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 27#if defined(CONFIG_MAGIC_SYSRQ) 28#define SUPPORT_SYSRQ 29#endif 30 31#include <linux/serial_core.h> 32 33#include "suncore.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 41static char *con_write_page; 42static char *con_read_page; 43 44static int hung_up = 0; 45 46static 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 59static 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 75static 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 118static 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 166struct 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 171static struct sunhv_ops bychar_ops = { 172 .transmit_chars = transmit_chars_putchar, 173 .receive_chars = receive_chars_getchar, 174}; 175 176static struct sunhv_ops bywrite_ops = { 177 .transmit_chars = transmit_chars_write, 178 .receive_chars = receive_chars_read, 179}; 180 181static struct sunhv_ops *sunhv_ops = &bychar_ops; 182 183static 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 196static 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 213static 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. */ 231static 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. */ 241static 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. */ 247static 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. */ 253static void sunhv_stop_tx(struct uart_port *port) 254{ 255 return; 256} 257 258/* port->lock held by caller. */ 259static void sunhv_start_tx(struct uart_port *port) 260{ 261 transmit_chars(port); 262} 263 264/* port->lock is not held. */ 265static 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. */ 283static void sunhv_stop_rx(struct uart_port *port) 284{ 285} 286 287/* port->lock held by caller. */ 288static void sunhv_enable_ms(struct uart_port *port) 289{ 290} 291 292/* port->lock is not held. */ 293static 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. */ 313static int sunhv_startup(struct uart_port *port) 314{ 315 return 0; 316} 317 318/* port->lock is not held. */ 319static void sunhv_shutdown(struct uart_port *port) 320{ 321} 322 323/* port->lock is not held. */ 324static 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 uart_update_timeout(port, cflag, 344 (port->uartclk / (16 * quot))); 345 346 spin_unlock_irqrestore(&port->lock, flags); 347} 348 349static const char *sunhv_type(struct uart_port *port) 350{ 351 return "SUN4V HCONS"; 352} 353 354static void sunhv_release_port(struct uart_port *port) 355{ 356} 357 358static int sunhv_request_port(struct uart_port *port) 359{ 360 return 0; 361} 362 363static void sunhv_config_port(struct uart_port *port, int flags) 364{ 365} 366 367static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser) 368{ 369 return -EINVAL; 370} 371 372static 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 .enable_ms = sunhv_enable_ms, 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 392static struct uart_driver sunhv_reg = { 393 .owner = THIS_MODULE, 394 .driver_name = "sunhv", 395 .dev_name = "ttyS", 396 .major = TTY_MAJOR, 397}; 398 399static 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 */ 406static 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 428static 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 local_irq_save(flags); 435 if (port->sysrq) { 436 locked = 0; 437 } else if (oops_in_progress) { 438 locked = spin_trylock(&port->lock); 439 } else 440 spin_lock(&port->lock); 441 442 while (n > 0) { 443 unsigned long ra = __pa(con_write_page); 444 unsigned long page_bytes; 445 unsigned int cpy = fill_con_write_page(s, n, 446 &page_bytes); 447 448 n -= cpy; 449 s += cpy; 450 while (page_bytes > 0) { 451 unsigned long written; 452 int limit = 1000000; 453 454 while (limit--) { 455 unsigned long stat; 456 457 stat = sun4v_con_write(ra, page_bytes, 458 &written); 459 if (stat == HV_EOK) 460 break; 461 udelay(1); 462 } 463 if (limit < 0) 464 break; 465 page_bytes -= written; 466 ra += written; 467 } 468 } 469 470 if (locked) 471 spin_unlock(&port->lock); 472 local_irq_restore(flags); 473} 474 475static inline void sunhv_console_putchar(struct uart_port *port, char c) 476{ 477 int limit = 1000000; 478 479 while (limit-- > 0) { 480 long status = sun4v_con_putchar(c); 481 if (status == HV_EOK) 482 break; 483 udelay(1); 484 } 485} 486 487static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n) 488{ 489 struct uart_port *port = sunhv_port; 490 unsigned long flags; 491 int i, locked = 1; 492 493 local_irq_save(flags); 494 if (port->sysrq) { 495 locked = 0; 496 } else if (oops_in_progress) { 497 locked = spin_trylock(&port->lock); 498 } else 499 spin_lock(&port->lock); 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(&port->lock); 509 local_irq_restore(flags); 510} 511 512static struct console sunhv_console = { 513 .name = "ttyHV", 514 .write = sunhv_console_write_bychar, 515 .device = uart_console_device, 516 .flags = CON_PRINTBUFFER, 517 .index = -1, 518 .data = &sunhv_reg, 519}; 520 521static int __devinit hv_probe(struct platform_device *op, const struct of_device_id *match) 522{ 523 struct uart_port *port; 524 unsigned long minor; 525 int err; 526 527 if (op->archdata.irqs[0] == 0xffffffff) 528 return -ENODEV; 529 530 port = kzalloc(sizeof(struct uart_port), GFP_KERNEL); 531 if (unlikely(!port)) 532 return -ENOMEM; 533 534 minor = 1; 535 if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 && 536 minor >= 1) { 537 err = -ENOMEM; 538 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 539 if (!con_write_page) 540 goto out_free_port; 541 542 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL); 543 if (!con_read_page) 544 goto out_free_con_write_page; 545 546 sunhv_console.write = sunhv_console_write_paged; 547 sunhv_ops = &bywrite_ops; 548 } 549 550 sunhv_port = port; 551 552 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 dev_set_drvdata(&op->dev, port); 579 580 return 0; 581 582out_remove_port: 583 uart_remove_one_port(&sunhv_reg, port); 584 585out_unregister_driver: 586 sunserial_unregister_minors(&sunhv_reg, 1); 587 588out_free_con_read_page: 589 kfree(con_read_page); 590 591out_free_con_write_page: 592 kfree(con_write_page); 593 594out_free_port: 595 kfree(port); 596 sunhv_port = NULL; 597 return err; 598} 599 600static int __devexit hv_remove(struct platform_device *dev) 601{ 602 struct uart_port *port = dev_get_drvdata(&dev->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); 609 610 kfree(port); 611 sunhv_port = NULL; 612 613 dev_set_drvdata(&dev->dev, NULL); 614 615 return 0; 616} 617 618static 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}; 629MODULE_DEVICE_TABLE(of, hv_match); 630 631static struct of_platform_driver hv_driver = { 632 .driver = { 633 .name = "hv", 634 .owner = THIS_MODULE, 635 .of_match_table = hv_match, 636 }, 637 .probe = hv_probe, 638 .remove = __devexit_p(hv_remove), 639}; 640 641static int __init sunhv_init(void) 642{ 643 if (tlb_type != hypervisor) 644 return -ENODEV; 645 646 return of_register_platform_driver(&hv_driver); 647} 648 649static void __exit sunhv_exit(void) 650{ 651 of_unregister_platform_driver(&hv_driver); 652} 653 654module_init(sunhv_init); 655module_exit(sunhv_exit); 656 657MODULE_AUTHOR("David S. Miller"); 658MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); 659MODULE_VERSION("2.0"); 660MODULE_LICENSE("GPL"); 661