
static void mux_config_port(struct uart_port *port, int type)
{
	port->type = PORT_MUX;
}

/**
 * mux_verify_port - Verify the port information.
 * @port: Ptr to the uart_port.
 * @ser: Ptr to the serial information.
 *
 * Verify the new serial port information contained within serinfo is
 * suitable for this port type.
 */
static int mux_verify_port(struct uart_port *port, struct serial_struct *ser)
{
	if(port->membase == NULL)
		return -EINVAL;

	return 0;
}

/**
 * mux_drv_poll - Mux poll function.
 * @unused: Unused variable
 *
 * This function periodically polls the Serial MUX to check for new data.
 */
static void mux_poll(unsigned long unused)
{  
	int i;

	for(i = 0; i < port_cnt; ++i) {
		if(!mux_ports[i].info)
			continue;

		mux_read(&mux_ports[i]);
		mux_write(&mux_ports[i]);
	}

	mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY);
}


#ifdef CONFIG_SERIAL_MUX_CONSOLE
static void mux_console_write(struct console *co, const char *s, unsigned count)
{
        while(count--)
                pdc_iodc_putc(*s++);
}

static int mux_console_setup(struct console *co, char *options)
{
        return 0;
}

struct tty_driver *mux_console_device(struct console *co, int *index)
{
        *index = co->index;
	return mux_driver.tty_driver;
}

static struct console mux_console = {
	.name =		"ttyB",
	.write =	mux_console_write,
	.device =	mux_console_device,
	.setup =	mux_console_setup,
	.flags =	CON_ENABLED | CON_PRINTBUFFER,
	.index =	0,
};

#define MUX_CONSOLE	&mux_console
#else
#define MUX_CONSOLE	NULL
#endif

static struct uart_ops mux_pops = {
	.tx_empty =		mux_tx_empty,
	.set_mctrl =		mux_set_mctrl,
	.get_mctrl =		mux_get_mctrl,
	.stop_tx =		mux_stop_tx,
	.start_tx =		mux_start_tx,
	.stop_rx =		mux_stop_rx,
	.enable_ms =		mux_enable_ms,
	.break_ctl =		mux_break_ctl,
	.startup =		mux_startup,
	.shutdown =		mux_shutdown,
	.set_termios =		mux_set_termios,
	.type =			mux_type,
	.release_port =		mux_release_port,
	.request_port =		mux_request_port,
	.config_port =		mux_config_port,
	.verify_port =		mux_verify_port,
};

/**
 * mux_probe - Determine if the Serial Mux should claim this device.
 * @dev: The parisc device.
 *
 * Deterimine if the Serial Mux should claim this chip (return 0)
 * or not (return 1).
 */
static int __init mux_probe(struct parisc_device *dev)
{
	int i, status, ports;
	u8 iodc_data[32];
	unsigned long bytecnt;
	struct uart_port *port;

	status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32);
	if(status != PDC_OK) {
		printk(KERN_ERR "Serial mux: Unable to read IODC.\n");
		return 1;
	}

	ports = GET_MUX_PORTS(iodc_data);
 	printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.3\n", ports);

	if(!port_cnt) {
		mux_driver.cons = MUX_CONSOLE;

		status = uart_register_driver(&mux_driver);
		if(status) {
			printk(KERN_ERR "Serial mux: Unable to register driver.\n");
			return 1;
		}

		init_timer(&mux_timer);
		mux_timer.function = mux_poll;
	}

	for(i = 0; i < ports; ++i, ++port_cnt) {
		port = &mux_ports[port_cnt];
		port->iobase	= 0;
		port->mapbase	= dev->hpa.start + MUX_OFFSET +
						(i * MUX_LINE_OFFSET);
		port->membase	= ioremap_nocache(port->mapbase, MUX_LINE_OFFSET);
		port->iotype	= UPIO_MEM;
		port->type	= PORT_MUX;
		port->irq	= NO_IRQ;
		port->uartclk	= 0;
		port->fifosize	= MUX_FIFO_SIZE;
		port->ops	= &mux_pops;
		port->flags	= UPF_BOOT_AUTOCONF;
		port->line	= port_cnt;

		/* The port->timeout needs to match what is present in
		 * uart_wait_until_sent in serial_core.c.  Otherwise
		 * the time spent in msleep_interruptable will be very
		 * long, causing the appearance of a console hang.
		 */
		port->timeout   = HZ / 50;
		spin_lock_init(&port->lock);
		status = uart_add_one_port(&mux_driver, port);
		BUG_ON(status);
	}

#ifdef CONFIG_SERIAL_MUX_CONSOLE
        register_console(&mux_console);
#endif
	return 0;
}

static struct parisc_device_id mux_tbl[] = {
	{ HPHW_A_DIRECT, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x0000D },
	{ 0, }
};

MODULE_DEVICE_TABLE(parisc, mux_tbl);

static struct parisc_driver serial_mux_driver = {
	.name =		"serial_mux",
	.id_table =	mux_tbl,
	.probe =	mux_probe,
};

/**
 * mux_init - Serial MUX initalization procedure.
 *
 * Register the Serial MUX driver.
 */
static int __init mux_init(void)
{
	return register_parisc_driver(&serial_mux_driver);
}

/**
 * mux_exit - Serial MUX cleanup procedure.
 *
 * Unregister the Serial MUX driver from the tty layer.
 */
static void __exit mux_exit(void)
{
	int i;

	for (i = 0; i < port_cnt; i++) {
		uart_remove_one_port(&mux_driver, &mux_ports[i]);
		if (mux_ports[i].membase)
			iounmap(mux_ports[i].membase);
	}

	uart_unregister_driver(&mux_driver);
}

module_init(mux_init);
module_exit(mux_exit);

MODULE_AUTHOR("Ryan Bradetich");
MODULE_DESCRIPTION("Serial MUX driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(MUX_MAJOR);