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

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