drivers/serial/zs.c

   1 /*
   2  * zs.c: Serial port driver for IOASIC DECstations.
   3  *
   4  * Derived from drivers/sbus/char/sunserial.c by Paul Mackerras.
   5  * Derived from drivers/macintosh/macserial.c by Harald Koerfgen.
   6  *
   7  * DECstation changes
   8  * Copyright (C) 1998-2000 Harald Koerfgen
   9  * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007  Maciej W. Rozycki
  10  *
  11  * For the rest of the code the original Copyright applies:
  12  * Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)
  13  * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
  14  *
  15  *
  16  * Note: for IOASIC systems the wiring is as follows:
  17  *
  18  * mouse/keyboard:
  19  * DIN-7 MJ-4  signal        SCC
  20  * 2     1     TxD       <-  A.TxD
  21  * 3     4     RxD       ->  A.RxD
  22  *
  23  * EIA-232/EIA-423:
  24  * DB-25 MMJ-6 signal        SCC
  25  * 2     2     TxD       <-  B.TxD
  26  * 3     5     RxD       ->  B.RxD
  27  * 4           RTS       <- ~A.RTS
  28  * 5           CTS       -> ~B.CTS
  29  * 6     6     DSR       -> ~A.SYNC
  30  * 8           CD        -> ~B.DCD
  31  * 12          DSRS(DCE) -> ~A.CTS  (*)
  32  * 15          TxC       ->  B.TxC
  33  * 17          RxC       ->  B.RxC
  34  * 20    1     DTR       <- ~A.DTR
  35  * 22          RI        -> ~A.DCD
  36  * 23          DSRS(DTE) <- ~B.RTS
  37  *
  38  * (*) EIA-232 defines the signal at this pin to be SCD, while DSRS(DCE)
  39  *     is shared with DSRS(DTE) at pin 23.
  40  *
  41  * As you can immediately notice the wiring of the RTS, DTR and DSR signals
  42  * is a bit odd.  This makes the handling of port B unnecessarily
  43  * complicated and prevents the use of some automatic modes of operation.
  44  */
  45
  46 #if defined(CONFIG_SERIAL_ZS_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  47 #define SUPPORT_SYSRQ
  48 #endif
  49
  50 #include <linux/bug.h>
  51 #include <linux/console.h>
  52 #include <linux/delay.h>
  53 #include <linux/errno.h>
  54 #include <linux/init.h>
  55 #include <linux/interrupt.h>
  56 #include <linux/io.h>
  57 #include <linux/ioport.h>
  58 #include <linux/irqflags.h>
  59 #include <linux/kernel.h>
  60 #include <linux/major.h>
  61 #include <linux/serial.h>
  62 #include <linux/serial_core.h>
  63 #include <linux/spinlock.h>
  64 #include <linux/sysrq.h>
  65 #include <linux/tty.h>
  66 #include <linux/types.h>
  67
  68 #include <asm/atomic.h>
  69 #include <asm/system.h>
  70
  71 #include <asm/dec/interrupts.h>
  72 #include <asm/dec/ioasic_addrs.h>
  73 #include <asm/dec/system.h>
  74
  75 #include "zs.h"
  76
  77
  78 MODULE_AUTHOR("Maciej W. Rozycki <macro@linux-mips.org>");
  79 MODULE_DESCRIPTION("DECstation Z85C30 serial driver");
  80 MODULE_LICENSE("GPL");
  81
  82
  83 static char zs_name[] __initdata = "DECstation Z85C30 serial driver version ";
  84 static char zs_version[] __initdata = "0.10";
  85
  86 /*
  87  * It would be nice to dynamically allocate everything that
  88  * depends on ZS_NUM_SCCS, so we could support any number of
  89  * Z85C30s, but for now...
  90  */
  91 #define ZS_NUM_SCCS     2               /* Max # of ZS chips supported.  */
  92 #define ZS_NUM_CHAN     2               /* 2 channels per chip.  */
  93 #define ZS_CHAN_A       0               /* Index of the channel A.  */
  94 #define ZS_CHAN_B       1               /* Index of the channel B.  */
  95 #define ZS_CHAN_IO_SIZE 8               /* IOMEM space size.  */
  96 #define ZS_CHAN_IO_STRIDE 4             /* Register alignment.  */
  97 #define ZS_CHAN_IO_OFFSET 1             /* The SCC resides on the high byte
  98                                            of the 16-bit IOBUS.  */
  99 #define ZS_CLOCK        7372800         /* Z85C30 PCLK input clock rate.  */
 100
 101 #define to_zport(uport) container_of(uport, struct zs_port, port)
 102
 103 struct zs_parms {
 104         resource_size_t scc[ZS_NUM_SCCS];
 105         int irq[ZS_NUM_SCCS];
 106 };
 107
 108 static struct zs_scc zs_sccs[ZS_NUM_SCCS];
 109
 110 static u8 zs_init_regs[ZS_NUM_REGS] __initdata = {
 111         0,                              /* write 0 */
 112         PAR_SPEC,                       /* write 1 */
 113         0,                              /* write 2 */
 114         0,                              /* write 3 */
 115         X16CLK | SB1,                   /* write 4 */
 116         0,                              /* write 5 */
 117         0, 0, 0,                        /* write 6, 7, 8 */
 118         MIE | DLC | NV,                 /* write 9 */
 119         NRZ,                            /* write 10 */
 120         TCBR | RCBR,                    /* write 11 */
 121         0, 0,                           /* BRG time constant, write 12 + 13 */
 122         BRSRC | BRENABL,                /* write 14 */
 123         0,                              /* write 15 */
 124 };
 125
 126 /*
 127  * Debugging.
 128  */
 129 #undef ZS_DEBUG_REGS
 130
 131
 132 /*
 133  * Reading and writing Z85C30 registers.
