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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         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         if (port->sysrq || oops_in_progress)
437                 locked = spin_trylock_irqsave(&port->lock, flags);
438         else
439                 spin_lock_irqsave(&port->lock, flags);
440 
441         while (n > 0) {
442                 unsigned long ra = __pa(con_write_page);
443                 unsigned long page_bytes;
444                 unsigned int cpy = fill_con_write_page(s, n,
445                                                        &page_bytes);
446 
447                 n -= cpy;
448                 s += cpy;
449                 while (page_bytes > 0) {
450                         unsigned long written;
451                         int limit = 1000000;
452 
453                         while (limit--) {
454                                 unsigned long stat;
455 
456                                 stat = sun4v_con_write(ra, page_bytes,
457                                                        &written);
458                                 if (stat == HV_EOK)
459                                         break;
460                                 udelay(1);
461                         }
462                         if (limit < 0)
463                                 break;
464                         page_bytes -= written;
465                         ra += written;
466                 }
467         }
468 
469         if (locked)
470                 spin_unlock_irqrestore(&port->lock, flags);
471 }
472 
473 static inline void sunhv_console_putchar(struct uart_port *port, char c)
474 {
475         int limit = 1000000;
476 
477         while (limit-- > 0) {
478                 long status = sun4v_con_putchar(c);
479                 if (status == HV_EOK)
480                         break;
481                 udelay(1);
482         }
483 }
484 
485 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
486 {
487         struct uart_port *port = sunhv_port;
488         unsigned long flags;
489         int i, locked = 1;
490 
491         if (port->sysrq || oops_in_progress)
492                 locked = spin_trylock_irqsave(&port->lock, flags);
493         else
494                 spin_lock_irqsave(&port->lock, 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_irqrestore(&port->lock, flags);
510 }
511 
512 static struct console sunhv_console = {
513         .name   =       "ttyHV",
514         .write  =       sunhv_console_write_bychar,
515         .device =       uart_console_device,
516         .flags  =       CON_PRINTBUFFER,
517         .index  =       -1,
518         .data   =       &sunhv_reg,
519 };
520 
521 static int hv_probe(struct platform_device *op)
522 {
523         struct uart_port *port;
524         unsigned long minor;
525         int err;
526 
527         if (op->archdata.irqs[0] == 0xffffffff)
528                 return -ENODEV;
529 
530         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
531         if (unlikely(!port))
532                 return -ENOMEM;
533 
534         minor = 1;
535         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
536             minor >= 1) {
537                 err = -ENOMEM;
538                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
539                 if (!con_write_page)
540                         goto out_free_port;
541 
542                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
543                 if (!con_read_page)
544                         goto out_free_con_write_page;
545 
546                 sunhv_console.write = sunhv_console_write_paged;
547                 sunhv_ops = &bywrite_ops;
548         }
549 
550         sunhv_port = port;
551 
552         port->line = 0;
553         port->ops = &sunhv_pops;
554         port->type = PORT_SUNHV;
555         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
556 
557         port->membase = (unsigned char __iomem *) __pa(port);
558 
559         port->irq = op->archdata.irqs[0];
560 
561         port->dev = &op->dev;
562 
563         err = sunserial_register_minors(&sunhv_reg, 1);
564         if (err)
565                 goto out_free_con_read_page;
566 
567         sunserial_console_match(&sunhv_console, op->dev.of_node,
568                                 &sunhv_reg, port->line, false);
569 
570         err = uart_add_one_port(&sunhv_reg, port);
571         if (err)
572                 goto out_unregister_driver;
573 
574         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
575         if (err)
576                 goto out_remove_port;
577 
578         platform_set_drvdata(op, port);
579 
580         return 0;
581 
582 out_remove_port:
583         uart_remove_one_port(&sunhv_reg, port);
584 
585 out_unregister_driver:
586         sunserial_unregister_minors(&sunhv_reg, 1);
587 
588 out_free_con_read_page:
589         kfree(con_read_page);
590 
591 out_free_con_write_page:
592         kfree(con_write_page);
593 
594 out_free_port:
595         kfree(port);
596         sunhv_port = NULL;
597         return err;
598 }
599 
600 static int hv_remove(struct platform_device *dev)
601 {
602         struct uart_port *port = platform_get_drvdata(dev);
603 
604         free_irq(port->irq, port);
605 
606         uart_remove_one_port(&sunhv_reg, port);
607 
608         sunserial_unregister_minors(&sunhv_reg, 1);
609 
610         kfree(port);
611         sunhv_port = NULL;
612 
613         return 0;
614 }
615 
616 static const struct of_device_id hv_match[] = {
617         {
618                 .name = "console",
619                 .compatible = "qcn",
620         },
621         {
622                 .name = "console",
623                 .compatible = "SUNW,sun4v-console",
624         },
625         {},
626 };
627 MODULE_DEVICE_TABLE(of, hv_match);
628 
629 static struct platform_driver hv_driver = {
630         .driver = {
631                 .name = "hv",
632                 .owner = THIS_MODULE,
633                 .of_match_table = hv_match,
634         },
635         .probe          = hv_probe,
636         .remove         = hv_remove,
637 };
638 
639 static int __init sunhv_init(void)
640 {
641         if (tlb_type != hypervisor)
642                 return -ENODEV;
643 
644         return platform_driver_register(&hv_driver);
645 }
646 
647 static void __exit sunhv_exit(void)
648 {
649         platform_driver_unregister(&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");
659 

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