1 /* sunhv.c: Serial driver for SUN4V hypervisor console.
2 *
3 * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
4 */
5
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/errno.h>
9 #include <linux/tty.h>
10 #include <linux/tty_flip.h>
11 #include <linux/major.h>
12 #include <linux/circ_buf.h>
13 #include <linux/serial.h>
14 #include <linux/sysrq.h>
15 #include <linux/console.h>
16 #include <linux/spinlock.h>
17 #include <linux/slab.h>
18 #include <linux/delay.h>
19 #include <linux/init.h>
20
21 #include <asm/hypervisor.h>
22 #include <asm/spitfire.h>
23 #include <asm/prom.h>
24 #include <asm/of_device.h>
25 #include <asm/irq.h>
26
27 #if defined(CONFIG_MAGIC_SYSRQ)
28 #define SUPPORT_SYSRQ
29 #endif
30
31 #include <linux/serial_core.h>
32
33 #include "suncore.h"
34
35 #define CON_BREAK ((long)-1)
36 #define CON_HUP ((long)-2)
37
38 #define IGNORE_BREAK 0x1
39 #define IGNORE_ALL 0x2
40
41 static char *con_write_page;
42 static char *con_read_page;
43
44 static int hung_up = 0;
45
46 static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit)
47 {
48 while (!uart_circ_empty(xmit)) {
49 long status = sun4v_con_putchar(xmit->buf[xmit->tail]);
50
51 if (status != HV_EOK)
52 break;
53
54 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
55 port->icount.tx++;
56 }
57 }
58
59 static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
60 {
61 while (!uart_circ_empty(xmit)) {
62 unsigned long ra = __pa(xmit->buf + xmit->tail);
63 unsigned long len, status, sent;
64
65 len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
66 UART_XMIT_SIZE);
67 status = sun4v_con_write(ra, len, &sent);
68 if (status != HV_EOK)
69 break;
70 xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1);
71 port->icount.tx += sent;
72 }
73 }
74
75 static int receive_chars_getchar(struct uart_port *port, struct tty_struct *tty)
76 {
77 int saw_console_brk = 0;
78 int limit = 10000;
79
80 while (limit-- > 0) {
81 long status;
82 long c = sun4v_con_getchar(&status);
83
84 if (status == HV_EWOULDBLOCK)
85 break;
86
87 if (c == CON_BREAK) {
88 if (uart_handle_break(port))
89 continue;
90 saw_console_brk = 1;
91 c = 0;
92 }
93
94 if (c == CON_HUP) {
95 hung_up = 1;
96 uart_handle_dcd_change(port, 0);
97 } else if (hung_up) {
98 hung_up = 0;
99 uart_handle_dcd_change(port, 1);
100 }
101
102 if (tty == NULL) {
103 uart_handle_sysrq_char(port, c);
104 continue;
105 }
106
107 port->icount.rx++;
108
109 if (uart_handle_sysrq_char(port, c))
110 continue;
111
112 tty_insert_flip_char(tty, c, TTY_NORMAL);
113 }
114
115 return saw_console_brk;
116 }
117
118 static int receive_chars_read(struct uart_port *port, struct tty_struct *tty)
119 {
120 int saw_console_brk = 0;
121 int limit = 10000;
122
123 while (limit-- > 0) {
124 unsigned long ra = __pa(con_read_page);
125 unsigned long bytes_read, i;
126 long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);
127
128 if (stat != HV_EOK) {
129 bytes_read = 0;
130
131 if (stat == CON_BREAK) {
132 if (uart_handle_break(port))
133 continue;
134 saw_console_brk = 1;
135 *con_read_page = 0;
136 bytes_read = 1;
137 } else if (stat == CON_HUP) {
138 hung_up = 1;
139 uart_handle_dcd_change(port, 0);
140 continue;
141 } else {
142 /* HV_EWOULDBLOCK, etc. */
143 break;
144 }
145 }
146
147 if (hung_up) {
148 hung_up = 0;
149 uart_handle_dcd_change(port, 1);
150 }
151
152 for (i = 0; i < bytes_read; i++)
153 uart_handle_sysrq_char(port, con_read_page[i]);
154
155 if (tty == NULL)
156 continue;
157
158 port->icount.rx += bytes_read;
159
160 tty_insert_flip_string(tty, con_read_page, bytes_read);
161 }
162
163 return saw_console_brk;
164 }
165
166 struct sunhv_ops {
167 void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
168 int (*receive_chars)(struct uart_port *port, struct tty_struct *tty);
169 };
170
171 static struct sunhv_ops bychar_ops = {
