Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6.git] / drivers / serial / sunhv.c
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
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->state != NULL)                /* Unopened serial console */
188                 tty = port->state->port.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->state)
201                 return;
202
203         xmit = &port->state->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            = "sunhv",
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         for (i = 0; i < n; i++) {
503                 if (*s == '\n')
504                         sunhv_console_putchar(port, '\r');
505                 sunhv_console_putchar(port, *s++);
506         }
507
508         if (locked)
509                 spin_unlock(&port->lock);
510         local_irq_restore(flags);
511 }
512
513 static struct console sunhv_console = {
514         .name   =       "ttyHV",
515         .write  =       sunhv_console_write_bychar,
516         .device =       uart_console_device,
517         .flags  =       CON_PRINTBUFFER,
518         .index  =       -1,
519         .data   =       &sunhv_reg,
520 };
521
522 static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match)
523 {
524         struct uart_port *port;
525         unsigned long minor;
526         int err;
527
528         if (op->irqs[0] == 0xffffffff)
529                 return -ENODEV;
530
531         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
532         if (unlikely(!port))
533                 return -ENOMEM;
534
535         minor = 1;
536         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
537             minor >= 1) {
538                 err = -ENOMEM;
539                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
540                 if (!con_write_page)
541                         goto out_free_port;
542
543                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
544                 if (!con_read_page)
545                         goto out_free_con_write_page;
546
547                 sunhv_console.write = sunhv_console_write_paged;
548                 sunhv_ops = &bywrite_ops;
549         }
550
551         sunhv_port = port;
552
553         port->line = 0;
554         port->ops = &sunhv_pops;
555         port->type = PORT_SUNHV;
556         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
557
558         port->membase = (unsigned char __iomem *) __pa(port);
559
560         port->irq = op->irqs[0];
561
562         port->dev = &op->dev;
563
564         err = sunserial_register_minors(&sunhv_reg, 1);
565         if (err)
566                 goto out_free_con_read_page;
567
568         sunserial_console_match(&sunhv_console, op->node,
569                                 &sunhv_reg, port->line);
570
571         err = uart_add_one_port(&sunhv_reg, port);
572         if (err)
573                 goto out_unregister_driver;
574
575         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
576         if (err)
577                 goto out_remove_port;
578
579         dev_set_drvdata(&op->dev, port);
580
581         return 0;
582
583 out_remove_port:
584         uart_remove_one_port(&sunhv_reg, port);
585
586 out_unregister_driver:
587         sunserial_unregister_minors(&sunhv_reg, 1);
588
589 out_free_con_read_page:
590         kfree(con_read_page);
591
592 out_free_con_write_page:
593         kfree(con_write_page);
594
595 out_free_port:
596         kfree(port);
597         sunhv_port = NULL;
598         return err;
599 }
600
601 static int __devexit hv_remove(struct of_device *dev)
602 {
603         struct uart_port *port = dev_get_drvdata(&dev->dev);
604
605         free_irq(port->irq, port);
606
607         uart_remove_one_port(&sunhv_reg, port);
608
609         sunserial_unregister_minors(&sunhv_reg, 1);
610
611         kfree(port);
612         sunhv_port = NULL;
613
614         dev_set_drvdata(&dev->dev, NULL);
615
616         return 0;
617 }
618
619 static const struct of_device_id hv_match[] = {
620         {
621                 .name = "console",
622                 .compatible = "qcn",
623         },
624         {
625                 .name = "console",
626                 .compatible = "SUNW,sun4v-console",
627         },
628         {},
629 };
630 MODULE_DEVICE_TABLE(of, hv_match);
631
632 static struct of_platform_driver hv_driver = {
633         .name           = "hv",
634         .match_table    = hv_match,
635         .probe          = hv_probe,
636         .remove         = __devexit_p(hv_remove),
637 };
638
639 static int __init sunhv_init(void)
640 {
641         if (tlb_type != hypervisor)
642                 return -ENODEV;
643
644         return of_register_driver(&hv_driver, &of_bus_type);
645 }
646
647 static void __exit sunhv_exit(void)
648 {
649         of_unregister_driver(&hv_driver);
650 }
651
652 module_init(sunhv_init);
653 module_exit(sunhv_exit);
654
655 MODULE_AUTHOR("David S. Miller");
656 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
657 MODULE_VERSION("2.0");
658 MODULE_LICENSE("GPL");