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                 for (i = 0; i < bytes_read; i++)
 152                         uart_handle_sysrq_char(port, con_read_page[i]);
 153
 154                 if (port->state == NULL)
 155                         continue;
 156
 157                 port->icount.rx += bytes_read;
 158
 159                 tty_insert_flip_string(&port->state->port, con_read_page,
 160                                 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);
 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_port *receive_chars(struct uart_port *port)
 184 {
 185         struct tty_port *tport = NULL;
 186
 187         if (port->state != NULL)                /* Unopened serial console */
 188                 tport = &port->state->port;
 189
 190         if (sunhv_ops->receive_chars(port))
 191                 sun_do_break();
 192
 193         return tport;
 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_port *tport;
 217         unsigned long flags;
 218
 219         spin_lock_irqsave(&port->lock, flags);
 220         tport = receive_chars(port);
 221         transmit_chars(port);
 222         spin_unlock_irqrestore(&port->lock, flags);
 223
 224         if (tport)
 225                 tty_flip_buffer_push(tport);
 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         if (ch == __DISABLED_CHAR)
 271                 return;
 272
 273         spin_lock_irqsave(&port->lock, flags);
 274
 275         while (limit-- > 0) {
 276                 long status = sun4v_con_putchar(ch);
 277                 if (status == HV_EOK)
 278                         break;
 279                 udelay(1);
 280         }
 281
 282         spin_unlock_irqrestore(&port->lock, flags);
 283 }
 284
 285 /* port->lock held by caller.  */
 286 static void sunhv_stop_rx(struct uart_port *port)
 287 {
 288 }
 289
 290 /* port->lock is not held.  */
 291 static void sunhv_break_ctl(struct uart_port *port, int break_state)
 292 {
 293         if (break_state) {
 294                 unsigned long flags;
 295                 int limit = 10000;
 296
 297                 spin_lock_irqsave(&port->lock, flags);
 298
 299                 while (limit-- > 0) {
 300                         long status = sun4v_con_putchar(CON_BREAK);
 301                         if (status == HV_EOK)
 302                                 break;
 303                         udelay(1);
 304                 }
 305
 306                 spin_unlock_irqrestore(&port->lock, flags);
 307         }
 308 }
 309
 310 /* port->lock is not held.  */
 311 static int sunhv_startup(struct uart_port *port)
 312 {
 313         return 0;
 314 }
 315
 316 /* port->lock is not held.  */
 317 static void sunhv_shutdown(struct uart_port *port)
 318 {
 319 }
 320
 321 /* port->lock is not held.  */
 322 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
 323                               struct ktermios *old)
 324 {
 325         unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
 326         unsigned int quot = uart_get_divisor(port, baud);
 327         unsigned int iflag, cflag;
 328         unsigned long flags;
 329
 330         spin_lock_irqsave(&port->lock, flags);
 331
 332         iflag = termios->c_iflag;
 333         cflag = termios->c_cflag;
 334
 335         port->ignore_status_mask = 0;
 336         if (iflag & IGNBRK)
 337                 port->ignore_status_mask |= IGNORE_BREAK;
 338         if ((cflag & CREAD) == 0)
 339                 port->ignore_status_mask |= IGNORE_ALL;
 340
 341         /* XXX */
 342         uart_update_timeout(port, cflag,
 343                             (port->uartclk / (16 * quot)));
 344
 345         spin_unlock_irqrestore(&port->lock, flags);
 346 }
 347
 348 static const char *sunhv_type(struct uart_port *port)
 349 {
 350         return "SUN4V HCONS";
 351 }
 352
 353 static void sunhv_release_port(struct uart_port *port)
 354 {
 355 }
 356
 357 static int sunhv_request_port(struct uart_port *port)
 358 {
 359         return 0;
 360 }
 361
 362 static void sunhv_config_port(struct uart_port *port, int flags)
 363 {
 364 }
 365
 366 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
 367 {
 368         return -EINVAL;
 369 }
 370
 371 static struct uart_ops sunhv_pops = {
 372         .tx_empty       = sunhv_tx_empty,
 373         .set_mctrl      = sunhv_set_mctrl,
 374         .get_mctrl      = sunhv_get_mctrl,
