Free Electrons

Embedded Linux Experts

  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
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
/* sunhv.c: Serial driver for SUN4V hypervisor console.
 *
 * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/circ_buf.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/of_device.h>

#include <asm/hypervisor.h>
#include <asm/spitfire.h>
#include <asm/prom.h>
#include <asm/irq.h>
#include <asm/setup.h>

#if defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>
#include <linux/sunserialcore.h>

#define CON_BREAK	((long)-1)
#define CON_HUP		((long)-2)

#define IGNORE_BREAK	0x1
#define IGNORE_ALL	0x2

static char *con_write_page;
static char *con_read_page;

static int hung_up = 0;

static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit)
{
	while (!uart_circ_empty(xmit)) {
		long status = sun4v_con_putchar(xmit->buf[xmit->tail]);

		if (status != HV_EOK)
			break;

		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
	}
}

static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
{
	while (!uart_circ_empty(xmit)) {
		unsigned long ra = __pa(xmit->buf + xmit->tail);
		unsigned long len, status, sent;

		len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
				      UART_XMIT_SIZE);
		status = sun4v_con_write(ra, len, &sent);
		if (status != HV_EOK)
			break;
		xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1);
		port->icount.tx += sent;
	}
}

static int receive_chars_getchar(struct uart_port *port, struct tty_struct *tty)
{
	int saw_console_brk = 0;
	int limit = 10000;

	while (limit-- > 0) {
		long status;
		long c = sun4v_con_getchar(&status);

		if (status == HV_EWOULDBLOCK)
			break;

		if (c == CON_BREAK) {
			if (uart_handle_break(port))
				continue;
			saw_console_brk = 1;
			c = 0;
		}

		if (c == CON_HUP) {
			hung_up = 1;
			uart_handle_dcd_change(port, 0);
		} else if (hung_up) {
			hung_up = 0;
			uart_handle_dcd_change(port, 1);
		}

		if (tty == NULL) {
			uart_handle_sysrq_char(port, c);
			continue;
		}

		port->icount.rx++;

		if (uart_handle_sysrq_char(port, c))
			continue;

		tty_insert_flip_char(tty, c, TTY_NORMAL);
	}

	return saw_console_brk;
}

static int receive_chars_read(struct uart_port *port, struct tty_struct *tty)
{
	int saw_console_brk = 0;
	int limit = 10000;

	while (limit-- > 0) {
		unsigned long ra = __pa(con_read_page);
		unsigned long bytes_read, i;
		long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);

		if (stat != HV_EOK) {
			bytes_read = 0;

			if (stat == CON_BREAK) {
				if (uart_handle_break(port))
					continue;
				saw_console_brk = 1;
				*con_read_page = 0;
				bytes_read = 1;
			} else if (stat == CON_HUP) {
				hung_up = 1;
				uart_handle_dcd_change(port, 0);
				continue;
			} else {
				/* HV_EWOULDBLOCK, etc.  */
				break;
			}
		}

		if (hung_up) {
			hung_up = 0;
			uart_handle_dcd_change(port, 1);
		}

		for (i = 0; i < bytes_read; i++)
			uart_handle_sysrq_char(port, con_read_page[i]);

		if (tty == NULL)
			continue;

		port->icount.rx += bytes_read;

		tty_insert_flip_string(tty, con_read_page, bytes_read);
	}

	return saw_console_brk;
}

struct sunhv_ops {
	void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
	int (*receive_chars)(struct uart_port *port, struct tty_struct *tty);
};

static struct sunhv_ops bychar_ops = {
	.transmit_chars = transmit_chars_putchar,
	.receive_chars = receive_chars_getchar,
};

static struct sunhv_ops bywrite_ops = {
	.transmit_chars = transmit_chars_write,
	.receive_chars = receive_chars_read,
};

static struct sunhv_ops *sunhv_ops = &bychar_ops;

static struct tty_struct *receive_chars(struct uart_port *port)
{
	struct tty_struct *tty = NULL;

	if (port->state != NULL)		/* Unopened serial console */
		tty = port->state->port.tty;

	if (sunhv_ops->receive_chars(port, tty))
		sun_do_break();

	return tty;
}

static void transmit_chars(struct uart_port *port)
{
	struct circ_buf *xmit;

	if (!port->state)
		return;

	xmit = &port->state->xmit;
	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
		return;

	sunhv_ops->transmit_chars(port, xmit);

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

static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
{
	struct uart_port *port = dev_id;
	struct tty_struct *tty;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	tty = receive_chars(port);
	transmit_chars(port);
	spin_unlock_irqrestore(&port->lock, flags);

	if (tty)
		tty_flip_buffer_push(tty);

	return IRQ_HANDLED;
}

/* port->lock is not held.  */
static unsigned int sunhv_tx_empty(struct uart_port *port)
{
	/* Transmitter is always empty for us.  If the circ buffer
	 * is non-empty or there is an x_char pending, our caller
	 * will do the right thing and ignore what we return here.
	 */
	return TIOCSER_TEMT;
}

