drivers/tty/serial/dz.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * dz.c: Serial port driver for DECstations equipped
   4  *       with the DZ chipset.
   5  *
   6  * Copyright (C) 1998 Olivier A. D. Lebaillif
   7  *
   8  * Email: olivier.lebaillif@ifrsys.com
   9  *
  10  * Copyright (C) 2004, 2006, 2007  Maciej W. Rozycki
  11  *
  12  * [31-AUG-98] triemer
  13  * Changed IRQ to use Harald's dec internals interrupts.h
  14  * removed base_addr code - moving address assignment to setup.c
  15  * Changed name of dz_init to rs_init to be consistent with tc code
  16  * [13-NOV-98] triemer fixed code to receive characters
  17  *    after patches by harald to irq code.
  18  * [09-JAN-99] triemer minor fix for schedule - due to removal of timeout
  19  *            field from "current" - somewhere between 2.1.121 and 2.1.131
  20  Qua Jun 27 15:02:26 BRT 2001
  21  * [27-JUN-2001] Arnaldo Carvalho de Melo <acme@conectiva.com.br> - cleanups
  22  *
  23  * Parts (C) 1999 David Airlie, airlied@linux.ie
  24  * [07-SEP-99] Bugfixes
  25  *
  26  * [06-Jan-2002] Russell King <rmk@arm.linux.org.uk>
  27  * Converted to new serial core
  28  */
  29
  30 #undef DEBUG_DZ
  31
  32 #if defined(CONFIG_SERIAL_DZ_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  33 #define SUPPORT_SYSRQ
  34 #endif
  35
  36 #include <linux/bitops.h>
  37 #include <linux/compiler.h>
  38 #include <linux/console.h>
  39 #include <linux/delay.h>
  40 #include <linux/errno.h>
  41 #include <linux/init.h>
  42 #include <linux/interrupt.h>
  43 #include <linux/ioport.h>
  44 #include <linux/kernel.h>
  45 #include <linux/major.h>
  46 #include <linux/module.h>
  47 #include <linux/serial.h>
  48 #include <linux/serial_core.h>
  49 #include <linux/sysrq.h>
  50 #include <linux/tty.h>
  51 #include <linux/tty_flip.h>
  52
  53 #include <linux/atomic.h>
  54 #include <asm/bootinfo.h>
  55 #include <asm/io.h>
  56
  57 #include <asm/dec/interrupts.h>
  58 #include <asm/dec/kn01.h>
  59 #include <asm/dec/kn02.h>
  60 #include <asm/dec/machtype.h>
  61 #include <asm/dec/prom.h>
  62 #include <asm/dec/system.h>
  63
  64 #include "dz.h"
  65
  66
  67 MODULE_DESCRIPTION("DECstation DZ serial driver");
  68 MODULE_LICENSE("GPL");
  69
  70
  71 static char dz_name[] __initdata = "DECstation DZ serial driver version ";
  72 static char dz_version[] __initdata = "1.04";
  73
  74 struct dz_port {
  75         struct dz_mux           *mux;
  76         struct uart_port        port;
  77         unsigned int            cflag;
  78 };
  79
  80 struct dz_mux {
  81         struct dz_port          dport[DZ_NB_PORT];
  82         atomic_t                map_guard;
  83         atomic_t                irq_guard;
  84         int                     initialised;
  85 };
  86
  87 static struct dz_mux dz_mux;
  88
  89 static inline struct dz_port *to_dport(struct uart_port *uport)
  90 {
  91         return container_of(uport, struct dz_port, port);
  92 }
  93
  94 /*
  95  * ------------------------------------------------------------
  96  * dz_in () and dz_out ()
  97  *
  98  * These routines are used to access the registers of the DZ
  99  * chip, hiding relocation differences between implementation.
 100  * ------------------------------------------------------------
 101  */
 102
 103 static u16 dz_in(struct dz_port *dport, unsigned offset)
 104 {
 105         void __iomem *addr = dport->port.membase + offset;
 106
 107         return readw(addr);
 108 }
 109
 110 static void dz_out(struct dz_port *dport, unsigned offset, u16 value)
 111 {
 112         void __iomem *addr = dport->port.membase + offset;
 113
 114         writew(value, addr);
 115 }
 116
 117 /*
 118  * ------------------------------------------------------------
 119  * rs_stop () and rs_start ()
 120  *
 121  * These routines are called before setting or resetting
 122  * tty->stopped. They enable or disable transmitter interrupts,
 123  * as necessary.
