drivers/tty/serial/dz.c

   1 /*
   2  * dz.c: Serial port driver for DECstations equipped
   3  *       with the DZ chipset.
   4  *
   5  * Copyright (C) 1998 Olivier A. D. Lebaillif
   6  *
   7  * Email: olivier.lebaillif@ifrsys.com
   8  *
   9  * Copyright (C) 2004, 2006, 2007  Maciej W. Rozycki
  10  *
  11  * [31-AUG-98] triemer
  12  * Changed IRQ to use Harald's dec internals interrupts.h
  13  * removed base_addr code - moving address assignment to setup.c
  14  * Changed name of dz_init to rs_init to be consistent with tc code
  15  * [13-NOV-98] triemer fixed code to receive characters
  16  *    after patches by harald to irq code.
  17  * [09-JAN-99] triemer minor fix for schedule - due to removal of timeout
  18  *            field from "current" - somewhere between 2.1.121 and 2.1.131
  19  Qua Jun 27 15:02:26 BRT 2001
  20  * [27-JUN-2001] Arnaldo Carvalho de Melo <acme@conectiva.com.br> - cleanups
  21  *
  22  * Parts (C) 1999 David Airlie, airlied@linux.ie
  23  * [07-SEP-99] Bugfixes
  24  *
  25  * [06-Jan-2002] Russell King <rmk@arm.linux.org.uk>
  26  * Converted to new serial core
  27  */
  28
  29 #undef DEBUG_DZ
  30
  31 #if defined(CONFIG_SERIAL_DZ_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  32 #define SUPPORT_SYSRQ
  33 #endif
  34
  35 #include <linux/bitops.h>
  36 #include <linux/compiler.h>
  37 #include <linux/console.h>
  38 #include <linux/delay.h>
  39 #include <linux/errno.h>
  40 #include <linux/init.h>
  41 #include <linux/interrupt.h>
  42 #include <linux/ioport.h>
  43 #include <linux/kernel.h>
  44 #include <linux/major.h>
  45 #include <linux/module.h>
  46 #include <linux/serial.h>
  47 #include <linux/serial_core.h>
  48 #include <linux/sysrq.h>
  49 #include <linux/tty.h>
  50 #include <linux/tty_flip.h>
  51
  52 #include <linux/atomic.h>
  53 #include <asm/bootinfo.h>
  54 #include <asm/io.h>
  55
  56 #include <asm/dec/interrupts.h>
  57 #include <asm/dec/kn01.h>
  58 #include <asm/dec/kn02.h>
  59 #include <asm/dec/machtype.h>
  60 #include <asm/dec/prom.h>
  61 #include <asm/dec/system.h>
  62
  63 #include "dz.h"
  64
  65
  66 MODULE_DESCRIPTION("DECstation DZ serial driver");
  67 MODULE_LICENSE("GPL");
  68
  69
  70 static char dz_name[] __initdata = "DECstation DZ serial driver version ";
  71 static char dz_version[] __initdata = "1.04";
  72
  73 struct dz_port {
  74         struct dz_mux           *mux;
  75         struct uart_port        port;
  76         unsigned int            cflag;
  77 };
  78
  79 struct dz_mux {
  80         struct dz_port          dport[DZ_NB_PORT];
  81         atomic_t                map_guard;
  82         atomic_t                irq_guard;
  83         int                     initialised;
  84 };
  85
  86 static struct dz_mux dz_mux;
  87
  88 static inline struct dz_port *to_dport(struct uart_port *uport)
  89 {
  90         return container_of(uport, struct dz_port, port);
  91 }
  92
  93 /*
  94  * ------------------------------------------------------------
  95  * dz_in () and dz_out ()
  96  *
  97  * These routines are used to access the registers of the DZ
  98  * chip, hiding relocation differences between implementation.
  99  * ------------------------------------------------------------
 100  */
 101
 102 static u16 dz_in(struct dz_port *dport, unsigned offset)
 103 {
 104         void __iomem *addr = dport->port.membase + offset;
 105
 106         return readw(addr);
 107 }
 108
 109 static void dz_out(struct dz_port *dport, unsigned offset, u16 value)
 110 {
 111         void __iomem *addr = dport->port.membase + offset;
 112
 113         writew(value, addr);
 114 }
 115
 116 /*
 117  * ------------------------------------------------------------
 118  * rs_stop () and rs_start ()
 119  *
 120  * These routines are called before setting or resetting
 121  * tty->stopped. They enable or disable transmitter interrupts,
 122  * as necessary.
