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[5] |= TxENAB;
 791         zport->regs[15] |= BRKIE;
 792         write_zsreg(zport, R1, zport->regs[1]);
 793         write_zsreg(zport, R3, zport->regs[3]);
 794         write_zsreg(zport, R5, zport->regs[5]);
 795         write_zsreg(zport, R15, zport->regs[15]);
 796
 797         /* Record the current state of RR0.  */
 798         zport->mctrl = zs_raw_get_mctrl(zport);
 799         zport->brk = read_zsreg(zport, R0) & BRK_ABRT;
 800
 801         zport->tx_stopped = 1;
 802
 803         spin_unlock_irqrestore(&scc->zlock, flags);
 804
 805         return 0;
 806 }
 807
 808 static void zs_shutdown(struct uart_port *uport)
 809 {
 810         struct zs_port *zport = to_zport(uport);
 811         struct zs_scc *scc = zport->scc;
 812         unsigned long flags;
 813         int irq_guard;
 814
 815         spin_lock_irqsave(&scc->zlock, flags);
 816
 817         zport->regs[5] &= ~TxENAB;
 818         zport->regs[3] &= ~RxENABLE;
 819         write_zsreg(zport, R5, zport->regs[5]);
 820         write_zsreg(zport, R3, zport->regs[3]);
 821
 822         spin_unlock_irqrestore(&scc->zlock, flags);
 823
 824         irq_guard = atomic_add_return(-1, &scc->irq_guard);
 825         if (!irq_guard)
 826                 free_irq(zport->port.irq, scc);
 827 }
 828
 829
 830 static void zs_reset(struct zs_port *zport)
 831 {
 832         struct zs_scc *scc = zport->scc;
 833         int irq;
 834         unsigned long flags;
 835
 836         spin_lock_irqsave(&scc->zlock, flags);
 837         irq = !irqs_disabled_flags(flags);
 838         if (!scc->initialised) {
 839                 /* Reset the pointer first, just in case...  */
 840                 read_zsreg(zport, R0);
 841                 /* And let the current transmission finish.  */
 842                 zs_line_drain(zport, irq);
 843                 write_zsreg(zport, R9, FHWRES);
 844                 udelay(10);
 845                 write_zsreg(zport, R9, 0);
 846                 scc->initialised = 1;
 847         }
 848         load_zsregs(zport, zport->regs, irq);
 849         spin_unlock_irqrestore(&scc->zlock, flags);
 850 }
 851
 852 static void zs_set_termios(struct uart_port *uport, struct ktermios *termios,
 853                            struct ktermios *old_termios)
 854 {
 855         struct zs_port *zport = to_zport(uport);
 856         struct zs_scc *scc = zport->scc;
 857         struct zs_port *zport_a = &scc->zport[ZS_CHAN_A];
 858         int irq;
 859         unsigned int baud, brg;
 860         unsigned long flags;
 861
 862         spin_lock_irqsave(&scc->zlock, flags);
 863         irq = !irqs_disabled_flags(flags);
 864
 865         /* Byte size.  */
 866         zport->regs[3] &= ~RxNBITS_MASK;
 867         zport->regs[5] &= ~TxNBITS_MASK;
 868         switch (termios->c_cflag & CSIZE) {
 869         case CS5:
 870                 zport->regs[3] |= Rx5;
 871                 zport->regs[5] |= Tx5;
 872                 break;
 873         case CS6:
 874                 zport->regs[3] |= Rx6;
 875                 zport->regs[5] |= Tx6;
 876                 break;
 877         case CS7:
 878                 zport->regs[3] |= Rx7;
 879                 zport->regs[5] |= Tx7;
 880                 break;
 881         case CS8:
 882         default:
 883                 zport->regs[3] |= Rx8;
 884                 zport->regs[5] |= Tx8;
 885                 break;
 886         }
 887
 888         /* Parity and stop bits.  */
 889         zport->regs[4] &= ~(XCLK_MASK | SB_MASK | PAR_ENA | PAR_EVEN);
 890         if (termios->c_cflag & CSTOPB)
 891                 zport->regs[4] |= SB2;
 892         else
 893                 zport->regs[4] |= SB1;
 894         if (termios->c_cflag & PARENB)
 895                 zport->regs[4] |= PAR_ENA;
 896         if (!(termios->c_cflag & PARODD))
 897                 zport->regs[4] |= PAR_EVEN;
 898         switch (zport->clk_mode) {
 899         case 64:
 900                 zport->regs[4] |= X64CLK;
 901                 break;
 902         case 32:
 903                 zport->regs[4] |= X32CLK;
 904                 break;
 905         case 16:
 906                 zport->regs[4] |= X16CLK;
 907                 break;
 908         case 1:
 909                 zport->regs[4] |= X1CLK;
 910                 break;
 911         default:
 912                 BUG();
 913         }
 914
 915         baud = uart_get_baud_rate(uport, termios, old_termios, 0,
 916                                   uport->uartclk / zport->clk_mode / 4);
 917
 918         brg = ZS_BPS_TO_BRG(baud, uport->uartclk / zport->clk_mode);