 124  * ------------------------------------------------------------
 125  */
 126
 127 static void dz_stop_tx(struct uart_port *uport)
 128 {
 129         struct dz_port *dport = to_dport(uport);
 130         u16 tmp, mask = 1 << dport->port.line;
 131
 132         tmp = dz_in(dport, DZ_TCR);     /* read the TX flag */
 133         tmp &= ~mask;                   /* clear the TX flag */
 134         dz_out(dport, DZ_TCR, tmp);
 135 }
 136
 137 static void dz_start_tx(struct uart_port *uport)
 138 {
 139         struct dz_port *dport = to_dport(uport);
 140         u16 tmp, mask = 1 << dport->port.line;
 141
 142         tmp = dz_in(dport, DZ_TCR);     /* read the TX flag */
 143         tmp |= mask;                    /* set the TX flag */
 144         dz_out(dport, DZ_TCR, tmp);
 145 }
 146
 147 static void dz_stop_rx(struct uart_port *uport)
 148 {
 149         struct dz_port *dport = to_dport(uport);
 150
 151         dport->cflag &= ~DZ_RXENAB;
 152         dz_out(dport, DZ_LPR, dport->cflag);
 153 }
 154
 155 /*
 156  * ------------------------------------------------------------
 157  *
 158  * Here start the interrupt handling routines.  All of the following
 159  * subroutines are declared as inline and are folded into
 160  * dz_interrupt.  They were separated out for readability's sake.
 161  *
 162  * Note: dz_interrupt() is a "fast" interrupt, which means that it
 163  * runs with interrupts turned off.  People who may want to modify
 164  * dz_interrupt() should try to keep the interrupt handler as fast as
 165  * possible.  After you are done making modifications, it is not a bad
 166  * idea to do:
 167  *
 168  *      make drivers/serial/dz.s
 169  *
 170  * and look at the resulting assemble code in dz.s.
 171  *
 172  * ------------------------------------------------------------
 173  */
 174
 175 /*
 176  * ------------------------------------------------------------
 177  * receive_char ()
 178  *
 179  * This routine deals with inputs from any lines.
 180  * ------------------------------------------------------------
 181  */
 182 static inline void dz_receive_chars(struct dz_mux *mux)
 183 {
 184         struct uart_port *uport;
 185         struct dz_port *dport = &mux->dport[0];
 186         struct uart_icount *icount;
 187         int lines_rx[DZ_NB_PORT] = { [0 ... DZ_NB_PORT - 1] = 0 };
 188         unsigned char ch, flag;
 189         u16 status;
 190         int i;
 191
 192         while ((status = dz_in(dport, DZ_RBUF)) & DZ_DVAL) {
 193                 dport = &mux->dport[LINE(status)];
 194                 uport = &dport->port;
 195
 196                 ch = UCHAR(status);             /* grab the char */
 197                 flag = TTY_NORMAL;
 198
 199                 icount = &uport->icount;
 200                 icount->rx++;
 201
 202                 if (unlikely(status & (DZ_OERR | DZ_FERR | DZ_PERR))) {
 203
 204                         /*
 205                          * There is no separate BREAK status bit, so treat
 206                          * null characters with framing errors as BREAKs;
 207                          * normally, otherwise.  For this move the Framing
 208                          * Error bit to a simulated BREAK bit.