 134  */
 135 static void recovery_delay(void)
 136 {
 137         udelay(2);
 138 }
 139
 140 static u8 read_zsreg(struct zs_port *zport, int reg)
 141 {
 142         void __iomem *control = zport->port.membase + ZS_CHAN_IO_OFFSET;
 143         u8 retval;
 144
 145         if (reg != 0) {
 146                 writeb(reg & 0xf, control);
 147                 fast_iob();
 148                 recovery_delay();
 149         }
 150         retval = readb(control);
 151         recovery_delay();
 152         return retval;
 153 }
 154
 155 static void write_zsreg(struct zs_port *zport, int reg, u8 value)
 156 {
 157         void __iomem *control = zport->port.membase + ZS_CHAN_IO_OFFSET;
 158
 159         if (reg != 0) {
 160                 writeb(reg & 0xf, control);
 161                 fast_iob(); recovery_delay();
 162         }
 163         writeb(value, control);
 164         fast_iob();
 165         recovery_delay();
 166         return;
 167 }
 168
 169 static u8 read_zsdata(struct zs_port *zport)
 170 {
 171         void __iomem *data = zport->port.membase +
 172                              ZS_CHAN_IO_STRIDE + ZS_CHAN_IO_OFFSET;
 173         u8 retval;
 174
 175         retval = readb(data);
 176         recovery_delay();
 177         return retval;
 178 }
 179
 180 static void write_zsdata(struct zs_port *zport, u8 value)
 181 {
 182         void __iomem *data = zport->port.membase +
 183                              ZS_CHAN_IO_STRIDE + ZS_CHAN_IO_OFFSET;
 184
 185         writeb(value, data);
 186         fast_iob();
 187         recovery_delay();
 188         return;
 189 }
 190
 191 #ifdef ZS_DEBUG_REGS
 192 void zs_dump(void)
 193 {
 194         struct zs_port *zport;
 195         int i, j;
 196
 197         for (i = 0; i < ZS_NUM_SCCS * ZS_NUM_CHAN; i++) {
 198                 zport = &zs_sccs[i / ZS_NUM_CHAN].zport[i % ZS_NUM_CHAN];
 199
 200                 if (!zport->scc)
 201                         continue;
 202
 203                 for (j = 0; j < 16; j++)
 204                         printk("W%-2d = 0x%02x\t", j, zport->regs[j]);
 205                 printk("\n");
 206                 for (j = 0; j < 16; j++)
 207                         printk("R%-2d = 0x%02x\t", j, read_zsreg(zport, j));
 208                 printk("\n\n");
 209         }
 210 }
 211 #endif
 212
 213
 214 static void zs_spin_lock_cond_irq(spinlock_t *lock, int irq)
 215 {
 216         if (irq)
 217                 spin_lock_irq(lock);
 218         else
 219                 spin_lock(lock);
 220 }
 221
 222 static void zs_spin_unlock_cond_irq(spinlock_t *lock, int irq)
 223 {
 224         if (irq)
 225                 spin_unlock_irq(lock);
 226         else
 227                 spin_unlock(lock);
 228 }
 229
 230 static int zs_receive_drain(struct zs_port *zport)
 231 {
 232         int loops = 10000;
 233
 234         while ((read_zsreg(zport, R0) & Rx_CH_AV) && loops--)
 235                 read_zsdata(zport);
 236         return loops;
 237 }
 238
 239 static int zs_transmit_drain(struct zs_port *zport, int irq)
 240 {
 241         struct zs_scc *scc = zport->scc;
 242         int loops = 10000;
 243
 244         while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && loops--) {
 245                 zs_spin_unlock_cond_irq(&scc->zlock, irq);
 246                 udelay(2);
 247                 zs_spin_lock_cond_irq(&scc->zlock, irq);
 248         }
 249         return loops;
 250 }
 251
 252 static int zs_line_drain(struct zs_port *zport, int irq)
 253 {
 254         struct zs_scc *scc = zport->scc;
 255         int loops = 10000;
 256
 257         while (!(read_zsreg(zport, R1) & ALL_SNT) && loops--) {
 258                 zs_spin_unlock_cond_irq(&scc->zlock, irq);
 259                 udelay(2);
 260                 zs_spin_lock_cond_irq(&scc->zlock, irq);
 261         }
 262         return loops;
 263 }
 264
 265
 266 static void load_zsregs(struct zs_port *zport, u8 *regs, int irq)
 267 {
 268         /* Let the current transmission finish.  */
 269         zs_line_drain(zport, irq);
 270         /* Load 'em up.  */
 271         write_zsreg(zport, R3, regs[3] & ~RxENABLE);
 272         write_zsreg(zport, R5, regs[5] & ~TxENAB);
 273         write_zsreg(zport, R4, regs[4]);
 274         write_zsreg(zport, R9, regs[9]);
 275         write_zsreg(zport, R1, regs[1]);
 276         write_zsreg(zport, R2, regs[2]);
 277         write_zsreg(zport, R10, regs[10]);
 278         write_zsreg(zport, R14, regs[14] & ~BRENABL);
 279         write_zsreg(zport, R11, regs[11]);
 280         write_zsreg(zport, R12, regs[12]);
 281         write_zsreg(zport, R13, regs[13]);
 282         write_zsreg(zport, R14, regs[14]);
 283         write_zsreg(zport, R15, regs[15]);
 284         if (regs[3] & RxENABLE)
 285                 write_zsreg(zport, R3, regs[3]);
 286         if (regs[5] & TxENAB)
 287                 write_zsreg(zport, R5, regs[5]);
 288         return;
 289 }
 290
 291
 292 /*
 293  * Status handling routines.
 294  */
 295
 296 /*
 297  * zs_tx_empty() -- get the transmitter empty status
 298  *
 299  * Purpose: Let user call ioctl() to get info when the UART physically
 300  *          is emptied.  On bus types like RS485, the transmitter must
 301  *          release the bus after transmitting.  This must be done when
 302  *          the transmit shift register is empty, not be done when the
 303  *          transmit holding register is empty.  This functionality
 304  *          allows an RS485 driver to be written in user space.
