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Linux 3.11-rc3
[cris-mirror.git] / drivers / tty / serial / sunhv.c
blobcf86e729532b9fc11b768863c94bfb9fe1da7109
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 #include <linux/of_device.h>
21
22 #include <asm/hypervisor.h>
23 #include <asm/spitfire.h>
24 #include <asm/prom.h>
25 #include <asm/irq.h>
26 #include <asm/setup.h>
27
28 #if defined(CONFIG_MAGIC_SYSRQ)
29 #define SUPPORT_SYSRQ
30 #endif
31
32 #include <linux/serial_core.h>
33 #include <linux/sunserialcore.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)
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 (port->state == 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(&port->state->port, c, TTY_NORMAL);
113 }
114
115 return saw_console_brk;
116 }
117
118 static int receive_chars_read(struct uart_port *port)
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 (port->state == NULL)
156 continue;
157
158 port->icount.rx += bytes_read;
159
160 tty_insert_flip_string(&port->state->port, con_read_page,
161 bytes_read);
162 }
163
164 return saw_console_brk;
165 }
166
167 struct sunhv_ops {
168 void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
169 int (*receive_chars)(struct uart_port *port);
170 };
171
172 static struct sunhv_ops bychar_ops = {
173 .transmit_chars = transmit_chars_putchar,
174 .receive_chars = receive_chars_getchar,
175 };
176
177 static struct sunhv_ops bywrite_ops = {
178 .transmit_chars = transmit_chars_write,
179 .receive_chars = receive_chars_read,
180 };
181
182 static struct sunhv_ops *sunhv_ops = &bychar_ops;
183
184 static struct tty_port *receive_chars(struct uart_port *port)
185 {
186 struct tty_port *tport = NULL;
187
188 if (port->state != NULL) /* Unopened serial console */
189 tport = &port->state->port;
190
191 if (sunhv_ops->receive_chars(port))
192 sun_do_break();
193
194 return tport;
195 }
196
197 static void transmit_chars(struct uart_port *port)
198 {
199 struct circ_buf *xmit;
200
201 if (!port->state)
202 return;
203
204 xmit = &port->state->xmit;
205 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
206 return;
207
208 sunhv_ops->transmit_chars(port, xmit);
209
210 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
211 uart_write_wakeup(port);
212 }
213
214 static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
215 {
216 struct uart_port *port = dev_id;
217 struct tty_port *tport;
218 unsigned long flags;
219
220 spin_lock_irqsave(&port->lock, flags);
221 tport = receive_chars(port);
222 transmit_chars(port);
223 spin_unlock_irqrestore(&port->lock, flags);
224
225 if (tport)
226 tty_flip_buffer_push(tport);
227
228 return IRQ_HANDLED;
229 }
230
231 /* port->lock is not held. */
232 static unsigned int sunhv_tx_empty(struct uart_port *port)
233 {
234 /* Transmitter is always empty for us. If the circ buffer
235 * is non-empty or there is an x_char pending, our caller
236 * will do the right thing and ignore what we return here.
