1 // SPDX-License-Identifier: GPL-2.0
2 /* sunhv.c: Serial driver for SUN4V hypervisor console.
3 *
4 * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
5 */
6
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.h>
21 #include <linux/platform_device.h>
22
23 #include <asm/hypervisor.h>
24 #include <asm/spitfire.h>
25 #include <asm/irq.h>
26 #include <asm/setup.h>
27
28 #include <linux/serial_core.h>
29 #include <linux/sunserialcore.h>
30
31 #define CON_BREAK ((long)-1)
32 #define CON_HUP ((long)-2)
33
34 #define IGNORE_BREAK 0x1
35 #define IGNORE_ALL 0x2
36
37 static char *con_write_page;
38 static char *con_read_page;
39
40 static int hung_up = 0;
41
transmit_chars_putchar(struct uart_port * port,struct circ_buf * xmit)42 static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit)
43 {
44 while (!uart_circ_empty(xmit)) {
45 long status = sun4v_con_putchar(xmit->buf[xmit->tail]);
46
47 if (status != HV_EOK)
48 break;
49
50 uart_xmit_advance(port, 1);
51 }
52 }
53
transmit_chars_write(struct uart_port * port,struct circ_buf * xmit)54 static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
55 {
56 while (!uart_circ_empty(xmit)) {
57 unsigned long ra = __pa(xmit->buf + xmit->tail);
58 unsigned long len, status, sent;
59
60 len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
61 UART_XMIT_SIZE);
62 status = sun4v_con_write(ra, len, &sent);
63 if (status != HV_EOK)
64 break;
65 uart_xmit_advance(port, sent);
66 }
67 }
68
receive_chars_getchar(struct uart_port * port)69 static int receive_chars_getchar(struct uart_port *port)
70 {
71 int saw_console_brk = 0;
72 int limit = 10000;
73
74 while (limit-- > 0) {
75 long status;
76 long c = sun4v_con_getchar(&status);
77
78 if (status == HV_EWOULDBLOCK)
79 break;
80
81 if (c == CON_BREAK) {
82 if (uart_handle_break(port))
83 continue;
84 saw_console_brk = 1;
85 c = 0;
86 }
87
88 if (c == CON_HUP) {
89 hung_up = 1;
90 uart_handle_dcd_change(port, false);
91 } else if (hung_up) {
92 hung_up = 0;
93 uart_handle_dcd_change(port, true);
94 }
95
96 if (port->state == NULL) {
97 uart_handle_sysrq_char(port, c);
98 continue;
99 }
100
101 port->icount.rx++;
102
103 if (uart_handle_sysrq_char(port, c))
104 continue;
105
106 tty_insert_flip_char(&port->state->port, c, TTY_NORMAL);
107 }
108
109 return saw_console_brk;
110 }
111
receive_chars_read(struct uart_port * port)112 static int receive_chars_read(struct uart_port *port)
113 {
114 static int saw_console_brk;
115 int limit = 10000;
116
117 while (limit-- > 0) {
118 unsigned long ra = __pa(con_read_page);
119 unsigned long bytes_read, i;
120 long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);
121
122 if (stat != HV_EOK) {
123 bytes_read = 0;
124
125 if (stat == CON_BREAK) {
126 if (saw_console_brk)
127 sun_do_break();
128
129 if (uart_handle_break(port))
130 continue;
131 saw_console_brk = 1;
132 *con_read_page = 0;
133 bytes_read = 1;
134 } else if (stat == CON_HUP) {
135 hung_up = 1;
136 uart_handle_dcd_change(port, false);
137 continue;
138 } else {
139 /* HV_EWOULDBLOCK, etc. */
140 break;
141 }
142 }
143
144 if (hung_up) {
145 hung_up = 0;
146 uart_handle_dcd_change(port, true);
147 }
148
149 if (port->sysrq != 0 && *con_read_page) {
150 for (i = 0; i < bytes_read; i++)
151 uart_handle_sysrq_char(port, con_read_page[i]);
152 saw_console_brk = 0;
153 }
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 const struct sunhv_ops bychar_ops = {
173 .transmit_chars = transmit_chars_putchar,
174 .receive_chars = receive_chars_getchar,
175 };
176
177 static const struct sunhv_ops bywrite_ops = {
178 .transmit_chars = transmit_chars_write,
179 .receive_chars = receive_chars_read,
180 };
181
182 static const struct sunhv_ops *sunhv_ops = &bychar_ops;
183
receive_chars(struct uart_port * port)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
transmit_chars(struct uart_port * port)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
sunhv_interrupt(int irq,void * dev_id)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. */
sunhv_tx_empty(struct uart_port * port)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. */
sunhv_set_mctrl(struct uart_port * port,unsigned int mctrl)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. */
sunhv_get_mctrl(struct uart_port * port)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. */
sunhv_stop_tx(struct uart_port * port)254 static void sunhv_stop_tx(struct uart_port *port)
255 {
256 return;
257 }
258
259 /* port->lock held by caller. */
sunhv_start_tx(struct uart_port * port)260 static void sunhv_start_tx(struct uart_port *port)
261 {
262 transmit_chars(port);
263 }
264
265 /* port->lock is not held. */
