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/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 #include <asm/setup.h>
  27
  28 #if defined(CONFIG_MAGIC_SYSRQ)
  29 #define SUPPORT_SYSRQ
  30 #endif
  31
  32 #include <linux/serial_core.h>
  33 #include <linux/sunserialcore.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)
  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 (port->state == 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(&port->state->port, c, TTY_NORMAL);
 113         }
 114
 115         return saw_console_brk;
 116 }
 117
 118 static int receive_chars_read(struct uart_port *port)
 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 (port->state == NULL)
 156                         continue;
 157
 158                 port->icount.rx += bytes_read;
 159
 160                 tty_insert_flip_string(&port->state->port, con_read_page,
 161                                 bytes_read);
 162         }
 163
 164         return saw_console_brk;
 165 }
 166
 167 struct sunhv_ops {
 168         void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
 169         int (*receive_chars)(struct uart_port *port);
 170 };
 171
 172 static struct sunhv_ops bychar_ops = {
 173         .transmit_chars = transmit_chars_putchar,
 174         .receive_chars = receive_chars_getchar,
 175 };
 176
 177 static struct sunhv_ops bywrite_ops = {
 178         .transmit_chars = transmit_chars_write,
 179         .receive_chars = receive_chars_read,
 180 };
 181
 182 static struct sunhv_ops *sunhv_ops = &bychar_ops;
 183
 184 static struct tty_port *receive_chars(struct uart_port *port)
 185 {
 186         struct tty_port *tport = NULL;
 187
 188         if (port->state != NULL)                /* Unopened serial console */
 189                 tport = &port->state->port;
 190
 191         if (sunhv_ops->receive_chars(port))
 192                 sun_do_break();
 193
 194         return tport;
 195 }
 196
 197 static void transmit_chars(struct uart_port *port)
 198 {
 199         struct circ_buf *xmit;
 200
 201         if (!port->state)
 202                 return;
 203
 204         xmit = &port->state->xmit;
 205         if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 206                 return;
 207
 208         sunhv_ops->transmit_chars(port, xmit);
 209
 210         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 211                 uart_write_wakeup(port);
 212 }
 213
 214 static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
 215 {
 216         struct uart_port *port = dev_id;
 217         struct tty_port *tport;
 218         unsigned long flags;
 219
 220         spin_lock_irqsave(&port->lock, flags);
 221         tport = receive_chars(port);
 222         transmit_chars(port);
 223         spin_unlock_irqrestore(&port->lock, flags);
 224
 225         if (tport)
 226                 tty_flip_buffer_push(tport);
 227
 228         return IRQ_HANDLED;
 229 }
 230
 231 /* port->lock is not held.  */
 232 static unsigned int sunhv_tx_empty(struct uart_port *port)
 233 {
 234         /* Transmitter is always empty for us.  If the circ buffer
 235          * is non-empty or there is an x_char pending, our caller
 236          * will do the right thing and ignore what we return here.
