git.oblomov.eu Git - linux-2.6/blob - drivers/serial/ip22zilog.c

   1 /*
   2  * Driver for Zilog serial chips found on SGI workstations and
   3  * servers.  This driver could actually be made more generic.
   4  *
   5  * This is based on the drivers/serial/sunzilog.c code as of 2.6.0-test7 and the
   6  * old drivers/sgi/char/sgiserial.c code which itself is based of the original
   7  * drivers/sbus/char/zs.c code.  A lot of code has been simply moved over
   8  * directly from there but much has been rewritten.  Credits therefore go out
   9  * to David S. Miller, Eddie C. Dost, Pete Zaitcev, Ted Ts'o and Alex Buell
  10  * for their work there.
  11  *
  12  *  Copyright (C) 2002 Ralf Baechle (ralf@linux-mips.org)
  13  *  Copyright (C) 2002 David S. Miller (davem@redhat.com)
  14  */
  15 #include <linux/config.h>
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/errno.h>
  20 #include <linux/delay.h>
  21 #include <linux/tty.h>
  22 #include <linux/tty_flip.h>
  23 #include <linux/major.h>
  24 #include <linux/string.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/ioport.h>
  27 #include <linux/slab.h>
  28 #include <linux/circ_buf.h>
  29 #include <linux/serial.h>
  30 #include <linux/sysrq.h>
  31 #include <linux/console.h>
  32 #include <linux/spinlock.h>
  33 #include <linux/init.h>
  34
  35 #include <asm/io.h>
  36 #include <asm/irq.h>
  37 #include <asm/sgialib.h>
  38 #include <asm/sgi/ioc.h>
  39 #include <asm/sgi/hpc3.h>
  40 #include <asm/sgi/ip22.h>
  41
  42 #if defined(CONFIG_SERIAL_IP22_ZILOG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  43 #define SUPPORT_SYSRQ
  44 #endif
  45
  46 #include <linux/serial_core.h>
  47
  48 #include "ip22zilog.h"
  49
  50 void ip22_do_break(void);
  51
  52 /*
  53  * On IP22 we need to delay after register accesses but we do not need to
  54  * flush writes.
  55  */
  56 #define ZSDELAY()               udelay(5)
  57 #define ZSDELAY_LONG()          udelay(20)
  58 #define ZS_WSYNC(channel)       do { } while (0)
  59
  60 #define NUM_IP22ZILOG           1
  61 #define NUM_CHANNELS            (NUM_IP22ZILOG * 2)
  62
  63 #define ZS_CLOCK                3672000 /* Zilog input clock rate. */
  64 #define ZS_CLOCK_DIVISOR        16      /* Divisor this driver uses. */
  65
  66 /*
  67  * We wrap our port structure around the generic uart_port.
  68  */
  69 struct uart_ip22zilog_port {
  70         struct uart_port                port;
  71
  72         /* IRQ servicing chain.  */
  73         struct uart_ip22zilog_port      *next;
  74
  75         /* Current values of Zilog write registers.  */
  76         unsigned char                   curregs[NUM_ZSREGS];
  77
  78         unsigned int                    flags;
  79 #define IP22ZILOG_FLAG_IS_CONS          0x00000004
  80 #define IP22ZILOG_FLAG_IS_KGDB          0x00000008
  81 #define IP22ZILOG_FLAG_MODEM_STATUS     0x00000010
  82 #define IP22ZILOG_FLAG_IS_CHANNEL_A     0x00000020
  83 #define IP22ZILOG_FLAG_REGS_HELD        0x00000040
  84 #define IP22ZILOG_FLAG_TX_STOPPED       0x00000080
  85 #define IP22ZILOG_FLAG_TX_ACTIVE        0x00000100
  86
  87         unsigned int                    cflag;
  88
  89         /* L1-A keyboard break state.  */
  90         int                             kbd_id;
  91         int                             l1_down;
  92
  93         unsigned char                   parity_mask;
  94         unsigned char                   prev_status;
  95 };
  96
  97 #define ZILOG_CHANNEL_FROM_PORT(PORT)   ((struct zilog_channel *)((PORT)->membase))
  98 #define UART_ZILOG(PORT)                ((struct uart_ip22zilog_port *)(PORT))
  99 #define IP22ZILOG_GET_CURR_REG(PORT, REGNUM)            \
 100         (UART_ZILOG(PORT)->curregs[REGNUM])
 101 #define IP22ZILOG_SET_CURR_REG(PORT, REGNUM, REGVAL)    \
 102         ((UART_ZILOG(PORT)->curregs[REGNUM]) = (REGVAL))
 103 #define ZS_IS_CONS(UP)  ((UP)->flags & IP22ZILOG_FLAG_IS_CONS)
 104 #define ZS_IS_KGDB(UP)  ((UP)->flags & IP22ZILOG_FLAG_IS_KGDB)
 105 #define ZS_WANTS_MODEM_STATUS(UP)       ((UP)->flags & IP22ZILOG_FLAG_MODEM_STATUS)
 106 #define ZS_IS_CHANNEL_A(UP)     ((UP)->flags & IP22ZILOG_FLAG_IS_CHANNEL_A)
 107 #define ZS_REGS_HELD(UP)        ((UP)->flags & IP22ZILOG_FLAG_REGS_HELD)
 108 #define ZS_TX_STOPPED(UP)       ((UP)->flags & IP22ZILOG_FLAG_TX_STOPPED)
 109 #define ZS_TX_ACTIVE(UP)        ((UP)->flags & IP22ZILOG_FLAG_TX_ACTIVE)
 110
 111 /* Reading and writing Zilog8530 registers.  The delays are to make this
 112  * driver work on the IP22 which needs a settling delay after each chip
 113  * register access, other machines handle this in hardware via auxiliary
 114  * flip-flops which implement the settle time we do in software.
