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 uart_xmit_advance(port, 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(port, 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(port, 0); 91 } else if (hung_up) { 92 hung_up = 0; 93 uart_handle_dcd_change(port, 1); 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 } 111 112 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, 0); 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, 1); 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; 183 184 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 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. */ 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 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. */ 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, 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 } 348 349 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(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 = 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 } 475 476 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 = 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 }; 517 518 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 } 597 598 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 }; 635 636 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