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 static void dz_enable_ms(struct uart_port *uport)
 155 {
 156         /* nothing to do */
 157 }
 158
 159 /*
 160  * ------------------------------------------------------------
 161  *
 162  * Here start the interrupt handling routines.  All of the following
 163  * subroutines are declared as inline and are folded into
 164  * dz_interrupt.  They were separated out for readability's sake.
 165  *
 166  * Note: dz_interrupt() is a "fast" interrupt, which means that it
 167  * runs with interrupts turned off.  People who may want to modify
 168  * dz_interrupt() should try to keep the interrupt handler as fast as
 169  * possible.  After you are done making modifications, it is not a bad
 170  * idea to do:
 171  *
 172  *      make drivers/serial/dz.s
 173  *
 174  * and look at the resulting assemble code in dz.s.
 175  *
 176  * ------------------------------------------------------------
 177  */
 178
 179 /*
 180  * ------------------------------------------------------------
 181  * receive_char ()
 182  *
 183  * This routine deals with inputs from any lines.
 184  * ------------------------------------------------------------
 185  */
 186 static inline void dz_receive_chars(struct dz_mux *mux)
 187 {
 188         struct uart_port *uport;
 189         struct dz_port *dport = &mux->dport[0];
 190         struct uart_icount *icount;
 191         int lines_rx[DZ_NB_PORT] = { [0 ... DZ_NB_PORT - 1] = 0 };
 192         unsigned char ch, flag;
 193         u16 status;
 194         int i;
 195
 196         while ((status = dz_in(dport, DZ_RBUF)) & DZ_DVAL) {
 197                 dport = &mux->dport[LINE(status)];
 198                 uport = &dport->port;
 199
 200                 ch = UCHAR(status);             /* grab the char */
 201                 flag = TTY_NORMAL;
 202
 203                 icount = &uport->icount;
 204                 icount->rx++;
 205
 206                 if (unlikely(status & (DZ_OERR | DZ_FERR | DZ_PERR))) {
 207
 208                         /*
 209                          * There is no separate BREAK status bit, so treat
 210                          * null characters with framing errors as BREAKs;
 211                          * normally, otherwise.  For this move the Framing
 212                          * Error bit to a simulated BREAK bit.
 213                          */
 214                         if (!ch) {
 215                                 status |= (status & DZ_FERR) >>
 216                                           (ffs(DZ_FERR) - ffs(DZ_BREAK));
 217                                 status &= ~DZ_FERR;
 218                         }
 219
 220                         /* Handle SysRq/SAK & keep track of the statistics. */
 221                         if (status & DZ_BREAK) {
 222                                 icount->brk++;
 223                                 if (uart_handle_break(uport))
 224                                         continue;
 225                         } else if (status & DZ_FERR)
 226                                 icount->frame++;
 227                         else if (status & DZ_PERR)
 228                                 icount->parity++;
 229                         if (status & DZ_OERR)
 230                                 icount->overrun++;
 231
 232                         status &= uport->read_status_mask;
 233                         if (status & DZ_BREAK)
 234                                 flag = TTY_BREAK;
 235                         else if (status & DZ_FERR)
 236                                 flag = TTY_FRAME;
 237                         else if (status & DZ_PERR)
 238                                 flag = TTY_PARITY;
 239
 240                 }
 241
 242                 if (uart_handle_sysrq_char(uport, ch))
 243                         continue;
 244
 245                 uart_insert_char(uport, status, DZ_OERR, ch, flag);
 246                 lines_rx[LINE(status)] = 1;
 247         }
 248         for (i = 0; i < DZ_NB_PORT; i++)
 249                 if (lines_rx[i])
 250                         tty_flip_buffer_push(&mux->dport[i].port.state->port);
 251 }
 252
 253 /*
 254  * ------------------------------------------------------------
 255  * transmit_char ()
 256  *
 257  * This routine deals with outputs to any lines.