 115  *
 116  * The port lock must be held and local IRQs must be disabled
 117  * when {read,write}_zsreg is invoked.
 118  */
 119 static unsigned char read_zsreg(struct zilog_channel *channel,
 120                                 unsigned char reg)
 121 {
 122         unsigned char retval;
 123
 124         writeb(reg, &channel->control);
 125         ZSDELAY();
 126         retval = readb(&channel->control);
 127         ZSDELAY();
 128
 129         return retval;
 130 }
 131
 132 static void write_zsreg(struct zilog_channel *channel,
 133                         unsigned char reg, unsigned char value)
 134 {
 135         writeb(reg, &channel->control);
 136         ZSDELAY();
 137         writeb(value, &channel->control);
 138         ZSDELAY();
 139 }
 140
 141 static void ip22zilog_clear_fifo(struct zilog_channel *channel)
 142 {
 143         int i;
 144
 145         for (i = 0; i < 32; i++) {
 146                 unsigned char regval;
 147
 148                 regval = readb(&channel->control);
 149                 ZSDELAY();
 150                 if (regval & Rx_CH_AV)
 151                         break;
 152
 153                 regval = read_zsreg(channel, R1);
 154                 readb(&channel->data);
 155                 ZSDELAY();
 156
 157                 if (regval & (PAR_ERR | Rx_OVR | CRC_ERR)) {
 158                         writeb(ERR_RES, &channel->control);
 159                         ZSDELAY();
 160                         ZS_WSYNC(channel);
 161                 }
 162         }
 163 }
 164
 165 /* This function must only be called when the TX is not busy.  The UART
 166  * port lock must be held and local interrupts disabled.
 167  */
 168 static void __load_zsregs(struct zilog_channel *channel, unsigned char *regs)
 169 {
 170         int i;
 171
 172         /* Let pending transmits finish.  */
 173         for (i = 0; i < 1000; i++) {
 174                 unsigned char stat = read_zsreg(channel, R1);
 175                 if (stat & ALL_SNT)
 176                         break;
 177                 udelay(100);
 178         }
 179
 180         writeb(ERR_RES, &channel->control);
 181         ZSDELAY();
 182         ZS_WSYNC(channel);
 183
 184         ip22zilog_clear_fifo(channel);
 185
 186         /* Disable all interrupts.  */
 187         write_zsreg(channel, R1,
 188                     regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));
 189
 190         /* Set parity, sync config, stop bits, and clock divisor.  */
 191         write_zsreg(channel, R4, regs[R4]);
 192
 193         /* Set misc. TX/RX control bits.  */
 194         write_zsreg(channel, R10, regs[R10]);
 195
 196         /* Set TX/RX controls sans the enable bits.  */
 197         write_zsreg(channel, R3, regs[R3] & ~RxENAB);
 198         write_zsreg(channel, R5, regs[R5] & ~TxENAB);
 199
 200         /* Synchronous mode config.  */
 201         write_zsreg(channel, R6, regs[R6]);
 202         write_zsreg(channel, R7, regs[R7]);
 203
 204         /* Don't mess with the interrupt vector (R2, unused by us) and
 205          * master interrupt control (R9).  We make sure this is setup
 206          * properly at probe time then never touch it again.