 209                          */
 210                         if (!ch) {
 211                                 status |= (status & DZ_FERR) >>
 212                                           (ffs(DZ_FERR) - ffs(DZ_BREAK));
 213                                 status &= ~DZ_FERR;
 214                         }
 215
 216                         /* Handle SysRq/SAK & keep track of the statistics. */
 217                         if (status & DZ_BREAK) {
 218                                 icount->brk++;
 219                                 if (uart_handle_break(uport))
 220                                         continue;
 221                         } else if (status & DZ_FERR)
 222                                 icount->frame++;
 223                         else if (status & DZ_PERR)
 224                                 icount->parity++;
 225                         if (status & DZ_OERR)
 226                                 icount->overrun++;
 227
 228                         status &= uport->read_status_mask;
 229                         if (status & DZ_BREAK)
 230                                 flag = TTY_BREAK;
 231                         else if (status & DZ_FERR)
 232                                 flag = TTY_FRAME;
 233                         else if (status & DZ_PERR)
 234                                 flag = TTY_PARITY;
 235
 236                 }
 237
 238                 if (uart_handle_sysrq_char(uport, ch))
 239                         continue;
 240
 241                 uart_insert_char(uport, status, DZ_OERR, ch, flag);
 242                 lines_rx[LINE(status)] = 1;
 243         }
 244         for (i = 0; i < DZ_NB_PORT; i++)
 245                 if (lines_rx[i])
 246                         tty_flip_buffer_push(&mux->dport[i].port.state->port);
 247 }
 248
 249 /*
 250  * ------------------------------------------------------------
 251  * transmit_char ()
 252  *
 253  * This routine deals with outputs to any lines.
 254  * ------------------------------------------------------------
 255  */
 256 static inline void dz_transmit_chars(struct dz_mux *mux)
 257 {
 258         struct dz_port *dport = &mux->dport[0];
 259         struct circ_buf *xmit;
 260         unsigned char tmp;
 261         u16 status;
 262
 263         status = dz_in(dport, DZ_CSR);
 264         dport = &mux->dport[LINE(status)];
 265         xmit = &dport->port.state->xmit;
 266
 267         if (dport->port.x_char) {               /* XON/XOFF chars */
 268                 dz_out(dport, DZ_TDR, dport->port.x_char);
 269                 dport->port.icount.tx++;
 270                 dport->port.x_char = 0;
 271                 return;
 272         }
 273         /* If nothing to do or stopped or hardware stopped. */
 274         if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) {
 275                 spin_lock(&dport->port.lock);
 276                 dz_stop_tx(&dport->port);
 277                 spin_unlock(&dport->port.lock);
 278                 return;
 279         }
 280
 281         /*
 282          * If something to do... (remember the dz has no output fifo,
 283          * so we go one char at a time) :-<
 284          */
 285         tmp = xmit->buf[xmit->tail];
 286         xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1);
 287         dz_out(dport, DZ_TDR, tmp);
 288         dport->port.icount.tx++;
 289
 290         if (uart_circ_chars_pending(xmit) < DZ_WAKEUP_CHARS)
 291                 uart_write_wakeup(&dport->port);
 292
 293         /* Are we are done. */
 294         if (uart_circ_empty(xmit)) {
 295                 spin_lock(&dport->port.lock);
 296                 dz_stop_tx(&dport->port);
 297                 spin_unlock(&dport->port.lock);
 298         }
 299 }
 300
 301 /*
 302  * ------------------------------------------------------------
 303  * check_modem_status()
 304  *
 305  * DS 3100 & 5100: Only valid for the MODEM line, duh!
 306  * DS 5000/200: Valid for the MODEM and PRINTER line.
 307  * ------------------------------------------------------------
 308  */
 309 static inline void check_modem_status(struct dz_port *dport)
 310 {
 311         /*
 312          * FIXME:
 313          * 1. No status change interrupt; use a timer.
 314          * 2. Handle the 3100/5000 as appropriate. --macro
 315          */
 316         u16 status;
 317
 318         /* If not the modem line just return.  */
 319         if (dport->port.line != DZ_MODEM)
 320                 return;
 321
 322         status = dz_in(dport, DZ_MSR);
 323
 324         /* it's easy, since DSR2 is the only bit in the register */
 325         if (status)
 326                 dport->port.icount.dsr++;
 327 }
 328
 329 /*
 330  * ------------------------------------------------------------
 331  * dz_interrupt ()
 332  *
 333  * this is the main interrupt routine for the DZ chip.
 334  * It deals with the multiple ports.
 335  * ------------------------------------------------------------
 336  */
 337 static irqreturn_t dz_interrupt(int irq, void *dev_id)
 338 {
 339         struct dz_mux *mux = dev_id;
 340         struct dz_port *dport = &mux->dport[0];
 341         u16 status;
 342
 343         /* get the reason why we just got an irq */
 344         status = dz_in(dport, DZ_CSR);
 345
 346         if ((status & (DZ_RDONE | DZ_RIE)) == (DZ_RDONE | DZ_RIE))
 347                 dz_receive_chars(mux);
 348
 349         if ((status & (DZ_TRDY | DZ_TIE)) == (DZ_TRDY | DZ_TIE))
 350                 dz_transmit_chars(mux);
 351
 352         return IRQ_HANDLED;
 353 }
 354
 355 /*
 356  * -------------------------------------------------------------------
 357  * Here ends the DZ interrupt routines.