 123  * ------------------------------------------------------------
 124  */
 125
 126 static void dz_stop_tx(struct uart_port *uport)
 127 {
 128         struct dz_port *dport = to_dport(uport);
 129         u16 tmp, mask = 1 << dport->port.line;
 130
 131         tmp = dz_in(dport, DZ_TCR);     /* read the TX flag */
 132         tmp &= ~mask;                   /* clear the TX flag */
 133         dz_out(dport, DZ_TCR, tmp);
 134 }
 135
 136 static void dz_start_tx(struct uart_port *uport)
 137 {
 138         struct dz_port *dport = to_dport(uport);
 139         u16 tmp, mask = 1 << dport->port.line;
 140
 141         tmp = dz_in(dport, DZ_TCR);     /* read the TX flag */
 142         tmp |= mask;                    /* set the TX flag */
 143         dz_out(dport, DZ_TCR, tmp);
 144 }
 145
 146 static void dz_stop_rx(struct uart_port *uport)
 147 {
 148         struct dz_port *dport = to_dport(uport);
 149
 150         dport->cflag &= ~DZ_RXENAB;
 151         dz_out(dport, DZ_LPR, dport->cflag);
 152 }
 153
 154 /*
 155  * ------------------------------------------------------------
 156  *
 157  * Here start the interrupt handling routines.  All of the following
 158  * subroutines are declared as inline and are folded into
 159  * dz_interrupt.  They were separated out for readability's sake.
 160  *
 161  * Note: dz_interrupt() is a "fast" interrupt, which means that it
 162  * runs with interrupts turned off.  People who may want to modify
 163  * dz_interrupt() should try to keep the interrupt handler as fast as
 164  * possible.  After you are done making modifications, it is not a bad
 165  * idea to do:
 166  *
 167  *      make drivers/serial/dz.s
 168  *
 169  * and look at the resulting assemble code in dz.s.
 170  *
 171  * ------------------------------------------------------------
 172  */
 173
 174 /*
 175  * ------------------------------------------------------------
 176  * receive_char ()
 177  *
 178  * This routine deals with inputs from any lines.
 179  * ------------------------------------------------------------
 180  */
 181 static inline void dz_receive_chars(struct dz_mux *mux)
 182 {
 183         struct uart_port *uport;
 184         struct dz_port *dport = &mux->dport[0];
 185         struct uart_icount *icount;
 186         int lines_rx[DZ_NB_PORT] = { [0 ... DZ_NB_PORT - 1] = 0 };
 187         unsigned char ch, flag;
 188         u16 status;
 189         int i;
 190
 191         while ((status = dz_in(dport, DZ_RBUF)) & DZ_DVAL) {
 192                 dport = &mux->dport[LINE(status)];
 193                 uport = &dport->port;
 194
 195                 ch = UCHAR(status);             /* grab the char */
 196                 flag = TTY_NORMAL;
 197
 198                 icount = &uport->icount;
 199                 icount->rx++;
 200
 201                 if (unlikely(status & (DZ_OERR | DZ_FERR | DZ_PERR))) {
 202
 203                         /*
 204                          * There is no separate BREAK status bit, so treat
 205                          * null characters with framing errors as BREAKs;
 206                          * normally, otherwise.  For this move the Framing
 207                          * Error bit to a simulated BREAK bit.