 207          */
 208
 209         /* Disable baud generator.  */
 210         write_zsreg(channel, R14, regs[R14] & ~BRENAB);
 211
 212         /* Clock mode control.  */
 213         write_zsreg(channel, R11, regs[R11]);
 214
 215         /* Lower and upper byte of baud rate generator divisor.  */
 216         write_zsreg(channel, R12, regs[R12]);
 217         write_zsreg(channel, R13, regs[R13]);
 218
 219         /* Now rewrite R14, with BRENAB (if set).  */
 220         write_zsreg(channel, R14, regs[R14]);
 221
 222         /* External status interrupt control.  */
 223         write_zsreg(channel, R15, regs[R15]);
 224
 225         /* Reset external status interrupts.  */
 226         write_zsreg(channel, R0, RES_EXT_INT);
 227         write_zsreg(channel, R0, RES_EXT_INT);
 228
 229         /* Rewrite R3/R5, this time without enables masked.  */
 230         write_zsreg(channel, R3, regs[R3]);
 231         write_zsreg(channel, R5, regs[R5]);
 232
 233         /* Rewrite R1, this time without IRQ enabled masked.  */
 234         write_zsreg(channel, R1, regs[R1]);
 235 }
 236
 237 /* Reprogram the Zilog channel HW registers with the copies found in the
 238  * software state struct.  If the transmitter is busy, we defer this update
 239  * until the next TX complete interrupt.  Else, we do it right now.
 240  *
 241  * The UART port lock must be held and local interrupts disabled.
 242  */
 243 static void ip22zilog_maybe_update_regs(struct uart_ip22zilog_port *up,
 244                                        struct zilog_channel *channel)
 245 {
 246         if (!ZS_REGS_HELD(up)) {
 247                 if (ZS_TX_ACTIVE(up)) {
 248                         up->flags |= IP22ZILOG_FLAG_REGS_HELD;
 249                 } else {
 250                         __load_zsregs(channel, up->curregs);
 251                 }
 252         }
 253 }
 254
 255 static void ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
 256                                    struct zilog_channel *channel,
 257                                    struct pt_regs *regs)
 258 {
 259         struct tty_struct *tty = up->port.info->tty;    /* XXX info==NULL? */
 260
 261         while (1) {
 262                 unsigned char ch, r1;
 263
 264                 if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) {
 265                         tty->flip.work.func((void *)tty);
 266                         if (tty->flip.count >= TTY_FLIPBUF_SIZE)
 267                                 return;         /* XXX Ignores SysRq when we need it most. Fix. */
 268                 }
 269
 270                 r1 = read_zsreg(channel, R1);
 271                 if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
 272                         writeb(ERR_RES, &channel->control);
 273                         ZSDELAY();
 274                         ZS_WSYNC(channel);
 275                 }
 276
 277                 ch = readb(&channel->control);
 278                 ZSDELAY();
 279
 280                 /* This funny hack depends upon BRK_ABRT not interfering
 281                  * with the other bits we care about in R1.
 282                  */
 283                 if (ch & BRK_ABRT)
 284                         r1 |= BRK_ABRT;
 285
 286                 ch = readb(&channel->data);
 287                 ZSDELAY();
 288
 289                 ch &= up->parity_mask;
 290
 291                 if (ZS_IS_CONS(up) && (r1 & BRK_ABRT)) {
 292                         /* Wait for BREAK to deassert to avoid potentially
 293                          * confusing the PROM.