172 .transmit_chars = transmit_chars_putchar,
173 .receive_chars = receive_chars_getchar,
174 };
175
176 static struct sunhv_ops bywrite_ops = {
177 .transmit_chars = transmit_chars_write,
178 .receive_chars = receive_chars_read,
179 };
180
181 static struct sunhv_ops *sunhv_ops = &bychar_ops;
182
183 static struct tty_struct *receive_chars(struct uart_port *port)
184 {
185 struct tty_struct *tty = NULL;
186
187 if (port->info != NULL) /* Unopened serial console */
188 tty = port->info->tty;
189
190 if (sunhv_ops->receive_chars(port, tty))
191 sun_do_break();
192
193 return tty;
194 }
195
196 static void transmit_chars(struct uart_port *port)
197 {
198 struct circ_buf *xmit;
199
200 if (!port->info)
201 return;
202
203 xmit = &port->info->xmit;
204 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
205 return;
206
207 sunhv_ops->transmit_chars(port, xmit);
208
209 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
210 uart_write_wakeup(port);
211 }
212
213 static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
214 {
215 struct uart_port *port = dev_id;
216 struct tty_struct *tty;
217 unsigned long flags;
218
219 spin_lock_irqsave(&port->lock, flags);
220 tty = receive_chars(port);
221 transmit_chars(port);
222 spin_unlock_irqrestore(&port->lock, flags);
223
224 if (tty)
225 tty_flip_buffer_push(tty);
226
227 return IRQ_HANDLED;
228 }
229
230 /* port->lock is not held. */
231 static unsigned int sunhv_tx_empty(struct uart_port *port)
232 {
233 /* Transmitter is always empty for us. If the circ buffer
234 * is non-empty or there is an x_char pending, our caller
235 * will do the right thing and ignore what we return here.
236 */
237 return TIOCSER_TEMT;
238 }
239
240 /* port->lock held by caller. */
241 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
242 {
243 return;
244 }
245
246 /* port->lock is held by caller and interrupts are disabled. */
247 static unsigned int sunhv_get_mctrl(struct uart_port *port)
248 {
249 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
250 }
251
252 /* port->lock held by caller. */
253 static void sunhv_stop_tx(struct uart_port *port)
254 {
255 return;
256 }
257
258 /* port->lock held by caller. */
259 static void sunhv_start_tx(struct uart_port *port)
260 {
261 transmit_chars(port);
262 }
263
264 /* port->lock is not held. */
265 static void sunhv_send_xchar(struct uart_port *port, char ch)
266 {
267 unsigned long flags;
268 int limit = 10000;
269
270 spin_lock_irqsave(&port->lock, flags);
271
272 while (limit-- > 0) {
273 long status = sun4v_con_putchar(ch);
274 if (status == HV_EOK)
275 break;
276 udelay(1);
277 }
278
279 spin_unlock_irqrestore(&port->lock, flags);
280 }
281
282 /* port->lock held by caller. */
283 static void sunhv_stop_rx(struct uart_port *port)
284 {
285 }
286
287 /* port->lock held by caller. */
288 static void sunhv_enable_ms(struct uart_port *port)
289 {
290 }
291
292 /* port->lock is not held. */
293 static void sunhv_break_ctl(struct uart_port *port, int break_state)
294 {
295 if (break_state) {
296 unsigned long flags;
297 int limit = 10000;
298
299 spin_lock_irqsave(&port->lock, flags);
300
301 while (limit-- > 0) {
302 long status = sun4v_con_putchar(CON_BREAK);
303 if (status == HV_EOK)
304 break;
305 udelay(1);
306 }
307
308 spin_unlock_irqrestore(&port->lock, flags);
309 }
310 }
311
312 /* port->lock is not held. */
313 static int sunhv_startup(struct uart_port *port)
314 {
315 return 0;
316 }
317
318 /* port->lock is not held. */
319 static void sunhv_shutdown(struct uart_port *port)
320 {
321 }
322
323 /* port->lock is not held. */
324 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
325 struct ktermios *old)
326 {
327 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
328 unsigned int quot = uart_get_divisor(port, baud);
329 unsigned int iflag, cflag;
