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 21#include <asm/hypervisor.h> 22#include <asm/spitfire.h> 23#include <asm/prom.h> 24#include <asm/of_device.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->info != NULL) /* Unopened serial console */ 188 tty = port->info->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->info) 201 return; 202 203 xmit = &port->info->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 struct circ_buf *xmit = &port->info->xmit; 262 263 while (!uart_circ_empty(xmit)) { 264 long status = sun4v_con_putchar(xmit->buf[xmit->tail]); 265 266 if (status != HV_EOK) 267 break; 268 269 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 270 port->icount.tx++; 271 } 272} 273 274/* port->lock is not held. */ 275static void sunhv_send_xchar(struct uart_port *port, char ch) 276{ 277 unsigned long flags; 278 int limit = 10000; 279 280 spin_lock_irqsave(&port->lock, flags); 281 282 while (limit-- > 0) { 283 long status = sun4v_con_putchar(ch); 284 if (status == HV_EOK) 285 break; 286 udelay(1); 287 } 288 289 spin_unlock_irqrestore(&port->lock, flags); 290} 291 292/* port->lock held by caller. */ 293static void sunhv_stop_rx(struct uart_port *port) 294{ 295} 296 297/* port->lock held by caller. */ 298static void sunhv_enable_ms(struct uart_port *port) 299{ 300} 301 302/* port->lock is not held. */ 303static void sunhv_break_ctl(struct uart_port *port, int break_state) 304{ 305 if (break_state) { 306 unsigned long flags; 307 int limit = 10000; 308 309 spin_lock_irqsave(&port->lock, flags); 310 311 while (limit-- > 0) { 312 long status = sun4v_con_putchar(CON_BREAK); 313 if (status == HV_EOK) 314 break; 315 udelay(1); 316 } 317 318 spin_unlock_irqrestore(&port->lock, flags); 319 } 320} 321 322/* port->lock is not held. */ 323static int sunhv_startup(struct uart_port *port) 324{ 325 return 0; 326} 327 328/* port->lock is not held. */ 329static void sunhv_shutdown(struct uart_port *port) 330{ 331} 332 333/* port->lock is not held. */ 334static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios, 335 struct ktermios *old) 336{ 337 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000); 338 unsigned int quot = uart_get_divisor(port, baud); 339 unsigned int iflag, cflag; 340 unsigned long flags; 341 342 spin_lock_irqsave(&port->lock, flags); 343 344 iflag = termios->c_iflag; 345 cflag = termios->c_cflag; 346 347 port->ignore_status_mask = 0; 348 if (iflag & IGNBRK) 349 port->ignore_status_mask |= IGNORE_BREAK; 350 if ((cflag & CREAD) == 0) 351 port->ignore_status_mask |= IGNORE_ALL; 352 353 uart_update_timeout(port, cflag, 354 (port->uartclk / (16 * quot))); 355 356 spin_unlock_irqrestore(&port->lock, flags); 357} 358 359static const char *sunhv_type(struct uart_port *port) 360{ 361 return "SUN4V HCONS"; 362} 363 364static void sunhv_release_port(struct uart_port *port) 365{ 366} 367 368static int sunhv_request_port(struct uart_port *port) 369{ 370 return 0; 371} 372 373static void sunhv_config_port(struct uart_port *port, int flags) 374{ 375} 376 377static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser) 378{ 379 return -EINVAL; 380} 381 382static struct uart_ops sunhv_pops = { 383 .tx_empty = sunhv_tx_empty, 384 .set_mctrl = sunhv_set_mctrl, 385 .get_mctrl = sunhv_get_mctrl, 386 .stop_tx = sunhv_stop_tx, 387 .start_tx = sunhv_start_tx, 388 .send_xchar = sunhv_send_xchar, 389 .stop_rx = sunhv_stop_rx, 390 .enable_ms = sunhv_enable_ms, 391 .break_ctl = sunhv_break_ctl, 392 .startup = sunhv_startup, 393 .shutdown = sunhv_shutdown, 394 .set_termios = sunhv_set_termios, 395 .type = sunhv_type, 396 .release_port = sunhv_release_port, 397 .request_port = sunhv_request_port, 398 .config_port = sunhv_config_port, 399 .verify_port = sunhv_verify_port, 400}; 401 402static struct uart_driver sunhv_reg = { 403 .owner = THIS_MODULE, 404 .driver_name = "serial", 405 .dev_name = "ttyS", 406 .major = TTY_MAJOR, 407}; 408 409static struct uart_port *sunhv_port; 410 411/* Copy 's' into the con_write_page, decoding "\n" into 412 * "\r\n" along the way. We have to return two lengths 413 * because the caller needs to know how much to advance 414 * 's' and also how many bytes to output via con_write_page. 415 */ 416static int fill_con_write_page(const char *s, unsigned int n, 417 unsigned long *page_bytes) 418{ 419 const char *orig_s = s; 420 char *p = con_write_page; 421 int left = PAGE_SIZE; 422 423 while (n--) { 424 if (*s == '\n') { 425 if (left < 2) 426 break; 427 *p++ = '\r'; 428 left--; 429 } else if (left < 1) 430 break; 431 *p++ = *s++; 432 