 208                          */
 209                         if (!ch) {
 210                                 status |= (status & DZ_FERR) >>
 211                                           (ffs(DZ_FERR) - ffs(DZ_BREAK));
 212                                 status &= ~DZ_FERR;
 213                         }
 214
 215                         /* Handle SysRq/SAK & keep track of the statistics. */
 216                         if (status & DZ_BREAK) {
 217                                 icount->brk++;
 218                                 if (uart_handle_break(uport))
 219                                         continue;
 220                         } else if (status & DZ_FERR)
 221                                 icount->frame++;
 222                         else if (status & DZ_PERR)
 223                                 icount->parity++;
 224                         if (status & DZ_OERR)
 225                                 icount->overrun++;
 226
 227                         status &= uport->read_status_mask;
 228                         if (status & DZ_BREAK)
 229                                 flag = TTY_BREAK;
 230                         else if (status & DZ_FERR)
 231                                 flag = TTY_FRAME;
 232                         else if (status & DZ_PERR)
 233                                 flag = TTY_PARITY;
 234
 235                 }
 236
 237                 if (uart_handle_sysrq_char(uport, ch))
 238                         continue;
 239
 240                 uart_insert_char(uport, status, DZ_OERR, ch, flag);
 241                 lines_rx[LINE(status)] = 1;
 242         }
 243         for (i = 0; i < DZ_NB_PORT; i++)
 244                 if (lines_rx[i])
 245                         tty_flip_buffer_push(&mux->dport[i].port.state->port);
 246 }
 247
 248 /*
 249  * ------------------------------------------------------------
 250  * transmit_char ()
 251  *
 252  * This routine deals with outputs to any lines.
 253  * ------------------------------------------------------------
 254  */
 255 static inline void dz_transmit_chars(struct dz_mux *mux)
 256 {
 257         struct dz_port *dport = &mux->dport[0];
 258         struct circ_buf *xmit;
 259         unsigned char tmp;
 260         u16 status;
 261
 262         status = dz_in(dport, DZ_CSR);
 263         dport = &mux->dport[LINE(status)];
 264         xmit = &dport->port.state->xmit;
 265
 266         if (dport->port.x_char) {               /* XON/XOFF chars */
 267                 dz_out(dport, DZ_TDR, dport->port.x_char);
 268                 dport->port.icount.tx++;
 269                 dport->port.x_char = 0;
 270                 return;
 271         }
 272         /* If nothing to do or stopped or hardware stopped. */
 273         if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) {
 274                 spin_lock(&dport->port.lock);
 275                 dz_stop_tx(&dport->port);
 276                 spin_unlock(&dport->port.lock);
 277                 return;
 278         }
 279
 280         /*
 281          * If something to do... (remember the dz has no output fifo,
 282          * so we go one char at a time) :-<
 283          */
 284         tmp = xmit->buf[xmit->tail];
 285         xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1);
 286         dz_out(dport, DZ_TDR, tmp);
 287         dport->port.icount.tx++;
 288
 289         if (uart_circ_chars_pending(xmit) < DZ_WAKEUP_CHARS)
 290                 uart_write_wakeup(&dport->port);
 291
 292         /* Are we are done. */
 293         if (uart_circ_empty(xmit)) {
 294                 spin_lock(&dport->port.lock);
 295                 dz_stop_tx(&dport->port);
 296                 spin_unlock(&dport->port.lock);
 297         }
 298 }
 299
 300 /*
 301  * ------------------------------------------------------------
 302  * check_modem_status()
 303  *
 304  * DS 3100 & 5100: Only valid for the MODEM line, duh!
 305  * DS 5000/200: Valid for the MODEM and PRINTER line.
 306  * ------------------------------------------------------------
 307  */
 308 static inline void check_modem_status(struct dz_port *dport)
 309 {
 310         /*
 311          * FIXME:
 312          * 1. No status change interrupt; use a timer.
 313          * 2. Handle the 3100/5000 as appropriate. --macro
 314          */
 315         u16 status;
 316
 317         /* If not the modem line just return.  */
 318         if (dport->port.line != DZ_MODEM)
 319                 return;
 320
 321         status = dz_in(dport, DZ_MSR);
 322
 323         /* it's easy, since DSR2 is the only bit in the register */
 324         if (status)
 325                 dport->port.icount.dsr++;
 326 }
 327
 328 /*
 329  * ------------------------------------------------------------
 330  * dz_interrupt ()
 331  *
 332  * this is the main interrupt routine for the DZ chip.
 333  * It deals with the multiple ports.
 334  * ------------------------------------------------------------
 335  */
 336 static irqreturn_t dz_interrupt(int irq, void *dev_id)
 337 {
 338         struct dz_mux *mux = dev_id;
 339         struct dz_port *dport = &mux->dport[0];
 340         u16 status;
 341
 342         /* get the reason why we just got an irq */
 343         status = dz_in(dport, DZ_CSR);
 344
 345         if ((status & (DZ_RDONE | DZ_RIE)) == (DZ_RDONE | DZ_RIE))
 346                 dz_receive_chars(mux);
 347
 348         if ((status & (DZ_TRDY | DZ_TIE)) == (DZ_TRDY | DZ_TIE))
 349                 dz_transmit_chars(mux);
 350
 351         return IRQ_HANDLED;
 352 }
 353
 354 /*
 355  * -------------------------------------------------------------------
 356  * Here ends the DZ interrupt routines.