 237          */
 238         return TIOCSER_TEMT;
 239 }
 240
 241 /* port->lock held by caller.  */
 242 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
 243 {
 244         return;
 245 }
 246
 247 /* port->lock is held by caller and interrupts are disabled.  */
 248 static unsigned int sunhv_get_mctrl(struct uart_port *port)
 249 {
 250         return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
 251 }
 252
 253 /* port->lock held by caller.  */
 254 static void sunhv_stop_tx(struct uart_port *port)
 255 {
 256         return;
 257 }
 258
 259 /* port->lock held by caller.  */
 260 static void sunhv_start_tx(struct uart_port *port)
 261 {
 262         transmit_chars(port);
 263 }
 264
 265 /* port->lock is not held.  */
 266 static void sunhv_send_xchar(struct uart_port *port, char ch)
 267 {
 268         unsigned long flags;
 269         int limit = 10000;
 270
 271         spin_lock_irqsave(&port->lock, flags);
 272
 273         while (limit-- > 0) {
 274                 long status = sun4v_con_putchar(ch);
 275                 if (status == HV_EOK)
 276                         break;
 277                 udelay(1);
 278         }
 279
 280         spin_unlock_irqrestore(&port->lock, flags);
 281 }
 282
 283 /* port->lock held by caller.  */
 284 static void sunhv_stop_rx(struct uart_port *port)
 285 {
 286 }
 287
 288 /* port->lock is not held.  */
 289 static void sunhv_break_ctl(struct uart_port *port, int break_state)
 290 {
 291         if (break_state) {
 292                 unsigned long flags;
 293                 int limit = 10000;
 294
 295                 spin_lock_irqsave(&port->lock, flags);
 296
 297                 while (limit-- > 0) {
 298                         long status = sun4v_con_putchar(CON_BREAK);
 299                         if (status == HV_EOK)
 300                                 break;
 301                         udelay(1);
 302                 }
 303
 304                 spin_unlock_irqrestore(&port->lock, flags);
 305         }
 306 }
 307
 308 /* port->lock is not held.  */
 309 static int sunhv_startup(struct uart_port *port)
 310 {
 311         return 0;
 312 }
 313
 314 /* port->lock is not held.  */
 315 static void sunhv_shutdown(struct uart_port *port)
 316 {
 317 }
 318
 319 /* port->lock is not held.  */
 320 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
 321                               struct ktermios *old)
 322 {
 323         unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
 324         unsigned int quot = uart_get_divisor(port, baud);
 325         unsigned int iflag, cflag;
 326         unsigned long flags;
 327
 328         spin_lock_irqsave(&port->lock, flags);
 329
 330         iflag = termios->c_iflag;
 331         cflag = termios->c_cflag;
 332
 333         port->ignore_status_mask = 0;
 334         if (iflag & IGNBRK)
 335                 port->ignore_status_mask |= IGNORE_BREAK;
 336         if ((cflag & CREAD) == 0)
 337                 port->ignore_status_mask |= IGNORE_ALL;
 338
 339         /* XXX */
 340         uart_update_timeout(port, cflag,
 341                             (port->uartclk / (16 * quot)));
 342
 343         spin_unlock_irqrestore(&port->lock, flags);
 344 }
 345
 346 static const char *sunhv_type(struct uart_port *port)
 347 {
 348         return "SUN4V HCONS";
 349 }
 350
 351 static void sunhv_release_port(struct uart_port *port)
 352 {
 353 }
 354
 355 static int sunhv_request_port(struct uart_port *port)
 356 {
 357         return 0;
 358 }
 359
 360 static void sunhv_config_port(struct uart_port *port, int flags)
 361 {
 362 }
 363
 364 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
 365 {
 366         return -EINVAL;
 367 }
 368
 369 static struct uart_ops sunhv_pops = {
 370         .tx_empty       = sunhv_tx_empty,
 371         .set_mctrl      = sunhv_set_mctrl,
 372         .get_mctrl      = sunhv_get_mctrl,
 373         .stop_tx        = sunhv_stop_tx,
 374         .start_tx       = sunhv_start_tx,
 375         .send_xchar     = sunhv_send_xchar,
 376         .stop_rx        = sunhv_stop_rx,
 377         .break_ctl      = sunhv_break_ctl,
 378         .startup        = sunhv_startup,
 379         .shutdown       = sunhv_shutdown,
 380         .set_termios    = sunhv_set_termios,
 381         .type           = sunhv_type,
 382         .release_port   = sunhv_release_port,
 383         .request_port   = sunhv_request_port,
 384         .config_port    = sunhv_config_port,
 385         .verify_port    = sunhv_verify_port,
 386 };
 387
 388 static struct uart_driver sunhv_reg = {
 389         .owner                  = THIS_MODULE,
 390         .driver_name            = "sunhv",
 391         .dev_name               = "ttyS",
 392         .major                  = TTY_MAJOR,
 393 };
 394
 395 static struct uart_port *sunhv_port;
 396
 397 /* Copy 's' into the con_write_page, decoding "\n" into
 398  * "\r\n" along the way.  We have to return two lengths
 399  * because the caller needs to know how much to advance
 400  * 's' and also how many bytes to output via con_write_page.
