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Merge tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / drivers / tty / serial / sunhv.c
blobeafada8fb6fad8755104ffa4fdc7cb40c8cc1d6e
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_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 #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 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
51 port->icount.tx++;
52 }
53 }
54
55 static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
56 {
57 while (!uart_circ_empty(xmit)) {
58 unsigned long ra = __pa(xmit->buf + xmit->tail);
59 unsigned long len, status, sent;
60
61 len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
62 UART_XMIT_SIZE);
63 status = sun4v_con_write(ra, len, &sent);
64 if (status != HV_EOK)
65 break;
66 xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1);
67 port->icount.tx += sent;
68 }
69 }
70
71 static int receive_chars_getchar(struct uart_port *port)
72 {
73 int saw_console_brk = 0;
74 int limit = 10000;
75
76 while (limit-- > 0) {
77 long status;
78 long c = sun4v_con_getchar(&status);
79
80 if (status == HV_EWOULDBLOCK)
81 break;
82
83 if (c == CON_BREAK) {
84 if (uart_handle_break(port))
85 continue;
86 saw_console_brk = 1;
87 c = 0;
88 }
89
90 if (c == CON_HUP) {
91 hung_up = 1;
92 uart_handle_dcd_change(port, 0);
93 } else if (hung_up) {
94 hung_up = 0;
95 uart_handle_dcd_change(port, 1);
96 }
97
98 if (port->state == NULL) {
99 uart_handle_sysrq_char(port, c);
100 continue;
101 }
102
103 port->icount.rx++;
104
105 if (uart_handle_sysrq_char(port, c))
106 continue;
107
108 tty_insert_flip_char(&port->state->port, c, TTY_NORMAL);
109 }
110
111 return saw_console_brk;
112 }
113
114 static int receive_chars_read(struct uart_port *port)
115 {
116 static int saw_console_brk;
117 int limit = 10000;
118
119 while (limit-- > 0) {
120 unsigned long ra = __pa(con_read_page);
121 unsigned long bytes_read, i;
122 long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);
123
124 if (stat != HV_EOK) {
125 bytes_read = 0;
126
127 if (stat == CON_BREAK) {
128 if (saw_console_brk)
129 sun_do_break();
130
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 saw_console_brk = 0;
155 }
156
157 if (port->state == NULL)
158 continue;
159
160 port->icount.rx += bytes_read;
161
162 tty_insert_flip_string(&port->state->port, con_read_page,
163 bytes_read);
164 }
165
166 return saw_console_brk;
167 }
168
169 struct sunhv_ops {
170 void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
171 int (*receive_chars)(struct uart_port *port);
172 };
173
174 static const struct sunhv_ops bychar_ops = {
175 .transmit_chars = transmit_chars_putchar,
176 .receive_chars = receive_chars_getchar,
177 };
178
179 static const struct sunhv_ops bywrite_ops = {
180 .transmit_chars = transmit_chars_write,
181 .receive_chars = receive_chars_read,
182 };
183
184 static const struct sunhv_ops *sunhv_ops = &bychar_ops;
185
186 static struct tty_port *receive_chars(struct uart_port *port)
187 {
188 struct tty_port *tport = NULL;
189
190 if (port->state != NULL) /* Unopened serial console */
191 tport = &port->state->port;
192
193 if (sunhv_ops->receive_chars(port))
194 sun_do_break();
195
196 return tport;
197 }
198
199 static void transmit_chars(struct uart_port *port)
200 {
201 struct circ_buf *xmit;
202
203 if (!port->state)
204 return;
205
206 xmit = &port->state->xmit;
207 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
208 return;
209
210 sunhv_ops->transmit_chars(port, xmit);
211
212 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
213 uart_write_wakeup(port);
214 }
215
216 static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
217 {
218 struct uart_port *port = dev_id;
219 struct tty_port *tport;
220 unsigned long flags;
221
222 spin_lock_irqsave(&port->lock, flags);
223 tport = receive_chars(port);
224 transmit_chars(port);
225 spin_unlock_irqrestore(&port->lock, flags);
226
227 if (tport)
228 tty_flip_buffer_push(tport);
229
230 return IRQ_HANDLED;
231 }
232
233 /* port->lock is not held. */
234 static unsigned int sunhv_tx_empty(struct uart_port *port)
235 {
236 /* Transmitter is always empty for us. If the circ buffer
237 * is non-empty or there is an x_char pending, our caller
238 * will do the right thing and ignore what we return here.
239 */
240 return TIOCSER_TEMT;
241 }
242
243 /* port->lock held by caller. */
244 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
245 {
246 return;
247 }
248
249 /* port->lock is held by caller and interrupts are disabled. */
250 static unsigned int sunhv_get_mctrl(struct uart_port *port)
251 {
252 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
253 }
254
255 /* port->lock held by caller. */
256 static void sunhv_stop_tx(struct uart_port *port)
257 {
258 return;
259 }
260
261 /* port->lock held by caller. */
262 static void sunhv_start_tx(struct uart_port *port)
263 {
264 transmit_chars(port);
265 }
266
267 /* port->lock is not held. */
268 static void sunhv_send_xchar(struct uart_port *port, char ch)
269 {
270 unsigned long flags;
271 int limit = 10000;
272
273 if (ch == __DISABLED_CHAR)
274 return;
275
276 spin_lock_irqsave(&port->lock, flags);
277
278 while (limit-- > 0) {
279 long status = sun4v_con_putchar(ch);
280 if (status == HV_EOK)
281 break;
282 udelay(1);
283 }
284
285 spin_unlock_irqrestore(&port->lock, flags);
286 }
287
288 /* port->lock held by caller. */
289 static void sunhv_stop_rx(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 const 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 .break_ctl = sunhv_break_ctl,
383 .startup = sunhv_startup,
384 .shutdown = sunhv_shutdown,
385 .set_termios = sunhv_set_termios,
386 .type = sunhv_type,
387 .release_port = sunhv_release_port,
388 .request_port = sunhv_request_port,
389 .config_port = sunhv_config_port,
390 .verify_port = sunhv_verify_port,
391 };
392
393 static struct uart_driver sunhv_reg = {
394 .owner = THIS_MODULE,
395 .driver_name = "sunhv",
396 .dev_name = "ttyHV",
397 .major = TTY_MAJOR,
398 };
399
400 static struct uart_port *sunhv_port;
401
402 void sunhv_migrate_hvcons_irq(int cpu)
403 {
404 /* Migrate hvcons irq to param cpu */
405 irq_force_affinity(sunhv_port->irq, cpumask_of(cpu));
406 }
407
408 /* Copy 's' into the con_write_page, decoding "\n" into
409 * "\r\n" along the way. We have to return two lengths
410 * because the caller needs to know how much to advance
411 * 's' and also how many bytes to output via con_write_page.