 305  */
 306 static unsigned int zs_tx_empty(struct uart_port *uport)
 307 {
 308         struct zs_port *zport = to_zport(uport);
 309         struct zs_scc *scc = zport->scc;
 310         unsigned long flags;
 311         u8 status;
 312
 313         spin_lock_irqsave(&scc->zlock, flags);
 314         status = read_zsreg(zport, R1);
 315         spin_unlock_irqrestore(&scc->zlock, flags);
 316
 317         return status & ALL_SNT ? TIOCSER_TEMT : 0;
 318 }
 319
 320 static unsigned int zs_raw_get_ab_mctrl(struct zs_port *zport_a,
 321                                         struct zs_port *zport_b)
 322 {
 323         u8 status_a, status_b;
 324         unsigned int mctrl;
 325
 326         status_a = read_zsreg(zport_a, R0);
 327         status_b = read_zsreg(zport_b, R0);
 328
 329         mctrl = ((status_b & CTS) ? TIOCM_CTS : 0) |
 330                 ((status_b & DCD) ? TIOCM_CAR : 0) |
 331                 ((status_a & DCD) ? TIOCM_RNG : 0) |
 332                 ((status_a & SYNC_HUNT) ? TIOCM_DSR : 0);
 333
 334         return mctrl;
 335 }
 336
 337 static unsigned int zs_raw_get_mctrl(struct zs_port *zport)
 338 {
 339         struct zs_port *zport_a = &zport->scc->zport[ZS_CHAN_A];
 340
 341         return zport != zport_a ? zs_raw_get_ab_mctrl(zport_a, zport) : 0;
 342 }
 343
 344 static unsigned int zs_raw_xor_mctrl(struct zs_port *zport)
 345 {
 346         struct zs_port *zport_a = &zport->scc->zport[ZS_CHAN_A];
 347         unsigned int mmask, mctrl, delta;
 348         u8 mask_a, mask_b;
 349
 350         if (zport == zport_a)
 351                 return 0;
 352
 353         mask_a = zport_a->regs[15];
 354         mask_b = zport->regs[15];
 355
 356         mmask = ((mask_b & CTSIE) ? TIOCM_CTS : 0) |
 357                 ((mask_b & DCDIE) ? TIOCM_CAR : 0) |
 358                 ((mask_a & DCDIE) ? TIOCM_RNG : 0) |
 359                 ((mask_a & SYNCIE) ? TIOCM_DSR : 0);
 360
 361         mctrl = zport->mctrl;
 362         if (mmask) {
 363                 mctrl &= ~mmask;
 364                 mctrl |= zs_raw_get_ab_mctrl(zport_a, zport) & mmask;
 365         }
 366
 367         delta = mctrl ^ zport->mctrl;
 368         if (delta)
 369                 zport->mctrl = mctrl;
 370
 371         return delta;
 372 }
 373
 374 static unsigned int zs_get_mctrl(struct uart_port *uport)
 375 {
 376         struct zs_port *zport = to_zport(uport);
 377         struct zs_scc *scc = zport->scc;
 378         unsigned int mctrl;
 379
 380         spin_lock(&scc->zlock);
 381         mctrl = zs_raw_get_mctrl(zport);
 382         spin_unlock(&scc->zlock);
 383
 384         return mctrl;
 385 }
 386
 387 static void zs_set_mctrl(struct uart_port *uport, unsigned int mctrl)
 388 {
 389         struct zs_port *zport = to_zport(uport);
 390         struct zs_scc *scc = zport->scc;
 391         struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
 392         u8 oldloop, newloop;
 393
 394         spin_lock(&scc->zlock);
 395         if (zport != zport_a) {
 396                 if (mctrl & TIOCM_DTR)
 397                         zport_a->regs[5] |= DTR;
 398                 else
 399                         zport_a->regs[5] &= ~DTR;
 400                 if (mctrl & TIOCM_RTS)
 401                         zport_a->regs[5] |= RTS;
 402                 else
 403                         zport_a->regs[5] &= ~RTS;
 404                 write_zsreg(zport_a, R5, zport_a->regs[5]);
 405         }
 406
 407         /* Rarely modified, so don't poke at hardware unless necessary. */
 408         oldloop = zport->regs[14];
 409         newloop = oldloop;
 410         if (mctrl & TIOCM_LOOP)
 411                 newloop |= LOOPBAK;
 412         else
 413                 newloop &= ~LOOPBAK;
 414         if (newloop != oldloop) {
 415                 zport->regs[14] = newloop;
 416                 write_zsreg(zport, R14, zport->regs[14]);
 417         }
 418         spin_unlock(&scc->zlock);
 419 }
 420
 421 static void zs_raw_stop_tx(struct zs_port *zport)
 422 {
 423         write_zsreg(zport, R0, RES_Tx_P);
 424         zport->tx_stopped = 1;
 425 }
 426
 427 static void zs_stop_tx(struct uart_port *uport)
 428 {
 429         struct zs_port *zport = to_zport(uport);
 430         struct zs_scc *scc = zport->scc;
 431
 432         spin_lock(&scc->zlock);
 433         zs_raw_stop_tx(zport);
 434         spin_unlock(&scc->zlock);
 435 }
 436
 437 static void zs_raw_transmit_chars(struct zs_port *);
 438
 439 static void zs_start_tx(struct uart_port *uport)
 440 {
 441         struct zs_port *zport = to_zport(uport);
 442         struct zs_scc *scc = zport->scc;
 443
 444         spin_lock(&scc->zlock);
 445         if (zport->tx_stopped) {
 446                 zs_transmit_drain(zport, 0);
 447                 zport->tx_stopped = 0;
 448                 zs_raw_transmit_chars(zport);
 449         }
 450         spin_unlock(&scc->zlock);
 451 }
 452
 453 static void zs_stop_rx(struct uart_port *uport)
 454 {
 455         struct zs_port *zport = to_zport(uport);
 456         struct zs_scc *scc = zport->scc;
 457         struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
 458
 459         spin_lock(&scc->zlock);
 460         zport->regs[15] &= ~BRKIE;
 461         zport->regs[1] &= ~(RxINT_MASK | TxINT_ENAB);
 462         zport->regs[1] |= RxINT_DISAB;
 463
 464         if (zport != zport_a) {
 465                 /* A-side DCD tracks RI and SYNC tracks DSR.  */
 466                 zport_a->regs[15] &= ~(DCDIE | SYNCIE);
 467                 write_zsreg(zport_a, R15, zport_a->regs[15]);