 358  * -------------------------------------------------------------------
 359  */
 360
 361 static unsigned int dz_get_mctrl(struct uart_port *uport)
 362 {
 363         /*
 364          * FIXME: Handle the 3100/5000 as appropriate. --macro
 365          */
 366         struct dz_port *dport = to_dport(uport);
 367         unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
 368
 369         if (dport->port.line == DZ_MODEM) {
 370                 if (dz_in(dport, DZ_MSR) & DZ_MODEM_DSR)
 371                         mctrl &= ~TIOCM_DSR;
 372         }
 373
 374         return mctrl;
 375 }
 376
 377 static void dz_set_mctrl(struct uart_port *uport, unsigned int mctrl)
 378 {
 379         /*
 380          * FIXME: Handle the 3100/5000 as appropriate. --macro
 381          */
 382         struct dz_port *dport = to_dport(uport);
 383         u16 tmp;
 384
 385         if (dport->port.line == DZ_MODEM) {
 386                 tmp = dz_in(dport, DZ_TCR);
 387                 if (mctrl & TIOCM_DTR)
 388                         tmp &= ~DZ_MODEM_DTR;
 389                 else
 390                         tmp |= DZ_MODEM_DTR;
 391                 dz_out(dport, DZ_TCR, tmp);
 392         }
 393 }
 394
 395 /*
 396  * -------------------------------------------------------------------
 397  * startup ()
 398  *
 399  * various initialization tasks
 400  * -------------------------------------------------------------------
 401  */
 402 static int dz_startup(struct uart_port *uport)
 403 {
 404         struct dz_port *dport = to_dport(uport);
 405         struct dz_mux *mux = dport->mux;
 406         unsigned long flags;
 407         int irq_guard;
 408         int ret;
 409         u16 tmp;
 410
 411         irq_guard = atomic_add_return(1, &mux->irq_guard);
 412         if (irq_guard != 1)
 413                 return 0;
 414
 415         ret = request_irq(dport->port.irq, dz_interrupt,
 416                           IRQF_SHARED, "dz", mux);
 417         if (ret) {
 418                 atomic_add(-1, &mux->irq_guard);
 419                 printk(KERN_ERR "dz: Cannot get IRQ %d!\n", dport->port.irq);
 420                 return ret;
 421         }
 422
 423         spin_lock_irqsave(&dport->port.lock, flags);
 424
 425         /* Enable interrupts.  */
 426         tmp = dz_in(dport, DZ_CSR);
 427         tmp |= DZ_RIE | DZ_TIE;
 428         dz_out(dport, DZ_CSR, tmp);
 429
 430         spin_unlock_irqrestore(&dport->port.lock, flags);
 431
 432         return 0;
 433 }
 434
 435 /*
 436  * -------------------------------------------------------------------
 437  * shutdown ()
 438  *
 439  * This routine will shutdown a serial port; interrupts are disabled, and
 440  * DTR is dropped if the hangup on close termio flag is on.
 441  * -------------------------------------------------------------------
 442  */
 443 static void dz_shutdown(struct uart_port *uport)
 444 {
 445         struct dz_port *dport = to_dport(uport);
 446         struct dz_mux *mux = dport->mux;
 447         unsigned long flags;
 448         int irq_guard;
 449         u16 tmp;
 450
 451         spin_lock_irqsave(&dport->port.lock, flags);
 452         dz_stop_tx(&dport->port);
 453         spin_unlock_irqrestore(&dport->port.lock, flags);
 454
 455         irq_guard = atomic_add_return(-1, &mux->irq_guard);
 456         if (!irq_guard) {
 457                 /* Disable interrupts.  */
 458                 tmp = dz_in(dport, DZ_CSR);
 459                 tmp &= ~(DZ_RIE | DZ_TIE);
 460                 dz_out(dport, DZ_CSR, tmp);
 461
 462                 free_irq(dport->port.irq, mux);
 463         }
 464 }
 465
 466 /*
 467  * -------------------------------------------------------------------
 468  * dz_tx_empty() -- get the transmitter empty status
 469  *
 470  * Purpose: Let user call ioctl() to get info when the UART physically
 471  *          is emptied.  On bus types like RS485, the transmitter must
 472  *          release the bus after transmitting. This must be done when
 473  *          the transmit shift register is empty, not be done when the
 474  *          transmit holding register is empty.  This functionality
 475  *          allows an RS485 driver to be written in user space.
