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
  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, struct tty_struct *tty)
  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 (tty == 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(tty, c, TTY_NORMAL);
 112         }
 113
 114         return saw_console_brk;
 115 }
 116
 117 static int receive_chars_read(struct uart_port *port, struct tty_struct *tty)
 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                 for (i = 0; i < bytes_read; i++)
 152                         uart_handle_sysrq_char(port, con_read_page[i]);
 153
 154                 if (tty == NULL)
 155                         continue;
 156
 157                 port->icount.rx += bytes_read;
 158
 159                 tty_insert_flip_string(tty, con_read_page, bytes_read);
 160         }
 161
 162         return saw_console_brk;
 163 }
 164
 165 struct sunhv_ops {
 166         void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
 167         int (*receive_chars)(struct uart_port *port, struct tty_struct *tty);
 168 };
 169
 170 static struct sunhv_ops bychar_ops = {
 171         .transmit_chars = transmit_chars_putchar,
 172         .receive_chars = receive_chars_getchar,
 173 };
 174
 175 static struct sunhv_ops bywrite_ops = {
 176         .transmit_chars = transmit_chars_write,
 177         .receive_chars = receive_chars_read,
 178 };
 179
 180 static struct sunhv_ops *sunhv_ops = &bychar_ops;
 181
 182 static struct tty_struct *receive_chars(struct uart_port *port)
 183 {
 184         struct tty_struct *tty = NULL;
 185
 186         if (port->state != NULL)                /* Unopened serial console */
 187                 tty = port->state->port.tty;
 188
 189         if (sunhv_ops->receive_chars(port, tty))
 190                 sun_do_break();
 191
 192         return tty;
 193 }
 194
 195 static void transmit_chars(struct uart_port *port)
 196 {
 197         struct circ_buf *xmit;
 198
 199         if (!port->state)
 200                 return;
 201
 202         xmit = &port->state->xmit;
 203         if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 204                 return;
 205
 206         sunhv_ops->transmit_chars(port, xmit);
 207
 208         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 209                 uart_write_wakeup(port);
 210 }
 211
 212 static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
 213 {
 214         struct uart_port *port = dev_id;
 215         struct tty_struct *tty;
 216         unsigned long flags;
 217
 218         spin_lock_irqsave(&port->lock, flags);
 219         tty = receive_chars(port);
 220         transmit_chars(port);
 221         spin_unlock_irqrestore(&port->lock, flags);
 222
 223         if (tty)
 224                 tty_flip_buffer_push(tty);
 225
 226         return IRQ_HANDLED;
 227 }
 228
 229 /* port->lock is not held.  */
 230 static unsigned int sunhv_tx_empty(struct uart_port *port)
 231 {
 232         /* Transmitter is always empty for us.  If the circ buffer
 233          * is non-empty or there is an x_char pending, our caller
 234          * will do the right thing and ignore what we return here.
 235          */
 236         return TIOCSER_TEMT;
 237 }
 238
 239 /* port->lock held by caller.  */
 240 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
 241 {
 242         return;
 243 }
 244
 245 /* port->lock is held by caller and interrupts are disabled.  */
 246 static unsigned int sunhv_get_mctrl(struct uart_port *port)
 247 {
 248         return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
 249 }
 250
 251 /* port->lock held by caller.  */
 252 static void sunhv_stop_tx(struct uart_port *port)
 253 {
 254         return;
 255 }
 256
 257 /* port->lock held by caller.  */
 258 static void sunhv_start_tx(struct uart_port *port)
 259 {
 260         transmit_chars(port);
 261 }
 262
 263 /* port->lock is not held.  */
 264 static void sunhv_send_xchar(struct uart_port *port, char ch)
 265 {
 266         unsigned long flags;
 267         int limit = 10000;
 268
 269         spin_lock_irqsave(&port->lock, flags);
 270
 271         while (limit-- > 0) {
 272                 long status = sun4v_con_putchar(ch);
 273                 if (status == HV_EOK)
 274                         break;
 275                 udelay(1);
 276         }
 277
 278         spin_unlock_irqrestore(&port->lock, flags);
 279 }
 280
 281 /* port->lock held by caller.  */
 282 static void sunhv_stop_rx(struct uart_port *port)
 283 {
 284 }
 285
 286 /* port->lock held by caller.  */
 287 static void sunhv_enable_ms(struct uart_port *port)
 288 {
 289 }
 290
 291 /* port->lock is not held.  */
 292 static void sunhv_break_ctl(struct uart_port *port, int break_state)
 293 {
 294         if (break_state) {
 295                 unsigned long flags;
 296                 int limit = 10000;
 297