 468                 if (!(zport_a->regs[15] & BRKIE)) {
 469                         zport_a->regs[1] &= ~EXT_INT_ENAB;
 470                         write_zsreg(zport_a, R1, zport_a->regs[1]);
 471                 }
 472
 473                 /* This-side DCD tracks DCD and CTS tracks CTS.  */
 474                 zport->regs[15] &= ~(DCDIE | CTSIE);
 475                 zport->regs[1] &= ~EXT_INT_ENAB;
 476         } else {
 477                 /* DCD tracks RI and SYNC tracks DSR for the B side.  */
 478                 if (!(zport->regs[15] & (DCDIE | SYNCIE)))
 479                         zport->regs[1] &= ~EXT_INT_ENAB;
 480         }
 481
 482         write_zsreg(zport, R15, zport->regs[15]);
 483         write_zsreg(zport, R1, zport->regs[1]);
 484         spin_unlock(&scc->zlock);
 485 }
 486
 487 static void zs_enable_ms(struct uart_port *uport)
 488 {
 489         struct zs_port *zport = to_zport(uport);
 490         struct zs_scc *scc = zport->scc;
 491         struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
 492
 493         if (zport == zport_a)
 494                 return;
 495
 496         spin_lock(&scc->zlock);
 497
 498         /* Clear Ext interrupts if not being handled already.  */
 499         if (!(zport_a->regs[1] & EXT_INT_ENAB))
 500                 write_zsreg(zport_a, R0, RES_EXT_INT);
 501
 502         /* A-side DCD tracks RI and SYNC tracks DSR.  */
 503         zport_a->regs[1] |= EXT_INT_ENAB;
 504         zport_a->regs[15] |= DCDIE | SYNCIE;
 505
 506         /* This-side DCD tracks DCD and CTS tracks CTS.  */
 507         zport->regs[15] |= DCDIE | CTSIE;
 508
 509         zs_raw_xor_mctrl(zport);
 510
 511         write_zsreg(zport_a, R1, zport_a->regs[1]);
 512         write_zsreg(zport_a, R15, zport_a->regs[15]);
 513         write_zsreg(zport, R15, zport->regs[15]);
 514         spin_unlock(&scc->zlock);
 515 }
 516
 517 static void zs_break_ctl(struct uart_port *uport, int break_state)
 518 {
 519         struct zs_port *zport = to_zport(uport);
 520         struct zs_scc *scc = zport->scc;
 521         unsigned long flags;
 522
 523         spin_lock_irqsave(&scc->zlock, flags);
 524         if (break_state == -1)
 525                 zport->regs[5] |= SND_BRK;
 526         else
 527                 zport->regs[5] &= ~SND_BRK;
 528         write_zsreg(zport, R5, zport->regs[5]);
 529         spin_unlock_irqrestore(&scc->zlock, flags);
 530 }
 531
 532
 533 /*
 534  * Interrupt handling routines.
 535  */
 536 #define Rx_BRK 0x0100                   /* BREAK event software flag.  */
 537 #define Rx_SYS 0x0200                   /* SysRq event software flag.  */
 538
 539 static void zs_receive_chars(struct zs_port *zport)
 540 {
 541         struct uart_port *uport = &zport->port;
 542         struct zs_scc *scc = zport->scc;
 543         struct uart_icount *icount;
 544         unsigned int avail, status, ch, flag;
 545         int count;
 546
 547         for (count = 16; count; count--) {
 548                 spin_lock(&scc->zlock);
 549                 avail = read_zsreg(zport, R0) & Rx_CH_AV;
 550                 spin_unlock(&scc->zlock);
 551                 if (!avail)
 552                         break;
 553
 554                 spin_lock(&scc->zlock);
 555                 status = read_zsreg(zport, R1) & (Rx_OVR | FRM_ERR | PAR_ERR);
 556                 ch = read_zsdata(zport);
 557                 spin_unlock(&scc->zlock);
 558
 559                 flag = TTY_NORMAL;
 560
 561                 icount = &uport->icount;
 562                 icount->rx++;
 563
 564                 /* Handle the null char got when BREAK is removed.  */
 565                 if (!ch)
 566                         status |= zport->tty_break;
 567                 if (unlikely(status &
 568                              (Rx_OVR | FRM_ERR | PAR_ERR | Rx_SYS | Rx_BRK))) {
 569                         zport->tty_break = 0;
 570
 571                         /* Reset the error indication.  */
 572                         if (status & (Rx_OVR | FRM_ERR | PAR_ERR)) {
 573                                 spin_lock(&scc->zlock);
 574                                 write_zsreg(zport, R0, ERR_RES);
 575                                 spin_unlock(&scc->zlock);
 576                         }
 577
 578                         if (status & (Rx_SYS | Rx_BRK)) {
 579                                 icount->brk++;
 580                                 /* SysRq discards the null char.  */
 581                                 if (status & Rx_SYS)
 582                                         continue;
 583                         } else if (status & FRM_ERR)
 584                                 icount->frame++;
 585                         else if (status & PAR_ERR)
 586                                 icount->parity++;
 587                         if (status & Rx_OVR)
 588                                 icount->overrun++;
 589
 590                         status &= uport->read_status_mask;
 591                         if (status & Rx_BRK)
 592                                 flag = TTY_BREAK;
 593                         else if (status & FRM_ERR)
 594                                 flag = TTY_FRAME;
 595                         else if (status & PAR_ERR)
 596                                 flag = TTY_PARITY;
 597                 }
 598
 599                 if (uart_handle_sysrq_char(uport, ch))
 600                         continue;
 601
 602                 uart_insert_char(uport, status, Rx_OVR, ch, flag);