 401  */
 402 static int fill_con_write_page(const char *s, unsigned int n,
 403                                unsigned long *page_bytes)
 404 {
 405         const char *orig_s = s;
 406         char *p = con_write_page;
 407         int left = PAGE_SIZE;
 408
 409         while (n--) {
 410                 if (*s == '\n') {
 411                         if (left < 2)
 412                                 break;
 413                         *p++ = '\r';
 414                         left--;
 415                 } else if (left < 1)
 416                         break;
 417                 *p++ = *s++;
 418                 left--;
 419         }
 420         *page_bytes = p - con_write_page;
 421         return s - orig_s;
 422 }
 423
 424 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
 425 {
 426         struct uart_port *port = sunhv_port;
 427         unsigned long flags;
 428         int locked = 1;
 429
 430         if (port->sysrq || oops_in_progress)
 431                 locked = spin_trylock_irqsave(&port->lock, flags);
 432         else
 433                 spin_lock_irqsave(&port->lock, flags);
 434
 435         while (n > 0) {
 436                 unsigned long ra = __pa(con_write_page);
 437                 unsigned long page_bytes;
 438                 unsigned int cpy = fill_con_write_page(s, n,
 439                                                        &page_bytes);
 440
 441                 n -= cpy;
 442                 s += cpy;
 443                 while (page_bytes > 0) {
 444                         unsigned long written;
 445                         int limit = 1000000;
 446
 447                         while (limit--) {
 448                                 unsigned long stat;
 449
 450                                 stat = sun4v_con_write(ra, page_bytes,
 451                                                        &written);
 452                                 if (stat == HV_EOK)
 453                                         break;
 454                                 udelay(1);
 455                         }
 456                         if (limit < 0)
 457                                 break;
 458                         page_bytes -= written;
 459                         ra += written;
 460                 }
 461         }
 462
 463         if (locked)
 464                 spin_unlock_irqrestore(&port->lock, flags);
 465 }
 466
 467 static inline void sunhv_console_putchar(struct uart_port *port, char c)
 468 {
 469         int limit = 1000000;
 470
 471         while (limit-- > 0) {
 472                 long status = sun4v_con_putchar(c);
 473                 if (status == HV_EOK)
 474                         break;
 475                 udelay(1);
 476         }
 477 }
 478
 479 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
 480 {
 481         struct uart_port *port = sunhv_port;
 482         unsigned long flags;
 483         int i, locked = 1;
 484
 485         if (port->sysrq || oops_in_progress)
 486                 locked = spin_trylock_irqsave(&port->lock, flags);
 487         else
 488                 spin_lock_irqsave(&port->lock, flags);
 489         if (port->sysrq) {
 490                 locked = 0;
 491         } else if (oops_in_progress) {
 492                 locked = spin_trylock(&port->lock);
 493         } else
 494                 spin_lock(&port->lock);
 495
 496         for (i = 0; i < n; i++) {
 497                 if (*s == '\n')
 498                         sunhv_console_putchar(port, '\r');
 499                 sunhv_console_putchar(port, *s++);
 500         }
 501
 502         if (locked)
 503                 spin_unlock_irqrestore(&port->lock, flags);
 504 }
 505
 506 static struct console sunhv_console = {
 507         .name   =       "ttyHV",
 508         .write  =       sunhv_console_write_bychar,
 509         .device =       uart_console_device,
 510         .flags  =       CON_PRINTBUFFER,
 511         .index  =       -1,
 512         .data   =       &sunhv_reg,
 513 };
 514
 515 static int hv_probe(struct platform_device *op)