/* port->lock held by caller.  */
static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	return;
}

/* port->lock is held by caller and interrupts are disabled.  */
static unsigned int sunhv_get_mctrl(struct uart_port *port)
{
	return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
}

/* port->lock held by caller.  */
static void sunhv_stop_tx(struct uart_port *port)
{
	return;
}

/* port->lock held by caller.  */
static void sunhv_start_tx(struct uart_port *port)
{
	transmit_chars(port);
}

/* port->lock is not held.  */
static void sunhv_send_xchar(struct uart_port *port, char ch)
{
	unsigned long flags;
	int limit = 10000;

	spin_lock_irqsave(&port->lock, flags);

	while (limit-- > 0) {
		long status = sun4v_con_putchar(ch);
		if (status == HV_EOK)
			break;
		udelay(1);
	}

	spin_unlock_irqrestore(&port->lock, flags);
}

/* port->lock held by caller.  */
static void sunhv_stop_rx(struct uart_port *port)
{
}

/* port->lock held by caller.  */
static void sunhv_enable_ms(struct uart_port *port)
{
}

/* port->lock is not held.  */
static void sunhv_break_ctl(struct uart_port *port, int break_state)
{
	if (break_state) {
		unsigned long flags;
		int limit = 10000;

		spin_lock_irqsave(&port->lock, flags);

		while (limit-- > 0) {
			long status = sun4v_con_putchar(CON_BREAK);
			if (status == HV_EOK)
				break;
			udelay(1);
		}

		spin_unlock_irqrestore(&port->lock, flags);
	}
}

/* port->lock is not held.  */
static int sunhv_startup(struct uart_port *port)
{
	return 0;
}

/* port->lock is not held.  */
static void sunhv_shutdown(struct uart_port *port)
{
}

/* port->lock is not held.  */
static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
			      struct ktermios *old)
{
	unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
	unsigned int quot = uart_get_divisor(port, baud);
	unsigned int iflag, cflag;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);

	iflag = termios->c_iflag;
	cflag = termios->c_cflag;

	port->ignore_status_mask = 0;
	if (iflag & IGNBRK)
		port->ignore_status_mask |= IGNORE_BREAK;
	if ((cflag & CREAD) == 0)
		port->ignore_status_mask |= IGNORE_ALL;

	/* XXX */
	uart_update_timeout(port, cflag,
			    (port->uartclk / (16 * quot)));

	spin_unlock_irqrestore(&port->lock, flags);
}

static const char *sunhv_type(struct uart_port *port)
{
	return "SUN4V HCONS";
}

static void sunhv_release_port(struct uart_port *port)
{
}

static int sunhv_request_port(struct uart_port *port)
{
	return 0;
}

static void sunhv_config_port(struct uart_port *port, int flags)
{
}

static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
{
	return -EINVAL;
}

static struct uart_ops sunhv_pops = {
	.tx_empty	= sunhv_tx_empty,
	.set_mctrl	= sunhv_set_mctrl,
	.get_mctrl	= sunhv_get_mctrl,
	.stop_tx	= sunhv_stop_tx,
	.start_tx	= sunhv_start_tx,
	.send_xchar	= sunhv_send_xchar,
	.stop_rx	= sunhv_stop_rx,
	.enable_ms	= sunhv_enable_ms,
	.break_ctl	= sunhv_break_ctl,
	.startup	= sunhv_startup,
	.shutdown	= sunhv_shutdown,
	.set_termios	= sunhv_set_termios,
	.type		= sunhv_type,
	.release_port	= sunhv_release_port,
	.request_port	= sunhv_request_port,
	.config_port	= sunhv_config_port,
	.verify_port	= sunhv_verify_port,
};

static struct uart_driver sunhv_reg = {
	.owner			= THIS_MODULE,
	.driver_name		= "sunhv",
	.dev_name		= "ttyS",
	.major			= TTY_MAJOR,
};

static struct uart_port *sunhv_port;

/* Copy 's' into the con_write_page, decoding "\n" into
 * "\r\n" along the way.  We have to return two lengths
 * because the caller needs to know how much to advance
 * 's' and also how many bytes to output via con_write_page.
 */
static int fill_con_write_page(const char *s, unsigned int n,
			       unsigned long *page_bytes)
{
	const char *orig_s = s;
	char *p = con_write_page;
	int left = PAGE_SIZE;

	while (n--) {
		if (*s == '\n') {
			if (left < 2)
				break;
			*p++ = '\r';
			left--;
		} else if (left < 1)
			break;
		*p++ = *s++;
		left--;
	}
	*page_bytes = p - con_write_page;
	return s - orig_s;
}

static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
{
	struct uart_port *port = sunhv_port;
	unsigned long flags;
	int locked = 1;

	local_irq_save(flags);
	if (port->sysrq) {
		locked = 0;
	} else if (oops_in_progress) {
		locked = spin_trylock(&port->lock);
	} else
		spin_lock(&port->lock);