 603         }
 604
 605         tty_flip_buffer_push(uport->info->port.tty);
 606 }
 607
 608 static void zs_raw_transmit_chars(struct zs_port *zport)
 609 {
 610         struct circ_buf *xmit = &zport->port.info->xmit;
 611
 612         /* XON/XOFF chars.  */
 613         if (zport->port.x_char) {
 614                 write_zsdata(zport, zport->port.x_char);
 615                 zport->port.icount.tx++;
 616                 zport->port.x_char = 0;
 617                 return;
 618         }
 619
 620         /* If nothing to do or stopped or hardware stopped.  */
 621         if (uart_circ_empty(xmit) || uart_tx_stopped(&zport->port)) {
 622                 zs_raw_stop_tx(zport);
 623                 return;
 624         }
 625
 626         /* Send char.  */
 627         write_zsdata(zport, xmit->buf[xmit->tail]);
 628         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 629         zport->port.icount.tx++;
 630
 631         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 632                 uart_write_wakeup(&zport->port);
 633
 634         /* Are we are done?  */
 635         if (uart_circ_empty(xmit))
 636                 zs_raw_stop_tx(zport);
 637 }
 638
 639 static void zs_transmit_chars(struct zs_port *zport)
 640 {
 641         struct zs_scc *scc = zport->scc;
 642
 643         spin_lock(&scc->zlock);
 644         zs_raw_transmit_chars(zport);
 645         spin_unlock(&scc->zlock);
 646 }
 647
 648 static void zs_status_handle(struct zs_port *zport, struct zs_port *zport_a)
 649 {
 650         struct uart_port *uport = &zport->port;
 651         struct zs_scc *scc = zport->scc;
 652         unsigned int delta;
 653         u8 status, brk;
 654
 655         spin_lock(&scc->zlock);
 656
 657         /* Get status from Read Register 0.  */
 658         status = read_zsreg(zport, R0);
 659
 660         if (zport->regs[15] & BRKIE) {
 661                 brk = status & BRK_ABRT;
 662                 if (brk && !zport->brk) {
 663                         spin_unlock(&scc->zlock);
 664                         if (uart_handle_break(uport))
 665                                 zport->tty_break = Rx_SYS;
 666                         else
 667                                 zport->tty_break = Rx_BRK;
 668                         spin_lock(&scc->zlock);
 669                 }
 670                 zport->brk = brk;
 671         }
 672
 673         if (zport != zport_a) {
 674                 delta = zs_raw_xor_mctrl(zport);
 675                 spin_unlock(&scc->zlock);
 676
 677                 if (delta & TIOCM_CTS)
 678                         uart_handle_cts_change(uport,
 679                                                zport->mctrl & TIOCM_CTS);
 680                 if (delta & TIOCM_CAR)
 681                         uart_handle_dcd_change(uport,
 682                                                zport->mctrl & TIOCM_CAR);
 683                 if (delta & TIOCM_RNG)
 684                         uport->icount.dsr++;
 685                 if (delta & TIOCM_DSR)
 686                         uport->icount.rng++;
 687
 688                 if (delta)
 689                         wake_up_interruptible(&uport->info->delta_msr_wait);
 690
 691                 spin_lock(&scc->zlock);
 692         }
 693
 694         /* Clear the status condition...  */
 695         write_zsreg(zport, R0, RES_EXT_INT);
 696
 697         spin_unlock(&scc->zlock);
 698 }
 699
 700 /*
 701  * This is the Z85C30 driver's generic interrupt routine.
 702  */
 703 static irqreturn_t zs_interrupt(int irq, void *dev_id)
 704 {
 705         struct zs_scc *scc = dev_id;
 706         struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
 707         struct zs_port *zport_b = &scc->zport[ZS_CHAN_B];
 708         irqreturn_t status = IRQ_NONE;
 709         u8 zs_intreg;
 710         int count;
 711
 712         /*
 713          * NOTE: The read register 3, which holds the irq status,
 714          *       does so for both channels on each chip.  Although
 715          *       the status value itself must be read from the A
 716          *       channel and is only valid when read from channel A.
 717          *       Yes... broken hardware...
 718          */
 719         for (count = 16; count; count--) {
 720                 spin_lock(&scc->zlock);
 721                 zs_intreg = read_zsreg(zport_a, R3);
 722                 spin_unlock(&scc->zlock);
 723                 if (!zs_intreg)
 724                         break;
 725
 726                 /*
 727                  * We do not like losing characters, so we prioritise
 728                  * interrupt sources a little bit differently than
 729                  * the SCC would, was it allowed to.
 730                  */
 731                 if (zs_intreg & CHBRxIP)
 732                         zs_receive_chars(zport_b);
 733                 if (zs_intreg & CHARxIP)
 734                         zs_receive_chars(zport_a);
 735                 if (zs_intreg & CHBEXT)
 736                         zs_status_handle(zport_b, zport_a);
 737                 if (zs_intreg & CHAEXT)
 738                         zs_status_handle(zport_a, zport_a);
 739                 if (zs_intreg & CHBTxIP)
 740                         zs_transmit_chars(zport_b);
 741                 if (zs_intreg & CHATxIP)
 742                         zs_transmit_chars(zport_a);
 743
 744                 status = IRQ_HANDLED;
 745         }
 746
 747         return status;
 748 }
 749
 750
 751 /*
 752  * Finally, routines used to initialize the serial port.