 258  * ------------------------------------------------------------
 259  */
 260 static inline void dz_transmit_chars(struct dz_mux *mux)
 261 {
 262         struct dz_port *dport = &mux->dport[0];
 263         struct circ_buf *xmit;
 264         unsigned char tmp;
 265         u16 status;
 266
 267         status = dz_in(dport, DZ_CSR);
 268         dport = &mux->dport[LINE(status)];
 269         xmit = &dport->port.state->xmit;
 270
 271         if (dport->port.x_char) {               /* XON/XOFF chars */
 272                 dz_out(dport, DZ_TDR, dport->port.x_char);
 273                 dport->port.icount.tx++;
 274                 dport->port.x_char = 0;
 275                 return;
 276         }
 277         /* If nothing to do or stopped or hardware stopped. */
 278         if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) {
 279                 spin_lock(&dport->port.lock);
 280                 dz_stop_tx(&dport->port);
 281                 spin_unlock(&dport->port.lock);
 282                 return;
 283         }
 284
 285         /*
 286          * If something to do... (remember the dz has no output fifo,
 287          * so we go one char at a time) :-<
 288          */
 289         tmp = xmit->buf[xmit->tail];
 290         xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1);
 291         dz_out(dport, DZ_TDR, tmp);
 292         dport->port.icount.tx++;
 293
 294         if (uart_circ_chars_pending(xmit) < DZ_WAKEUP_CHARS)
 295                 uart_write_wakeup(&dport->port);
 296
 297         /* Are we are done. */
 298         if (uart_circ_empty(xmit)) {
 299                 spin_lock(&dport->port.lock);
 300                 dz_stop_tx(&dport->port);
 301                 spin_unlock(&dport->port.lock);
 302         }
 303 }
 304
 305 /*
 306  * ------------------------------------------------------------
 307  * check_modem_status()
 308  *
 309  * DS 3100 & 5100: Only valid for the MODEM line, duh!
 310  * DS 5000/200: Valid for the MODEM and PRINTER line.
 311  * ------------------------------------------------------------
 312  */
 313 static inline void check_modem_status(struct dz_port *dport)
 314 {
 315         /*
 316          * FIXME:
 317          * 1. No status change interrupt; use a timer.
 318          * 2. Handle the 3100/5000 as appropriate. --macro
 319          */
 320         u16 status;
 321
 322         /* If not the modem line just return.  */
 323         if (dport->port.line != DZ_MODEM)
 324                 return;
 325
 326         status = dz_in(dport, DZ_MSR);
 327
 328         /* it's easy, since DSR2 is the only bit in the register */
 329         if (status)
 330                 dport->port.icount.dsr++;
 331 }
 332
 333 /*
 334  * ------------------------------------------------------------
 335  * dz_interrupt ()
 336  *
 337  * this is the main interrupt routine for the DZ chip.
 338  * It deals with the multiple ports.
 339  * ------------------------------------------------------------
 340  */
 341 static irqreturn_t dz_interrupt(int irq, void *dev_id)
 342 {
 343         struct dz_mux *mux = dev_id;
 344         struct dz_port *dport = &mux->dport[0];
 345         u16 status;
 346
 347         /* get the reason why we just got an irq */
 348         status = dz_in(dport, DZ_CSR);
 349
 350         if ((status & (DZ_RDONE | DZ_RIE)) == (DZ_RDONE | DZ_RIE))
 351                 dz_receive_chars(mux);
 352
 353         if ((status & (DZ_TRDY | DZ_TIE)) == (DZ_TRDY | DZ_TIE))
 354                 dz_transmit_chars(mux);
 355
 356         return IRQ_HANDLED;
 357 }
 358
 359 /*
 360  * -------------------------------------------------------------------
 361  * Here ends the DZ interrupt routines.
