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, struct tty_struct *tty) 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 (tty == 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(tty, c, TTY_NORMAL); 113 } 114 115 return saw_console_brk; 116 } 117 118 static int receive_chars_read(struct uart_port *port, struct tty_struct *tty) 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 (tty == NULL) 156 continue; 157 158 port->icount.rx += bytes_read; 159 160 tty_insert_flip_string(tty, con_read_page, bytes_read); 161 } 162 163 return saw_console_brk; 164 } 165 166 struct sunhv_ops { 167 void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit); 168 int (*receive_chars)(struct uart_port *port, struct tty_struct *tty); 169 }; 170 171 static struct sunhv_ops bychar_ops = { 172 .transmit_chars = transmit_chars_putchar, 173 .receive_chars = receive_chars_getchar, 174 }; 175 176 static struct sunhv_ops bywrite_ops = { 177 .transmit_chars = transmit_chars_write, 178 .receive_chars = receive_chars_read, 179 }; 180 181 static struct sunhv_ops *sunhv_ops = &bychar_ops; 182 183 static struct tty_struct *receive_chars(struct uart_port *port) 184 { 185 struct tty_struct *tty = NULL; 186 187 if (port->state != NULL) /* Unopened serial console */ 188 tty = port->state->port.tty; 189 190 if (sunhv_ops->receive_chars(port, tty)) 191 sun_do_break(); 192 193 return tty; 194 } 195 196 static void transmit_chars(struct uart_port *port) 197 { 198 struct circ_buf *xmit; 199 200 if (!port->state) 201 return; 202 203 xmit = &port->state->xmit; 204 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) 205 return; 206 207 sunhv_ops->transmit_chars(port, xmit); 208 209 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 210 uart_write_wakeup(port); 211 } 212 213 static irqreturn_t sunhv_interrupt(int irq, void *dev_id) 214 { 215 struct uart_port *port = dev_id; 216 struct tty_struct *tty; 217 unsigned long flags; 218 219 spin_lock_irqsave(&port->lock, flags); 220 tty = receive_chars(port); 221 transmit_chars(port); 222 spin_unlock_irqrestore(&port->lock, flags); 223 224 if (tty) 225 tty_flip_buffer_push(tty); 226 227 return IRQ_HANDLED; 228 } 229 230 /* port->lock is not held. */ 231 static unsigned int sunhv_tx_empty(struct uart_port *port) 232 { 233 /* Transmitter is always empty for us. If the circ buffer 234 * is non-empty or there is an x_char pending, our caller 235 * will do the right thing and ignore what we return here. 236 */ 237 return TIOCSER_TEMT; 238 } 239 240 /* port->lock held by caller. */ 241 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl) 242 { 243 return; 244 } 245 246 /* port->lock is held by caller and interrupts are disabled. */ 247 static unsigned int sunhv_get_mctrl(struct uart_port *port) 248 { 249 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS; 250 } 251 252 /* port->lock held by caller. */ 253 static void sunhv_stop_tx(struct uart_port *port) 254 { 255 return; 256 } 257 258 /* port->lock held by caller. */ 259 static void sunhv_start_tx(struct uart_port *port) 260 { 261 transmit_chars(port); 262 } 263 264 /* port->lock is not held. */ 265 static void sunhv_send_xchar(struct uart_port *port, char ch) 266 { 267 unsigned long flags; 268 int limit = 10000; 269 270 spin_lock_irqsave(&port->lock, flags); 271 272 while (limit-- > 0) { 273 long status = sun4v_con_putchar(ch); 274 if (status == HV_EOK) 275 break; 276 udelay(1); 277 } 278 279 spin_unlock_irqrestore(&port->lock, flags); 280 } 281 282 /* port->lock held by caller. */ 283 static void sunhv_stop_rx(struct uart_port *port) 284 { 285 } 286 287 /* port->lock held by caller. */ 288 static void sunhv_enable_ms(struct uart_port *port) 289 { 290 } 291 292 /* port->lock is not held. */ 293 static void sunhv_break_ctl(struct uart_port *port, int break_state) 294 { 295 if (break_state) { 296 unsigned long flags; 297 int limit = 10000; 298 299 spin_lock_irqsave(&port->lock, flags); 300 301 while (limit-- > 0) { 302 long status = sun4v_con_putchar(CON_BREAK); 303 if (status == HV_EOK) 304 break; 305 udelay(1); 306 } 307 308 spin_unlock_irqrestore(&port->lock, flags); 309 } 310 } 311 312 /* port->lock is not held. */ 313 static int sunhv_startup(struct uart_port *port) 314 { 315 return 0; 316 } 317 318 /* port->lock is not held. */ 319 static void sunhv_shutdown(struct uart_port *port) 320 { 321 } 322 323 /* port->lock is not held. */ 324 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios, 325 struct ktermios *old) 326 { 327 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000); 328 unsigned int quot = uart_get_divisor(port, baud); 329 unsigned int iflag, cflag; 330 unsigned long flags; 331 332 spin_lock_irqsave(&port->lock, flags); 333 334 iflag = termios->c_iflag; 335 cflag = termios->c_cflag; 336 337 port->ignore_status_mask = 0; 338 if (iflag & IGNBRK) 339 port->ignore_status_mask |= IGNORE_BREAK; 340 if ((cflag & CREAD) == 0) 341 port->ignore_status_mask |= IGNORE_ALL; 342 343 /* XXX */ 344 uart_update_timeout(port, cflag, 345 (port->uartclk / (16 * quot))); 346 347 spin_unlock_irqrestore(&port->lock, flags); 348 } 349 350 static const char *sunhv_type(struct uart_port *port) 351 { 352 return "SUN4V HCONS"; 353 } 354 355 static void sunhv_release_port(struct uart_port *port) 356 { 357 } 358 359 static int sunhv_request_port(struct uart_port *port) 360 { 361 return 0; 362 } 363 364 static void sunhv_config_port(struct uart_port *port, int flags) 365 { 366 } 367 368 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser) 369 { 370 return -EINVAL; 371 } 372 373 static struct uart_ops sunhv_pops = { 374 .tx_empty = sunhv_tx_empty, 375 .set_mctrl = sunhv_set_mctrl, 376 .get_mctrl = sunhv_get_mctrl, 377 .stop_tx = sunhv_stop_tx, 378 .start_tx = sunhv_start_tx, 379 .send_xchar = sunhv_send_xchar, 380 .stop_rx = sunhv_stop_rx, 381 .enable_ms = sunhv_enable_ms, 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 = "ttyS", 397 .major = TTY_MAJOR, 398 }; 399 400 static struct uart_port *sunhv_port; 401 402 /* Copy 's' into the con_write_page, decoding "\n" into 403 * "\r\n" along the way. We have to return two lengths 404 * because the caller needs to know how much to advance 405 * 's' and also how many bytes to output via con_write_page. 406 */ 407 static int fill_con_write_page(const char *s, unsigned int n, 408 unsigned long *page_bytes) 409 { 410 const char *orig_s = s; 411 char *p = con_write_page; 412 int left = PAGE_SIZE; 413 414 while (n--) { 415 if (*s == '\n') { 416 if (left < 2) 417 break; 418 *p++ = '\r'; 419 left--; 420 } else if (left < 1) 421 break; 422 *p++ = *s++; 423 left--; 424 } 425 *page_bytes = p - con_write_page; 426 return s - orig_s; 427 } 428 429 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n) 430 { 431 struct uart_port *port = sunhv_port; 432 unsigned long flags; 433 int locked = 1; 434 435 local_irq_save(flags); 436 if (port->sysrq) { 437 locked = 0; 438 } else if (oops_in_progress) { 439 locked = spin_trylock(&port->lock); 440 } else 441 spin_lock(&port->lock); 442 443 while (n > 0) { 444 unsigned long ra = __pa(con_write_page); 445 unsigned long page_bytes; 446 unsigned int cpy = fill_con_write_page(s, n, 447 &page_bytes); 448 449 n -= cpy; 450 s += cpy; 451 while (page_bytes > 0) { 452 unsigned long written; 453 int limit = 1000000; 454 455 while (limit--) { 456 unsigned long stat; 457 458 stat = sun4v_con_write(ra, page_bytes, 459 &written); 460 if (stat == HV_EOK) 461 break; 462 udelay(1); 463 } 464 if (limit < 0) 465 break; 466 page_bytes -= written; 467 ra += written; 468 } 469 } 470 471 if (locked) 472 spin_unlock(&port->lock); 473 local_irq_restore(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 