 375         .stop_tx        = sunhv_stop_tx,
 376         .start_tx       = sunhv_start_tx,
 377         .send_xchar     = sunhv_send_xchar,
 378         .stop_rx        = sunhv_stop_rx,
 379         .break_ctl      = sunhv_break_ctl,
 380         .startup        = sunhv_startup,
 381         .shutdown       = sunhv_shutdown,
 382         .set_termios    = sunhv_set_termios,
 383         .type           = sunhv_type,
 384         .release_port   = sunhv_release_port,
 385         .request_port   = sunhv_request_port,
 386         .config_port    = sunhv_config_port,
 387         .verify_port    = sunhv_verify_port,
 388 };
 389
 390 static struct uart_driver sunhv_reg = {
 391         .owner                  = THIS_MODULE,
 392         .driver_name            = "sunhv",
 393         .dev_name               = "ttyS",
 394         .major                  = TTY_MAJOR,
 395 };
 396
 397 static struct uart_port *sunhv_port;
 398
 399 /* Copy 's' into the con_write_page, decoding "\n" into
 400  * "\r\n" along the way.  We have to return two lengths
 401  * because the caller needs to know how much to advance
 402  * 's' and also how many bytes to output via con_write_page.
 403  */
 404 static int fill_con_write_page(const char *s, unsigned int n,
 405                                unsigned long *page_bytes)
 406 {
 407         const char *orig_s = s;
 408         char *p = con_write_page;
 409         int left = PAGE_SIZE;
 410
 411         while (n--) {
 412                 if (*s == '\n') {
 413                         if (left < 2)
 414                                 break;
 415                         *p++ = '\r';
 416                         left--;
 417                 } else if (left < 1)
 418                         break;
 419                 *p++ = *s++;
 420                 left--;
 421         }
 422         *page_bytes = p - con_write_page;
 423         return s - orig_s;
 424 }
 425
 426 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
 427 {
 428         struct uart_port *port = sunhv_port;
 429         unsigned long flags;
 430         int locked = 1;
 431
 432         if (port->sysrq || oops_in_progress)
 433                 locked = spin_trylock_irqsave(&port->lock, flags);
 434         else
 435                 spin_lock_irqsave(&port->lock, flags);
 436
 437         while (n > 0) {
 438                 unsigned long ra = __pa(con_write_page);
 439                 unsigned long page_bytes;
 440                 unsigned int cpy = fill_con_write_page(s, n,
 441                                                        &page_bytes);
 442
 443                 n -= cpy;
 444                 s += cpy;
 445                 while (page_bytes > 0) {
 446                         unsigned long written;
 447                         int limit = 1000000;
 448
 449                         while (limit--) {
 450                                 unsigned long stat;
 451
 452                                 stat = sun4v_con_write(ra, page_bytes,
 453                                                        &written);
 454                                 if (stat == HV_EOK)
 455                                         break;
 456                                 udelay(1);
 457                         }
 458                         if (limit < 0)
 459                                 break;
 460                         page_bytes -= written;
 461                         ra += written;
 462                 }
 463         }
 464
 465         if (locked)
 466                 spin_unlock_irqrestore(&port->lock, flags);
 467 }
 468
 469 static inline void sunhv_console_putchar(struct uart_port *port, char c)
 470 {
 471         int limit = 1000000;
 472
 473         while (limit-- > 0) {
 474                 long status = sun4v_con_putchar(c);
 475                 if (status == HV_EOK)
 476                         break;
 477                 udelay(1);
 478         }
 479 }
 480
 481 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
 482 {
 483         struct uart_port *port = sunhv_port;
 484         unsigned long flags;
 485         int i, locked = 1;
 486
 487         if (port->sysrq || oops_in_progress)
 488                 locked = spin_trylock_irqsave(&port->lock, flags);
 489         else
 490                 spin_lock_irqsave(&port->lock, flags);
 491         if (port->sysrq) {
 492                 locked = 0;