 357  * -------------------------------------------------------------------
 358  */
 359
 360 static unsigned int dz_get_mctrl(struct uart_port *uport)
 361 {
 362         /*
 363          * FIXME: Handle the 3100/5000 as appropriate. --macro
 364          */
 365         struct dz_port *dport = to_dport(uport);
 366         unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
 367
 368         if (dport->port.line == DZ_MODEM) {
 369                 if (dz_in(dport, DZ_MSR) & DZ_MODEM_DSR)
 370                         mctrl &= ~TIOCM_DSR;
 371         }
 372
 373         return mctrl;
 374 }
 375
 376 static void dz_set_mctrl(struct uart_port *uport, unsigned int mctrl)
 377 {
 378         /*
 379          * FIXME: Handle the 3100/5000 as appropriate. --macro
 380          */
 381         struct dz_port *dport = to_dport(uport);
 382         u16 tmp;
 383
 384         if (dport->port.line == DZ_MODEM) {
 385                 tmp = dz_in(dport, DZ_TCR);
 386                 if (mctrl & TIOCM_DTR)
 387                         tmp &= ~DZ_MODEM_DTR;
 388                 else
 389                         tmp |= DZ_MODEM_DTR;
 390                 dz_out(dport, DZ_TCR, tmp);
 391         }
 392 }
 393
 394 /*
 395  * -------------------------------------------------------------------
 396  * startup ()
 397  *
 398  * various initialization tasks
 399  * -------------------------------------------------------------------
 400  */
 401 static int dz_startup(struct uart_port *uport)
 402 {
 403         struct dz_port *dport = to_dport(uport);
 404         struct dz_mux *mux = dport->mux;
 405         unsigned long flags;
 406         int irq_guard;
 407         int ret;
 408         u16 tmp;
 409
 410         irq_guard = atomic_add_return(1, &mux->irq_guard);
 411         if (irq_guard != 1)
 412                 return 0;
 413
 414         ret = request_irq(dport->port.irq, dz_interrupt,
 415                           IRQF_SHARED, "dz", mux);
 416         if (ret) {
 417                 atomic_add(-1, &mux->irq_guard);
 418                 printk(KERN_ERR "dz: Cannot get IRQ %d!\n", dport->port.irq);
 419                 return ret;
 420         }
 421
 422         spin_lock_irqsave(&dport->port.lock, flags);
 423
 424         /* Enable interrupts.  */
 425         tmp = dz_in(dport, DZ_CSR);
 426         tmp |= DZ_RIE | DZ_TIE;
 427         dz_out(dport, DZ_CSR, tmp);
 428
 429         spin_unlock_irqrestore(&dport->port.lock, flags);
 430
 431         return 0;
 432 }
 433
 434 /*
 435  * -------------------------------------------------------------------
 436  * shutdown ()
 437  *
 438  * This routine will shutdown a serial port; interrupts are disabled, and
 439  * DTR is dropped if the hangup on close termio flag is on.
 440  * -------------------------------------------------------------------
 441  */
 442 static void dz_shutdown(struct uart_port *uport)
 443 {
 444         struct dz_port *dport = to_dport(uport);
 445         struct dz_mux *mux = dport->mux;
 446         unsigned long flags;
 447         int irq_guard;
 448         u16 tmp;
 449
 450         spin_lock_irqsave(&dport->port.lock, flags);
 451         dz_stop_tx(&dport->port);
 452         spin_unlock_irqrestore(&dport->port.lock, flags);
 453
 454         irq_guard = atomic_add_return(-1, &mux->irq_guard);
 455         if (!irq_guard) {
 456                 /* Disable interrupts.  */
 457                 tmp = dz_in(dport, DZ_CSR);
 458                 tmp &= ~(DZ_RIE | DZ_TIE);
 459                 dz_out(dport, DZ_CSR, tmp);
 460
 461                 free_irq(dport->port.irq, mux);
 462         }
 463 }
 464
 465 /*
 466  * -------------------------------------------------------------------
 467  * dz_tx_empty() -- get the transmitter empty status
 468  *
 469  * Purpose: Let user call ioctl() to get info when the UART physically
 470  *          is emptied.  On bus types like RS485, the transmitter must
 471  *          release the bus after transmitting. This must be done when
 472  *          the transmit shift register is empty, not be done when the
 473  *          transmit holding register is empty.  This functionality
 474  *          allows an RS485 driver to be written in user space.