 476  * -------------------------------------------------------------------
 477  */
 478 static unsigned int dz_tx_empty(struct uart_port *uport)
 479 {
 480         struct dz_port *dport = to_dport(uport);
 481         unsigned short tmp, mask = 1 << dport->port.line;
 482
 483         tmp = dz_in(dport, DZ_TCR);
 484         tmp &= mask;
 485
 486         return tmp ? 0 : TIOCSER_TEMT;
 487 }
 488
 489 static void dz_break_ctl(struct uart_port *uport, int break_state)
 490 {
 491         /*
 492          * FIXME: Can't access BREAK bits in TDR easily;
 493          * reuse the code for polled TX. --macro
 494          */
 495         struct dz_port *dport = to_dport(uport);
 496         unsigned long flags;
 497         unsigned short tmp, mask = 1 << dport->port.line;
 498
 499         spin_lock_irqsave(&uport->lock, flags);
 500         tmp = dz_in(dport, DZ_TCR);
 501         if (break_state)
 502                 tmp |= mask;
 503         else
 504                 tmp &= ~mask;
 505         dz_out(dport, DZ_TCR, tmp);
 506         spin_unlock_irqrestore(&uport->lock, flags);
 507 }
 508
 509 static int dz_encode_baud_rate(unsigned int baud)
 510 {
 511         switch (baud) {
 512         case 50:
 513                 return DZ_B50;
 514         case 75:
 515                 return DZ_B75;
 516         case 110:
 517                 return DZ_B110;
 518         case 134:
 519                 return DZ_B134;
 520         case 150:
 521                 return DZ_B150;
 522         case 300:
 523                 return DZ_B300;
 524         case 600:
 525                 return DZ_B600;
 526         case 1200:
 527                 return DZ_B1200;
 528         case 1800:
 529                 return DZ_B1800;
 530         case 2000:
 531                 return DZ_B2000;
 532         case 2400:
 533                 return DZ_B2400;
 534         case 3600:
 535                 return DZ_B3600;
 536         case 4800:
 537                 return DZ_B4800;
 538         case 7200:
 539                 return DZ_B7200;
 540         case 9600:
 541                 return DZ_B9600;
 542         default:
 543                 return -1;
 544         }
 545 }
 546
 547
 548 static void dz_reset(struct dz_port *dport)
 549 {
 550         struct dz_mux *mux = dport->mux;
 551
 552         if (mux->initialised)
 553                 return;
 554
 555         dz_out(dport, DZ_CSR, DZ_CLR);
 556         while (dz_in(dport, DZ_CSR) & DZ_CLR);
 557         iob();
 558
 559         /* Enable scanning.  */
 560         dz_out(dport, DZ_CSR, DZ_MSE);
 561
 562         mux->initialised = 1;
 563 }
 564
 565 static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
 566                            struct ktermios *old_termios)
 567 {
 568         struct dz_port *dport = to_dport(uport);
 569         unsigned long flags;
 570         unsigned int cflag, baud;
 571         int bflag;
 572
 573         cflag = dport->port.line;
 574
 575         switch (termios->c_cflag & CSIZE) {
 576         case CS5:
 577                 cflag |= DZ_CS5;
 578                 break;
 579         case CS6:
 580                 cflag |= DZ_CS6;
 581                 break;
 582         case CS7:
 583                 cflag |= DZ_CS7;
 584                 break;
 585         case CS8:
 586         default:
 587                 cflag |= DZ_CS8;
 588         }
 589
 590         if (termios->c_cflag & CSTOPB)
 591                 cflag |= DZ_CSTOPB;
 592         if (termios->c_cflag & PARENB)
 593                 cflag |= DZ_PARENB;
 594         if (termios->c_cflag & PARODD)
 595                 cflag |= DZ_PARODD;
 596
 597         baud = uart_get_baud_rate(uport, termios, old_termios, 50, 9600);
 598         bflag = dz_encode_baud_rate(baud);
 599         if (bflag < 0)  {                       /* Try to keep unchanged.  */
 600                 baud = uart_get_baud_rate(uport, old_termios, NULL, 50, 9600);
 601                 bflag = dz_encode_baud_rate(baud);
 602                 if (bflag < 0)  {               /* Resort to 9600.  */
 603                         baud = 9600;
 604                         bflag = DZ_B9600;
 605                 }
 606                 tty_termios_encode_baud_rate(termios, baud, baud);
 607         }