 362  * -------------------------------------------------------------------
 363  */
 364
 365 static unsigned int dz_get_mctrl(struct uart_port *uport)
 366 {
 367         /*
 368          * FIXME: Handle the 3100/5000 as appropriate. --macro
 369          */
 370         struct dz_port *dport = to_dport(uport);
 371         unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
 372
 373         if (dport->port.line == DZ_MODEM) {
 374                 if (dz_in(dport, DZ_MSR) & DZ_MODEM_DSR)
 375                         mctrl &= ~TIOCM_DSR;
 376         }
 377
 378         return mctrl;
 379 }
 380
 381 static void dz_set_mctrl(struct uart_port *uport, unsigned int mctrl)
 382 {
 383         /*
 384          * FIXME: Handle the 3100/5000 as appropriate. --macro
 385          */
 386         struct dz_port *dport = to_dport(uport);
 387         u16 tmp;
 388
 389         if (dport->port.line == DZ_MODEM) {
 390                 tmp = dz_in(dport, DZ_TCR);
 391                 if (mctrl & TIOCM_DTR)
 392                         tmp &= ~DZ_MODEM_DTR;
 393                 else
 394                         tmp |= DZ_MODEM_DTR;
 395                 dz_out(dport, DZ_TCR, tmp);
 396         }
 397 }
 398
 399 /*
 400  * -------------------------------------------------------------------
 401  * startup ()
 402  *
 403  * various initialization tasks
 404  * -------------------------------------------------------------------
 405  */
 406 static int dz_startup(struct uart_port *uport)
 407 {
 408         struct dz_port *dport = to_dport(uport);
 409         struct dz_mux *mux = dport->mux;
 410         unsigned long flags;
 411         int irq_guard;
 412         int ret;
 413         u16 tmp;
 414
 415         irq_guard = atomic_add_return(1, &mux->irq_guard);
 416         if (irq_guard != 1)
 417                 return 0;
 418
 419         ret = request_irq(dport->port.irq, dz_interrupt,
 420                           IRQF_SHARED, "dz", mux);
 421         if (ret) {
 422                 atomic_add(-1, &mux->irq_guard);
 423                 printk(KERN_ERR "dz: Cannot get IRQ %d!\n", dport->port.irq);
 424                 return ret;
 425         }
 426
 427         spin_lock_irqsave(&dport->port.lock, flags);
 428
 429         /* Enable interrupts.  */
 430         tmp = dz_in(dport, DZ_CSR);
 431         tmp |= DZ_RIE | DZ_TIE;
 432         dz_out(dport, DZ_CSR, tmp);
 433
 434         spin_unlock_irqrestore(&dport->port.lock, flags);
 435
 436         return 0;
 437 }
 438
 439 /*
 440  * -------------------------------------------------------------------
 441  * shutdown ()
 442  *
 443  * This routine will shutdown a serial port; interrupts are disabled, and
 444  * DTR is dropped if the hangup on close termio flag is on.
 445  * -------------------------------------------------------------------
 446  */
 447 static void dz_shutdown(struct uart_port *uport)
 448 {
 449         struct dz_port *dport = to_dport(uport);
 450         struct dz_mux *mux = dport->mux;
 451         unsigned long flags;
 452         int irq_guard;
 453         u16 tmp;
 454
 455         spin_lock_irqsave(&dport->port.lock, flags);
 456         dz_stop_tx(&dport->port);
 457         spin_unlock_irqrestore(&dport->port.lock, flags);
 458
 459         irq_guard = atomic_add_return(-1, &mux->irq_guard);
 460         if (!irq_guard) {
 461                 /* Disable interrupts.  */
 462                 tmp = dz_in(dport, DZ_CSR);
 463                 tmp &= ~(DZ_RIE | DZ_TIE);
 464                 dz_out(dport, DZ_CSR, tmp);
 465
 466                 free_irq(dport->port.irq, mux);
 467         }
 468 }
 469
 470 /*
 471  * -------------------------------------------------------------------
 472  * dz_tx_empty() -- get the transmitter empty status
 473  *
 474  * Purpose: Let user call ioctl() to get info when the UART physically
 475  *          is emptied.  On bus types like RS485, the transmitter must
 476  *          release the bus after transmitting. This must be done when
 477  *          the transmit shift register is empty, not be done when the
 478  *          transmit holding register is empty.  This functionality
 479  *          allows an RS485 driver to be written in user space.
