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 #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
  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->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
 196 static 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
 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         transmit_chars(port);
 262 }
 263
 264 /* port->lock is not held.  */
 265 static 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.  */
 283 static void sunhv_stop_rx(struct uart_port *port)
 284 {
 285 }
 286
 287 /* port->lock held by caller.  */
 288 static void sunhv_enable_ms(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         .enable_ms      = sunhv_enable_ms,
 382         .break_ctl      = sunhv_break_ctl,
 383         .startup        = sunhv_startup,
 384         .shutdown       = sunhv_shutdown,
 385         .set_termios    = sunhv_set_termios,
 386         .type           = sunhv_type,
 387         .release_port   = sunhv_release_port,
 388         .request_port   = sunhv_request_port,
 389         .config_port    = sunhv_config_port,
 390         .verify_port    = sunhv_verify_port,
 391 };
 392
 393 static struct uart_driver sunhv_reg = {
 394         .owner                  = THIS_MODULE,
 395         .driver_name            = "sunhv",
 396         .dev_name               = "ttyS",
 397         .major                  = TTY_MAJOR,
 398 };
 399
 400 static struct uart_port *sunhv_port;
 401
 402 /* Copy 's' into the con_write_page, decoding "\n" into
 403  * "\r\n" along the way.  We have to return two lengths
 404  * because the caller needs to know how much to advance
 405  * 's' and also how many bytes to output via con_write_page.
 406  */
 407 static int fill_con_write_page(const char *s, unsigned int n,
 408                                unsigned long *page_bytes)
 409 {
 410         const char *orig_s = s;
 411         char *p = con_write_page;
 412         int left = PAGE_SIZE;
 413
 414         while (n--) {
 415                 if (*s == '\n') {
 416                         if (left < 2)
 417                                 break;
 418                         *p++ = '\r';
 419                         left--;
 420                 } else if (left < 1)
 421                         break;
 422                 *p++ = *s++;
 423                 left--;
 424         }
 425         *page_bytes = p - con_write_page;
 426         return s - orig_s;
 427 }
 428
 429 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
 430 {
 431         struct uart_port *port = sunhv_port;
 432         unsigned long flags;
 433         int locked = 1;
 434
 435         local_irq_save(flags);
 436         if (port->sysrq) {
 437                 locked = 0;
 438         } else if (oops_in_progress) {
 439                 locked = spin_trylock(&port->lock);
 440         } else
 441                 spin_lock(&port->lock);
 442
 443         while (n > 0) {
 444                 unsigned long ra = __pa(con_write_page);
 445                 unsigned long page_bytes;
 446                 unsigned int cpy = fill_con_write_page(s, n,
 447                                                        &page_bytes);
 448
 449                 n -= cpy;
 450                 s += cpy;
 451                 while (page_bytes > 0) {
 452                         unsigned long written;
 453                         int limit = 1000000;
 454
 455                         while (limit--) {
 456                                 unsigned long stat;
 457
 458                                 stat = sun4v_con_write(ra, page_bytes,
 459                                                        &written);
 460                                 if (stat == HV_EOK)
 461                                         break;
 462                                 udelay(1);
 463                         }
 464                         if (limit < 0)
 465                                 break;
 466                         page_bytes -= written;
 467                         ra += written;
 468                 }
 469         }
 470
 471         if (locked)
 472                 spin_unlock(&port->lock);
 473         local_irq_restore(flags);
 474 }
 475
 476 static inline void sunhv_console_putchar(struct uart_port *port, char c)
 477 {
 478         int limit = 1000000;
 479
 480         while (limit-- > 0) {
 481                 long status = sun4v_con_putchar(c);
 482                 if (status == HV_EOK)
 483                         break;
 484                 udelay(1);
 485         }
 486 }
 487
 488 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
 489 {
 490         struct uart_port *port = sunhv_port;
 491         unsigned long flags;
 492         int i, locked = 1;
 493
 494         local_irq_save(flags);
 495         if (port->sysrq) {
 496                 locked = 0;
 497         } else if (oops_in_progress) {