 608         cflag |= bflag;
 609
 610         if (termios->c_cflag & CREAD)
 611                 cflag |= DZ_RXENAB;
 612
 613         spin_lock_irqsave(&dport->port.lock, flags);
 614
 615         uart_update_timeout(uport, termios->c_cflag, baud);
 616
 617         dz_out(dport, DZ_LPR, cflag);
 618         dport->cflag = cflag;
 619
 620         /* setup accept flag */
 621         dport->port.read_status_mask = DZ_OERR;
 622         if (termios->c_iflag & INPCK)
 623                 dport->port.read_status_mask |= DZ_FERR | DZ_PERR;
 624         if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
 625                 dport->port.read_status_mask |= DZ_BREAK;
 626
 627         /* characters to ignore */
 628         uport->ignore_status_mask = 0;
 629         if ((termios->c_iflag & (IGNPAR | IGNBRK)) == (IGNPAR | IGNBRK))
 630                 dport->port.ignore_status_mask |= DZ_OERR;
 631         if (termios->c_iflag & IGNPAR)
 632                 dport->port.ignore_status_mask |= DZ_FERR | DZ_PERR;
 633         if (termios->c_iflag & IGNBRK)
 634                 dport->port.ignore_status_mask |= DZ_BREAK;
 635
 636         spin_unlock_irqrestore(&dport->port.lock, flags);
 637 }
 638
 639 /*
 640  * Hack alert!
 641  * Required solely so that the initial PROM-based console
 642  * works undisturbed in parallel with this one.
 643  */
 644 static void dz_pm(struct uart_port *uport, unsigned int state,
 645                   unsigned int oldstate)
 646 {
 647         struct dz_port *dport = to_dport(uport);
 648         unsigned long flags;
 649
 650         spin_lock_irqsave(&dport->port.lock, flags);
 651         if (state < 3)
 652                 dz_start_tx(&dport->port);
 653         else
 654                 dz_stop_tx(&dport->port);
 655         spin_unlock_irqrestore(&dport->port.lock, flags);
 656 }
 657
 658
 659 static const char *dz_type(struct uart_port *uport)
 660 {
 661         return "DZ";
 662 }
 663
 664 static void dz_release_port(struct uart_port *uport)
 665 {
 666         struct dz_mux *mux = to_dport(uport)->mux;
 667         int map_guard;
 668
 669         iounmap(uport->membase);
 670         uport->membase = NULL;
 671
 672         map_guard = atomic_add_return(-1, &mux->map_guard);
 673         if (!map_guard)
 674                 release_mem_region(uport->mapbase, dec_kn_slot_size);
 675 }
 676
 677 static int dz_map_port(struct uart_port *uport)
 678 {
 679         if (!uport->membase)
 680                 uport->membase = ioremap_nocache(uport->mapbase,
 681                                                  dec_kn_slot_size);
 682         if (!uport->membase) {
 683                 printk(KERN_ERR "dz: Cannot map MMIO\n");
 684                 return -ENOMEM;
 685         }
 686         return 0;
 687 }
 688
 689 static int dz_request_port(struct uart_port *uport)
 690 {
 691         struct dz_mux *mux = to_dport(uport)->mux;
 692         int map_guard;
 693         int ret;
 694
 695         map_guard = atomic_add_return(1, &mux->map_guard);
 696         if (map_guard == 1) {
 697                 if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
 698                                         "dz")) {
 699                         atomic_add(-1, &mux->map_guard);
 700                         printk(KERN_ERR
 701                                "dz: Unable to reserve MMIO resource\n");
 702                         return -EBUSY;
 703                 }
 704         }
 705         ret = dz_map_port(uport);
 706         if (ret) {
 707                 map_guard = atomic_add_return(-1, &mux->map_guard);
 708                 if (!map_guard)
 709                         release_mem_region(uport->mapbase, dec_kn_slot_size);
 710                 return ret;
 711         }
 712         return 0;
 713 }
 714
 715 static void dz_config_port(struct uart_port *uport, int flags)
 716 {
 717         struct dz_port *dport = to_dport(uport);
 718
 719         if (flags & UART_CONFIG_TYPE) {
 720                 if (dz_request_port(uport))
 721                         return;
 722
 723                 uport->type = PORT_DZ;
 724
 725                 dz_reset(dport);
 726         }
 727 }
 728
 729 /*
 730  * Verify the new serial_struct (for TIOCSSERIAL).