 298                 spin_lock_irqsave(&port->lock, flags);
 299
 300                 while (limit-- > 0) {
 301                         long status = sun4v_con_putchar(CON_BREAK);
 302                         if (status == HV_EOK)
 303                                 break;
 304                         udelay(1);
 305                 }
 306
 307                 spin_unlock_irqrestore(&port->lock, flags);
 308         }
 309 }
 310
 311 /* port->lock is not held.  */
 312 static int sunhv_startup(struct uart_port *port)
 313 {
 314         return 0;
 315 }
 316
 317 /* port->lock is not held.  */
 318 static void sunhv_shutdown(struct uart_port *port)
 319 {
 320 }
 321
 322 /* port->lock is not held.  */
 323 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
 324                               struct ktermios *old)
 325 {
 326         unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
 327         unsigned int quot = uart_get_divisor(port, baud);
 328         unsigned int iflag, cflag;
 329         unsigned long flags;
 330
 331         spin_lock_irqsave(&port->lock, flags);
 332
 333         iflag = termios->c_iflag;
 334         cflag = termios->c_cflag;
 335
 336         port->ignore_status_mask = 0;
 337         if (iflag & IGNBRK)
 338                 port->ignore_status_mask |= IGNORE_BREAK;
 339         if ((cflag & CREAD) == 0)
 340                 port->ignore_status_mask |= IGNORE_ALL;
 341
 342         /* XXX */
 343         uart_update_timeout(port, cflag,
 344                             (port->uartclk / (16 * quot)));
 345
 346         spin_unlock_irqrestore(&port->lock, flags);
 347 }
 348
 349 static const char *sunhv_type(struct uart_port *port)
 350 {
 351         return "SUN4V HCONS";
 352 }
 353
 354 static void sunhv_release_port(struct uart_port *port)
 355 {
 356 }
 357
 358 static int sunhv_request_port(struct uart_port *port)
 359 {
 360         return 0;
 361 }
 362
 363 static void sunhv_config_port(struct uart_port *port, int flags)
 364 {
 365 }
 366
 367 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
 368 {
 369         return -EINVAL;
 370 }
 371
 372 static struct uart_ops sunhv_pops = {
 373         .tx_empty       = sunhv_tx_empty,
 374         .set_mctrl      = sunhv_set_mctrl,
 375         .get_mctrl      = sunhv_get_mctrl,
 376         .stop_tx        = sunhv_stop_tx,
 377         .start_tx       = sunhv_start_tx,
 378         .send_xchar     = sunhv_send_xchar,
 379         .stop_rx        = sunhv_stop_rx,
 380         .enable_ms      = sunhv_enable_ms,
 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         local_irq_save(flags);
 435         if (port->sysrq) {
 436                 locked = 0;
 437         } else if (oops_in_progress) {
 438                 locked = spin_trylock(&port->lock);
 439         } else
 440                 spin_lock(&port->lock);
 441
 442         while (n > 0) {
 443                 unsigned long ra = __pa(con_write_page);
 444                 unsigned long page_bytes;
 445                 unsigned int cpy = fill_con_write_page(s, n,
 446                                                        &page_bytes);
 447
 448                 n -= cpy;
 449                 s += cpy;
 450                 while (page_bytes > 0) {
 451                         unsigned long written;
 452                         int limit = 1000000;
 453
 454                         while (limit--) {
 455                                 unsigned long stat;
 456
 457                                 stat = sun4v_con_write(ra, page_bytes,
 458                                                        &written);
 459                                 if (stat == HV_EOK)
 460                                         break;
 461                                 udelay(1);
 462                         }
 463                         if (limit < 0)
 464                                 break;
 465                         page_bytes -= written;
 466                         ra += written;
 467                 }
 468         }
 469
 470         if (locked)
 471                 spin_unlock(&port->lock);
 472         local_irq_restore(flags);
 473 }
 474
 475 static inline void sunhv_console_putchar(struct uart_port *port, char c)
 476 {
 477         int limit = 1000000;
 478
 479         while (limit-- > 0) {
 480                 long status = sun4v_con_putchar(c);
 481                 if (status == HV_EOK)
 482                         break;
 483                 udelay(1);
 484         }
 485 }
 486
 487 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
 488 {
 489         struct uart_port *port = sunhv_port;
 490         unsigned long flags;
 491         int i, locked = 1;
 492
 493         local_irq_save(flags);
 494         if (port->sysrq) {
 495                 locked = 0;
 496         } else if (oops_in_progress) {
 497                 locked = spin_trylock(&port->lock);