 919         zport->regs[12] = brg & 0xff;
 920         zport->regs[13] = (brg >> 8) & 0xff;
 921
 922         uart_update_timeout(uport, termios->c_cflag, baud);
 923
 924         uport->read_status_mask = Rx_OVR;
 925         if (termios->c_iflag & INPCK)
 926                 uport->read_status_mask |= FRM_ERR | PAR_ERR;
 927         if (termios->c_iflag & (BRKINT | PARMRK))
 928                 uport->read_status_mask |= Rx_BRK;
 929
 930         uport->ignore_status_mask = 0;
 931         if (termios->c_iflag & IGNPAR)
 932                 uport->ignore_status_mask |= FRM_ERR | PAR_ERR;
 933         if (termios->c_iflag & IGNBRK) {
 934                 uport->ignore_status_mask |= Rx_BRK;
 935                 if (termios->c_iflag & IGNPAR)
 936                         uport->ignore_status_mask |= Rx_OVR;
 937         }
 938
 939         if (termios->c_cflag & CREAD)
 940                 zport->regs[3] |= RxENABLE;
 941         else
 942                 zport->regs[3] &= ~RxENABLE;
 943
 944         if (zport != zport_a) {
 945                 if (!(termios->c_cflag & CLOCAL)) {
 946                         zport->regs[15] |= DCDIE;
 947                 } else
 948                         zport->regs[15] &= ~DCDIE;
 949                 if (termios->c_cflag & CRTSCTS) {
 950                         zport->regs[15] |= CTSIE;
 951                 } else
 952                         zport->regs[15] &= ~CTSIE;
 953                 zs_raw_xor_mctrl(zport);
 954         }
 955
 956         /* Load up the new values.  */
 957         load_zsregs(zport, zport->regs, irq);
 958
 959         spin_unlock_irqrestore(&scc->zlock, flags);
 960 }
 961
 962
 963 static const char *zs_type(struct uart_port *uport)
 964 {
 965         return "Z85C30 SCC";
 966 }
 967
 968 static void zs_release_port(struct uart_port *uport)
 969 {
 970         iounmap(uport->membase);
 971         uport->membase = 0;
 972         release_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE);
 973 }
 974
 975 static int zs_map_port(struct uart_port *uport)
 976 {
 977         if (!uport->membase)
 978                 uport->membase = ioremap_nocache(uport->mapbase,
 979                                                  ZS_CHAN_IO_SIZE);
 980         if (!uport->membase) {
 981                 printk(KERN_ERR "zs: Cannot map MMIO\n");
 982                 return -ENOMEM;
 983         }
 984         return 0;
 985 }
 986
 987 static int zs_request_port(struct uart_port *uport)
 988 {
 989         int ret;
 990
 991         if (!request_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE, "scc")) {
 992                 printk(KERN_ERR "zs: Unable to reserve MMIO resource\n");
 993                 return -EBUSY;
 994         }
 995         ret = zs_map_port(uport);
 996         if (ret) {
 997                 release_mem_region(uport->mapbase, ZS_CHAN_IO_SIZE);
 998                 return ret;
 999         }
1000         return 0;
1001 }
1002
1003 static void zs_config_port(struct uart_port *uport, int flags)
1004 {
1005         struct zs_port *zport = to_zport(uport);
1006
1007         if (flags & UART_CONFIG_TYPE) {
1008                 if (zs_request_port(uport))
1009                         return;
1010
1011                 uport->type = PORT_ZS;
1012
1013                 zs_reset(zport);
1014         }
1015 }
1016
1017 static int zs_verify_port(struct uart_port *uport, struct serial_struct *ser)
1018 {
1019         struct zs_port *zport = to_zport(uport);
1020         int ret = 0;
1021
1022         if (ser->type != PORT_UNKNOWN && ser->type != PORT_ZS)
1023                 ret = -EINVAL;
1024         if (ser->irq != uport->irq)
1025                 ret = -EINVAL;
1026         if (ser->baud_base != uport->uartclk / zport->clk_mode / 4)
1027                 ret = -EINVAL;
1028         return ret;
1029 }
1030
1031
1032 static struct uart_ops zs_ops = {
1033         .tx_empty       = zs_tx_empty,
1034         .set_mctrl      = zs_set_mctrl,
1035         .get_mctrl      = zs_get_mctrl,
1036         .stop_tx        = zs_stop_tx,
1037         .start_tx       = zs_start_tx,
1038         .stop_rx        = zs_stop_rx,
1039         .enable_ms      = zs_enable_ms,
1040         .break_ctl      = zs_break_ctl,
1041         .startup        = zs_startup,
1042         .shutdown       = zs_shutdown,
1043         .set_termios    = zs_set_termios,
1044         .type           = zs_type,
1045         .release_port   = zs_release_port,
1046         .request_port   = zs_request_port,
1047         .config_port    = zs_config_port,
1048         .verify_port    = zs_verify_port,
1049 };
1050
1051 /*
1052  * Initialize Z85C30 port structures.
