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/kernel.h> 7 #include <linux/errno.h> 8 #include <linux/tty.h> 9 #include <linux/tty_flip.h> 10 #include <linux/major.h> 11 #include <linux/circ_buf.h> 12 #include <linux/serial.h> 13 #include <linux/sysrq.h> 14 #include <linux/console.h> 15 #include <linux/spinlock.h> 16 #include <linux/slab.h> 17 #include <linux/delay.h> 18 #include <linux/init.h> 19 #include <linux/of_device.h> 20 21 #include <asm/hypervisor.h> 22 #include <asm/spitfire.h> 23 #include <asm/prom.h> 24 #include <asm/irq.h> 25 #include <asm/setup.h> 26 27 #if defined(CONFIG_MAGIC_SYSRQ) 28 #define SUPPORT_SYSRQ 29 #endif 30 31 #include <linux/serial_core.h> 32 #include <linux/sunserialcore.h> 33 34 #define CON_BREAK ((long)-1) 35 #define CON_HUP ((long)-2) 36 37 #define IGNORE_BREAK 0x1 38 #define IGNORE_ALL 0x2 39 40 static char *con_write_page; 41 static char *con_read_page; 42 43 static int hung_up = 0; 44 45 static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit) 46 { 47 while (!uart_circ_empty(xmit)) { 48 long status = sun4v_con_putchar(xmit->buf[xmit->tail]); 49 50 if (status != HV_EOK) 51 break; 52 53 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 54 port->icount.tx++; 55 } 56 } 57 58 static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit) 59 { 60 while (!uart_circ_empty(xmit)) { 61 unsigned long ra = __pa(xmit->buf + xmit->tail); 62 unsigned long len, status, sent; 63 64 len = CIRC_CNT_TO_END(xmit->head, xmit->tail, 65 UART_XMIT_SIZE); 66 status = sun4v_con_write(ra, len, &sent); 67 if (status != HV_EOK) 68 break; 69 xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1); 70 port->icount.tx += 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, 0); 96 } else if (hung_up) { 97 hung_up = 0; 98 uart_handle_dcd_change(port, 1); 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 int saw_console_brk = 0; 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 (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 } 155 156 if (port->state == NULL) 157 continue; 158 159 port->icount.rx += bytes_read; 160 161 tty_insert_flip_string(&port->state->port, con_read_page, 162 bytes_read); 163 } 164 165 return saw_console_brk; 166 } 167 168 struct sunhv_ops { 169 void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit); 170 int (*receive_chars)(struct uart_port *port); 171 }; 172 173 static const struct sunhv_ops bychar_ops = { 174 .transmit_chars = transmit_chars_putchar, 175 .receive_chars = receive_chars_getchar, 176 }; 177 178 static const struct sunhv_ops bywrite_ops = { 179 .transmit_chars = transmit_chars_write, 180 .receive_chars = receive_chars_read, 181 }; 182 183 static const struct sunhv_ops *sunhv_ops = &bychar_ops; 184 185 static struct tty_port *receive_chars(struct uart_port *port) 186 { 187 struct tty_port *tport = NULL; 188 189 if (port->state != NULL) /* Unopened serial console */ 190 tport = &port->state->port; 191 192 if (sunhv_ops->receive_chars(port)) 193 sun_do_break(); 194 195 return tport; 196 } 197 198 static void transmit_chars(struct uart_port *port) 199 { 200 struct circ_buf *xmit; 201 202 if (!port->state) 203 return; 204 205 xmit = &port->state->xmit; 206 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) 207 return; 208 209 sunhv_ops->transmit_chars(port, xmit); 210 211 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 212 uart_write_wakeup(port); 213 } 214 215 static irqreturn_t sunhv_interrupt(int irq, void *dev_id) 216 { 217 struct uart_port *port = dev_id; 218 struct tty_port *tport; 219 unsigned long flags; 220 221 spin_lock_irqsave(&port->lock, flags); 222 tport = receive_chars(port); 223 transmit_chars(port); 224 spin_unlock_irqrestore(&port->lock, flags); 225 226 if (tport) 227 tty_flip_buffer_push(tport); 228 229 return IRQ_HANDLED; 230 } 231 232 /* port->lock is not held. */ 233 static unsigned int sunhv_tx_empty(struct uart_port *port) 234 { 235 /* Transmitter is always empty for us. If the circ buffer 236 * is non-empty or there is an x_char pending, our caller 237 * will do the right thing and ignore what we return here. 238 */ 239 return TIOCSER_TEMT; 240 } 241 242 /* port->lock held by caller. */ 243 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl) 244 { 245 return; 246 } 247 248 /* port->lock is held by caller and interrupts are disabled. */ 249 static unsigned int sunhv_get_mctrl(struct uart_port *port) 250 { 251 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS; 252 } 253 254 /* port->lock held by caller. */ 255 static void sunhv_stop_tx(struct uart_port *port) 256 { 257 return; 258 } 259 260 /* port->lock held by caller. */ 261 static void sunhv_start_tx(struct uart_port *port) 262 { 263 transmit_chars(port); 264 } 265 266 /* port->lock is not held. */ 267 static void sunhv_send_xchar(struct uart_port *port, char ch) 268 { 269 unsigned long flags; 270 int limit = 10000; 271 272 if (ch == __DISABLED_CHAR) 273 return; 274 275 spin_lock_irqsave(&port->lock, flags); 276 277 while (limit-- > 0) { 278 long status = sun4v_con_putchar(ch); 279 if (status == HV_EOK) 280 break; 281 udelay(1); 282 } 283 284 spin_unlock_irqrestore(&port->lock, flags); 285 } 286 287 /* port->lock held by caller. */ 288 static void sunhv_stop_rx(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 .break_ctl = sunhv_break_ctl, 382 .startup = sunhv_startup, 383 .shutdown = sunhv_shutdown, 384 .set_termios = sunhv_set_termios, 385 .type = sunhv_type, 386 .release_port = sunhv_release_port, 387 .request_port = sunhv_request_port, 388 .config_port = sunhv_config_port, 389 .verify_port = sunhv_verify_port, 390 }; 391 392 static struct uart_driver sunhv_reg = { 393 .owner = THIS_MODULE, 394 .driver_name = "sunhv", 395 .dev_name = "ttyS", 396 .major = TTY_MAJOR, 397 }; 398 399 static struct uart_port *sunhv_port; 400 401 /* Copy 's' into the con_write_page, decoding "\n" into 402 * "\r\n" along the way. We have to return two lengths 403 * because the caller needs to know how much to advance 404 * 's' and also how many bytes to output via con_write_page. 405 */ 406 static int fill_con_write_page(const char *s, unsigned int n, 407 unsigned long *page_bytes) 408 { 409 const char *orig_s = s; 410 char *p = con_write_page; 411 int left = PAGE_SIZE; 412 413 while (n--) { 414 if (*s == '\n') { 415 if (left < 2) 416 break; 417 *p++ = '\r'; 418 left--; 419 } else if (left < 1) 420 break; 421 *p++ = *s++; 422 left--; 423 } 424 *page_bytes = p - con_write_page; 425 return s - orig_s; 426 } 427 428 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n) 429 { 430 struct uart_port *port = sunhv_port; 431 unsigned long flags; 432 int locked = 1; 433 434 if (port->sysrq || oops_in_progress) 435 locked = spin_trylock_irqsave(&port->lock, flags); 436 else 437 spin_lock_irqsave(&port->lock, flags); 438 439 while (n > 0) { 440 unsigned long ra = __pa(con_write_page); 441 unsigned long page_bytes; 442 unsigned int cpy = fill_con_write_page(s, n, 443 &page_bytes); 444 445 n -= cpy; 446 s += cpy; 447 while (page_bytes > 0) { 448 unsigned long written; 449 int limit = 1000000; 450 451 while (limit--) { 452 unsigned long stat; 453 454 stat = sun4v_con_write(ra, page_bytes, 455 &written); 456 if (stat == HV_EOK) 457 break; 458 udelay(1); 459 } 460 if (limit < 0) 461 break; 462 page_bytes -= written; 463 ra += written; 464 } 465 } 466 467 if (locked) 468 spin_unlock_irqrestore(&port->lock, flags); 469 } 470 471 static inline void sunhv_console_putchar(struct uart_port *port, char c) 472 { 473 int limit = 1000000; 474 475 while (limit-- > 0) { 476 long status = sun4v_con_putchar(c); 477 if (status == HV_EOK) 478 break; 479 udelay(1); 480 } 481 } 482 483 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n) 484 { 485 struct uart_port *port = sunhv_port; 486 unsigned long flags; 487 int i, locked = 1; 488 489 if (port->sysrq || oops_in_progress) 490 locked = spin_trylock_irqsave(&port->lock, flags); 491 else 492 spin_lock_irqsave(&port->lock, flags); 493 if (port->sysrq) { 494 locked = 0; 495 } else if (oops_in_progress) { 496 locked = spin_trylock(&port->lock); 497 } else 498 spin_lock(&port->lock); 499 500 for (i = 0; i < n; i++) { 501 if (*s == '\n') 502 sunhv_console_putchar(port, '\r'); 503 sunhv_console_putchar(port, *s++); 504 } 505 506 if (locked) 507 spin_unlock_irqrestore(&port->lock, flags); 508 } 509 510 static struct console sunhv_console = { 511 .name = "ttyHV", 512 .write = sunhv_console_write_bychar, 513 .device = uart_console_device, 514 .flags = CON_PRINTBUFFER, 515 .index = -1, 516 .data = &sunhv_reg, 517 }; 518 519 static int hv_probe(struct platform_device *op) 520 { 521 struct uart_port *port; 522 unsigned long minor; 523 int err; 524 525 if (op->archdata.irqs[0] == 0xffffffff) 526 return -ENODEV; 527 528 port = kzalloc(sizeof(struct uart_port), GFP_KERNEL); 529 if (unlikely(!port)) 530 return -ENOMEM; 531 532 minor = 1; 533 if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 && 534 minor >= 1) { 535 err = -ENOMEM; 536 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 537 if (!con_write_page) 538 goto out_free_port; 539 540 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 541 if (!con_read_page) 542 goto out_free_con_write_page; 543 544 sunhv_console.write = sunhv_console_write_paged; 545 sunhv_ops = &bywrite_ops; 546 } 547 548 sunhv_port = port; 549 550 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); 607 608 kfree(port); 609 sunhv_port = NULL; 610 611 return 0; 612 } 613 614 static const struct of_device_id hv_match[] = { 615 { 616 .name = "console", 617 .compatible = "qcn", 618 }, 619 { 620 .name = "console", 621 .compatible = "SUNW,sun4v-console", 622 }, 623 {}, 624 }; 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 device_initcall(sunhv_init); 643 644 #if 0 /* ...def MODULE ; never supported as such */ 645 MODULE_AUTHOR("David S. Miller"); 646 MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); 647 MODULE_VERSION("2.0"); 648 MODULE_LICENSE("GPL"); 649 #endif 650