 498         } else
 499                 spin_lock(&port->lock);
 500
 501         for (i = 0; i < n; i++) {
 502                 if (*s == '\n')
 503                         sunhv_console_putchar(port, '\r');
 504                 sunhv_console_putchar(port, *s++);
 505         }
 506
 507         if (locked)
 508                 spin_unlock(&port->lock);
 509         local_irq_restore(flags);
 510 }
 511
 512 static struct console sunhv_console = {
 513         .name   =       "ttyHV",
 514         .write  =       sunhv_console_write_bychar,
 515         .device =       uart_console_device,
 516         .flags  =       CON_PRINTBUFFER,
 517         .index  =       -1,
 518         .data   =       &sunhv_reg,
 519 };
 520
 521 static int __devinit hv_probe(struct platform_device *op)
 522 {
 523         struct uart_port *port;
 524         unsigned long minor;
 525         int err;
 526
 527         if (op->archdata.irqs[0] == 0xffffffff)
 528                 return -ENODEV;
 529
 530         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
 531         if (unlikely(!port))
 532                 return -ENOMEM;
 533
 534         minor = 1;
 535         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
 536             minor >= 1) {
 537                 err = -ENOMEM;
 538                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 539                 if (!con_write_page)
 540                         goto out_free_port;
 541
 542                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 543                 if (!con_read_page)
 544                         goto out_free_con_write_page;
 545
 546                 sunhv_console.write = sunhv_console_write_paged;
 547                 sunhv_ops = &bywrite_ops;
 548         }
 549
 550         sunhv_port = port;
 551
 552         port->line = 0;
 553         port->ops = &sunhv_pops;
 554         port->type = PORT_SUNHV;
 555         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
 556
 557         port->membase = (unsigned char __iomem *) __pa(port);
 558
 559         port->irq = op->archdata.irqs[0];
 560
 561         port->dev = &op->dev;
 562
 563         err = sunserial_register_minors(&sunhv_reg, 1);
 564         if (err)
 565                 goto out_free_con_read_page;
 566
 567         sunserial_console_match(&sunhv_console, op->dev.of_node,
 568                                 &sunhv_reg, port->line, false);
 569
 570         err = uart_add_one_port(&sunhv_reg, port);
 571         if (err)
 572                 goto out_unregister_driver;
 573
 574         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
 575         if (err)
 576                 goto out_remove_port;
 577
 578         dev_set_drvdata(&op->dev, port);
 579
 580         return 0;
 581
 582 out_remove_port:
 583         uart_remove_one_port(&sunhv_reg, port);
 584
 585 out_unregister_driver:
 586         sunserial_unregister_minors(&sunhv_reg, 1);
 587
 588 out_free_con_read_page:
 589         kfree(con_read_page);
 590
 591 out_free_con_write_page:
 592         kfree(con_write_page);
 593
 594 out_free_port:
 595         kfree(port);
 596         sunhv_port = NULL;
 597         return err;
 598 }
 599
 600 static int __devexit hv_remove(struct platform_device *dev)
 601 {
 602         struct uart_port *port = dev_get_drvdata(&dev->dev);
 603
 604         free_irq(port->irq, port);
 605
 606         uart_remove_one_port(&sunhv_reg, port);
 607
 608         sunserial_unregister_minors(&sunhv_reg, 1);
 609
 610         kfree(port);
 611         sunhv_port = NULL;
 612
 613         dev_set_drvdata(&dev->dev, NULL);
 614
 615         return 0;
 616 }
 617
 618 static const struct of_device_id hv_match[] = {
 619         {
 620                 .name = "console",
 621                 .compatible = "qcn",
 622         },
 623         {
 624                 .name = "console",
 625                 .compatible = "SUNW,sun4v-console",
 626         },
 627         {},
 628 };
 629 MODULE_DEVICE_TABLE(of, hv_match);
 630
 631 static struct platform_driver hv_driver = {
 632         .driver = {
 633                 .name = "hv",
 634                 .owner = THIS_MODULE,
 635                 .of_match_table = hv_match,
 636         },
 637         .probe          = hv_probe,
 638         .remove         = __devexit_p(hv_remove),
 639 };
 640
 641 static int __init sunhv_init(void)
 642 {
 643         if (tlb_type != hypervisor)
 644                 return -ENODEV;
 645
 646         return platform_driver_register(&hv_driver);
 647 }
 648
 649 static void __exit sunhv_exit(void)
 650 {
 651         platform_driver_unregister(&hv_driver);
 652 }
 653
 654 module_init(sunhv_init);
 655 module_exit(sunhv_exit);
 656
 657 MODULE_AUTHOR("David S. Miller");
 658 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
 659 MODULE_VERSION("2.0");
 660 MODULE_LICENSE("GPL");