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Linux/drivers/tty/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 #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         if (ch == __DISABLED_CHAR)
272                 return;
273 
274         spin_lock_irqsave(&port->lock, flags);
275 
276         while (limit-- > 0) {
277                 long status = sun4v_con_putchar(ch);
278                 if (status == HV_EOK)
279                         break;
280                 udelay(1);
281         }
282 
283         spin_unlock_irqrestore(&port->lock, flags);
284 }
285 
286 /* port->lock held by caller.  */
287 static void sunhv_stop_rx(struct uart_port *port)
288 {
289 }
290 
291 /* port->lock is not held.  */
292 static void sunhv_break_ctl(struct uart_port *port, int break_state)
293 {
294         if (break_state) {
295                 unsigned long flags;
296                 int limit = 10000;
297 
298                 spin_lock_irqsave(&port->lock, flags);
299 
300                 while (limit-- > 0) {
301                         long status = sun4v_con_putchar(CON_BREAK);
302                         if (status == HV_EOK)
303                                 break;
304                         udelay(1);
305                 }
306 
307                 spin_unlock_irqrestore(&port->lock, flags);
308         }
309 }
310 
311 /* port->lock is not held.  */
312 static int sunhv_startup(struct uart_port *port)
313 {
314         return 0;
315 }
316 
317 /* port->lock is not held.  */
318 static void sunhv_shutdown(struct uart_port *port)
319 {
320 }
321 
322 /* port->lock is not held.  */
323 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
324                               struct ktermios *old)
325 {
326         unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
327         unsigned int quot = uart_get_divisor(port, baud);
328         unsigned int iflag, cflag;
329         unsigned long flags;
330 
331         spin_lock_irqsave(&port->lock, flags);
332 
333         iflag = termios->c_iflag;
334         cflag = termios->c_cflag;
335 
336         port->ignore_status_mask = 0;
337         if (iflag & IGNBRK)
338                 port->ignore_status_mask |= IGNORE_BREAK;
339         if ((cflag & CREAD) == 0)
340                 port->ignore_status_mask |= IGNORE_ALL;
341 
342         /* XXX */
343         uart_update_timeout(port, cflag,
344                             (port->uartclk / (16 * quot)));
345 
346         spin_unlock_irqrestore(&port->lock, flags);
347 }
348 
349 static const char *sunhv_type(struct uart_port *port)
350 {
351         return "SUN4V HCONS";
352 }
353 
354 static void sunhv_release_port(struct uart_port *port)
355 {
356 }
357 
358 static int sunhv_request_port(struct uart_port *port)
359 {
360         return 0;
361 }
362 
363 static void sunhv_config_port(struct uart_port *port, int flags)
364 {
365 }
366 
367 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
368 {
369         return -EINVAL;
370 }
371 
372 static struct uart_ops sunhv_pops = {
373         .tx_empty       = sunhv_tx_empty,
374         .set_mctrl      = sunhv_set_mctrl,
375         .get_mctrl      = sunhv_get_mctrl,
376         .stop_tx        = sunhv_stop_tx,
377         .start_tx       = sunhv_start_tx,
378         .send_xchar     = sunhv_send_xchar,
379         .stop_rx        = sunhv_stop_rx,
380         .break_ctl      = sunhv_break_ctl,
381         .startup        = sunhv_startup,
382         .shutdown       = sunhv_shutdown,
383         .set_termios    = sunhv_set_termios,
384         .type           = sunhv_type,
385         .release_port   = sunhv_release_port,
386         .request_port   = sunhv_request_port,
387         .config_port    = sunhv_config_port,
388         .verify_port    = sunhv_verify_port,
389 };
390 
391 static struct uart_driver sunhv_reg = {
392         .owner                  = THIS_MODULE,
393         .driver_name            = "sunhv",
394         .dev_name               = "ttyS",
395         .major                  = TTY_MAJOR,
396 };
397 
398 static struct uart_port *sunhv_port;
399 
400 /* Copy 's' into the con_write_page, decoding "\n" into
401  * "\r\n" along the way.  We have to return two lengths
402  * because the caller needs to know how much to advance
403  * 's' and also how many bytes to output via con_write_page.
