drivers/tty/serial/sunhv.c

   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