1053  */
1054 static int __init zs_probe_sccs(void)
1055 {
1056         static int probed;
1057         struct zs_parms zs_parms;
1058         int chip, side, irq;
1059         int n_chips = 0;
1060         int i;
1061
1062         if (probed)
1063                 return 0;
1064
1065         irq = dec_interrupt[DEC_IRQ_SCC0];
1066         if (irq >= 0) {
1067                 zs_parms.scc[n_chips] = IOASIC_SCC0;
1068                 zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC0];
1069                 n_chips++;
1070         }
1071         irq = dec_interrupt[DEC_IRQ_SCC1];
1072         if (irq >= 0) {
1073                 zs_parms.scc[n_chips] = IOASIC_SCC1;
1074                 zs_parms.irq[n_chips] = dec_interrupt[DEC_IRQ_SCC1];
1075                 n_chips++;
1076         }
1077         if (!n_chips)
1078                 return -ENXIO;
1079
1080         probed = 1;
1081
1082         for (chip = 0; chip < n_chips; chip++) {
1083                 spin_lock_init(&zs_sccs[chip].zlock);
1084                 for (side = 0; side < ZS_NUM_CHAN; side++) {
1085                         struct zs_port *zport = &zs_sccs[chip].zport[side];
1086                         struct uart_port *uport = &zport->port;
1087
1088                         zport->scc      = &zs_sccs[chip];
1089                         zport->clk_mode = 16;
1090
1091                         uport->irq      = zs_parms.irq[chip];
1092                         uport->uartclk  = ZS_CLOCK;
1093                         uport->fifosize = 1;
1094                         uport->iotype   = UPIO_MEM;
1095                         uport->flags    = UPF_BOOT_AUTOCONF;
1096                         uport->ops      = &zs_ops;
1097                         uport->line     = chip * ZS_NUM_CHAN + side;
1098                         uport->mapbase  = dec_kn_slot_base +
1099                                           zs_parms.scc[chip] +
1100                                           (side ^ ZS_CHAN_B) * ZS_CHAN_IO_SIZE;
1101
1102                         for (i = 0; i < ZS_NUM_REGS; i++)
1103                                 zport->regs[i] = zs_init_regs[i];
1104                 }
1105         }
1106
1107         return 0;
1108 }
1109
1110
1111 #ifdef CONFIG_SERIAL_ZS_CONSOLE
1112 static void zs_console_putchar(struct uart_port *uport, int ch)
1113 {
1114         struct zs_port *zport = to_zport(uport);
1115         struct zs_scc *scc = zport->scc;
1116         int irq;
1117         unsigned long flags;
1118
1119         spin_lock_irqsave(&scc->zlock, flags);
1120         irq = !irqs_disabled_flags(flags);
1121         if (zs_transmit_drain(zport, irq))
1122                 write_zsdata(zport, ch);
1123         spin_unlock_irqrestore(&scc->zlock, flags);
1124 }
1125
1126 /*
1127  * Print a string to the serial port trying not to disturb
1128  * any possible real use of the port...
1129  */
1130 static void zs_console_write(struct console *co, const char *s,
1131                              unsigned int count)
1132 {
1133         int chip = co->index / ZS_NUM_CHAN, side = co->index % ZS_NUM_CHAN;
1134         struct zs_port *zport = &zs_sccs[chip].zport[side];
1135         struct zs_scc *scc = zport->scc;
1136         unsigned long flags;
1137         u8 txint, txenb;
1138         int irq;
1139
1140         /* Disable transmit interrupts and enable the transmitter. */
1141         spin_lock_irqsave(&scc->zlock, flags);
1142         txint = zport->regs[1];
1143         txenb = zport->regs[5];
1144         if (txint & TxINT_ENAB) {
1145                 zport->regs[1] = txint & ~TxINT_ENAB;
1146                 write_zsreg(zport, R1, zport->regs[1]);
1147         }
1148         if (!(txenb & TxENAB)) {
1149                 zport->regs[5] = txenb | TxENAB;
1150                 write_zsreg(zport, R5, zport->regs[5]);
1151         }
1152         spin_unlock_irqrestore(&scc->zlock, flags);
1153
1154         uart_console_write(&zport->port, s, count, zs_console_putchar);
1155
1156         /* Restore transmit interrupts and the transmitter enable. */
1157         spin_lock_irqsave(&scc->zlock, flags);
1158         irq = !irqs_disabled_flags(flags);
1159         zs_line_drain(zport, irq);
1160         if (!(txenb & TxENAB)) {
1161                 zport->regs[5] &= ~TxENAB;
1162                 write_zsreg(zport, R5, zport->regs[5]);
1163         }
1164         if (txint & TxINT_ENAB) {
1165                 zport->regs[1] |= TxINT_ENAB;
1166                 write_zsreg(zport, R1, zport->regs[1]);
1167         }
1168         spin_unlock_irqrestore(&scc->zlock, flags);
1169 }
1170
1171 /*
1172  * Setup serial console baud/bits/parity.  We do two things here:
1173  * - construct a cflag setting for the first uart_open()
1174  * - initialise the serial port
1175  * Return non-zero if we didn't find a serial port.