412 */
413 static int fill_con_write_page(const char *s, unsigned int n,
414 unsigned long *page_bytes)
415 {
416 const char *orig_s = s;
417 char *p = con_write_page;
418 int left = PAGE_SIZE;
419
420 while (n--) {
421 if (*s == '\n') {
422 if (left < 2)
423 break;
424 *p++ = '\r';
425 left--;
426 } else if (left < 1)
427 break;
428 *p++ = *s++;
429 left--;
430 }
431 *page_bytes = p - con_write_page;
432 return s - orig_s;
433 }
434
435 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
436 {
437 struct uart_port *port = sunhv_port;
438 unsigned long flags;
439 int locked = 1;
440
441 if (port->sysrq || oops_in_progress)
442 locked = spin_trylock_irqsave(&port->lock, flags);
443 else
444 spin_lock_irqsave(&port->lock, flags);
445
446 while (n > 0) {
447 unsigned long ra = __pa(con_write_page);
448 unsigned long page_bytes;
449 unsigned int cpy = fill_con_write_page(s, n,
450 &page_bytes);
451
452 n -= cpy;
453 s += cpy;
454 while (page_bytes > 0) {
455 unsigned long written;
456 int limit = 1000000;
457
458 while (limit--) {
459 unsigned long stat;
460
461 stat = sun4v_con_write(ra, page_bytes,
462 &written);
463 if (stat == HV_EOK)
464 break;
465 udelay(1);
466 }
467 if (limit < 0)
468 break;
469 page_bytes -= written;
470 ra += written;
471 }
472 }
473
474 if (locked)
475 spin_unlock_irqrestore(&port->lock, flags);
476 }
477
478 static inline void sunhv_console_putchar(struct uart_port *port, char c)
479 {
480 int limit = 1000000;
481
482 while (limit-- > 0) {
483 long status = sun4v_con_putchar(c);
484 if (status == HV_EOK)
485 break;
486 udelay(1);
487 }
488 }
489
490 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
491 {
492 struct uart_port *port = sunhv_port;
493 unsigned long flags;
494 int i, locked = 1;
495
496 if (port->sysrq || oops_in_progress)
497 locked = spin_trylock_irqsave(&port->lock, flags);
498 else
499 spin_lock_irqsave(&port->lock, flags);
500
501 for (i = 0; i < n; i++) {
502 if (*s == '\n')
503 sunhv_console_putchar(port, '\r');
504 sunhv_console_putchar(port, *s++);
505 }
506
507 if (locked)
508 spin_unlock_irqrestore(&port->lock, flags);
509 }
510
511 static struct console sunhv_console = {
512 .name = "ttyHV",
513 .write = sunhv_console_write_bychar,
514 .device = uart_console_device,
515 .flags = CON_PRINTBUFFER,
516 .index = -1,
517 .data = &sunhv_reg,
518 };
519
520 static int hv_probe(struct platform_device *op)
521 {
522 struct uart_port *port;
523 unsigned long minor;
524 int err;
525
526 if (op->archdata.irqs[0] == 0xffffffff)
527 return -ENODEV;
528
529 port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
530 if (unlikely(!port))
531 return -ENOMEM;
532
533 minor = 1;
534 if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
535 minor >= 1) {
536 err = -ENOMEM;
537 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
538 if (!con_write_page)
539 goto out_free_port;
540
541 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
542 if (!con_read_page)
543 goto out_free_con_write_page;
544
545 sunhv_console.write = sunhv_console_write_paged;
546 sunhv_ops = &bywrite_ops;
547 }
548
549 sunhv_port = port;
550
551 port->has_sysrq = 1;
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 kfree(con_read_page);
610 kfree(con_write_page);
611 kfree(port);
612 sunhv_port = NULL;
613
614 return 0;
615 }
616
617 static const struct of_device_id hv_match[] = {
618 {
619 .name = "console",
620 .compatible = "qcn",
621 },
622 {
623 .name = "console",
624 .compatible = "SUNW,sun4v-console",
625 },
626 {},
627 };
628
629 static struct platform_driver hv_driver = {
630 .driver = {
631 .name = "hv",
632 .of_match_table = hv_match,
633 },
634 .probe = hv_probe,
635 .remove = hv_remove,
636 };
637
638 static int __init sunhv_init(void)
639 {
640 if (tlb_type != hypervisor)
641 return -ENODEV;
642
643 return platform_driver_register(&hv_driver);
644 }
645 device_initcall(sunhv_init);
646
647 #if 0 /* ...def MODULE ; never supported as such */
648 MODULE_AUTHOR("David S. Miller");
649 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
650 MODULE_VERSION("2.0");
651 MODULE_LICENSE("GPL");
652 #endif
Linux with added FPC-III support