 480  * -------------------------------------------------------------------
 481  */
 482 static unsigned int dz_tx_empty(struct uart_port *uport)
 483 {
 484         struct dz_port *dport = to_dport(uport);
 485         unsigned short tmp, mask = 1 << dport->port.line;
 486
 487         tmp = dz_in(dport, DZ_TCR);
 488         tmp &= mask;
 489
 490         return tmp ? 0 : TIOCSER_TEMT;
 491 }
 492
 493 static void dz_break_ctl(struct uart_port *uport, int break_state)
 494 {
 495         /*
 496          * FIXME: Can't access BREAK bits in TDR easily;
 497          * reuse the code for polled TX. --macro
 498          */
 499         struct dz_port *dport = to_dport(uport);
 500         unsigned long flags;
 501         unsigned short tmp, mask = 1 << dport->port.line;
 502
 503         spin_lock_irqsave(&uport->lock, flags);
 504         tmp = dz_in(dport, DZ_TCR);
 505         if (break_state)
 506                 tmp |= mask;
 507         else
 508                 tmp &= ~mask;
 509         dz_out(dport, DZ_TCR, tmp);
 510         spin_unlock_irqrestore(&uport->lock, flags);
 511 }
 512
 513 static int dz_encode_baud_rate(unsigned int baud)
 514 {
 515         switch (baud) {
 516         case 50:
 517                 return DZ_B50;
 518         case 75:
 519                 return DZ_B75;
 520         case 110:
 521                 return DZ_B110;
 522         case 134:
 523                 return DZ_B134;
 524         case 150:
 525                 return DZ_B150;
 526         case 300:
 527                 return DZ_B300;
 528         case 600:
 529                 return DZ_B600;
 530         case 1200:
 531                 return DZ_B1200;
 532         case 1800:
 533                 return DZ_B1800;
 534         case 2000:
 535                 return DZ_B2000;
 536         case 2400:
 537                 return DZ_B2400;
 538         case 3600:
 539                 return DZ_B3600;
 540         case 4800:
 541                 return DZ_B4800;
 542         case 7200:
 543                 return DZ_B7200;
 544         case 9600:
 545                 return DZ_B9600;
 546         default:
 547                 return -1;
 548         }
 549 }
 550
 551
 552 static void dz_reset(struct dz_port *dport)
 553 {
 554         struct dz_mux *mux = dport->mux;
 555
 556         if (mux->initialised)
 557                 return;
 558
 559         dz_out(dport, DZ_CSR, DZ_CLR);
 560         while (dz_in(dport, DZ_CSR) & DZ_CLR);
 561         iob();
 562
 563         /* Enable scanning.  */
 564         dz_out(dport, DZ_CSR, DZ_MSE);
 565
 566         mux->initialised = 1;
 567 }
 568
 569 static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
 570                            struct ktermios *old_termios)
 571 {
 572         struct dz_port *dport = to_dport(uport);
 573         unsigned long flags;
 574         unsigned int cflag, baud;
 575         int bflag;
 576
 577         cflag = dport->port.line;
 578
 579         switch (termios->c_cflag & CSIZE) {
 580         case CS5:
 581                 cflag |= DZ_CS5;
 582                 break;
 583         case CS6:
 584                 cflag |= DZ_CS6;
 585                 break;
 586         case CS7:
 587                 cflag |= DZ_CS7;
 588                 break;
 589         case CS8:
 590         default:
 591                 cflag |= DZ_CS8;
 592         }
 593
 594         if (termios->c_cflag & CSTOPB)
 595                 cflag |= DZ_CSTOPB;
 596         if (termios->c_cflag & PARENB)
 597                 cflag |= DZ_PARENB;
 598         if (termios->c_cflag & PARODD)
 599                 cflag |= DZ_PARODD;
 600
 601         baud = uart_get_baud_rate(uport, termios, old_termios, 50, 9600);
 602         bflag = dz_encode_baud_rate(baud);
 603         if (bflag < 0)  {                       /* Try to keep unchanged.  */
 604                 baud = uart_get_baud_rate(uport, old_termios, NULL, 50, 9600);
 605                 bflag = dz_encode_baud_rate(baud);
 606                 if (bflag < 0)  {               /* Resort to 9600.  */
 607                         baud = 9600;
 608                         bflag = DZ_B9600;
 609                 }
 610                 tty_termios_encode_baud_rate(termios, baud, baud);
