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 | |
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(up: port, chars: 1); |
51 | } |
52 | } |
53 | |
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(up: port, chars: sent); |
66 | } |
67 | } |
68 | |
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(uport: port, active: false); |
91 | } else if (hung_up) { |
92 | hung_up = 0; |
93 | uart_handle_dcd_change(uport: port, active: true); |
94 | } |
95 | |
96 | if (port->state == NULL) { |
97 | uart_handle_sysrq_char(port, ch: c); |
98 | continue; |
99 | } |
100 | |
101 | port->icount.rx++; |
102 | |
103 | if (uart_handle_sysrq_char(port, ch: c)) |
104 | continue; |
105 | |
106 | tty_insert_flip_char(port: &port->state->port, ch: c, TTY_NORMAL); |
107 | } |
108 | |
109 | return saw_console_brk; |
110 | } |
111 | |
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(uport: port, active: 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(uport: port, active: 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, ch: 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: &port->state->port, chars: con_read_page, |
161 | size: 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 | |
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 | uart_port_lock_irqsave(up: port, flags: &flags); |
221 | tport = receive_chars(port); |
222 | transmit_chars(port); |
223 | uart_port_unlock_irqrestore(up: port, flags); |
224 | |
225 | if (tport) |
226 | tty_flip_buffer_push(port: 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 | uart_port_lock_irqsave(up: port, flags: &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 | uart_port_unlock_irqrestore(up: port, 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 | uart_port_lock_irqsave(up: port, flags: &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 | uart_port_unlock_irqrestore(up: port, 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 | const struct ktermios *old) |
325 | { |
326 | unsigned int baud = uart_get_baud_rate(port, termios, old, min: 0, max: 4000000); |
327 | unsigned int quot = uart_get_divisor(port, baud); |
328 | unsigned int iflag, cflag; |
329 | unsigned long flags; |
330 | |
331 | uart_port_lock_irqsave(up: port, flags: &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 | baud: (port->uartclk / (16 * quot))); |
345 | |
346 | uart_port_unlock_irqrestore(up: port, 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 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 | |
400 | void sunhv_migrate_hvcons_irq(int cpu) |
401 | { |
402 | /* Migrate hvcons irq to param cpu */ |
403 | irq_force_affinity(irq: 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 | */ |
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 | |
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 = uart_port_trylock_irqsave(up: port, flags: &flags); |
441 | else |
442 | uart_port_lock_irqsave(up: port, flags: &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: &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 | uart_port_unlock_irqrestore(up: port, 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 | if (port->sysrq || oops_in_progress) |
495 | locked = uart_port_trylock_irqsave(up: port, flags: &flags); |
496 | else |
497 | uart_port_lock_irqsave(up: port, flags: &flags); |
498 | |
499 | for (i = 0; i < n; i++) { |
500 | if (*s == '\n') |
501 | sunhv_console_putchar(port, c: '\r'); |
502 | sunhv_console_putchar(port, c: *s++); |
503 | } |
504 | |
505 | if (locked) |
506 | uart_port_unlock_irqrestore(up: port, 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(size: 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(reg: &sunhv_reg, port); |
569 | if (err) |
570 | goto out_unregister_driver; |
571 | |
572 | err = request_irq(irq: port->irq, handler: sunhv_interrupt, flags: 0, name: "hvcons" , dev: port); |
573 | if (err) |
574 | goto out_remove_port; |
575 | |
576 | platform_set_drvdata(pdev: op, data: port); |
577 | |
578 | return 0; |
579 | |
580 | out_remove_port: |
581 | uart_remove_one_port(reg: &sunhv_reg, port); |
582 | |
583 | out_unregister_driver: |
584 | sunserial_unregister_minors(&sunhv_reg, 1); |
585 | |
586 | out_free_con_read_page: |
587 | kfree(objp: con_read_page); |
588 | |
589 | out_free_con_write_page: |
590 | kfree(objp: con_write_page); |
591 | |
592 | out_free_port: |
593 | kfree(objp: 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(pdev: dev); |
601 | |
602 | free_irq(port->irq, port); |
603 | |
604 | uart_remove_one_port(reg: &sunhv_reg, port); |
605 | |
606 | sunserial_unregister_minors(&sunhv_reg, 1); |
607 | kfree(objp: con_read_page); |
608 | kfree(objp: con_write_page); |
609 | kfree(objp: 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 | |
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 | |