left--; 433 } 434 *page_bytes = p - con_write_page; 435 return s - orig_s; 436} 437 438static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n) 439{ 440 struct uart_port *port = sunhv_port; 441 unsigned long flags; 442 443 spin_lock_irqsave(&port->lock, flags); 444 while (n > 0) { 445 unsigned long ra = __pa(con_write_page); 446 unsigned long page_bytes; 447 unsigned int cpy = fill_con_write_page(s, n, 448 &page_bytes); 449 450 n -= cpy; 451 s += cpy; 452 while (page_bytes > 0) { 453 unsigned long written; 454 int limit = 1000000; 455 456 while (limit--) { 457 unsigned long stat; 458 459 stat = sun4v_con_write(ra, page_bytes, 460 &written); 461 if (stat == HV_EOK) 462 break; 463 udelay(1); 464 } 465 if (limit <= 0) 466 break; 467 page_bytes -= written; 468 ra += written; 469 } 470 } 471 spin_unlock_irqrestore(&port->lock, flags); 472} 473 474static inline void sunhv_console_putchar(struct uart_port *port, char c) 475{ 476 int limit = 1000000; 477 478 while (limit-- > 0) { 479 long status = sun4v_con_putchar(c); 480 if (status == HV_EOK) 481 break; 482 udelay(1); 483 } 484} 485 486static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n) 487{ 488 struct uart_port *port = sunhv_port; 489 unsigned long flags; 490 int i; 491 492 spin_lock_irqsave(&port->lock, flags); 493 for (i = 0; i < n; i++) { 494 if (*s == '\n') 495 sunhv_console_putchar(port, '\r'); 496 sunhv_console_putchar(port, *s++); 497 } 498 spin_unlock_irqrestore(&port->lock, flags); 499} 500 501static struct console sunhv_console = { 502 .name = "ttyHV", 503 .write = sunhv_console_write_bychar, 504 .device = uart_console_device, 505 .flags = CON_PRINTBUFFER, 506 .index = -1, 507 .data = &sunhv_reg, 508}; 509 510static inline struct console *SUNHV_CONSOLE(void) 511{ 512 if (con_is_present()) 513 return NULL; 514 515 sunhv_console.index = 0; 516 517 return &sunhv_console; 518} 519 520static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match) 521{ 522 struct uart_port *port; 523 unsigned long minor; 524 int err; 525 526 if (op->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->line = 0; 552 port->ops = &sunhv_pops; 553 port->type = PORT_SUNHV; 554 port->uartclk = ( 29491200 / 16 ); /* arbitrary */ 555 556 port->membase = (unsigned char __iomem *) __pa(port); 557 558 port->irq = op->irqs[0]; 559 560 port->dev = &op->dev; 561 562 sunhv_reg.minor = sunserial_current_minor; 563 sunhv_reg.nr = 1; 564 565 err = uart_register_driver(&sunhv_reg); 566 if (err) 567 goto out_free_con_read_page; 568 569 sunhv_reg.tty_driver->name_base = sunhv_reg.minor - 64; 570 sunserial_current_minor += 1; 571 572 sunhv_reg.cons = SUNHV_CONSOLE(); 573 574 err = uart_add_one_port(&sunhv_reg, port); 575 if (err) 576 goto out_unregister_driver; 577 578 err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port); 579 if (err) 580 goto out_remove_port; 581 582 dev_set_drvdata(&op->dev, port); 583 584 return 0; 585 586out_remove_port: 587 uart_remove_one_port(&sunhv_reg, port); 588 589out_unregister_driver: 590 sunserial_current_minor -= 1; 591 uart_unregister_driver(&sunhv_reg); 592 593out_free_con_read_page: 594 kfree(con_read_page); 595 596out_free_con_write_page: 597 kfree(con_write_page); 598 599out_free_port: 600 kfree(port); 601 sunhv_port = NULL; 602 return err; 603} 604 605static int __devexit hv_remove(struct of_device *dev) 606{ 607 struct uart_port *port = dev_get_drvdata(&dev->dev); 608 609 free_irq(port->irq, port); 610 611 uart_remove_one_port(&sunhv_reg, port); 612 613 sunserial_current_minor -= 1; 614 uart_unregister_driver(&sunhv_reg); 615 616 kfree(port); 617 sunhv_port = NULL; 618 619 dev_set_drvdata(&dev->dev, NULL); 620 621 return 0; 622} 623 624static struct of_device_id hv_match[] = { 625 { 626 .name = "console", 627 .compatible = "qcn", 628 }, 629 { 630 .name = "console", 631 .compatible = "SUNW,sun4v-console", 632 }, 633 {}, 634}; 635MODULE_DEVICE_TABLE(of, hv_match); 636 637static struct of_platform_driver hv_driver = { 638 .name = "hv", 639 .match_table = hv_match, 640 .probe = hv_probe, 641 .remove = __devexit_p(hv_remove), 642}; 643 644static int __init sunhv_init(void) 645{ 646 if (tlb_type != hypervisor) 647 return -ENODEV; 648 649 return of_register_driver(&hv_driver, &of_bus_type); 650} 651 652static void __exit sunhv_exit(void) 653{ 654 of_unregister_driver(&hv_driver); 655} 656 657module_init(sunhv_init); 658module_exit(sunhv_exit); 659 660MODULE_AUTHOR("David S. Miller"); 661MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); 662MODULE_VERSION("2.0"); 663MODULE_LICENSE("GPL"); 664