 731  */
 732 static int dz_verify_port(struct uart_port *uport, struct serial_struct *ser)
 733 {
 734         int ret = 0;
 735
 736         if (ser->type != PORT_UNKNOWN && ser->type != PORT_DZ)
 737                 ret = -EINVAL;
 738         if (ser->irq != uport->irq)
 739                 ret = -EINVAL;
 740         return ret;
 741 }
 742
 743 static const struct uart_ops dz_ops = {
 744         .tx_empty       = dz_tx_empty,
 745         .get_mctrl      = dz_get_mctrl,
 746         .set_mctrl      = dz_set_mctrl,
 747         .stop_tx        = dz_stop_tx,
 748         .start_tx       = dz_start_tx,
 749         .stop_rx        = dz_stop_rx,
 750         .break_ctl      = dz_break_ctl,
 751         .startup        = dz_startup,
 752         .shutdown       = dz_shutdown,
 753         .set_termios    = dz_set_termios,
 754         .pm             = dz_pm,
 755         .type           = dz_type,
 756         .release_port   = dz_release_port,
 757         .request_port   = dz_request_port,
 758         .config_port    = dz_config_port,
 759         .verify_port    = dz_verify_port,
 760 };
 761
 762 static void __init dz_init_ports(void)
 763 {
 764         static int first = 1;
 765         unsigned long base;
 766         int line;
 767
 768         if (!first)
 769                 return;
 770         first = 0;
 771
 772         if (mips_machtype == MACH_DS23100 || mips_machtype == MACH_DS5100)
 773                 base = dec_kn_slot_base + KN01_DZ11;
 774         else
 775                 base = dec_kn_slot_base + KN02_DZ11;
 776
 777         for (line = 0; line < DZ_NB_PORT; line++) {
 778                 struct dz_port *dport = &dz_mux.dport[line];
 779                 struct uart_port *uport = &dport->port;
 780
 781                 dport->mux      = &dz_mux;
 782
 783                 uport->irq      = dec_interrupt[DEC_IRQ_DZ11];
 784                 uport->fifosize = 1;
 785                 uport->iotype   = UPIO_MEM;
 786                 uport->flags    = UPF_BOOT_AUTOCONF;
 787                 uport->ops      = &dz_ops;
 788                 uport->line     = line;
 789                 uport->mapbase  = base;
 790         }
 791 }
 792
 793 #ifdef CONFIG_SERIAL_DZ_CONSOLE
 794 /*
 795  * -------------------------------------------------------------------
 796  * dz_console_putchar() -- transmit a character
 797  *
 798  * Polled transmission.  This is tricky.  We need to mask transmit
 799  * interrupts so that they do not interfere, enable the transmitter
 800  * for the line requested and then wait till the transmit scanner
 801  * requests data for this line.  But it may request data for another
 802  * line first, in which case we have to disable its transmitter and
 803  * repeat waiting till our line pops up.  Only then the character may
 804  * be transmitted.  Finally, the state of the transmitter mask is
 805  * restored.  Welcome to the world of PDP-11!
