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 653