 475  * -------------------------------------------------------------------
 476  */
 477 static unsigned int dz_tx_empty(struct uart_port *uport)
 478 {
 479         struct dz_port *dport = to_dport(uport);
 480         unsigned short tmp, mask = 1 << dport->port.line;
 481
 482         tmp = dz_in(dport, DZ_TCR);
 483         tmp &= mask;
 484
 485         return tmp ? 0 : TIOCSER_TEMT;
 486 }
 487
 488 static void dz_break_ctl(struct uart_port *uport, int break_state)
 489 {
 490         /*
 491          * FIXME: Can't access BREAK bits in TDR easily;
 492          * reuse the code for polled TX. --macro
 493          */
 494         struct dz_port *dport = to_dport(uport);
 495         unsigned long flags;
 496         unsigned short tmp, mask = 1 << dport->port.line;
 497
 498         spin_lock_irqsave(&uport->lock, flags);
 499         tmp = dz_in(dport, DZ_TCR);
 500         if (break_state)
 501                 tmp |= mask;
 502         else
 503                 tmp &= ~mask;
 504         dz_out(dport, DZ_TCR, tmp);
 505         spin_unlock_irqrestore(&uport->lock, flags);
 506 }
 507
 508 static int dz_encode_baud_rate(unsigned int baud)
 509 {
 510         switch (baud) {
 511         case 50:
 512                 return DZ_B50;
 513         case 75:
 514                 return DZ_B75;
 515         case 110:
 516                 return DZ_B110;
 517         case 134:
 518                 return DZ_B134;
 519         case 150:
 520                 return DZ_B150;
 521         case 300:
 522                 return DZ_B300;
 523         case 600:
 524                 return DZ_B600;
 525         case 1200:
 526                 return DZ_B1200;
 527         case 1800:
 528                 return DZ_B1800;
 529         case 2000:
 530                 return DZ_B2000;
 531         case 2400:
 532                 return DZ_B2400;
 533         case 3600:
 534                 return DZ_B3600;
 535         case 4800:
 536                 return DZ_B4800;
 537         case 7200:
 538                 return DZ_B7200;
 539         case 9600:
 540                 return DZ_B9600;
 541         default:
 542                 return -1;
 543         }
 544 }
 545
 546
 547 static void dz_reset(struct dz_port *dport)
 548 {
 549         struct dz_mux *mux = dport->mux;
 550
 551         if (mux->initialised)
 552                 return;
 553
 554         dz_out(dport, DZ_CSR, DZ_CLR);
 555         while (dz_in(dport, DZ_CSR) & DZ_CLR);
 556         iob();
 557
 558         /* Enable scanning.  */
 559         dz_out(dport, DZ_CSR, DZ_MSE);
 560
 561         mux->initialised = 1;
 562 }
 563
 564 static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
 565                            struct ktermios *old_termios)
 566 {
 567         struct dz_port *dport = to_dport(uport);
 568         unsigned long flags;
 569         unsigned int cflag, baud;
 570         int bflag;
 571
 572         cflag = dport->port.line;
 573
 574         switch (termios->c_cflag & CSIZE) {
 575         case CS5:
 576                 cflag |= DZ_CS5;
 577                 break;
 578         case CS6:
 579                 cflag |= DZ_CS6;
 580                 break;
 581         case CS7:
 582                 cflag |= DZ_CS7;
 583                 break;
 584         case CS8:
 585         default:
 586                 cflag |= DZ_CS8;
 587         }
 588
 589         if (termios->c_cflag & CSTOPB)
 590                 cflag |= DZ_CSTOPB;
 591         if (termios->c_cflag & PARENB)
 592                 cflag |= DZ_PARENB;
 593         if (termios->c_cflag & PARODD)
 594                 cflag |= DZ_PARODD;
 595
 596         baud = uart_get_baud_rate(uport, termios, old_termios, 50, 9600);
 597         bflag = dz_encode_baud_rate(baud);
 598         if (bflag < 0)  {                       /* Try to keep unchanged.  */
 599                 baud = uart_get_baud_rate(uport, old_termios, NULL, 50, 9600);
 600                 bflag = dz_encode_baud_rate(baud);
 601                 if (bflag < 0)  {               /* Resort to 9600.  */
 602                         baud = 9600;
 603                         bflag = DZ_B9600;
 604                 }
 605                 tty_termios_encode_baud_rate(termios, baud, baud);
 606         }
