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, 43 struct tty_port *tport) 44 { 45 unsigned char ch; 46 47 while (kfifo_peek(&tport->xmit_fifo, &ch)) { 48 long status = sun4v_con_putchar(ch); 49 50 if (status != HV_EOK) 51 break; 52 53 uart_xmit_advance(port, 1); 54 } 55 } 56 57 static void transmit_chars_write(struct uart_port *port, struct tty_port *tport) 58 { 59 while (!kfifo_is_empty(&tport->xmit_fifo)) { 60 unsigned long len, ra, status, sent; 61 unsigned char *tail; 62 63 len = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, 64 UART_XMIT_SIZE); 65 ra = __pa(tail); 66 67 status = sun4v_con_write(ra, len, &sent); 68 if (status != HV_EOK) 69 break; 70 uart_xmit_advance(port, sent); 71 } 72 } 73 74 static int receive_chars_getchar(struct uart_port *port) 75 { 76 int saw_console_brk = 0; 77 int limit = 10000; 78 79 while (limit-- > 0) { 80 long status; 81 long c = sun4v_con_getchar(&status); 82 83 if (status == HV_EWOULDBLOCK) 84 break; 85 86 if (c == CON_BREAK) { 87 if (uart_handle_break(port)) 88 continue; 89 saw_console_brk = 1; 90 c = 0; 91 } 92 93 if (c == CON_HUP) { 94 hung_up = 1; 95 uart_handle_dcd_change(port, false); 96 } else if (hung_up) { 97 hung_up = 0; 98 uart_handle_dcd_change(port, true); 99 } 100 101 if (port->state == NULL) { 102 uart_handle_sysrq_char(port, c); 103 continue; 104 } 105 106 port->icount.rx++; 107 108 if (uart_handle_sysrq_char(port, c)) 109 continue; 110 111 tty_insert_flip_char(&port->state->port, c, TTY_NORMAL); 112 } 113 114 return saw_console_brk; 115 } 116 117 static int receive_chars_read(struct uart_port *port) 118 { 119 static int saw_console_brk; 120 int limit = 10000; 121 122 while (limit-- > 0) { 123 unsigned long ra = __pa(con_read_page); 124 unsigned long bytes_read, i; 125 long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read); 126 127 if (stat != HV_EOK) { 128 bytes_read = 0; 129 130 if (stat == CON_BREAK) { 131 if (saw_console_brk) 132 sun_do_break(); 133 134 if (uart_handle_break(port)) 135 continue; 136 saw_console_brk = 1; 137 *con_read_page = 0; 138 bytes_read = 1; 139 } else if (stat == CON_HUP) { 140 hung_up = 1; 141 uart_handle_dcd_change(port, false); 142 continue; 143 } else { 144 /* HV_EWOULDBLOCK, etc. */ 145 break; 146 } 147 } 148 149 if (hung_up) { 150 hung_up = 0; 151 uart_handle_dcd_change(port, true); 152 } 153 154 if (port->sysrq != 0 && *con_read_page) { 155 for (i = 0; i < bytes_read; i++) 156 uart_handle_sysrq_char(port, con_read_page[i]); 157 saw_console_brk = 0; 158 } 159 160 if (port->state == NULL) 161 continue; 162 163 port->icount.rx += bytes_read; 164 165 tty_insert_flip_string(&port->state->port, con_read_page, 166 bytes_read); 167 } 168 169 return saw_console_brk; 170 } 171 172 struct sunhv_ops { 173 void (*transmit_chars)(struct uart_port *port, struct tty_port *tport); 174 int (*receive_chars)(struct uart_port *port); 175 }; 176 177 static const struct sunhv_ops bychar_ops = { 178 .transmit_chars = transmit_chars_putchar, 179 .receive_chars = receive_chars_getchar, 180 }; 181 182 static const struct sunhv_ops bywrite_ops = { 183 .transmit_chars = transmit_chars_write, 184 .receive_chars = receive_chars_read, 185 }; 186 187 static const struct sunhv_ops *sunhv_ops = &bychar_ops; 188 189 static struct tty_port *receive_chars(struct uart_port *port) 190 { 191 struct tty_port *tport = NULL; 192 193 if (port->state != NULL) /* Unopened serial console */ 194 tport = &port->state->port; 195 196 if (sunhv_ops->receive_chars(port)) 197 sun_do_break(); 198 199 return