 806  * -------------------------------------------------------------------
 807  */
 808 static void dz_console_putchar(struct uart_port *uport, int ch)
 809 {
 810         struct dz_port *dport = to_dport(uport);
 811         unsigned long flags;
 812         unsigned short csr, tcr, trdy, mask;
 813         int loops = 10000;
 814
 815         spin_lock_irqsave(&dport->port.lock, flags);
 816         csr = dz_in(dport, DZ_CSR);
 817         dz_out(dport, DZ_CSR, csr & ~DZ_TIE);
 818         tcr = dz_in(dport, DZ_TCR);
 819         tcr |= 1 << dport->port.line;
 820         mask = tcr;
 821         dz_out(dport, DZ_TCR, mask);
 822         iob();
 823         spin_unlock_irqrestore(&dport->port.lock, flags);
 824
 825         do {
 826                 trdy = dz_in(dport, DZ_CSR);
 827                 if (!(trdy & DZ_TRDY))
 828                         continue;
 829                 trdy = (trdy & DZ_TLINE) >> 8;
 830                 if (trdy == dport->port.line)
 831                         break;
 832                 mask &= ~(1 << trdy);
 833                 dz_out(dport, DZ_TCR, mask);
 834                 iob();
 835                 udelay(2);
 836         } while (--loops);
 837
 838         if (loops)                              /* Cannot send otherwise. */
 839                 dz_out(dport, DZ_TDR, ch);
 840
 841         dz_out(dport, DZ_TCR, tcr);
 842         dz_out(dport, DZ_CSR, csr);
 843 }
 844
 845 /*
 846  * -------------------------------------------------------------------
 847  * dz_console_print ()
 848  *
 849  * dz_console_print is registered for printk.
 850  * The console must be locked when we get here.
 851  * -------------------------------------------------------------------
 852  */
 853 static void dz_console_print(struct console *co,
 854                              const char *str,
 855                              unsigned int count)
 856 {
 857         struct dz_port *dport = &dz_mux.dport[co->index];
 858 #ifdef DEBUG_DZ
 859         prom_printf((char *) str);
 860 #endif
 861         uart_console_write(&dport->port, str, count, dz_console_putchar);
 862 }
 863
 864 static int __init dz_console_setup(struct console *co, char *options)
 865 {
 866         struct dz_port *dport = &dz_mux.dport[co->index];
 867         struct uart_port *uport = &dport->port;
 868         int baud = 9600;
 869         int bits = 8;
 870         int parity = 'n';
 871         int flow = 'n';
 872         int ret;
 873
 874         ret = dz_map_port(uport);
 875         if (ret)
 876                 return ret;
 877
 878         spin_lock_init(&dport->port.lock);      /* For dz_pm().  */
 879
 880         dz_reset(dport);
 881         dz_pm(uport, 0, -1);
 882
 883         if (options)
 884                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 885
 886         return uart_set_options(&dport->port, co, baud, parity, bits, flow);
 887 }
 888
 889 static struct uart_driver dz_reg;
 890 static struct console dz_console = {
 891         .name   = "ttyS",
 892         .write  = dz_console_print,
 893         .device = uart_console_device,
 894         .setup  = dz_console_setup,
 895         .flags  = CON_PRINTBUFFER,
 896         .index  = -1,
 897         .data   = &dz_reg,
 898 };
 899
 900 static int __init dz_serial_console_init(void)
 901 {
 902         if (!IOASIC) {
 903                 dz_init_ports();
 904                 register_console(&dz_console);
 905                 return 0;
 906         } else
 907                 return -ENXIO;
 908 }
 909
 910 console_initcall(dz_serial_console_init);
 911
 912 #define SERIAL_DZ_CONSOLE       &dz_console
 913 #else
 914 #define SERIAL_DZ_CONSOLE       NULL
 915 #endif /* CONFIG_SERIAL_DZ_CONSOLE */
 916
 917 static struct uart_driver dz_reg = {
 918         .owner                  = THIS_MODULE,
 919         .driver_name            = "serial",
 920         .dev_name               = "ttyS",
 921         .major                  = TTY_MAJOR,
 922         .minor                  = 64,
 923         .nr                     = DZ_NB_PORT,
 924         .cons                   = SERIAL_DZ_CONSOLE,
 925 };
 926
 927 static int __init dz_init(void)
 928 {
 929         int ret, i;
 930
 931         if (IOASIC)
 932                 return -ENXIO;
 933
 934         printk("%s%s\n", dz_name, dz_version);
 935
 936         dz_init_ports();
 937
 938         ret = uart_register_driver(&dz_reg);
 939         if (ret)
 940                 return ret;
 941
 942         for (i = 0; i < DZ_NB_PORT; i++)
 943                 uart_add_one_port(&dz_reg, &dz_mux.dport[i].port);
 944
 945         return 0;
 946 }
 947
 948 module_init(dz_init);