 607         cflag |= bflag;
 608
 609         if (termios->c_cflag & CREAD)
 610                 cflag |= DZ_RXENAB;
 611
 612         spin_lock_irqsave(&dport->port.lock, flags);
 613
 614         uart_update_timeout(uport, termios->c_cflag, baud);
 615
 616         dz_out(dport, DZ_LPR, cflag);
 617         dport->cflag = cflag;
 618
 619         /* setup accept flag */
 620         dport->port.read_status_mask = DZ_OERR;
 621         if (termios->c_iflag & INPCK)
 622                 dport->port.read_status_mask |= DZ_FERR | DZ_PERR;
 623         if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
 624                 dport->port.read_status_mask |= DZ_BREAK;
 625
 626         /* characters to ignore */
 627         uport->ignore_status_mask = 0;
 628         if ((termios->c_iflag & (IGNPAR | IGNBRK)) == (IGNPAR | IGNBRK))
 629                 dport->port.ignore_status_mask |= DZ_OERR;
 630         if (termios->c_iflag & IGNPAR)
 631                 dport->port.ignore_status_mask |= DZ_FERR | DZ_PERR;
 632         if (termios->c_iflag & IGNBRK)
 633                 dport->port.ignore_status_mask |= DZ_BREAK;
 634
 635         spin_unlock_irqrestore(&dport->port.lock, flags);
 636 }
 637
 638 /*
 639  * Hack alert!
 640  * Required solely so that the initial PROM-based console
 641  * works undisturbed in parallel with this one.
 642  */
 643 static void dz_pm(struct uart_port *uport, unsigned int state,
 644                   unsigned int oldstate)
 645 {
 646         struct dz_port *dport = to_dport(uport);
 647         unsigned long flags;
 648
 649         spin_lock_irqsave(&dport->port.lock, flags);
 650         if (state < 3)
 651                 dz_start_tx(&dport->port);
 652         else
 653                 dz_stop_tx(&dport->port);
 654         spin_unlock_irqrestore(&dport->port.lock, flags);
 655 }
 656
 657
 658 static const char *dz_type(struct uart_port *uport)
 659 {
 660         return "DZ";
 661 }
 662
 663 static void dz_release_port(struct uart_port *uport)
 664 {
 665         struct dz_mux *mux = to_dport(uport)->mux;
 666         int map_guard;
 667
 668         iounmap(uport->membase);
 669         uport->membase = NULL;
 670
 671         map_guard = atomic_add_return(-1, &mux->map_guard);
 672         if (!map_guard)
 673                 release_mem_region(uport->mapbase, dec_kn_slot_size);
 674 }
 675
 676 static int dz_map_port(struct uart_port *uport)
 677 {
 678         if (!uport->membase)
 679                 uport->membase = ioremap_nocache(uport->mapbase,
 680                                                  dec_kn_slot_size);
 681         if (!uport->membase) {
 682                 printk(KERN_ERR "dz: Cannot map MMIO\n");
 683                 return -ENOMEM;
 684         }
 685         return 0;
 686 }
 687
 688 static int dz_request_port(struct uart_port *uport)
 689 {
 690         struct dz_mux *mux = to_dport(uport)->mux;
 691         int map_guard;
 692         int ret;
 693
 694         map_guard = atomic_add_return(1, &mux->map_guard);
 695         if (map_guard == 1) {
 696                 if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
 697                                         "dz")) {
 698                         atomic_add(-1, &mux->map_guard);
 699                         printk(KERN_ERR
 700                                "dz: Unable to reserve MMIO resource\n");
 701                         return -EBUSY;
 702                 }
 703         }
 704         ret = dz_map_port(uport);
 705         if (ret) {
 706                 map_guard = atomic_add_return(-1, &mux->map_guard);
 707                 if (!map_guard)
 708                         release_mem_region(uport->mapbase, dec_kn_slot_size);
 709                 return ret;
 710         }
 711         return 0;
 712 }
 713
 714 static void dz_config_port(struct uart_port *uport, int flags)
 715 {
 716         struct dz_port *dport = to_dport(uport);
 717
 718         if (flags & UART_CONFIG_TYPE) {
 719                 if (dz_request_port(uport))
 720                         return;
 721
 722                 uport->type = PORT_DZ;
 723
 724                 dz_reset(dport);
 725         }
 726 }
 727
 728 /*
 729  * Verify the new serial_struct (for TIOCSSERIAL).