 516 {
 517         struct uart_port *port;
 518         unsigned long minor;
 519         int err;
 520
 521         if (op->archdata.irqs[0] == 0xffffffff)
 522                 return -ENODEV;
 523
 524         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
 525         if (unlikely(!port))
 526                 return -ENOMEM;
 527
 528         minor = 1;
 529         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
 530             minor >= 1) {
 531                 err = -ENOMEM;
 532                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 533                 if (!con_write_page)
 534                         goto out_free_port;
 535
 536                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 537                 if (!con_read_page)
 538                         goto out_free_con_write_page;
 539
 540                 sunhv_console.write = sunhv_console_write_paged;
 541                 sunhv_ops = &bywrite_ops;
 542         }
 543
 544         sunhv_port = port;
 545
 546         port->line = 0;
 547         port->ops = &sunhv_pops;
 548         port->type = PORT_SUNHV;
 549         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
 550
 551         port->membase = (unsigned char __iomem *) __pa(port);
 552
 553         port->irq = op->archdata.irqs[0];
 554
 555         port->dev = &op->dev;
 556
 557         err = sunserial_register_minors(&sunhv_reg, 1);
 558         if (err)
 559                 goto out_free_con_read_page;
 560
 561         sunserial_console_match(&sunhv_console, op->dev.of_node,
 562                                 &sunhv_reg, port->line, false);
 563
 564         err = uart_add_one_port(&sunhv_reg, port);
 565         if (err)
 566                 goto out_unregister_driver;
 567
 568         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
 569         if (err)
 570                 goto out_remove_port;
 571
 572         platform_set_drvdata(op, port);
 573
 574         return 0;
 575
 576 out_remove_port:
 577         uart_remove_one_port(&sunhv_reg, port);
 578
 579 out_unregister_driver:
 580         sunserial_unregister_minors(&sunhv_reg, 1);
 581
 582 out_free_con_read_page:
 583         kfree(con_read_page);
 584
 585 out_free_con_write_page:
 586         kfree(con_write_page);
 587
 588 out_free_port:
 589         kfree(port);
 590         sunhv_port = NULL;
 591         return err;
 592 }
 593
 594 static int hv_remove(struct platform_device *dev)
 595 {
 596         struct uart_port *port = platform_get_drvdata(dev);
 597
 598         free_irq(port->irq, port);
 599
 600         uart_remove_one_port(&sunhv_reg, port);
 601
 602         sunserial_unregister_minors(&sunhv_reg, 1);
 603
 604         kfree(port);
 605         sunhv_port = NULL;
 606
 607         return 0;
 608 }
 609
 610 static const struct of_device_id hv_match[] = {
 611         {
 612                 .name = "console",
 613                 .compatible = "qcn",
 614         },
 615         {
 616                 .name = "console",
 617                 .compatible = "SUNW,sun4v-console",
 618         },
 619         {},
 620 };
 621 MODULE_DEVICE_TABLE(of, hv_match);
 622
 623 static struct platform_driver hv_driver = {
 624         .driver = {
 625                 .name = "hv",
 626                 .owner = THIS_MODULE,
 627                 .of_match_table = hv_match,
 628         },
 629         .probe          = hv_probe,
 630         .remove         = hv_remove,
 631 };
 632
 633 static int __init sunhv_init(void)
 634 {
 635         if (tlb_type != hypervisor)
 636                 return -ENODEV;
 637
 638         return platform_driver_register(&hv_driver);
 639 }
 640
 641 static void __exit sunhv_exit(void)
 642 {
 643         platform_driver_unregister(&hv_driver);
 644 }
 645
 646 module_init(sunhv_init);
 647 module_exit(sunhv_exit);
 648
 649 MODULE_AUTHOR("David S. Miller");
 650 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
 651 MODULE_VERSION("2.0");
 652 MODULE_LICENSE("GPL");