 753  */
 754 static int zs_startup(struct uart_port *uport)
 755 {
 756         struct zs_port *zport = to_zport(uport);
 757         struct zs_scc *scc = zport->scc;
 758         unsigned long flags;
 759         int irq_guard;
 760         int ret;
 761
 762         irq_guard = atomic_add_return(1, &scc->irq_guard);
 763         if (irq_guard == 1) {
 764                 ret = request_irq(zport->port.irq, zs_interrupt,
 765                                   IRQF_SHARED, "scc", scc);
 766                 if (ret) {
 767                         atomic_add(-1, &scc->irq_guard);
 768                         printk(KERN_ERR "zs: can't get irq %d\n",
 769                                zport->port.irq);
 770                         return ret;
 771                 }
 772         }
 773
 774         spin_lock_irqsave(&scc->zlock, flags);
 775
 776         /* Clear the receive FIFO.  */
 777         zs_receive_drain(zport);
 778
 779         /* Clear the interrupt registers.  */
 780         write_zsreg(zport, R0, ERR_RES);
 781         write_zsreg(zport, R0, RES_Tx_P);
 782         /* But Ext only if not being handled already.  */
 783         if (!(zport->regs[1] & EXT_INT_ENAB))
 784                 write_zsreg(zport, R0, RES_EXT_INT);
 785
 786         /* Finally, enable sequencing and interrupts.  */
 787         zport->regs[1] &= ~RxINT_MASK;
 788         zport->regs[1] |= RxINT_ALL | TxINT_ENAB | EXT_INT_ENAB;
 789         zport->regs[3] |= RxENABLE;
 790         zport->regs[15] |= BRKIE;
 791         write_zsreg(zport, R1, zport->regs[1]);
 792         write_zsreg(zport, R3, zport->regs[3]);
 793         write_zsreg(zport, R5, zport->regs[5]);
 794         write_zsreg(zport, R15, zport->regs[15]);
 795
 796         /* Record the current state of RR0.  */
 797         zport->mctrl = zs_raw_get_mctrl(zport);
 798         zport->brk = read_zsreg(zport, R0) & BRK_ABRT;
 799
 800         zport->tx_stopped = 1;
 801
 802         spin_unlock_irqrestore(&scc->zlock, flags);
 803
 804         return 0;
 805 }
 806
 807 static void zs_shutdown(struct uart_port *uport)
 808 {
 809         struct zs_port *zport = to_zport(uport);
 810         struct zs_scc *scc = zport->scc;
 811         unsigned long flags;
 812         int irq_guard;
 813
 814         spin_lock_irqsave(&scc->zlock, flags);
 815
 816         zport->regs[3] &= ~RxENABLE;
 817         write_zsreg(zport, R5, zport->regs[5]);
 818         write_zsreg(zport, R3, zport->regs[3]);
 819
 820         spin_unlock_irqrestore(&scc->zlock, flags);
 821
 822         irq_guard = atomic_add_return(-1, &scc->irq_guard);
 823         if (!irq_guard)
 824                 free_irq(zport->port.irq, scc);
 825 }
 826
 827
 828 static void zs_reset(struct zs_port *zport)
 829 {
 830         struct zs_scc *scc = zport->scc;
 831         int irq;
 832         unsigned long flags;
 833
 834         spin_lock_irqsave(&scc->zlock, flags);
 835         irq = !irqs_disabled_flags(flags);
 836         if (!scc->initialised) {
 837                 /* Reset the pointer first, just in case...  */
 838                 read_zsreg(zport, R0);
 839                 /* And let the current transmission finish.  */
 840                 zs_line_drain(zport, irq);
 841                 write_zsreg(zport, R9, FHWRES);
 842                 udelay(10);
 843                 write_zsreg(zport, R9, 0);
 844                 scc->initialised = 1;
 845         }
 846         load_zsregs(zport, zport->regs, irq);
 847         spin_unlock_irqrestore(&scc->zlock, flags);
 848 }
 849
 850 static void zs_set_termios(struct uart_port *uport, struct ktermios *termios,
 851                            struct ktermios *old_termios)
 852 {
 853         struct zs_port *zport = to_zport(uport);
 854         struct zs_scc *scc = zport->scc;
 855         struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
 856         int irq;
 857         unsigned int baud, brg;
 858         unsigned long flags;
 859
 860         spin_lock_irqsave(&scc->zlock, flags);
 861         irq = !irqs_disabled_flags(flags);
 862
 863         /* Byte size.  */
 864         zport->regs[3] &= ~RxNBITS_MASK;
 865         zport->regs[5] &= ~TxNBITS_MASK;
 866         switch (termios->c_cflag & CSIZE) {
 867         case CS5:
 868                 zport->regs[3] |= Rx5;
 869                 zport->regs[5] |= Tx5;
 870                 break;
 871         case CS6:
 872                 zport->regs[3] |= Rx6;
 873                 zport->regs[5] |= Tx6;
 874                 break;
 875         case CS7:
 876                 zport->regs[3] |= Rx7;
 877                 zport->regs[5] |= Tx7;
 878                 break;
 879         case CS8:
 880         default:
 881                 zport->regs[3] |= Rx8;
 882                 zport->regs[5] |= Tx8;
 883                 break;
 884         }
 885
 886         /* Parity and stop bits.  */
 887         zport->regs[4] &= ~(XCLK_MASK | SB_MASK | PAR_ENA | PAR_EVEN);
 888         if (termios->c_cflag & CSTOPB)
 889                 zport->regs[4] |= SB2;
 890         else
 891                 zport->regs[4] |= SB1;
 892         if (termios->c_cflag & PARENB)
 893                 zport->regs[4] |= PAR_ENA;
 894         if (!(termios->c_cflag & PARODD))
 895                 zport->regs[4] |= PAR_EVEN;
 896         switch (zport->clk_mode) {
 897         case 64:
 898                 zport->regs[4] |= X64CLK;
 899                 break;
 900         case 32:
 901                 zport->regs[4] |= X32CLK;
 902                 break;
 903         case 16:
 904                 zport->regs[4] |= X16CLK;
 905                 break;
 906         case 1:
 907                 zport->regs[4] |= X1CLK;
 908                 break;
 909         default:
 910                 BUG();
 911         }
 912
 913         baud = uart_get_baud_rate(uport, termios, old_termios, 0,
 914                                   uport->uartclk / zport->clk_mode / 4);
 915
 916         brg = ZS_BPS_TO_BRG(baud, uport->uartclk / zport->clk_mode);
 917         zport->regs[12] = brg & 0xff;
 918         zport->regs[13] = (brg >> 8) & 0xff;
 919
 920         uart_update_timeout(uport, termios->c_cflag, baud);
 921
 922         uport->read_status_mask = Rx_OVR;
 923         if (termios->c_iflag & INPCK)
 924                 uport->read_status_mask |= FRM_ERR | PAR_ERR;
 925         if (termios->c_iflag & (BRKINT | PARMRK))
 926                 uport->read_status_mask |= Rx_BRK;
 927
 928         uport->ignore_status_mask = 0;
 929         if (termios->c_iflag & IGNPAR)
 930                 uport->ignore_status_mask |= FRM_ERR | PAR_ERR;
 931         if (termios->c_iflag & IGNBRK) {
 932                 uport->ignore_status_mask |= Rx_BRK;
 933                 if (termios->c_iflag & IGNPAR)
 934                         uport->ignore_status_mask |= Rx_OVR;
 935         }
 936
 937         if (termios->c_cflag & CREAD)
 938                 zport->regs[3] |= RxENABLE;
 939         else
 940                 zport->regs[3] &= ~RxENABLE;
 941
 942         if (zport != zport_a) {
 943                 if (!(termios->c_cflag & CLOCAL)) {
 944                         zport->regs[15] |= DCDIE;
 945                 } else
 946                         zport->regs[15] &= ~DCDIE;
 947                 if (termios->c_cflag & CRTSCTS) {
 948                         zport->regs[15] |= CTSIE;
 949                 } else
 950                         zport->regs[15] &= ~CTSIE;
 951                 zs_raw_xor_mctrl(zport);
 952         }
 953
 954         /* Load up the new values.  */
 955         load_zsregs(zport, zport->regs, irq);
 956
 957         spin_unlock_irqrestore(&scc->zlock, flags);
 958 }
 959
 960 /*
 961  * Hack alert!