237 */
238 return TIOCSER_TEMT;
239 }
240
241 /* port->lock held by caller. */
242 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
243 {
244 return;
245 }
246
247 /* port->lock is held by caller and interrupts are disabled. */
248 static unsigned int sunhv_get_mctrl(struct uart_port *port)
249 {
250 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
251 }
252
253 /* port->lock held by caller. */
254 static void sunhv_stop_tx(struct uart_port *port)
255 {
256 return;
257 }
258
259 /* port->lock held by caller. */
260 static void sunhv_start_tx(struct uart_port *port)
261 {
262 transmit_chars(port);
263 }
264
265 /* port->lock is not held. */
266 static void sunhv_send_xchar(struct uart_port *port, char ch)
267 {
268 unsigned long flags;
269 int limit = 10000;
270
271 spin_lock_irqsave(&port->lock, flags);
272
273 while (limit-- > 0) {
274 long status = sun4v_con_putchar(ch);
275 if (status == HV_EOK)
276 break;
277 udelay(1);
278 }
279
280 spin_unlock_irqrestore(&port->lock, flags);
281 }
282
283 /* port->lock held by caller. */
284 static void sunhv_stop_rx(struct uart_port *port)
285 {
286 }
287
288 /* port->lock held by caller. */
289 static void sunhv_enable_ms(struct uart_port *port)
290 {
291 }
292
293 /* port->lock is not held. */
294 static void sunhv_break_ctl(struct uart_port *port, int break_state)
295 {
296 if (break_state) {
297 unsigned long flags;
298 int limit = 10000;
299
300 spin_lock_irqsave(&port->lock, flags);
301
302 while (limit-- > 0) {
303 long status = sun4v_con_putchar(CON_BREAK);
304 if (status == HV_EOK)
305 break;
306 udelay(1);
307 }
308
309 spin_unlock_irqrestore(&port->lock, flags);
310 }
311 }
312
313 /* port->lock is not held. */
314 static int sunhv_startup(struct uart_port *port)
315 {
316 return 0;
317 }
318
319 /* port->lock is not held. */
320 static void sunhv_shutdown(struct uart_port *port)
321 {
322 }
323
324 /* port->lock is not held. */
325 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
326 struct ktermios *old)
327 {
328 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
329 unsigned int quot = uart_get_divisor(port, baud);
330 unsigned int iflag, cflag;
331 unsigned long flags;
332
333 spin_lock_irqsave(&port->lock, flags);
334
335 iflag = termios->c_iflag;
336 cflag = termios->c_cflag;
337
338 port->ignore_status_mask = 0;
339 if (iflag & IGNBRK)
340 port->ignore_status_mask |= IGNORE_BREAK;
341 if ((cflag & CREAD) == 0)
342 port->ignore_status_mask |= IGNORE_ALL;
343
344 /* XXX */
345 uart_update_timeout(port, cflag,
346 (port->uartclk / (16 * quot)));
347
348 spin_unlock_irqrestore(&port->lock, flags);
349 }
350
351 static const char *sunhv_type(struct uart_port *port)
352 {
353 return "SUN4V HCONS";
354 }
355
356 static void sunhv_release_port(struct uart_port *port)
357 {
358 }
359
360 static int sunhv_request_port(struct uart_port *port)
361 {
362 return 0;
363 }
364
365 static void sunhv_config_port(struct uart_port *port, int flags)
366 {
367 }
368
369 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
370 {
371 return -EINVAL;
372 }
373
374 static struct uart_ops sunhv_pops = {
375 .tx_empty = sunhv_tx_empty,
376 .set_mctrl = sunhv_set_mctrl,
377 .get_mctrl = sunhv_get_mctrl,
378 .stop_tx = sunhv_stop_tx,
379 .start_tx = sunhv_start_tx,
380 .send_xchar = sunhv_send_xchar,
381 .stop_rx = sunhv_stop_rx,
382 .enable_ms = sunhv_enable_ms,
383 .break_ctl = sunhv_break_ctl,
384 .startup = sunhv_startup,
385 .shutdown = sunhv_shutdown,
386 .set_termios = sunhv_set_termios,
387 .type = sunhv_type,
388 .release_port = sunhv_release_port,
389 .request_port = sunhv_request_port,
390 .config_port = sunhv_config_port,
391 .verify_port = sunhv_verify_port,
392 };
393
394 static struct uart_driver sunhv_reg = {
395 .owner = THIS_MODULE,
396 .driver_name = "sunhv",
397 .dev_name = "ttyS",
398 .major = TTY_MAJOR,
399 };
400
401 static struct uart_port *sunhv_port;
402
403 /* Copy 's' into the con_write_page, decoding "\n" into
404 * "\r\n" along the way. We have to return two lengths
405 * because the caller needs to know how much to advance
406 * 's' and also how many bytes to output via con_write_page.