 730  */
 731 static int dz_verify_port(struct uart_port *uport, struct serial_struct *ser)
 732 {
 733         int ret = 0;
 734
 735         if (ser->type != PORT_UNKNOWN && ser->type != PORT_DZ)
 736                 ret = -EINVAL;
 737         if (ser->irq != uport->irq)
 738                 ret = -EINVAL;
 739         return ret;
 740 }
 741
 742 static struct uart_ops dz_ops = {
 743         .tx_empty       = dz_tx_empty,
 744         .get_mctrl      = dz_get_mctrl,
 745         .set_mctrl      = dz_set_mctrl,
 746         .stop_tx        = dz_stop_tx,
 747         .start_tx       = dz_start_tx,
 748         .stop_rx        = dz_stop_rx,
 749         .break_ctl      = dz_break_ctl,
 750         .startup        = dz_startup,
 751         .shutdown       = dz_shutdown,
 752         .set_termios    = dz_set_termios,
 753         .pm             = dz_pm,
 754         .type           = dz_type,
 755         .release_port   = dz_release_port,
 756         .request_port   = dz_request_port,
 757         .config_port    = dz_config_port,
 758         .verify_port    = dz_verify_port,
 759 };
 760
 761 static void __init dz_init_ports(void)
 762 {
 763         static int first = 1;
 764         unsigned long base;
 765         int line;
 766
 767         if (!first)
 768                 return;
 769         first = 0;
 770
 771         if (mips_machtype == MACH_DS23100 || mips_machtype == MACH_DS5100)
 772                 base = dec_kn_slot_base + KN01_DZ11;
 773         else
 774                 base = dec_kn_slot_base + KN02_DZ11;
 775
 776         for (line = 0; line < DZ_NB_PORT; line++) {
 777                 struct dz_port *dport = &dz_mux.dport[line];
 778                 struct uart_port *uport = &dport->port;
 779
 780                 dport->mux      = &dz_mux;
 781
 782                 uport->irq      = dec_interrupt[DEC_IRQ_DZ11];
 783                 uport->fifosize = 1;
 784                 uport->iotype   = UPIO_MEM;
 785                 uport->flags    = UPF_BOOT_AUTOCONF;
 786                 uport->ops      = &dz_ops;
 787                 uport->line     = line;
 788                 uport->mapbase  = base;
 789         }
 790 }
 791
 792 #ifdef CONFIG_SERIAL_DZ_CONSOLE
 793 /*
 794  * -------------------------------------------------------------------
 795  * dz_console_putchar() -- transmit a character
 796  *
 797  * Polled transmission.  This is tricky.  We need to mask transmit
 798  * interrupts so that they do not interfere, enable the transmitter
 799  * for the line requested and then wait till the transmit scanner
 800  * requests data for this line.  But it may request data for another
 801  * line first, in which case we have to disable its transmitter and
 802  * repeat waiting till our line pops up.  Only then the character may
 803  * be transmitted.  Finally, the state of the transmitter mask is
 804  * restored.  Welcome to the world of PDP-11!