 498                 locked = spin_trylock(&port->lock);
 499         } else
 500                 spin_lock(&port->lock);
 501
 502         for (i = 0; i < n; i++) {
 503                 if (*s == '\n')
 504                         sunhv_console_putchar(port, '\r');
 505                 sunhv_console_putchar(port, *s++);
 506         }
 507
 508         if (locked)
 509                 spin_unlock(&port->lock);
 510         local_irq_restore(flags);
 511 }
 512
 513 static struct console sunhv_console = {
 514         .name   =       "ttyHV",
 515         .write  =       sunhv_console_write_bychar,
 516         .device =       uart_console_device,
 517         .flags  =       CON_PRINTBUFFER,
 518         .index  =       -1,
 519         .data   =       &sunhv_reg,
 520 };
 521
 522 static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match)
 523 {
 524         struct uart_port *port;
 525         unsigned long minor;
 526         int err;
 527
 528         if (op->archdata.irqs[0] == 0xffffffff)
 529                 return -ENODEV;
 530
 531         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
 532         if (unlikely(!port))
 533                 return -ENOMEM;
 534
 535         minor = 1;
 536         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
 537             minor >= 1) {
 538                 err = -ENOMEM;
 539                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 540                 if (!con_write_page)
 541                         goto out_free_port;
 542
 543                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 544                 if (!con_read_page)
 545                         goto out_free_con_write_page;
 546
 547                 sunhv_console.write = sunhv_console_write_paged;
 548                 sunhv_ops = &bywrite_ops;
 549         }
 550
 551         sunhv_port = port;
 552
 553         port->line = 0;
 554         port->ops = &sunhv_pops;
 555         port->type = PORT_SUNHV;
 556         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
 557
 558         port->membase = (unsigned char __iomem *) __pa(port);
 559
 560         port->irq = op->archdata.irqs[0];
 561
 562         port->dev = &op->dev;
 563
 564         err = sunserial_register_minors(&sunhv_reg, 1);
 565         if (err)
 566                 goto out_free_con_read_page;
 567
 568         sunserial_console_match(&sunhv_console, op->dev.of_node,
 569                                 &sunhv_reg, port->line, false);
 570
 571         err = uart_add_one_port(&sunhv_reg, port);
 572         if (err)
 573                 goto out_unregister_driver;
 574
 575         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
 576         if (err)
 577                 goto out_remove_port;
 578
 579         dev_set_drvdata(&op->dev, port);
 580
 581         return 0;
 582
 583 out_remove_port:
 584         uart_remove_one_port(&sunhv_reg, port);
 585
 586 out_unregister_driver:
 587         sunserial_unregister_minors(&sunhv_reg, 1);
 588
 589 out_free_con_read_page:
 590         kfree(con_read_page);
 591
 592 out_free_con_write_page:
 593         kfree(con_write_page);
 594
 595 out_free_port:
 596         kfree(port);
 597         sunhv_port = NULL;
 598         return err;
 599 }
 600
 601 static int __devexit hv_remove(struct of_device *dev)
 602 {
 603         struct uart_port *port = dev_get_drvdata(&dev->dev);
 604
 605         free_irq(port->irq, port);
 606
 607         uart_remove_one_port(&sunhv_reg, port);
 608
 609         sunserial_unregister_minors(&sunhv_reg, 1);
 610
 611         kfree(port);
 612         sunhv_port = NULL;
 613
 614         dev_set_drvdata(&dev->dev, NULL);
 615
 616         return 0;
 617 }
 618
 619 static const struct of_device_id hv_match[] = {
 620         {
 621                 .name = "console",
 622                 .compatible = "qcn",
 623         },
 624         {
 625                 .name = "console",
 626                 .compatible = "SUNW,sun4v-console",
 627         },
 628         {},
 629 };
 630 MODULE_DEVICE_TABLE(of, hv_match);
 631
 632 static struct of_platform_driver hv_driver = {
 633         .driver = {
 634                 .name = "hv",
 635                 .owner = THIS_MODULE,
 636                 .of_match_table = hv_match,
 637         },
 638         .probe          = hv_probe,
 639         .remove         = __devexit_p(hv_remove),
 640 };
 641
 642 static int __init sunhv_init(void)
 643 {
 644         if (tlb_type != hypervisor)
 645                 return -ENODEV;
 646
 647         return of_register_platform_driver(&hv_driver);
 648 }
 649
 650 static void __exit sunhv_exit(void)
 651 {
 652         of_unregister_platform_driver(&hv_driver);
 653 }
 654
 655 module_init(sunhv_init);
 656 module_exit(sunhv_exit);
 657
 658 MODULE_AUTHOR("David S. Miller");
 659 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
 660 MODULE_VERSION("2.0");
 661 MODULE_LICENSE("GPL");