1 /* sunhv.c: Serial driver for SUN4V hypervisor console. 2 * 3 * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net) 4 */ 5 6 #include <linux/module.h> 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 #if defined(CONFIG_MAGIC_SYSRQ) 29 #define SUPPORT_SYSRQ 30 #endif 31 32 #include <linux/serial_core.h> 33 #include <linux/sunserialcore.h> 34 35 #define CON_BREAK ((long)-1) 36 #define CON_HUP ((long)-2) 37 38 #define IGNORE_BREAK 0x1 39 #define IGNORE_ALL 0x2 40 41 static char *con_write_page; 42 static char *con_read_page; 43 44 static int hung_up = 0; 45 46 static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit) 47 { 48 while (!uart_circ_empty(xmit)) { 49 long status = sun4v_con_putchar(xmit->buf[xmit->tail]); 50 51 if (status != HV_EOK) 52 break; 53 54 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 55 port->icount.tx++; 56 } 57 } 58 59 static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit) 60 { 61 while (!uart_circ_empty(xmit)) { 62 unsigned long ra = __pa(xmit->buf + xmit->tail); 63 unsigned long len, status, sent; 64 65 len = CIRC_CNT_TO_END(xmit->head, xmit->tail, 66 UART_XMIT_SIZE); 67 status = sun4v_con_write(ra, len, &sent); 68 if (status != HV_EOK) 69 break; 70 xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1); 71 port->icount.tx += sent; 72 } 73 } 74 75 static int receive_chars_getchar(struct uart_port *port) 76 { 77 int saw_console_brk = 0; 78 int limit = 10000; 79 80 while (limit-- > 0) { 81 long status; 82 long c = sun4v_con_getchar(&status); 83 84 if (status == HV_EWOULDBLOCK) 85 break; 86 87 if (c == CON_BREAK) { 88 if (uart_handle_break(port)) 89 continue; 90 saw_console_brk = 1; 91 c = 0; 92 } 93 94 if (c == CON_HUP) { 95 hung_up = 1; 96 uart_handle_dcd_change(port, 0); 97 } else if (hung_up) { 98 hung_up = 0; 99 uart_handle_dcd_change(port, 1); 100 } 101 102 if (port->state == NULL) { 103 uart_handle_sysrq_char(port, c); 104 continue; 105 } 106 107 port->icount.rx++; 108 109 if (uart_handle_sysrq_char(port, c)) 110 continue; 111 112 tty_insert_flip_char(&port->state->port, c, TTY_NORMAL); 113 } 114 115 return saw_console_brk; 116 } 117 118 static int receive_chars_read(struct uart_port *port) 119 { 120 int saw_console_brk = 0; 121 int limit = 10000; 122 123 while (limit-- > 0) { 124 unsigned long ra = __pa(con_read_page); 125 unsigned long bytes_read, i; 126 long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read); 127 128 if (stat != HV_EOK) { 129 bytes_read = 0; 130 131 if (stat == CON_BREAK) { 132 if (uart_handle_break(port)) 133 continue; 134 saw_console_brk = 1; 135 *con_read_page = 0; 136 bytes_read = 1; 137 } else if (stat == CON_HUP) { 138 hung_up = 1; 139 uart_handle_dcd_change(port, 0); 140 continue; 141 } else { 142 /* HV_EWOULDBLOCK, etc. */ 143 break; 144 } 145 } 146 147 if (hung_up) { 148 hung_up = 0; 149 uart_handle_dcd_change(port, 1); 150 } 151 152 for (i = 0; i < bytes_read; i++) 153 uart_handle_sysrq_char(port, con_read_page[i]); 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 struct sunhv_ops bychar_ops = { 173 .transmit_chars = transmit_chars_putchar, 174 .receive_chars = receive_chars_getchar, 175 }; 176 177 static struct sunhv_ops bywrite_ops = { 178 .transmit_chars = transmit_chars_write, 179 .receive_chars = receive_chars_read, 180 }; 181 182 static 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 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 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 = "ttyS", 395 .major = TTY_MAJOR, 396 }; 397 398 static struct uart_port *sunhv_port; 399 400 /* Copy 's' into the con_write_page, decoding "\n" into 401 * "\r\n" along the way. We have to return two lengths 402 * because the caller needs to know how much to advance 403 * 's' and also how many bytes to output via con_write_page. 404 */ 405 static int fill_con_write_page(const char *s, unsigned int n, 406 unsigned long *page_bytes) 407 { 408 const char *orig_s = s; 409 char *p = con_write_page; 410 int left = PAGE_SIZE; 411 412 while (n--) { 413 if (*s == '\n') { 414 if (left < 2) 415 break; 416 *p++ = '\r'; 417 left--; 418 } else if (left < 1) 419 break; 420 *p++ = *s++; 421 left--; 422 } 423 *page_bytes = p - con_write_page; 424 return s - orig_s; 425 } 426 427 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n) 428 { 429 struct uart_port *port = sunhv_port; 430 unsigned long flags; 431 int locked = 1; 432 433 if (port->sysrq || oops_in_progress) 434 locked = spin_trylock_irqsave(&port->lock, flags); 435 else 436 spin_lock_irqsave(&port->lock, flags); 437 438 while (n > 0) { 439 unsigned long ra = __pa(con_write_page); 440 unsigned long page_bytes; 441 unsigned int cpy = fill_con_write_page(s, n, 442 &page_bytes); 443 444 n -= cpy; 445 s += cpy; 446 while (page_bytes > 0) { 447 unsigned long written; 448 int limit = 1000000; 449 450 while (limit--) { 451 unsigned long stat; 452 453 stat = sun4v_con_write(ra, page_bytes, 454 &written); 455 if (stat == HV_EOK) 456 break; 457 udelay(1); 458 } 459 if (limit < 0) 460 break; 461 page_bytes -= written; 462 ra += written; 463 } 464 } 465 466 if (locked) 467 spin_unlock_irqrestore(&port->lock, flags); 468 } 469 470 static inline void sunhv_console_putchar(struct uart_port *port, char c) 471 { 472 int limit = 1000000; 473 474 while (limit-- > 0) { 475 long status = sun4v_con_putchar(c); 476 if (status == HV_EOK) 477 break; 478 udelay(1); 479 } 480 } 481 482 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n) 483 { 484 struct uart_port *port = sunhv_port; 485 unsigned long flags; 486 int i, locked = 1; 487 488 if (port->sysrq || oops_in_progress) 489 locked = spin_trylock_irqsave(&port->lock, flags); 490 else 491 spin_lock_irqsave(&port->lock, flags); 492 if (port->sysrq) { 493 locked = 0; 494 } else if (oops_in_progress) { 495 locked = spin_trylock(&port->lock); 496 } else 497 spin_lock(&port->lock); 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->line = 0; 550 port->ops = &sunhv_pops; 551 port->type = PORT_SUNHV; 552 port->uartclk = ( 29491200 / 16 ); /* arbitrary */ 553 554 port->membase = (unsigned char __iomem *) __pa(port); 555 556 port->irq = op->archdata.irqs[0]; 557 558 port->dev = &op->dev; 559 560 err = sunserial_register_minors(&sunhv_reg, 1); 561 if (err) 562 goto out_free_con_read_page; 563 564 sunserial_console_match(&sunhv_console, op->dev.of_node, 565 &sunhv_reg, port->line, false); 566 567 err = uart_add_one_port(&sunhv_reg, port); 568 if (err) 569 goto out_unregister_driver; 570 571 err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port); 572 if (err) 573 goto out_remove_port; 574 575 platform_set_drvdata(op, port); 576 577 return 0; 578 579 out_remove_port: 580 uart_remove_one_port(&sunhv_reg, port); 581 582 out_unregister_driver: 583 sunserial_unregister_minors(&sunhv_reg, 1); 584 585 out_free_con_read_page: 586 kfree(con_read_page); 587 588 out_free_con_write_page: 589 kfree(con_write_page); 590 591 out_free_port: 592 kfree(port); 593 sunhv_port = NULL; 594 return err; 595 } 596 597 static int hv_remove(struct platform_device *dev) 598 { 599 struct uart_port *port = platform_get_drvdata(dev); 600 601 free_irq(port->irq, port); 602 603 uart_remove_one_port(&sunhv_reg, port); 604 605 sunserial_unregister_minors(&sunhv_reg, 1); 606 607 kfree(port); 608 sunhv_port = NULL; 609 610 return 0; 611 } 612 613 static const struct of_device_id hv_match[] = { 614 { 615 .name = "console", 616 .compatible = "qcn", 617 }, 618 { 619 .name = "console", 620 .compatible = "SUNW,sun4v-console", 621 }, 622 {}, 623 }; 624 MODULE_DEVICE_TABLE(of, hv_match); 625 626 static struct platform_driver hv_driver = { 627 .driver = { 628 .name = "hv", 629 .of_match_table = hv_match, 630 }, 631 .probe = hv_probe, 632 .remove = hv_remove, 633 }; 634 635 static int __init sunhv_init(void) 636 { 637 if (tlb_type != hypervisor) 638 return -ENODEV; 639 640 return platform_driver_register(&hv_driver); 641 } 642 643 static void __exit sunhv_exit(void) 644 { 645 platform_driver_unregister(&hv_driver); 646 } 647 648 module_init(sunhv_init); 649 module_exit(sunhv_exit); 650 651 MODULE_AUTHOR("David S. Miller"); 652 MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); 653 MODULE_VERSION("2.0"); 654 MODULE_LICENSE("GPL"); 655