 493         } else if (oops_in_progress) {
 494                 locked = spin_trylock(&port->lock);
 495         } else
 496                 spin_lock(&port->lock);
 497
 498         for (i = 0; i < n; i++) {
 499                 if (*s == '\n')
 500                         sunhv_console_putchar(port, '\r');
 501                 sunhv_console_putchar(port, *s++);
 502         }
 503
 504         if (locked)
 505                 spin_unlock_irqrestore(&port->lock, flags);
 506 }
 507
 508 static struct console sunhv_console = {
 509         .name   =       "ttyHV",
 510         .write  =       sunhv_console_write_bychar,
 511         .device =       uart_console_device,
 512         .flags  =       CON_PRINTBUFFER,
 513         .index  =       -1,
 514         .data   =       &sunhv_reg,
 515 };
 516
 517 static int hv_probe(struct platform_device *op)
 518 {
 519         struct uart_port *port;
 520         unsigned long minor;
 521         int err;
 522
 523         if (op->archdata.irqs[0] == 0xffffffff)
 524                 return -ENODEV;
 525
 526         port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
 527         if (unlikely(!port))
 528                 return -ENOMEM;
 529
 530         minor = 1;
 531         if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
 532             minor >= 1) {
 533                 err = -ENOMEM;
 534                 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 535                 if (!con_write_page)
 536                         goto out_free_port;
 537
 538                 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
 539                 if (!con_read_page)
 540                         goto out_free_con_write_page;
 541
 542                 sunhv_console.write = sunhv_console_write_paged;
 543                 sunhv_ops = &bywrite_ops;
 544         }
 545
 546         sunhv_port = port;
 547
 548         port->line = 0;
 549         port->ops = &sunhv_pops;
 550         port->type = PORT_SUNHV;
 551         port->uartclk = ( 29491200 / 16 ); /* arbitrary */
 552
 553         port->membase = (unsigned char __iomem *) __pa(port);
 554
 555         port->irq = op->archdata.irqs[0];
 556
 557         port->dev = &op->dev;
 558
 559         err = sunserial_register_minors(&sunhv_reg, 1);
 560         if (err)
 561                 goto out_free_con_read_page;
 562
 563         sunserial_console_match(&sunhv_console, op->dev.of_node,
 564                                 &sunhv_reg, port->line, false);
 565
 566         err = uart_add_one_port(&sunhv_reg, port);
 567         if (err)
 568                 goto out_unregister_driver;
 569
 570         err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
 571         if (err)
 572                 goto out_remove_port;
 573
 574         platform_set_drvdata(op, port);
 575
 576         return 0;
 577
 578 out_remove_port:
 579         uart_remove_one_port(&sunhv_reg, port);
 580
 581 out_unregister_driver:
 582         sunserial_unregister_minors(&sunhv_reg, 1);
 583
 584 out_free_con_read_page:
 585         kfree(con_read_page);
 586
 587 out_free_con_write_page:
 588         kfree(con_write_page);
 589
 590 out_free_port:
 591         kfree(port);
 592         sunhv_port = NULL;
 593         return err;
 594 }
 595
 596 static int hv_remove(struct platform_device *dev)
 597 {
 598         struct uart_port *port = platform_get_drvdata(dev);
 599
 600         free_irq(port->irq, port);
 601
 602         uart_remove_one_port(&sunhv_reg, port);
 603
 604         sunserial_unregister_minors(&sunhv_reg, 1);
 605
 606         kfree(port);
 607         sunhv_port = NULL;
 608
 609         return 0;
 610 }
 611
 612 static const struct of_device_id hv_match[] = {
 613         {
 614                 .name = "console",
 615                 .compatible = "qcn",
 616         },
 617         {
 618                 .name = "console",
 619                 .compatible = "SUNW,sun4v-console",
 620         },
 621         {},
 622 };
 623
 624 static struct platform_driver hv_driver = {
 625         .driver = {
 626                 .name = "hv",
 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 device_initcall(sunhv_init);
 641
 642 #if 0 /* ...def MODULE ; never supported as such */
 643 MODULE_AUTHOR("David S. Miller");
 644 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
 645 MODULE_VERSION("2.0");
 646 MODULE_LICENSE("GPL");
 647 #endif