tport; 200 } 201 202 static void transmit_chars(struct uart_port *port) 203 { 204 struct tty_port *tport; 205 206 if (!port->state) 207 return; 208 209 tport = &port->state->port; 210 if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) 211 return; 212 213 sunhv_ops->transmit_chars(port, tport); 214 215 if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) 216 uart_write_wakeup(port); 217 } 218 219 static irqreturn_t sunhv_interrupt(int irq, void *dev_id) 220 { 221 struct uart_port *port = dev_id; 222 struct tty_port *tport; 223 unsigned long flags; 224 225 uart_port_lock_irqsave(port, &flags); 226 tport = receive_chars(port); 227 transmit_chars(port); 228 uart_port_unlock_irqrestore(port, flags); 229 230 if (tport) 231 tty_flip_buffer_push(tport); 232 233 return IRQ_HANDLED; 234 } 235 236 /* port->lock is not held. */ 237 static unsigned int sunhv_tx_empty(struct uart_port *port) 238 { 239 /* Transmitter is always empty for us. If the circ buffer 240 * is non-empty or there is an x_char pending, our caller 241 * will do the right thing and ignore what we return here. 242 */ 243 return TIOCSER_TEMT; 244 } 245 246 /* port->lock held by caller. */ 247 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl) 248 { 249 return; 250 } 251 252 /* port->lock is held by caller and interrupts are disabled. */ 253 static unsigned int sunhv_get_mctrl(struct uart_port *port) 254 { 255 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS; 256 } 257 258 /* port->lock held by caller. */ 259 static void sunhv_stop_tx(struct uart_port *port) 260 { 261 return; 262 } 263 264 /* port->lock held by caller. */ 265 static void sunhv_start_tx(struct uart_port *port) 266 { 267 transmit_chars(port); 268 } 269 270 /* port->lock is not held. */ 271 static void sunhv_send_xchar(struct uart_port *port, char ch) 272 { 273 unsigned long flags; 274 int limit = 10000; 275 276 if (ch == __DISABLED_CHAR) 277 return; 278 279 uart_port_lock_irqsave(port, &flags); 280 281 while (limit-- > 0) { 282 long status = sun4v_con_putchar(ch); 283 if (status == HV_EOK) 284 break; 285 udelay(1); 286 } 287 288 uart_port_unlock_irqrestore(port, flags); 289 } 290 291 /* port->lock held by caller. */ 292 static void sunhv_stop_rx(struct uart_port *port) 293 { 294 } 295 296 /* port->lock is not held. */ 297 static void sunhv_break_ctl(struct uart_port *port, int break_state) 298 { 299 if (break_state) { 300 unsigned long flags; 301 int limit = 10000; 302 303 uart_port_lock_irqsave(port, &flags); 304 305 while (limit-- > 0) { 306 long status = sun4v_con_putchar(CON_BREAK); 307 if (status == HV_EOK) 308 break; 309 udelay(1); 310 } 311 312 uart_port_unlock_irqrestore(port, flags); 313 } 314 } 315 316 /* port->lock is not held. */ 317 static int sunhv_startup(struct uart_port *port) 318 { 319 return 0; 320 } 321 322 /* port->lock is not held. */ 323 static void sunhv_shutdown(struct uart_port *port) 324 { 325 } 326 327 /* port->lock is not held. */ 328 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios, 329 const struct ktermios *old) 330 { 331 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000); 332 unsigned int quot = uart_get_divisor(port, baud); 333 unsigned int iflag, cflag; 334 unsigned long flags; 335 336 uart_port_lock_irqsave(port, &flags); 337 338 iflag = termios->c_iflag; 339 cflag = termios->c_cflag; 340 341 port->ignore_status_mask = 0; 342 if (iflag & IGNBRK) 343 port->ignore_status_mask |= IGNORE_BREAK; 344 if ((cflag & CREAD) == 0) 345 port->ignore_status_mask |= IGNORE_ALL; 346 347 /* XXX */ 348 uart_update_timeout(port, cflag, 349 (port->uartclk / (16 * quot))); 350 351 uart_port_unlock_irqrestore(port, flags); 352 } 353 354 static const char *sunhv_type(struct uart_port *port) 355 { 356 return "SUN4V HCONS"; 357 } 358 359 static void sunhv_release_port(struct uart_port *port) 360 { 361 } 362 363 static int sunhv_request_port(struct uart_port *port) 364 { 365 return 0; 366 } 367 368 static void sunhv_config_port(struct uart_port *port, int flags) 369 { 370 } 371 372 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser) 373 { 374 return -EINVAL; 375 } 376 377 static const struct uart_ops sunhv_pops = { 378 .tx_empty = sunhv_tx_empty, 379 .set_mctrl = sunhv_set_mctrl, 380 .get_mctrl = sunhv_get_mctrl, 381 .stop_tx = sunhv_stop_tx, 382 .start_tx = sunhv_start_tx, 383 .send_xchar = sunhv_send_xchar, 384 .stop_rx = sunhv_stop_rx, 385 .break_ctl = sunhv_break_ctl, 386 .startup = sunhv_startup, 387 .shutdown = sunhv_shutdown, 388 .set_termios = sunhv_set_termios, 389 .type = sunhv_type, 390 .release_port = sunhv_release_port, 391 .request_port = sunhv_request_port, 392 .config_port = sunhv_config_port, 393 .verify_port = sunhv_verify_port, 394 }; 395 396 static struct uart_driver sunhv_reg = { 397 .owner = THIS_MODULE, 398 .driver_name = "sunhv", 399 .dev_name = "ttyHV", 400 .major = TTY_MAJOR, 401 }; 402 403 static struct uart_port *sunhv_port; 404 405 void sunhv_migrate_hvcons_irq(int cpu) 406 { 407 /* Migrate hvcons irq to param cpu */ 408 irq_force_affinity(sunhv_port->irq, cpumask_of(cpu)); 409 } 410 411 /* Copy 's' into the con_write_page, decoding "\n" into 412 * "\r\n" along the way. We have to return two lengths 413 * because the caller needs to know how much to advance 414 * 's' and also how many bytes to output via con_write_page. 415 */ 416 static int fill_con_write_page(const char *s, unsigned int n, 417 unsigned long *page_bytes) 418 { 419 const char *orig_s = s; 420 char *p = con_write_page; 421 int left = PAGE_SIZE; 422 423 while (n--) { 424 if (*s == '\n') { 425 if (left < 2) 426 break; 427 *p++ = '\r'; 428 left--; 429 } else if (left < 1) 430 break; 431 *p++ = *s++; 432 left--; 433 } 434 *page_bytes = p - con_write_page; 435 return s - orig_s; 436 } 437 438 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n) 439 { 440 struct uart_port *port = sunhv_port; 441 unsigned long flags; 442 int locked = 1; 443 444 if (port->sysrq || oops_in_progress) 445 locked = uart_port_trylock_irqsave(port, &flags); 446 else 447 uart_port_lock_irqsave(port, &flags); 448 449 while (n > 0) { 450 unsigned long ra = __pa(con_write_page); 451 unsigned long page_bytes; 452 unsigned int cpy = fill_con_write_page(s, n, 453 &page_bytes); 454 455 n -= cpy; 456 s += cpy; 457 while (page_bytes > 0) { 458 unsigned long written; 459 int limit = 1000000; 460 461 while (limit--) { 462 unsigned long stat; 463 464 stat = sun4v_con_write(ra, page_bytes, 465 &written); 466 if (stat == HV_EOK) 467 break; 468 udelay(1); 469 } 470 if (limit < 0) 471 break; 472 page_bytes -= written; 473 ra += written; 474 } 475 } 476 477 if (locked) 478 uart_port_unlock_irqrestore(port, flags); 479 } 480 481 static inline void sunhv_console_putchar(struct uart_port *port, char c) 482 { 483 int limit = 1000000; 484 485 while (limit-- > 0) { 486 long status = sun4v_con_putchar(c); 487 if (status == HV_EOK) 488 break; 489 udelay(1); 490 } 491 } 492 493 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n) 494 { 495 struct uart_port *port = sunhv_port; 496 unsigned long flags; 497 