 962  * Required solely so that the initial PROM-based console
 963  * works undisturbed in parallel with this one.
 964  */
 965 static void zs_pm(struct uart_port *uport, unsigned int state,
 966                   unsigned int oldstate)
 967 {
 968         struct zs_port *zport = to_zport(uport);
 969
 970         if (state < 3)
 971                 zport->regs[5] |= TxENAB;
 972         else
 973                 zport->regs[5] &= ~TxENAB;
 974         write_zsreg(zport, R5, zport->regs[5]);
 975 }
 976
 977
 978 static const char *zs_type(struct uart_port *uport)
 979 {
 980         return "Z85C30 SCC";
 981 }
 982
 983 static void zs_release_port(struct uart_port *uport)
 984 {
 985         iounmap(uport->membase);
 986         uport->membase = 0;
 987         release_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE);
 988 }
 989
 990 static int zs_map_port(struct uart_port *uport)
 991 {
 992         if (!uport->membase)
 993                 uport->membase = ioremap_nocache(uport->mapbase,
 994                                                  ZS_CHAN_IO_SIZE);
 995         if (!uport->membase) {
 996                 printk(KERN_ERR "zs: Cannot map MMIO\n");
 997                 return -ENOMEM;
 998         }
 999         return 0;
1000 }
1001
1002 static int zs_request_port(struct uart_port *uport)
1003 {
1004         int ret;
1005
1006         if (!request_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE, "scc")) {
1007                 printk(KERN_ERR "zs: Unable to reserve MMIO resource\n");
1008                 return -EBUSY;
1009         }
1010         ret = zs_map_port(uport);
1011         if (ret) {
1012                 release_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE);
1013                 return ret;
1014         }
1015         return 0;
1016 }
1017
1018 static void zs_config_port(struct uart_port *uport, int flags)
1019 {
1020         struct zs_port *zport = to_zport(uport);
1021
1022         if (flags & UART_CONFIG_TYPE) {
1023                 if (zs_request_port(uport))
1024                         return;
1025
1026                 uport->type = PORT_ZS;
1027
1028                 zs_reset(zport);
1029         }
1030 }
1031
1032 static int zs_verify_port(struct uart_port *uport, struct serial_struct *ser)
1033 {
1034         struct zs_port *zport = to_zport(uport);
1035         int ret = 0;
1036
1037         if (ser->type != PORT_UNKNOWN && ser->type != PORT_ZS)
1038                 ret = -EINVAL;
1039         if (ser->irq != uport->irq)
1040                 ret = -EINVAL;
1041         if (ser->baud_base != uport->uartclk / zport->clk_mode / 4)
1042                 ret = -EINVAL;
1043         return ret;
1044 }
1045
1046
1047 static struct uart_ops zs_ops = {
1048         .tx_empty       = zs_tx_empty,
1049         .set_mctrl      = zs_set_mctrl,
1050         .get_mctrl      = zs_get_mctrl,
1051         .stop_tx        = zs_stop_tx,
1052         .start_tx       = zs_start_tx,
1053         .stop_rx        = zs_stop_rx,
1054         .enable_ms      = zs_enable_ms,
1055         .break_ctl      = zs_break_ctl,
1056         .startup        = zs_startup,
1057         .shutdown       = zs_shutdown,
1058         .set_termios    = zs_set_termios,
1059         .pm             = zs_pm,
1060         .type           = zs_type,
1061         .release_port   = zs_release_port,
1062         .request_port   = zs_request_port,
1063         .config_port    = zs_config_port,
1064         .verify_port    = zs_verify_port,
1065 };
1066
1067 /*
1068  * Initialize Z85C30 port structures.
1069  */
1070 static int __init zs_probe_sccs(void)
1071 {
1072         static int probed;
1073         struct zs_parms zs_parms;
1074         int chip, side, irq;
1075         int n_chips = 0;
1076         int i;
1077
1078         if (probed)
1079                 return 0;
1080
1081         irq = dec_interrupt[DEC_IRQ_SCC0];
1082         if (irq >= 0) {
1083                 zs_parms.scc[n_chips] = IOASIC_SCC0;
1084                 zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC0];
1085                 n_chips++;
1086         }
1087         irq = dec_interrupt[DEC_IRQ_SCC1];
1088         if (irq >= 0) {
1089                 zs_parms.scc[n_chips] = IOASIC_SCC1;
1090                 zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC1];
1091                 n_chips++;
1092         }
1093         if (!n_chips)
1094                 return -ENXIO;
1095
1096         probed = 1;
1097
1098         for (chip = 0; chip < n_chips; chip++) {
1099                 spin_lock_init(&zs_sccs[chip].zlock);
1100                 for (side = 0; side < ZS_NUM_CHAN; side++) {
1101                         struct zs_port *zport = &zs_sccs[chip].zport[side];
1102                         struct uart_port *uport = &zport->port;
1103
1104                         zport->scc      = &zs_sccs[chip];
1105                         zport->clk_mode = 16;
1106
1107                         uport->irq      = zs_parms.irq[chip];
1108                         uport->uartclk  = ZS_CLOCK;
1109                         uport->fifosize = 1;
1110                         uport->iotype   = UPIO_MEM;
1111                         uport->flags    = UPF_BOOT_AUTOCONF;
1112                         uport->ops      = &zs_ops;
1113                         uport->line     = chip * ZS_NUM_CHAN + side;
1114                         uport->mapbase  = dec_kn_slot_base +
1115                                           zs_parms.scc[chip] +
1116                                           (side ^ ZS_CHAN_B) * ZS_CHAN_IO_SIZE;
1117
1118                         for (i = 0; i < ZS_NUM_REGS; i++)
1119                                 zport->regs[i] = zs_init_regs[i];
1120                 }
1121         }
1122
1123         return 0;
1124 }
1125
1126
1127 #ifdef CONFIG_SERIAL_ZS_CONSOLE
1128 static void zs_console_putchar(struct uart_port *uport, int ch)
1129 {
1130         struct zs_port *zport = to_zport(uport);
1131         struct zs_scc *scc = zport->scc;
1132         int irq;
1133         unsigned long flags;
1134
1135         spin_lock_irqsave(&scc->zlock, flags);
1136         irq = !irqs_disabled_flags(flags);
1137         if (zs_transmit_drain(zport, irq))
1138                 write_zsdata(zport, ch);
1139         spin_unlock_irqrestore(&scc->zlock, flags);
1140 }
1141
1142 /*
1143  * Print a string to the serial port trying not to disturb
1144  * any possible real use of the port...