 805  * -------------------------------------------------------------------
 806  */
 807 static void dz_console_putchar(struct uart_port *uport, int ch)
 808 {
 809         struct dz_port *dport = to_dport(uport);
 810         unsigned long flags;
 811         unsigned short csr, tcr, trdy, mask;
 812         int loops = 10000;
 813
 814         spin_lock_irqsave(&dport->port.lock, flags);
 815         csr = dz_in(dport, DZ_CSR);
 816         dz_out(dport, DZ_CSR, csr & ~DZ_TIE);
 817         tcr = dz_in(dport, DZ_TCR);
 818         tcr |= 1 << dport->port.line;
 819         mask = tcr;
 820         dz_out(dport, DZ_TCR, mask);
 821         iob();
 822         spin_unlock_irqrestore(&dport->port.lock, flags);
 823
 824         do {
 825                 trdy = dz_in(dport, DZ_CSR);
 826                 if (!(trdy & DZ_TRDY))
 827                         continue;
 828                 trdy = (trdy & DZ_TLINE) >> 8;
 829                 if (trdy == dport->port.line)
 830                         break;
 831                 mask &= ~(1 << trdy);
 832                 dz_out(dport, DZ_TCR, mask);
 833                 iob();
 834                 udelay(2);
 835         } while (--loops);
 836
 837         if (loops)                              /* Cannot send otherwise. */
 838                 dz_out(dport, DZ_TDR, ch);
 839
 840         dz_out(dport, DZ_TCR, tcr);
 841         dz_out(dport, DZ_CSR, csr);
 842 }
 843
 844 /*
 845  * -------------------------------------------------------------------
 846  * dz_console_print ()
 847  *
 848  * dz_console_print is registered for printk.
 849  * The console must be locked when we get here.
 850  * -------------------------------------------------------------------
 851  */
 852 static void dz_console_print(struct console *co,
 853                              const char *str,
 854                              unsigned int count)
 855 {
 856         struct dz_port *dport = &dz_mux.dport[co->index];
 857 #ifdef DEBUG_DZ
 858         prom_printf((char *) str);
 859 #endif
 860         uart_console_write(&dport->port, str, count, dz_console_putchar);
 861 }
 862
 863 static int __init dz_console_setup(struct console *co, char *options)
 864 {
 865         struct dz_port *dport = &dz_mux.dport[co->index];
 866         struct uart_port *uport = &dport->port;
 867         int baud = 9600;
 868         int bits = 8;
 869         int parity = 'n';
 870         int flow = 'n';
 871         int ret;
 872
 873         ret = dz_map_port(uport);
 874         if (ret)
 875                 return ret;
 876
 877         spin_lock_init(&dport->port.lock);      /* For dz_pm().  */
 878
 879         dz_reset(dport);
 880         dz_pm(uport, 0, -1);
 881
 882         if (options)
 883                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 884
 885         return uart_set_options(&dport->port, co, baud, parity, bits, flow);
 886 }
 887
 888 static struct uart_driver dz_reg;
 889 static struct console dz_console = {
 890         .name   = "ttyS",
 891         .write  = dz_console_print,
 892         .device = uart_console_device,
 893         .setup  = dz_console_setup,
 894         .flags  = CON_PRINTBUFFER,
 895         .index  = -1,
 896         .data   = &dz_reg,
 897 };
 898
 899 static int __init dz_serial_console_init(void)
 900 {
 901         if (!IOASIC) {
 902                 dz_init_ports();
 903                 register_console(&dz_console);
 904                 return 0;
 905         } else
 906                 return -ENXIO;
 907 }
 908
 909 console_initcall(dz_serial_console_init);
 910
 911 #define SERIAL_DZ_CONSOLE       &dz_console
 912 #else
 913 #define SERIAL_DZ_CONSOLE       NULL
 914 #endif /* CONFIG_SERIAL_DZ_CONSOLE */
 915
 916 static struct uart_driver dz_reg = {
 917         .owner                  = THIS_MODULE,
 918         .driver_name            = "serial",
 919         .dev_name               = "ttyS",
 920         .major                  = TTY_MAJOR,
 921         .minor                  = 64,
 922         .nr                     = DZ_NB_PORT,
 923         .cons                   = SERIAL_DZ_CONSOLE,
 924 };
 925
 926 static int __init dz_init(void)
 927 {
 928         int ret, i;
 929
 930         if (IOASIC)
 931                 return -ENXIO;
 932
 933         printk("%s%s\n", dz_name, dz_version);
 934
 935         dz_init_ports();
 936
 937         ret = uart_register_driver(&dz_reg);
 938         if (ret)
 939                 return ret;
 940
 941         for (i = 0; i < DZ_NB_PORT; i++)
 942                 uart_add_one_port(&dz_reg, &dz_mux.dport[i].port);
 943
 944         return 0;
 945 }
 946
 947 module_init(dz_init);