 611         }
 612         cflag |= bflag;
 613
 614         if (termios->c_cflag & CREAD)
 615                 cflag |= DZ_RXENAB;
 616
 617         spin_lock_irqsave(&dport->port.lock, flags);
 618
 619         uart_update_timeout(uport, termios->c_cflag, baud);
 620
 621         dz_out(dport, DZ_LPR, cflag);
 622         dport->cflag = cflag;
 623
 624         /* setup accept flag */
 625         dport->port.read_status_mask = DZ_OERR;
 626         if (termios->c_iflag & INPCK)
 627                 dport->port.read_status_mask |= DZ_FERR | DZ_PERR;
 628         if (termios->c_iflag & (BRKINT | PARMRK))
 629                 dport->port.read_status_mask |= DZ_BREAK;
 630
 631         /* characters to ignore */
 632         uport->ignore_status_mask = 0;
 633         if ((termios->c_iflag & (IGNPAR | IGNBRK)) == (IGNPAR | IGNBRK))
 634                 dport->port.ignore_status_mask |= DZ_OERR;
 635         if (termios->c_iflag & IGNPAR)
 636                 dport->port.ignore_status_mask |= DZ_FERR | DZ_PERR;
 637         if (termios->c_iflag & IGNBRK)
 638                 dport->port.ignore_status_mask |= DZ_BREAK;
 639
 640         spin_unlock_irqrestore(&dport->port.lock, flags);
 641 }
 642
 643 /*
 644  * Hack alert!
 645  * Required solely so that the initial PROM-based console
 646  * works undisturbed in parallel with this one.
 647  */
 648 static void dz_pm(struct uart_port *uport, unsigned int state,
 649                   unsigned int oldstate)
 650 {
 651         struct dz_port *dport = to_dport(uport);
 652         unsigned long flags;
 653
 654         spin_lock_irqsave(&dport->port.lock, flags);
 655         if (state < 3)
 656                 dz_start_tx(&dport->port);
 657         else
 658                 dz_stop_tx(&dport->port);
 659         spin_unlock_irqrestore(&dport->port.lock, flags);
 660 }
 661
 662
 663 static const char *dz_type(struct uart_port *uport)
 664 {
 665         return "DZ";
 666 }
 667
 668 static void dz_release_port(struct uart_port *uport)
 669 {
 670         struct dz_mux *mux = to_dport(uport)->mux;
 671         int map_guard;
 672
 673         iounmap(uport->membase);
 674         uport->membase = NULL;
 675
 676         map_guard = atomic_add_return(-1, &mux->map_guard);
 677         if (!map_guard)
 678                 release_mem_region(uport->mapbase, dec_kn_slot_size);
 679 }
 680
 681 static int dz_map_port(struct uart_port *uport)
 682 {
 683         if (!uport->membase)
 684                 uport->membase = ioremap_nocache(uport->mapbase,
 685                                                  dec_kn_slot_size);
 686         if (!uport->membase) {
 687                 printk(KERN_ERR "dz: Cannot map MMIO\n");
 688                 return -ENOMEM;
 689         }
 690         return 0;
 691 }
 692
 693 static int dz_request_port(struct uart_port *uport)
 694 {
 695         struct dz_mux *mux = to_dport(uport)->mux;
 696         int map_guard;
 697         int ret;
 698
 699         map_guard = atomic_add_return(1, &mux->map_guard);
 700         if (map_guard == 1) {
 701                 if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
 702                                         "dz")) {
 703                         atomic_add(-1, &mux->map_guard);
 704                         printk(KERN_ERR
 705                                "dz: Unable to reserve MMIO resource\n");
 706                         return -EBUSY;
 707                 }
 708         }
 709         ret = dz_map_port(uport);
 710         if (ret) {
 711                 map_guard = atomic_add_return(-1, &mux->map_guard);
 712                 if (!map_guard)
 713                         release_mem_region(uport->mapbase, dec_kn_slot_size);
 714                 return ret;
 715         }
 716         return 0;
 717 }
 718
 719 static void dz_config_port(struct uart_port *uport, int flags)
 720 {
 721         struct dz_port *dport = to_dport(uport);
 722
 723         if (flags & UART_CONFIG_TYPE) {
 724                 if (dz_request_port(uport))
 725                         return;
 726
 727                 uport->type = PORT_DZ;
 728
 729                 dz_reset(dport);
 730         }
 731 }
 732
 733 /*
 734  * Verify the new serial_struct (for TIOCSSERIAL).