1145  */
1146 static void zs_console_write(struct console *co, const char *s,
1147                              unsigned int count)
1148 {
1149         int chip = co->index / ZS_NUM_CHAN, side = co->index % ZS_NUM_CHAN;
1150         struct zs_port *zport = &zs_sccs[chip].zport[side];
1151         struct zs_scc *scc = zport->scc;
1152         unsigned long flags;
1153         u8 txint, txenb;
1154         int irq;
1155
1156         /* Disable transmit interrupts and enable the transmitter. */
1157         spin_lock_irqsave(&scc->zlock, flags);
1158         txint = zport->regs[1];
1159         txenb = zport->regs[5];
1160         if (txint & TxINT_ENAB) {
1161                 zport->regs[1] = txint & ~TxINT_ENAB;
1162                 write_zsreg(zport, R1, zport->regs[1]);
1163         }
1164         if (!(txenb & TxENAB)) {
1165                 zport->regs[5] = txenb | TxENAB;
1166                 write_zsreg(zport, R5, zport->regs[5]);
1167         }
1168         spin_unlock_irqrestore(&scc->zlock, flags);
1169
1170         uart_console_write(&zport->port, s, count, zs_console_putchar);
1171
1172         /* Restore transmit interrupts and the transmitter enable. */
1173         spin_lock_irqsave(&scc->zlock, flags);
1174         irq = !irqs_disabled_flags(flags);
1175         zs_line_drain(zport, irq);
1176         if (!(txenb & TxENAB)) {
1177                 zport->regs[5] &= ~TxENAB;
1178                 write_zsreg(zport, R5, zport->regs[5]);
1179         }
1180         if (txint & TxINT_ENAB) {
1181                 zport->regs[1] |= TxINT_ENAB;
1182                 write_zsreg(zport, R1, zport->regs[1]);
1183         }
1184         spin_unlock_irqrestore(&scc->zlock, flags);
1185 }
1186
1187 /*
1188  * Setup serial console baud/bits/parity.  We do two things here:
1189  * - construct a cflag setting for the first uart_open()
1190  * - initialise the serial port
1191  * Return non-zero if we didn't find a serial port.
1192  */
1193 static int __init zs_console_setup(struct console *co, char *options)
1194 {
1195         int chip = co->index / ZS_NUM_CHAN, side = co->index % ZS_NUM_CHAN;
1196         struct zs_port *zport = &zs_sccs[chip].zport[side];
1197         struct uart_port *uport = &zport->port;
1198         int baud = 9600;
1199         int bits = 8;
1200         int parity = 'n';
1201         int flow = 'n';
1202         int ret;
1203
1204         ret = zs_map_port(uport);
1205         if (ret)
1206                 return ret;
1207
1208         zs_reset(zport);
1209         zs_pm(uport, 0, -1);
1210
1211         if (options)
1212                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1213         return uart_set_options(uport, co, baud, parity, bits, flow);
1214 }
1215
1216 static struct uart_driver zs_reg;
1217 static struct console zs_console = {
1218         .name   = "ttyS",
1219         .write  = zs_console_write,
1220         .device = uart_console_device,
1221         .setup  = zs_console_setup,
1222         .flags  = CON_PRINTBUFFER,
1223         .index  = -1,
1224         .data   = &zs_reg,
1225 };
1226
1227 /*
1228  *      Register console.
1229  */
1230 static int __init zs_serial_console_init(void)
1231 {
1232         int ret;
1233
1234         ret = zs_probe_sccs();
1235         if (ret)
1236                 return ret;
1237         register_console(&zs_console);
1238
1239         return 0;
1240 }
1241
1242 console_initcall(zs_serial_console_init);
1243
1244 #define SERIAL_ZS_CONSOLE       &zs_console
1245 #else
1246 #define SERIAL_ZS_CONSOLE       NULL
1247 #endif /* CONFIG_SERIAL_ZS_CONSOLE */
1248
1249 static struct uart_driver zs_reg = {
1250         .owner                  = THIS_MODULE,
1251         .driver_name            = "serial",
1252         .dev_name               = "ttyS",
1253         .major                  = TTY_MAJOR,
1254         .minor                  = 64,
1255         .nr                     = ZS_NUM_SCCS * ZS_NUM_CHAN,
1256         .cons                   = SERIAL_ZS_CONSOLE,
1257 };
1258
1259 /* zs_init inits the driver. */
1260 static int __init zs_init(void)
1261 {
1262         int i, ret;
1263
1264         pr_info("%s%s\n", zs_name, zs_version);
1265
1266         /* Find out how many Z85C30 SCCs we have.  */
1267         ret = zs_probe_sccs();
1268         if (ret)
1269                 return ret;
1270
1271         ret = uart_register_driver(&zs_reg);
1272         if (ret)
1273                 return ret;
1274
1275         for (i = 0; i < ZS_NUM_SCCS * ZS_NUM_CHAN; i++) {
1276                 struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
1277                 struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
1278                 struct uart_port *uport = &zport->port;
1279
1280                 if (zport->scc)
1281                         uart_add_one_port(&zs_reg, uport);
1282         }
1283
1284         return 0;
1285 }
1286
1287 static void __exit zs_exit(void)
1288 {
1289         int i;
1290
1291         for (i = ZS_NUM_SCCS * ZS_NUM_CHAN - 1; i >= 0; i--) {
1292                 struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
1293                 struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
1294                 struct uart_port *uport = &zport->port;
1295
1296                 if (zport->scc)
1297                         uart_remove_one_port(&zs_reg, uport);
1298         }
1299
1300         uart_unregister_driver(&zs_reg);
1301 }
1302
1303 module_init(zs_init);
1304 module_exit(zs_exit);