	while (n > 0) {
		unsigned long ra = __pa(con_write_page);
		unsigned long page_bytes;
		unsigned int cpy = fill_con_write_page(s, n,
						       &page_bytes);

		n -= cpy;
		s += cpy;
		while (page_bytes > 0) {
			unsigned long written;
			int limit = 1000000;

			while (limit--) {
				unsigned long stat;

				stat = sun4v_con_write(ra, page_bytes,
						       &written);
				if (stat == HV_EOK)
					break;
				udelay(1);
			}
			if (limit < 0)
				break;
			page_bytes -= written;
			ra += written;
		}
	}

	if (locked)
		spin_unlock(&port->lock);
	local_irq_restore(flags);
}

static inline void sunhv_console_putchar(struct uart_port *port, char c)
{
	int limit = 1000000;

	while (limit-- > 0) {
		long status = sun4v_con_putchar(c);
		if (status == HV_EOK)
			break;
		udelay(1);
	}
}

static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
{
	struct uart_port *port = sunhv_port;
	unsigned long flags;
	int i, locked = 1;

	local_irq_save(flags);
	if (port->sysrq) {
		locked = 0;
	} else if (oops_in_progress) {
		locked = spin_trylock(&port->lock);
	} else
		spin_lock(&port->lock);

	for (i = 0; i < n; i++) {
		if (*s == '\n')
			sunhv_console_putchar(port, '\r');
		sunhv_console_putchar(port, *s++);
	}

	if (locked)
		spin_unlock(&port->lock);
	local_irq_restore(flags);
}

static struct console sunhv_console = {
	.name	=	"ttyHV",
	.write	=	sunhv_console_write_bychar,
	.device	=	uart_console_device,
	.flags	=	CON_PRINTBUFFER,
	.index	=	-1,
	.data	=	&sunhv_reg,
};

static int __devinit hv_probe(struct platform_device *op)
{
	struct uart_port *port;
	unsigned long minor;
	int err;

	if (op->archdata.irqs[0] == 0xffffffff)
		return -ENODEV;

	port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
	if (unlikely(!port))
		return -ENOMEM;

	minor = 1;
	if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
	    minor >= 1) {
		err = -ENOMEM;
		con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
		if (!con_write_page)
			goto out_free_port;

		con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
		if (!con_read_page)
			goto out_free_con_write_page;

		sunhv_console.write = sunhv_console_write_paged;
		sunhv_ops = &bywrite_ops;
	}

	sunhv_port = port;

	port->line = 0;
	port->ops = &sunhv_pops;
	port->type = PORT_SUNHV;
	port->uartclk = ( 29491200 / 16 ); /* arbitrary */

	port->membase = (unsigned char __iomem *) __pa(port);

	port->irq = op->archdata.irqs[0];

	port->dev = &op->dev;

	err = sunserial_register_minors(&sunhv_reg, 1);
	if (err)
		goto out_free_con_read_page;

	sunserial_console_match(&sunhv_console, op->dev.of_node,
				&sunhv_reg, port->line, false);

	err = uart_add_one_port(&sunhv_reg, port);
	if (err)
		goto out_unregister_driver;

	err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
	if (err)
		goto out_remove_port;

	dev_set_drvdata(&op->dev, port);

	return 0;

out_remove_port:
	uart_remove_one_port(&sunhv_reg, port);

out_unregister_driver:
	sunserial_unregister_minors(&sunhv_reg, 1);

out_free_con_read_page:
	kfree(con_read_page);

out_free_con_write_page:
	kfree(con_write_page);

out_free_port:
	kfree(port);
	sunhv_port = NULL;
	return err;
}

static int __devexit hv_remove(struct platform_device *dev)
{
	struct uart_port *port = dev_get_drvdata(&dev->dev);

	free_irq(port->irq, port);

	uart_remove_one_port(&sunhv_reg, port);

	sunserial_unregister_minors(&sunhv_reg, 1);

	kfree(port);
	sunhv_port = NULL;

	dev_set_drvdata(&dev->dev, NULL);

	return 0;
}

static const struct of_device_id hv_match[] = {
	{
		.name = "console",
		.compatible = "qcn",
	},
	{
		.name = "console",
		.compatible = "SUNW,sun4v-console",
	},
	{},
};
MODULE_DEVICE_TABLE(of, hv_match);

static struct platform_driver hv_driver = {
	.driver = {
		.name = "hv",
		.owner = THIS_MODULE,
		.of_match_table = hv_match,
	},
	.probe		= hv_probe,
	.remove		= __devexit_p(hv_remove),
};

static int __init sunhv_init(void)
{
	if (tlb_type != hypervisor)
		return -ENODEV;

	return platform_driver_register(&hv_driver);
}

static void __exit sunhv_exit(void)
{
	platform_driver_unregister(&hv_driver);
}

module_init(sunhv_init);
module_exit(sunhv_exit);

MODULE_AUTHOR("David S. Miller");
MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");