 735  */
 736 static int dz_verify_port(struct uart_port *uport, struct serial_struct *ser)
 737 {
 738         int ret = 0;
 739
 740         if (ser->type != PORT_UNKNOWN && ser->type != PORT_DZ)
 741                 ret = -EINVAL;
 742         if (ser->irq != uport->irq)
 743                 ret = -EINVAL;
 744         return ret;
 745 }
 746
 747 static struct uart_ops dz_ops = {
 748         .tx_empty       = dz_tx_empty,
 749         .get_mctrl      = dz_get_mctrl,
 750         .set_mctrl      = dz_set_mctrl,
 751         .stop_tx        = dz_stop_tx,
 752         .start_tx       = dz_start_tx,
 753         .stop_rx        = dz_stop_rx,
 754         .enable_ms      = dz_enable_ms,
 755         .break_ctl      = dz_break_ctl,
 756         .startup        = dz_startup,
 757         .shutdown       = dz_shutdown,
 758         .set_termios    = dz_set_termios,
 759         .pm             = dz_pm,
 760         .type           = dz_type,
 761         .release_port   = dz_release_port,
 762         .request_port   = dz_request_port,
 763         .config_port    = dz_config_port,
 764         .verify_port    = dz_verify_port,
 765 };
 766
 767 static void __init dz_init_ports(void)
 768 {
 769         static int first = 1;
 770         unsigned long base;
 771         int line;
 772
 773         if (!first)
 774                 return;
 775         first = 0;
 776
 777         if (mips_machtype == MACH_DS23100 || mips_machtype == MACH_DS5100)
 778                 base = dec_kn_slot_base + KN01_DZ11;
 779         else
 780                 base = dec_kn_slot_base + KN02_DZ11;
 781
 782         for (line = 0; line < DZ_NB_PORT; line++) {
 783                 struct dz_port *dport = &dz_mux.dport[line];
 784                 struct uart_port *uport = &dport->port;
 785
 786                 dport->mux      = &dz_mux;
 787
 788                 uport->irq      = dec_interrupt[DEC_IRQ_DZ11];
 789                 uport->fifosize = 1;
 790                 uport->iotype   = UPIO_MEM;
 791                 uport->flags    = UPF_BOOT_AUTOCONF;
 792                 uport->ops      = &dz_ops;
 793                 uport->line     = line;
 794                 uport->mapbase  = base;
 795         }
 796 }
 797
 798 #ifdef CONFIG_SERIAL_DZ_CONSOLE
 799 /*
 800  * -------------------------------------------------------------------
 801  * dz_console_putchar() -- transmit a character
 802  *
 803  * Polled transmission.  This is tricky.  We need to mask transmit
 804  * interrupts so that they do not interfere, enable the transmitter
 805  * for the line requested and then wait till the transmit scanner
 806  * requests data for this line.  But it may request data for another
 807  * line first, in which case we have to disable its transmitter and
 808  * repeat waiting till our line pops up.  Only then the character may
 809  * be transmitted.  Finally, the state of the transmitter mask is
 810  * restored.  Welcome to the world of PDP-11!