local_irq_save(flags); 495 if (port->sysrq) { 496 locked = 0; 497 } else if (oops_in_progress) { 498 locked = spin_trylock(&port->lock); 499 } else 500 spin_lock(&port->lock); 501 502 for (i = 0; i < n; i++) { 503 if (*s == '\n') 504 sunhv_console_putchar(port, '\r'); 505 sunhv_console_putchar(port, *s++); 506 } 507 508 if (locked) 509 spin_unlock(&port->lock); 510 local_irq_restore(flags); 511 } 512 513 static struct console sunhv_console = { 514 .name = "ttyHV", 515 .write = sunhv_console_write_bychar, 516 .device = uart_console_device, 517 .flags = CON_PRINTBUFFER, 518 .index = -1, 519 .data = &sunhv_reg, 520 }; 521 522 static int hv_probe(struct platform_device *op) 523 { 524 struct uart_port *port; 525 unsigned long minor; 526 int err; 527 528 if (op->archdata.irqs[0] == 0xffffffff) 529 return -ENODEV; 530 531 port = kzalloc(sizeof(struct uart_port), GFP_KERNEL); 532 if (unlikely(!port)) 533 return -ENOMEM; 534 535 minor = 1; 536 if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 && 537 minor >= 1) { 538 err = -ENOMEM; 539 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 540 if (!con_write_page) 541 goto out_free_port; 542 543 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 544 if (!con_read_page) 545 goto out_free_con_write_page; 546 547 sunhv_console.write = sunhv_console_write_paged; 548 sunhv_ops = &bywrite_ops; 549 } 550 551 sunhv_port = port; 552 553 port->line = 0; 554 port->ops = &sunhv_pops; 555 port->type = PORT_SUNHV; 556 port->uartclk = ( 29491200 / 16 ); /* arbitrary */ 557 558 port->membase = (unsigned char __iomem *) __pa(port); 559 560 port->irq = op->archdata.irqs[0]; 561 562 port->dev = &op->dev; 563 564 err = sunserial_register_minors(&sunhv_reg, 1); 565 if (err) 566 goto out_free_con_read_page; 567 568 sunserial_console_match(&sunhv_console, op->dev.of_node, 569 &sunhv_reg, port->line, false); 570 571 err = uart_add_one_port(&sunhv_reg, port); 572 if (err) 573 goto out_unregister_driver; 574 575 err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port); 576 if (err) 577 goto out_remove_port; 578 579 dev_set_drvdata(&op->dev, port); 580 581 return 0; 582 583 out_remove_port: 584 uart_remove_one_port(&sunhv_reg, port); 585 586 out_unregister_driver: 587 sunserial_unregister_minors(&sunhv_reg, 1); 588 589 out_free_con_read_page: 590 kfree(con_read_page); 591 592 out_free_con_write_page: 593 kfree(con_write_page); 594 595 out_free_port: 596 kfree(port); 597 sunhv_port = NULL; 598 return err; 599 } 600 601 static int hv_remove(struct platform_device *dev) 602 { 603 struct uart_port *port = dev_get_drvdata(&dev->dev); 604 605 free_irq(port->irq, port); 606 607 uart_remove_one_port(&sunhv_reg, port); 608 609 sunserial_unregister_minors(&sunhv_reg, 1); 610 611 kfree(port); 612 sunhv_port = NULL; 613 614 dev_set_drvdata(&dev->dev, NULL); 615 616 return 0; 617 } 618 619 static const struct of_device_id hv_match[] = { 620 { 621 .name = "console", 622 .compatible = "qcn", 623 }, 624 { 625 .name = "console", 626 .compatible = "SUNW,sun4v-console", 627 }, 628 {}, 629 }; 630 MODULE_DEVICE_TABLE(of, hv_match); 631 632 static struct platform_driver hv_driver = { 633 .driver = { 634 .name = "hv", 635 .owner = THIS_MODULE, 636 .of_match_table = hv_match, 637 }, 638 .probe = hv_probe, 639 .remove = hv_remove, 640 }; 641 642 static int __init sunhv_init(void) 643 { 644 if (tlb_type != hypervisor) 645 return -ENODEV; 646 647 return platform_driver_register(&hv_driver); 648 } 649 650 static void __exit sunhv_exit(void) 651 { 652 platform_driver_unregister(&hv_driver); 653 } 654 655 module_init(sunhv_init); 656 module_exit(sunhv_exit); 657 658 MODULE_AUTHOR("David S. Miller"); 659 MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); 660 MODULE_VERSION("2.0"); 661 MODULE_LICENSE("GPL"); 662