1176  */
1177 static int __init zs_console_setup(struct console *co, char *options)
1178 {
1179         int chip = co->index / ZS_NUM_CHAN, side = co->index % ZS_NUM_CHAN;
1180         struct zs_port *zport = &zs_sccs[chip].zport[side];
1181         struct uart_port *uport = &zport->port;
1182         int baud = 9600;
1183         int bits = 8;
1184         int parity = 'n';
1185         int flow = 'n';
1186         int ret;
1187
1188         ret = zs_map_port(uport);
1189         if (ret)
1190                 return ret;
1191
1192         zs_reset(zport);
1193
1194         if (options)
1195                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1196         return uart_set_options(uport, co, baud, parity, bits, flow);
1197 }
1198
1199 static struct uart_driver zs_reg;
1200 static struct console zs_console = {
1201         .name   = "ttyS",
1202         .write  = zs_console_write,
1203         .device = uart_console_device,
1204         .setup  = zs_console_setup,
1205         .flags  = CON_PRINTBUFFER,
1206         .index  = -1,
1207         .data   = &zs_reg,
1208 };
1209
1210 /*
1211  *      Register console.
1212  */
1213 static int __init zs_serial_console_init(void)
1214 {
1215         int ret;
1216
1217         ret = zs_probe_sccs();
1218         if (ret)
1219                 return ret;
1220         register_console(&zs_console);
1221
1222         return 0;
1223 }
1224
1225 console_initcall(zs_serial_console_init);
1226
1227 #define SERIAL_ZS_CONSOLE       &zs_console
1228 #else
1229 #define SERIAL_ZS_CONSOLE       NULL
1230 #endif /* CONFIG_SERIAL_ZS_CONSOLE */
1231
1232 static struct uart_driver zs_reg = {
1233         .owner                  = THIS_MODULE,
1234         .driver_name            = "serial",
1235         .dev_name               = "ttyS",
1236         .major                  = TTY_MAJOR,
1237         .minor                  = 64,
1238         .nr                     = ZS_NUM_SCCS * ZS_NUM_CHAN,
1239         .cons                   = SERIAL_ZS_CONSOLE,
1240 };
1241
1242 /* zs_init inits the driver. */
1243 static int __init zs_init(void)
1244 {
1245         int i, ret;
1246
1247         pr_info("%s%s\n", zs_name, zs_version);
1248
1249         /* Find out how many Z85C30 SCCs we have.  */
1250         ret = zs_probe_sccs();
1251         if (ret)
1252                 return ret;
1253
1254         ret = uart_register_driver(&zs_reg);
1255         if (ret)
1256                 return ret;
1257
1258         for (i = 0; i < ZS_NUM_SCCS * ZS_NUM_CHAN; i++) {
1259                 struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
1260                 struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
1261                 struct uart_port *uport = &zport->port;
1262
1263                 if (zport->scc)
1264                         uart_add_one_port(&zs_reg, uport);
1265         }
1266
1267         return 0;
1268 }
1269
1270 static void __exit zs_exit(void)
1271 {
1272         int i;
1273
1274         for (i = ZS_NUM_SCCS * ZS_NUM_CHAN - 1; i >= 0; i--) {
1275                 struct zs_scc *scc = &zs_sccs[i / ZS_NUM_CHAN];
1276                 struct zs_port *zport = &scc->zport[i % ZS_NUM_CHAN];
1277                 struct uart_port *uport = &zport->port;
1278
1279                 if (zport->scc)
1280                         uart_remove_one_port(&zs_reg, uport);
1281         }
1282
1283         uart_unregister_driver(&zs_reg);
1284 }
1285
1286 module_init(zs_init);
1287 module_exit(zs_exit);