 811  * -------------------------------------------------------------------
 812  */
 813 static void dz_console_putchar(struct uart_port *uport, int ch)
 814 {
 815         struct dz_port *dport = to_dport(uport);
 816         unsigned long flags;
 817         unsigned short csr, tcr, trdy, mask;
 818         int loops = 10000;
 819
 820         spin_lock_irqsave(&dport->port.lock, flags);
 821         csr = dz_in(dport, DZ_CSR);
 822         dz_out(dport, DZ_CSR, csr & ~DZ_TIE);
 823         tcr = dz_in(dport, DZ_TCR);
 824         tcr |= 1 << dport->port.line;
 825         mask = tcr;
 826         dz_out(dport, DZ_TCR, mask);
 827         iob();
 828         spin_unlock_irqrestore(&dport->port.lock, flags);
 829
 830         do {
 831                 trdy = dz_in(dport, DZ_CSR);
 832                 if (!(trdy & DZ_TRDY))
 833                         continue;
 834                 trdy = (trdy & DZ_TLINE) >> 8;
 835                 if (trdy == dport->port.line)
 836                         break;
 837                 mask &= ~(1 << trdy);
 838                 dz_out(dport, DZ_TCR, mask);
 839                 iob();
 840                 udelay(2);
 841         } while (--loops);
 842
 843         if (loops)                              /* Cannot send otherwise. */
 844                 dz_out(dport, DZ_TDR, ch);
 845
 846         dz_out(dport, DZ_TCR, tcr);
 847         dz_out(dport, DZ_CSR, csr);
 848 }
 849
 850 /*
 851  * -------------------------------------------------------------------
 852  * dz_console_print ()
 853  *
 854  * dz_console_print is registered for printk.
 855  * The console must be locked when we get here.
 856  * -------------------------------------------------------------------
 857  */
 858 static void dz_console_print(struct console *co,
 859                              const char *str,
 860                              unsigned int count)
 861 {
 862         struct dz_port *dport = &dz_mux.dport[co->index];
 863 #ifdef DEBUG_DZ
 864         prom_printf((char *) str);
 865 #endif
 866         uart_console_write(&dport->port, str, count, dz_console_putchar);
 867 }
 868
 869 static int __init dz_console_setup(struct console *co, char *options)
 870 {
 871         struct dz_port *dport = &dz_mux.dport[co->index];
 872         struct uart_port *uport = &dport->port;
 873         int baud = 9600;
 874         int bits = 8;
 875         int parity = 'n';
 876         int flow = 'n';
 877         int ret;
 878
 879         ret = dz_map_port(uport);
 880         if (ret)
 881                 return ret;
 882
 883         spin_lock_init(&dport->port.lock);      /* For dz_pm().  */
 884
 885         dz_reset(dport);
 886         dz_pm(uport, 0, -1);
 887
 888         if (options)
 889                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 890
 891         return uart_set_options(&dport->port, co, baud, parity, bits, flow);
 892 }
 893
 894 static struct uart_driver dz_reg;
 895 static struct console dz_console = {
 896         .name   = "ttyS",
 897         .write  = dz_console_print,
 898         .device = uart_console_device,
 899         .setup  = dz_console_setup,
 900         .flags  = CON_PRINTBUFFER,
 901         .index  = -1,
 902         .data   = &dz_reg,
 903 };
 904
 905 static int __init dz_serial_console_init(void)
 906 {
 907         if (!IOASIC) {
 908                 dz_init_ports();
 909                 register_console(&dz_console);
 910                 return 0;
 911         } else
 912                 return -ENXIO;
 913 }
 914
 915 console_initcall(dz_serial_console_init);
 916
 917 #define SERIAL_DZ_CONSOLE       &dz_console
 918 #else
 919 #define SERIAL_DZ_CONSOLE       NULL
 920 #endif /* CONFIG_SERIAL_DZ_CONSOLE */
 921
 922 static struct uart_driver dz_reg = {
 923         .owner                  = THIS_MODULE,
 924         .driver_name            = "serial",
 925         .dev_name               = "ttyS",
 926         .major                  = TTY_MAJOR,
 927         .minor                  = 64,
 928         .nr                     = DZ_NB_PORT,
 929         .cons                   = SERIAL_DZ_CONSOLE,
 930 };
 931
 932 static int __init dz_init(void)
 933 {
 934         int ret, i;
 935
 936         if (IOASIC)
 937                 return -ENXIO;
 938
 939         printk("%s%s\n", dz_name, dz_version);
 940
 941         dz_init_ports();
 942
 943         ret = uart_register_driver(&dz_reg);
 944         if (ret)
 945                 return ret;
 946
 947         for (i = 0; i < DZ_NB_PORT; i++)
 948                 uart_add_one_port(&dz_reg, &dz_mux.dport[i].port);
 949
 950         return 0;
 951 }
 952
 953 module_init(dz_init);