330 unsigned long flags;
331
332 spin_lock_irqsave(&port->lock, flags);
333
334 iflag = termios->c_iflag;
335 cflag = termios->c_cflag;
336
337 port->ignore_status_mask = 0;
338 if (iflag & IGNBRK)
339 port->ignore_status_mask |= IGNORE_BREAK;
340 if ((cflag & CREAD) == 0)
341 port->ignore_status_mask |= IGNORE_ALL;
342
343 /* XXX */
344 uart_update_timeout(port, cflag,
345 (port->uartclk / (16 * quot)));
346
347 spin_unlock_irqrestore(&port->lock, flags);
348 }
349
350 static const char *sunhv_type(struct uart_port *port)
351 {
352 return "SUN4V HCONS";
353 }
354
355 static void sunhv_release_port(struct uart_port *port)
356 {
357 }
358
359 static int sunhv_request_port(struct uart_port *port)
360 {
361 return 0;
362 }
363
364 static void sunhv_config_port(struct uart_port *port, int flags)
365 {
366 }
367
368 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
369 {
370 return -EINVAL;
371 }
372
373 static struct uart_ops sunhv_pops = {
374 .tx_empty = sunhv_tx_empty,
375 .set_mctrl = sunhv_set_mctrl,
376 .get_mctrl = sunhv_get_mctrl,
377 .stop_tx = sunhv_stop_tx,
378 .start_tx = sunhv_start_tx,
379 .send_xchar = sunhv_send_xchar,
380 .stop_rx = sunhv_stop_rx,
381 .enable_ms = sunhv_enable_ms,
382 .break_ctl = sunhv_break_ctl,
383 .startup = sunhv_startup,
384 .shutdown = sunhv_shutdown,
385 .set_termios = sunhv_set_termios,
386 .type = sunhv_type,
387 .release_port = sunhv_release_port,
388 .request_port = sunhv_request_port,
389 .config_port = sunhv_config_port,
390 .verify_port = sunhv_verify_port,
391 };
392
393 static struct uart_driver sunhv_reg = {
394 .owner = THIS_MODULE,
395 .driver_name = "serial",
396 .dev_name = "ttyS",
397 .major = TTY_MAJOR,
398 };
399
400 static struct uart_port *sunhv_port;
401
402 /* Copy 's' into the con_write_page, decoding "\n" into
403 * "\r\n" along the way. We have to return two lengths
404 * because the caller needs to know how much to advance
405 * 's' and also how many bytes to output via con_write_page.
406 */
407 static int fill_con_write_page(const char *s, unsigned int n,
408 unsigned long *page_bytes)
409 {
410 const char *orig_s = s;
411 char *p = con_write_page;
412 int left = PAGE_SIZE;
413
414 while (n--) {
415 if (*s == '\n') {
416 if (left < 2)
417 break;
418 *p++ = '\r';
419 left--;
420 } else if (left < 1)
421 break;
422 *p++ = *s++;
423 left--;
424 }
425 *page_bytes = p - con_write_page;
426 return s - orig_s;
427 }
428
429 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
430 {
431 struct uart_port *port = sunhv_port;
432 unsigned long flags;
433 int locked = 1;
434
435 local_irq_save(flags);
436 if (port->sysrq) {
437 locked = 0;
438 } else if (oops_in_progress) {
439 locked = spin_trylock(&port->lock);
440 } else
441 spin_lock(&port->lock);
442
443 while (n > 0) {
444 unsigned long ra = __pa(con_write_page);
445 unsigned long page_bytes;
446 unsigned int cpy = fill_con_write_page(s, n,
447 &page_bytes);
448
449 n -= cpy;
450 s += cpy;
451 while (page_bytes > 0) {
452 unsigned long written;
453 int limit = 1000000;
454
455 while (limit--) {
456 unsigned long stat;
457
458 stat = sun4v_con_write(ra, page_bytes,
459 &written);
460 if (stat == HV_EOK)
461 break;
462 udelay(1);
463 }
464 if (limit <= 0)
465 break;
466 page_bytes -= written;
467 ra += written;
468 }
469 }
470
471 if (locked)
472 spin_unlock(&port->lock);
473 local_irq_restore(flags);
474 }
475
476 static inline void sunhv_console_putchar(struct uart_port *port, char c)
477 {
478 int limit = 1000000;
479
480 while (limit-- > 0) {
481 long status = sun4v_con_putchar(c);
482 if (status == HV_EOK)
483 break;
484 udelay(1);
485 }
486 }
487
488 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
489 {
490 struct uart_port *port = sunhv_port;
491 unsigned long flags;
492 int i, locked = 1;
493
