drivers/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/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
  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->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
 196 static 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
 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         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.  */
 275 static 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.  */
 293 static void sunhv_stop_rx(struct uart_port *port)
 294 {
 295 }
 296
 297 /* port->lock held by caller.  */
 298 static void sunhv_enable_ms(struct uart_port *port)
 299 {
 300 }
 301
 302 /* port->lock is not held.  */
 303 static 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.  */
 323 static int sunhv_startup(struct uart_port *port)
 324 {
 325         return 0;
 326 }
 327
 328 /* port->lock is not held.  */
 329 static void sunhv_shutdown(struct uart_port *port)
 330 {
 331 }
 332
 333 /* port->lock is not held.  */
 334 static 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         /* XXX */
 354         uart_update_timeout(port, cflag,
 355                             (port->uartclk / (16 * quot)));
 356
 357         spin_unlock_irqrestore(&port->lock, flags);
 358 }
 359
 360 static const char *sunhv_type(struct uart_port *port)
 361 {
 362         return "SUN4V HCONS";
 363 }
 364
 365 static void sunhv_release_port(struct uart_port *port)
 366 {
 367 }
 368
 369 static int sunhv_request_port(struct uart_port *port)
 370 {
 371         return 0;
 372 }
 373
 374 static void sunhv_config_port(struct uart_port *port, int flags)
 375 {
 376 }
 377
 378 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
 379 {
 380         return -EINVAL;
 381 }
 382
 383 static struct uart_ops sunhv_pops = {
 384         .tx_empty       = sunhv_tx_empty,
 385         .set_mctrl      = sunhv_set_mctrl,
 386         .get_mctrl      = sunhv_get_mctrl,
 387         .stop_tx        = sunhv_stop_tx,
 388         .start_tx       = sunhv_start_tx,
 389         .send_xchar     = sunhv_send_xchar,
 390         .stop_rx        = sunhv_stop_rx,
 391         .enable_ms      = sunhv_enable_ms,
 392         .break_ctl      = sunhv_break_ctl,
 393         .startup        = sunhv_startup,
 394         .shutdown       = sunhv_shutdown,
 395         .set_termios    = sunhv_set_termios,
 396         .type           = sunhv_type,
 397         .release_port   = sunhv_release_port,
 398         .request_port   = sunhv_request_port,
 399         .config_port    = sunhv_config_port,
 400         .verify_port    = sunhv_verify_port,
 401 };
 402
 403 static struct uart_driver sunhv_reg = {
 404         .owner                  = THIS_MODULE,
 405         .driver_name            = "serial",
 406         .dev_name               = "ttyS",
 407         .major                  = TTY_MAJOR,
 408 };
 409
 410 static struct uart_port *sunhv_port;
 411
 412 /* Copy 's' into the con_write_page, decoding "\n" into
 413  * "\r\n" along the way.  We have to return two lengths
 414  * because the caller needs to know how much to advance
 415  * 's' and also how many bytes to output via con_write_page.
 416  */
 417 static int fill_con_write_page(const char *s, unsigned int n,
 418                                unsigned long *page_bytes)
 419 {
 420         const char *orig_s = s;
 421         char *p = con_write_page;
 422         int left = PAGE_SIZE;
 423
 424         while (n--) {
 425                 if (*s == '\n') {
 426                         if (left < 2)
 427                                 break;
 428                         *p++ = '\r';
 429                         left--;
 430                 } else if (left < 1)
 431                         break;
 432                 *p++ = *s++;
 433                 left--;
 434         }
 435         *page_bytes = p - con_write_page;
 436         return s - orig_s;
 437 }
 438
 439 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
 440 {
 441         struct uart_port *port = sunhv_port;
 442         unsigned long flags;
 443         int locked = 1;
 444
 445         local_irq_save(flags);
 446         if (port->sysrq) {
 447                 locked = 0;
 448         } else if (oops_in_progress) {
 449                 locked = spin_trylock(&port->lock);
 450         } else
 451                 spin_lock(&port->lock);
 452
 453         while (n > 0) {
 454                 unsigned long ra = __pa(con_write_page);
 455                 unsigned long page_bytes;
 456                 unsigned int cpy = fill_con_write_page(s, n,
 457                                                        &page_bytes);
 458
 459                 n -= cpy;
 460                 s += cpy;
 461                 while (page_bytes > 0) {
 462                         unsigned long written;
 463                         int limit = 1000000;
 464
 465                         while (limit--) {
 466                                 unsigned long stat;
 467
 468                                 stat = sun4v_con_write(ra, page_bytes,
 469                                                        &written);
 470                                 if (stat == HV_EOK)
 471                                         break;
 472                                 udelay(1);
 473                         }
 474                         if (limit <= 0)
 475                                 break;
 476                         page_bytes -= written;
 477                         ra += written;
 478                 }
 479         }
 480
 481         if (locked)
 482                 spin_unlock(&port->lock);
 483         local_irq_restore(flags);
 484 }
 485
 486 static inline void sunhv_console_putchar(struct uart_port *port, char c)
 487 {
 488         int limit = 1000000;
 489
 490         while (limit-- > 0) {