int i, locked = 1; 498 499 if (port->sysrq || oops_in_progress) 500 locked = uart_port_trylock_irqsave(port, &flags); 501 else 502 uart_port_lock_irqsave(port, &flags); 503 504 for (i = 0; i < n; i++) { 505 if (*s == '\n') 506 sunhv_console_putchar(port, '\r'); 507 sunhv_console_putchar(port, *s++); 508 } 509 510 if (locked) 511 uart_port_unlock_irqrestore(port, flags); 512 } 513 514 static struct console sunhv_console = { 515 .name = "ttyHV", 516 .write = sunhv_console_write_bychar, 517 .device = uart_console_device, 518 .flags = CON_PRINTBUFFER, 519 .index = -1, 520 .data = &sunhv_reg, 521 }; 522 523 static int hv_probe(struct platform_device *op) 524 { 525 struct uart_port *port; 526 unsigned long minor; 527 int err; 528 529 if (op->archdata.irqs[0] == 0xffffffff) 530 return -ENODEV; 531 532 port = kzalloc(sizeof(struct uart_port), GFP_KERNEL); 533 if (unlikely(!port)) 534 return -ENOMEM; 535 536 minor = 1; 537 if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 && 538 minor >= 1) { 539 err = -ENOMEM; 540 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 541 if (!con_write_page) 542 goto out_free_port; 543 544 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 545 if (!con_read_page) 546 goto out_free_con_write_page; 547 548 sunhv_console.write = sunhv_console_write_paged; 549 sunhv_ops = &bywrite_ops; 550 } 551 552 sunhv_port = port; 553 554 port->has_sysrq = 1; 555 port->line = 0; 556 port->ops = &sunhv_pops; 557 port->type = PORT_SUNHV; 558 port->uartclk = ( 29491200 / 16 ); /* arbitrary */ 559 560 port->membase = (unsigned char __iomem *) __pa(port); 561 562 port->irq = op->archdata.irqs[0]; 563 564 port->dev = &op->dev; 565 566 err = sunserial_register_minors(&sunhv_reg, 1); 567 if (err) 568 goto out_free_con_read_page; 569 570 sunserial_console_match(&sunhv_console, op->dev.of_node, 571 &sunhv_reg, port->line, false); 572 573 err = uart_add_one_port(&sunhv_reg, port); 574 if (err) 575 goto out_unregister_driver; 576 577 err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port); 578 if (err) 579 goto out_remove_port; 580 581 platform_set_drvdata(op, port); 582 583 return 0; 584 585 out_remove_port: 586 uart_remove_one_port(&sunhv_reg, port); 587 588 out_unregister_driver: 589 sunserial_unregister_minors(&sunhv_reg, 1); 590 591 out_free_con_read_page: 592 kfree(con_read_page); 593 594 out_free_con_write_page: 595 kfree(con_write_page); 596 597 out_free_port: 598 kfree(port); 599 sunhv_port = NULL; 600 return err; 601 } 602 603 static void hv_remove(struct platform_device *dev) 604 { 605 struct uart_port *port = platform_get_drvdata(dev); 606 607 free_irq(port->irq, port); 608 609 uart_remove_one_port(&sunhv_reg, port); 610 611 sunserial_unregister_minors(&sunhv_reg, 1); 612 kfree(con_read_page); 613 kfree(con_write_page); 614 kfree(port); 615 sunhv_port = NULL; 616 } 617 618 static const struct of_device_id hv_match[] = { 619 { 620 .name = "console", 621 .compatible = "qcn", 622 }, 623 { 624 .name = "console", 625 .compatible = "SUNW,sun4v-console", 626 }, 627 {}, 628 }; 629 630 static struct platform_driver hv_driver = { 631 .driver = { 632 .name = "hv", 633 .of_match_table = hv_match, 634 }, 635 .probe = hv_probe, 636 .remove_new = 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 device_initcall(sunhv_init); 647 648 #if 0 /* ...def MODULE ; never supported as such */ 649 MODULE_AUTHOR("David S. Miller"); 650 MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); 651 MODULE_VERSION("2.0"); 652 MODULE_LICENSE("GPL"); 653 #endif 654