sunhv_send_xchar(struct uart_port * port,char ch)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. */
sunhv_stop_rx(struct uart_port * port)287 static void sunhv_stop_rx(struct uart_port *port)
288 {
289 }
290
291 /* port->lock is not held. */
sunhv_break_ctl(struct uart_port * port,int break_state)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. */
sunhv_startup(struct uart_port * port)312 static int sunhv_startup(struct uart_port *port)
313 {
314 return 0;
315 }
316
317 /* port->lock is not held. */
sunhv_shutdown(struct uart_port * port)318 static void sunhv_shutdown(struct uart_port *port)
319 {
320 }
321
322 /* port->lock is not held. */
sunhv_set_termios(struct uart_port * port,struct ktermios * termios,const struct ktermios * old)323 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
324 const 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
sunhv_type(struct uart_port * port)349 static const char *sunhv_type(struct uart_port *port)
350 {
351 return "SUN4V HCONS";
352 }
353
sunhv_release_port(struct uart_port * port)354 static void sunhv_release_port(struct uart_port *port)
355 {
356 }
357
sunhv_request_port(struct uart_port * port)358 static int sunhv_request_port(struct uart_port *port)
359 {
360 return 0;
361 }
362
sunhv_config_port(struct uart_port * port,int flags)363 static void sunhv_config_port(struct uart_port *port, int flags)
364 {
365 }
366
sunhv_verify_port(struct uart_port * port,struct serial_struct * ser)367 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
368 {
369 return -EINVAL;
370 }
371
372 static const 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 = "ttyHV",
395 .major = TTY_MAJOR,
396 };
397
398 static struct uart_port *sunhv_port;
399
sunhv_migrate_hvcons_irq(int cpu)400 void sunhv_migrate_hvcons_irq(int cpu)
401 {
402 /* Migrate hvcons irq to param cpu */
403 irq_force_affinity(sunhv_port->irq, cpumask_of(cpu));
404 }
405
406 /* Copy 's' into the con_write_page, decoding "\n" into
407 * "\r\n" along the way. We have to return two lengths
408 * because the caller needs to know how much to advance
409 * 's' and also how many bytes to output via con_write_page.
410 */
fill_con_write_page(const char * s,unsigned int n,unsigned long * page_bytes)411 static int fill_con_write_page(const char *s, unsigned int n,
412 unsigned long *page_bytes)
413 {
414 const char *orig_s = s;
415 char *p = con_write_page;
416 int left = PAGE_SIZE;
417
418 while (n--) {
419 if (*s == '\n') {
420 if (left < 2)
421 break;
422 *p++ = '\r';
423 left--;
424 } else if (left < 1)
425 break;
426 *p++ = *s++;
427 left--;
428 }
429 *page_bytes = p - con_write_page;
430 return s - orig_s;
431 }
432
sunhv_console_write_paged(struct console * con,const char * s,unsigned n)433 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
434 {
435 struct uart_port *port = sunhv_port;
436 unsigned long flags;
437 int locked = 1;
438
439 if (port->sysrq || oops_in_progress)
440 locked = spin_trylock_irqsave(&port->lock, flags);
441 else
442 spin_lock_irqsave(&port->lock, flags);
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_irqrestore(&port->lock, flags);
474 }
475
sunhv_console_putchar(struct uart_port * port,char c)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
sunhv_console_write_bychar(struct console * con,const char * s,unsigned n)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 if (port->sysrq || oops_in_progress)
495 locked = spin_trylock_irqsave(&port->lock, flags);
496 else
497 spin_lock_irqsave(&port->lock, flags);
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
hv_probe(struct platform_device * op)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->has_sysrq = 1;
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
hv_remove(struct platform_device * dev)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 kfree(con_read_page);
608 kfree(con_write_page);
609 kfree(port);
610 sunhv_port = NULL;
611
612 return 0;
613 }
614
615 static const struct of_device_id hv_match[] = {
616 {
617 .name = "console",
618 .compatible = "qcn",
619 },
620 {
621 .name = "console",
622 .compatible = "SUNW,sun4v-console",
623 },
624 {},
625 };
626
627 static struct platform_driver hv_driver = {
628 .driver = {
629 .name = "hv",
630 .of_match_table = hv_match,
631 },
632 .probe = hv_probe,
633 .remove = hv_remove,
634 };
635
sunhv_init(void)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 device_initcall(sunhv_init);
644
645 #if 0 /* ...def MODULE ; never supported as such */
646 MODULE_AUTHOR("David S. Miller");
647 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
648 MODULE_VERSION("2.0");
649 MODULE_LICENSE("GPL");
650 #endif
651