 491                 long status = sun4v_con_putchar(c);
 492                 if (status == HV_EOK)
 493                         break;
 494                 udelay(1);
 495         }
 496 }
 497
 498 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
 499 {
 500         struct uart_port *port = sunhv_port;
 501         unsigned long flags;
 502         int i, locked = 1;
 503
 504         local_irq_save(flags);
 505         if (port->sysrq) {
 506                 locked = 0;
 507         } else if (oops_in_progress) {
 508                 locked = spin_trylock(&port->lock);
 509         } else
 510                 spin_lock(&port->lock);
 511
 512         spin_lock_irqsave(&port->lock, flags);
 513         for (i = 0; i < n; i++) {
 514                 if (*s == '\n')
 515                         sunhv_console_putchar(port, '\r');
 516                 sunhv_console_putchar(port, *s++);
 517         }
 518
 519         if (locked)
 520                 spin_unlock(&port->lock);
 521         local_irq_restore(flags);
 522 }
 523
 524 static struct console sunhv_console = {
 525         .name   =       "ttyHV",
 526         .write  =       sunhv_console_write_bychar,
 527         .device =       uart_console_device,
 528         .flags  =       CON_PRINTBUFFER,
 529         .index  =       -1,
 530         .data   =       &sunhv_reg,
 531 };
 532
 533 static inline struct console *SUNHV_CONSOLE(void)
 534 {
 535         if (con_is_present())
 536                 return NULL;
 537
 538         sunhv_console.index = 0;
 539
 540         return &sunhv_console;
 541 }
 542
 543 static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match)
 544 {
 545         struct uart_port *port;
 546         unsigned long minor;
 547         int err;
 548
 549         if (op->irqs[0] == 0xffffffff)
 550                 return -ENODEV;
 551
 552         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
 553         if (unlikely(!port))
 554                 return -ENOMEM;
 555
 556         minor = 1;
 557         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
 558             minor >= 1) {
 559                 err = -ENOMEM;
 560                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 561                 if (!con_write_page)
 562                         goto out_free_port;
 563
 564                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 565                 if (!con_read_page)
 566                         goto out_free_con_write_page;
 567
 568                 sunhv_console.write = sunhv_console_write_paged;
 569                 sunhv_ops = &bywrite_ops;
 570         }
 571
 572         sunhv_port = port;
 573
 574         port->line = 0;
 575         port->ops = &sunhv_pops;
 576         port->type = PORT_SUNHV;
 577         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
 578
 579         port->membase = (unsigned char __iomem *) __pa(port);
 580
 581         port->irq = op->irqs[0];
 582
 583         port->dev = &op->dev;
 584
 585         sunhv_reg.minor = sunserial_current_minor;
 586         sunhv_reg.nr = 1;
 587
 588         err = uart_register_driver(&sunhv_reg);
 589         if (err)
 590                 goto out_free_con_read_page;
 591
 592         sunhv_reg.tty_driver->name_base = sunhv_reg.minor - 64;
 593         sunserial_current_minor += 1;
 594
 595         sunhv_reg.cons = SUNHV_CONSOLE();
 596
 597         err = uart_add_one_port(&sunhv_reg, port);
 598         if (err)
 599                 goto out_unregister_driver;
 600
 601         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
 602         if (err)
 603                 goto out_remove_port;
 604
 605         dev_set_drvdata(&op->dev, port);
 606
 607         return 0;
 608
 609 out_remove_port:
 610         uart_remove_one_port(&sunhv_reg, port);
 611
 612 out_unregister_driver:
 613         sunserial_current_minor -= 1;
 614         uart_unregister_driver(&sunhv_reg);
 615
 616 out_free_con_read_page:
 617         kfree(con_read_page);
 618
 619 out_free_con_write_page:
 620         kfree(con_write_page);
 621
 622 out_free_port:
 623         kfree(port);
 624         sunhv_port = NULL;
 625         return err;
 626 }
 627
 628 static int __devexit hv_remove(struct of_device *dev)
 629 {
 630         struct uart_port *port = dev_get_drvdata(&dev->dev);
 631
 632         free_irq(port->irq, port);
 633
 634         uart_remove_one_port(&sunhv_reg, port);
 635
 636         sunserial_current_minor -= 1;
 637         uart_unregister_driver(&sunhv_reg);
 638
 639         kfree(port);
 640         sunhv_port = NULL;
 641
 642         dev_set_drvdata(&dev->dev, NULL);
 643
 644         return 0;
 645 }
 646
 647 static struct of_device_id hv_match[] = {
 648         {
 649                 .name = "console",
 650                 .compatible = "qcn",
 651         },
 652         {
 653                 .name = "console",
 654                 .compatible = "SUNW,sun4v-console",
 655         },
 656         {},
 657 };
 658 MODULE_DEVICE_TABLE(of, hv_match);
 659
 660 static struct of_platform_driver hv_driver = {
 661         .name           = "hv",
 662         .match_table    = hv_match,
 663         .probe          = hv_probe,
 664         .remove         = __devexit_p(hv_remove),
 665 };
 666
 667 static int __init sunhv_init(void)
 668 {
 669         if (tlb_type != hypervisor)
 670                 return -ENODEV;
 671
 672         return of_register_driver(&hv_driver, &of_bus_type);
 673 }
 674
 675 static void __exit sunhv_exit(void)
 676 {
 677         of_unregister_driver(&hv_driver);
 678 }
 679
 680 module_init(sunhv_init);
 681 module_exit(sunhv_exit);
 682
 683 MODULE_AUTHOR("David S. Miller");
 684 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
 685 MODULE_VERSION("2.0");
 686 MODULE_LICENSE("GPL");