407 */
408 static int fill_con_write_page(const char *s, unsigned int n,
409 unsigned long *page_bytes)
410 {
411 const char *orig_s = s;
412 char *p = con_write_page;
413 int left = PAGE_SIZE;
414
415 while (n--) {
416 if (*s == '\n') {
417 if (left < 2)
418 break;
419 *p++ = '\r';
420 left--;
421 } else if (left < 1)
422 break;
423 *p++ = *s++;
424 left--;
425 }
426 *page_bytes = p - con_write_page;
427 return s - orig_s;
428 }
429
430 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
431 {
432 struct uart_port *port = sunhv_port;
433 unsigned long flags;
434 int locked = 1;
435
436 local_irq_save(flags);
437 if (port->sysrq) {
438 locked = 0;
439 } else if (oops_in_progress) {
440 locked = spin_trylock(&port->lock);
441 } else
442 spin_lock(&port->lock);
443
444 while (n > 0) {
445 unsigned long ra = __pa(con_write_page);
446 unsigned long page_bytes;
447 unsigned int cpy = fill_con_write_page(s, n,
448 &page_bytes);
449
450 n -= cpy;
451 s += cpy;
452 while (page_bytes > 0) {
453 unsigned long written;
454 int limit = 1000000;
455
456 while (limit--) {
457 unsigned long stat;
458
459 stat = sun4v_con_write(ra, page_bytes,
460 &written);
461 if (stat == HV_EOK)
462 break;
463 udelay(1);
464 }
465 if (limit < 0)
466 break;
467 page_bytes -= written;
468 ra += written;
469 }
470 }
471
472 if (locked)
473 spin_unlock(&port->lock);
474 local_irq_restore(flags);
475 }
476
477 static inline void sunhv_console_putchar(struct uart_port *port, char c)
478 {
479 int limit = 1000000;
480
481 while (limit-- > 0) {
482 long status = sun4v_con_putchar(c);
483 if (status == HV_EOK)
484 break;
485 udelay(1);
486 }
487 }
488
489 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
490 {
491 struct uart_port *port = sunhv_port;
492 unsigned long flags;
493 int i, locked = 1;
494
495 local_irq_save(flags);
496 if (port->sysrq) {
497 locked = 0;
498 } else if (oops_in_progress) {
499 locked = spin_trylock(&port->lock);
500 } else
501 spin_lock(&port->lock);
502
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 hv_probe(struct platform_device *op)
524 {
525 struct uart_port *port;
526 unsigned long minor;
527 int err;
528
529 if (op->archdata.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->archdata.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->dev.of_node,
570 &sunhv_reg, port->line, false);
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 platform_set_drvdata(op, 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 hv_remove(struct platform_device *dev)
603 {
604 struct uart_port *port = platform_get_drvdata(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 return 0;
616 }
617
618 static const struct of_device_id hv_match[] = {
619 {
620 .name = "console",
621 .compatible = "qcn",
622 },
623 {
624 .name = "console",
625 .compatible = "SUNW,sun4v-console",
626 },
627 {},
628 };
629 MODULE_DEVICE_TABLE(of, hv_match);
630
631 static struct platform_driver hv_driver = {
632 .driver = {
633 .name = "hv",
634 .owner = THIS_MODULE,
635 .of_match_table = hv_match,
636 },
637 .probe = hv_probe,
638 .remove = hv_remove,
639 };
640
641 static int __init sunhv_init(void)
642 {
643 if (tlb_type != hypervisor)
644 return -ENODEV;
645
646 return platform_driver_register(&hv_driver);
647 }
648
649 static void __exit sunhv_exit(void)
650 {
651 platform_driver_unregister(&hv_driver);
652 }
653
654 module_init(sunhv_init);
655 module_exit(sunhv_exit);
656
657 MODULE_AUTHOR("David S. Miller");
658 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
659 MODULE_VERSION("2.0");
660 MODULE_LICENSE("GPL");
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