494 local_irq_save(flags);
495 if (port->sysrq) {
496 locked = 0;
497 } else if (oops_in_progress) {
498 locked = spin_trylock(&port->lock);
499 } else
500 spin_lock(&port->lock);
501
502 spin_lock_irqsave(&port->lock, flags);
503 for (i = 0; i < n; i++) {
504 if (*s == '\n')
505 sunhv_console_putchar(port, '\r');
506 sunhv_console_putchar(port, *s++);
507 }
508
509 if (locked)
510 spin_unlock(&port->lock);
511 local_irq_restore(flags);
512 }
513
514 static struct console sunhv_console = {
515 .name = "ttyHV",
516 .write = sunhv_console_write_bychar,
517 .device = uart_console_device,
518 .flags = CON_PRINTBUFFER,
519 .index = -1,
520 .data = &sunhv_reg,
521 };
522
523 static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match)
524 {
525 struct uart_port *port;
526 unsigned long minor;
527 int err;
528
529 if (op->irqs[0] == 0xffffffff)
530 return -ENODEV;
531
532 port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
533 if (unlikely(!port))
534 return -ENOMEM;
535
536 minor = 1;
537 if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
538 minor >= 1) {
539 err = -ENOMEM;
540 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
541 if (!con_write_page)
542 goto out_free_port;
543
544 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
545 if (!con_read_page)
546 goto out_free_con_write_page;
547
548 sunhv_console.write = sunhv_console_write_paged;
549 sunhv_ops = &bywrite_ops;
550 }
551
552 sunhv_port = port;
553
554 port->line = 0;
555 port->ops = &sunhv_pops;
556 port->type = PORT_SUNHV;
557 port->uartclk = ( 29491200 / 16 ); /* arbitrary */
558
559 port->membase = (unsigned char __iomem *) __pa(port);
560
561 port->irq = op->irqs[0];
562
563 port->dev = &op->dev;
564
565 err = sunserial_register_minors(&sunhv_reg, 1);
566 if (err)
567 goto out_free_con_read_page;
568
569 sunserial_console_match(&sunhv_console, op->node,
570 &sunhv_reg, port->line);
571
572 err = uart_add_one_port(&sunhv_reg, port);
573 if (err)
574 goto out_unregister_driver;
575
576 err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
577 if (err)
578 goto out_remove_port;
579
580 dev_set_drvdata(&op->dev, port);
581
582 return 0;
583
584 out_remove_port:
585 uart_remove_one_port(&sunhv_reg, port);
586
587 out_unregister_driver:
588 sunserial_unregister_minors(&sunhv_reg, 1);
589
590 out_free_con_read_page:
591 kfree(con_read_page);
592
593 out_free_con_write_page:
594 kfree(con_write_page);
595
596 out_free_port:
597 kfree(port);
598 sunhv_port = NULL;
599 return err;
600 }
601
602 static int __devexit hv_remove(struct of_device *dev)
603 {
604 struct uart_port *port = dev_get_drvdata(&dev->dev);
605
606 free_irq(port->irq, port);
607
608 uart_remove_one_port(&sunhv_reg, port);
609
610 sunserial_unregister_minors(&sunhv_reg, 1);
611
612 kfree(port);
613 sunhv_port = NULL;
614
615 dev_set_drvdata(&dev->dev, NULL);
616
617 return 0;
618 }
619
620 static struct of_device_id hv_match[] = {
621 {
622 .name = "console",
623 .compatible = "qcn",
624 },
625 {
626 .name = "console",
627 .compatible = "SUNW,sun4v-console",
628 },
629 {},
630 };
631 MODULE_DEVICE_TABLE(of, hv_match);
632
633 static struct of_platform_driver hv_driver = {
634 .name = "hv",
635 .match_table = hv_match,
636 .probe = hv_probe,
637 .remove = __devexit_p(hv_remove),
638 };
639
640 static int __init sunhv_init(void)
641 {
642 if (tlb_type != hypervisor)
643 return -ENODEV;
644
645 return of_register_driver(&hv_driver, &of_bus_type);
646 }
647
648 static void __exit sunhv_exit(void)
649 {
650 of_unregister_driver(&hv_driver);
651 }
652
653 module_init(sunhv_init);
654 module_exit(sunhv_exit);
655
656 MODULE_AUTHOR("David S. Miller");
657 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
658 MODULE_VERSION("2.0");
659 MODULE_LICENSE("GPL");
660
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