404  */
405 static int fill_con_write_page(const char *s, unsigned int n,
406                                unsigned long *page_bytes)
407 {
408         const char *orig_s = s;
409         char *p = con_write_page;
410         int left = PAGE_SIZE;
411 
412         while (n--) {
413                 if (*s == '\n') {
414                         if (left < 2)
415                                 break;
416                         *p++ = '\r';
417                         left--;
418                 } else if (left < 1)
419                         break;
420                 *p++ = *s++;
421                 left--;
422         }
423         *page_bytes = p - con_write_page;
424         return s - orig_s;
425 }
426 
427 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
428 {
429         struct uart_port *port = sunhv_port;
430         unsigned long flags;
431         int locked = 1;
432 
433         if (port->sysrq || oops_in_progress)
434                 locked = spin_trylock_irqsave(&port->lock, flags);
435         else
436                 spin_lock_irqsave(&port->lock, flags);
437 
438         while (n > 0) {
439                 unsigned long ra = __pa(con_write_page);
440                 unsigned long page_bytes;
441                 unsigned int cpy = fill_con_write_page(s, n,
442                                                        &page_bytes);
443 
444                 n -= cpy;
445                 s += cpy;
446                 while (page_bytes > 0) {
447                         unsigned long written;
448                         int limit = 1000000;
449 
450                         while (limit--) {
451                                 unsigned long stat;
452 
453                                 stat = sun4v_con_write(ra, page_bytes,
454                                                        &written);
455                                 if (stat == HV_EOK)
456                                         break;
457                                 udelay(1);
458                         }
459                         if (limit < 0)
460                                 break;
461                         page_bytes -= written;
462                         ra += written;
463                 }
464         }
465 
466         if (locked)
467                 spin_unlock_irqrestore(&port->lock, flags);
468 }
469 
470 static inline void sunhv_console_putchar(struct uart_port *port, char c)
471 {
472         int limit = 1000000;
473 
474         while (limit-- > 0) {
475                 long status = sun4v_con_putchar(c);
476                 if (status == HV_EOK)
477                         break;
478                 udelay(1);
479         }
480 }
481 
482 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
483 {
484         struct uart_port *port = sunhv_port;
485         unsigned long flags;
486         int i, locked = 1;
487 
488         if (port->sysrq || oops_in_progress)
489                 locked = spin_trylock_irqsave(&port->lock, flags);
490         else
491                 spin_lock_irqsave(&port->lock, flags);
492         if (port->sysrq) {
493                 locked = 0;
494         } else if (oops_in_progress) {
495                 locked = spin_trylock(&port->lock);
496         } else
497                 spin_lock(&port->lock);
498 
499         for (i = 0; i < n; i++) {
500                 if (*s == '\n')
501                         sunhv_console_putchar(port, '\r');
502                 sunhv_console_putchar(port, *s++);
503         }
504 
505         if (locked)
506                 spin_unlock_irqrestore(&port->lock, flags);
507 }
508 
509 static struct console sunhv_console = {
510         .name   =       "ttyHV",
511         .write  =       sunhv_console_write_bychar,
512         .device =       uart_console_device,
513         .flags  =       CON_PRINTBUFFER,
514         .index  =       -1,
515         .data   =       &sunhv_reg,
516 };
517 
518 static int hv_probe(struct platform_device *op)
519 {
520         struct uart_port *port;
521         unsigned long minor;
522         int err;
523 
524         if (op->archdata.irqs[0] == 0xffffffff)
525                 return -ENODEV;
526 
527         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
528         if (unlikely(!port))
529                 return -ENOMEM;
530 
531         minor = 1;
532         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
533             minor >= 1) {
534                 err = -ENOMEM;
535                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
536                 if (!con_write_page)
537                         goto out_free_port;
538 
539                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
540                 if (!con_read_page)
541                         goto out_free_con_write_page;
542 
543                 sunhv_console.write = sunhv_console_write_paged;
544                 sunhv_ops = &bywrite_ops;
545         }
546 
547         sunhv_port = port;
548 
549         port->line = 0;
550         port->ops = &sunhv_pops;
551         port->type = PORT_SUNHV;
552         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
553 
554         port->membase = (unsigned char __iomem *) __pa(port);
555 
556         port->irq = op->archdata.irqs[0];
557 
558         port->dev = &op->dev;
559 
560         err = sunserial_register_minors(&sunhv_reg, 1);
561         if (err)
562                 goto out_free_con_read_page;
563 
564         sunserial_console_match(&sunhv_console, op->dev.of_node,
565                                 &sunhv_reg, port->line, false);
566 
567         err = uart_add_one_port(&sunhv_reg, port);
568         if (err)
569                 goto out_unregister_driver;
570 
571         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
572         if (err)
573                 goto out_remove_port;
574 
575         platform_set_drvdata(op, port);
576 
577         return 0;
578 
579 out_remove_port:
580         uart_remove_one_port(&sunhv_reg, port);
581 
582 out_unregister_driver:
583         sunserial_unregister_minors(&sunhv_reg, 1);
584 
585 out_free_con_read_page:
586         kfree(con_read_page);
587 
588 out_free_con_write_page:
589         kfree(con_write_page);
590 
591 out_free_port:
592         kfree(port);
593         sunhv_port = NULL;
594         return err;
595 }
596 
597 static int hv_remove(struct platform_device *dev)
598 {
599         struct uart_port *port = platform_get_drvdata(dev);
600 
601         free_irq(port->irq, port);
602 
603         uart_remove_one_port(&sunhv_reg, port);
604 
605         sunserial_unregister_minors(&sunhv_reg, 1);
606 
607         kfree(port);
608         sunhv_port = NULL;
609 
610         return 0;
611 }
612 
613 static const struct of_device_id hv_match[] = {
614         {
615                 .name = "console",
616                 .compatible = "qcn",
617         },
618         {
619                 .name = "console",
620                 .compatible = "SUNW,sun4v-console",
621         },
622         {},
623 };
624 MODULE_DEVICE_TABLE(of, hv_match);
625 
626 static struct platform_driver hv_driver = {
627         .driver = {
628                 .name = "hv",
629                 .owner = THIS_MODULE,
630                 .of_match_table = hv_match,
631         },
632         .probe          = hv_probe,
633         .remove         = hv_remove,
634 };
635 
636 static int __init sunhv_init(void)
637 {
638         if (tlb_type != hypervisor)
639                 return -ENODEV;
640 
641         return platform_driver_register(&hv_driver);
642 }
643 
644 static void __exit sunhv_exit(void)
645 {
646         platform_driver_unregister(&hv_driver);
647 }
648 
649 module_init(sunhv_init);
650 module_exit(sunhv_exit);
651 
652 MODULE_AUTHOR("David S. Miller");
653 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
654 MODULE_VERSION("2.0");
655 MODULE_LICENSE("GPL");
656 

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