 294                          */
 295                         while (1) {
 296                                 ch = readb(&channel->control);
 297                                 ZSDELAY();
 298                                 if (!(ch & BRK_ABRT))
 299                                         break;
 300                         }
 301                         ip22_do_break();
 302                         return;
 303                 }
 304
 305                 /* A real serial line, record the character and status.  */
 306                 *tty->flip.char_buf_ptr = ch;
 307                 *tty->flip.flag_buf_ptr = TTY_NORMAL;
 308                 up->port.icount.rx++;
 309                 if (r1 & (BRK_ABRT | PAR_ERR | Rx_OVR | CRC_ERR)) {
 310                         if (r1 & BRK_ABRT) {
 311                                 r1 &= ~(PAR_ERR | CRC_ERR);
 312                                 up->port.icount.brk++;
 313                                 if (uart_handle_break(&up->port))
 314                                         goto next_char;
 315                         }
 316                         else if (r1 & PAR_ERR)
 317                                 up->port.icount.parity++;
 318                         else if (r1 & CRC_ERR)
 319                                 up->port.icount.frame++;
 320                         if (r1 & Rx_OVR)
 321                                 up->port.icount.overrun++;
 322                         r1 &= up->port.read_status_mask;
 323                         if (r1 & BRK_ABRT)
 324                                 *tty->flip.flag_buf_ptr = TTY_BREAK;
 325                         else if (r1 & PAR_ERR)
 326                                 *tty->flip.flag_buf_ptr = TTY_PARITY;
 327                         else if (r1 & CRC_ERR)
 328                                 *tty->flip.flag_buf_ptr = TTY_FRAME;
 329                 }
 330                 if (uart_handle_sysrq_char(&up->port, ch, regs))
 331                         goto next_char;
 332
 333                 if (up->port.ignore_status_mask == 0xff ||
 334                     (r1 & up->port.ignore_status_mask) == 0) {
 335                         tty->flip.flag_buf_ptr++;
 336                         tty->flip.char_buf_ptr++;
 337                         tty->flip.count++;
 338                 }
 339                 if ((r1 & Rx_OVR) &&
 340                     tty->flip.count < TTY_FLIPBUF_SIZE) {
 341                         *tty->flip.flag_buf_ptr = TTY_OVERRUN;
 342                         tty->flip.flag_buf_ptr++;
 343                         tty->flip.char_buf_ptr++;
 344                         tty->flip.count++;
 345                 }
 346         next_char:
 347                 ch = readb(&channel->control);
 348                 ZSDELAY();
 349                 if (!(ch & Rx_CH_AV))
 350                         break;
 351         }
 352
 353         tty_flip_buffer_push(tty);
 354 }
 355
 356 static void ip22zilog_status_handle(struct uart_ip22zilog_port *up,
 357                                    struct zilog_channel *channel,
 358                                    struct pt_regs *regs)
 359 {
 360         unsigned char status;
 361
 362         status = readb(&channel->control);
 363         ZSDELAY();
 364
 365         writeb(RES_EXT_INT, &channel->control);
 366         ZSDELAY();
 367         ZS_WSYNC(channel);
 368
 369         if (ZS_WANTS_MODEM_STATUS(up)) {
 370                 if (status & SYNC)
 371                         up->port.icount.dsr++;
 372
 373                 /* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
 374                  * But it does not tell us which bit has changed, we have to keep
 375                  * track of this ourselves.
 376                  */
 377                 if ((status & DCD) ^ up->prev_status)
 378                         uart_handle_dcd_change(&up->port,
 379                                                (status & DCD));
 380                 if ((status & CTS) ^ up->prev_status)
 381                         uart_handle_cts_change(&up->port,
 382                                                (status & CTS));
 383
 384                 wake_up_interruptible(&up->port.info->delta_msr_wait);
 385         }
 386
 387         up->prev_status = status;
 388 }
 389
 390 static void ip22zilog_transmit_chars(struct uart_ip22zilog_port *up,
 391                                     struct zilog_channel *channel)
 392 {
 393         struct circ_buf *xmit;
 394
 395         if (ZS_IS_CONS(up)) {
 396                 unsigned char status = readb(&channel->control);
 397                 ZSDELAY();
 398
 399                 /* TX still busy?  Just wait for the next TX done interrupt.
 400                  *
 401                  * It can occur because of how we do serial console writes.  It would
 402                  * be nice to transmit console writes just like we normally would for
 403                  * a TTY line. (ie. buffered and TX interrupt driven).  That is not
 404                  * easy because console writes cannot sleep.  One solution might be
 405                  * to poll on enough port->xmit space becomming free.  -DaveM
 406                  */
 407                 if (!(status & Tx_BUF_EMP))
 408                         return;
 409         }
 410
 411         up->flags &= ~IP22ZILOG_FLAG_TX_ACTIVE;
 412
 413         if (ZS_REGS_HELD(up)) {
 414                 __load_zsregs(channel, up->curregs);
 415                 up->flags &= ~IP22ZILOG_FLAG_REGS_HELD;
 416         }
 417
 418         if (ZS_TX_STOPPED(up)) {
 419                 up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
 420                 goto ack_tx_int;
 421         }
 422
 423         if (up->port.x_char) {
 424                 up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
 425                 writeb(up->port.x_char, &channel->data);
 426                 ZSDELAY();
 427                 ZS_WSYNC(channel);
 428
 429                 up->port.icount.tx++;
 430                 up->port.x_char = 0;
 431                 return;
 432         }
 433
 434         if (up->port.info == NULL)
 435                 goto ack_tx_int;
 436         xmit = &up->port.info->xmit;
 437         if (uart_circ_empty(xmit)) {
 438                 uart_write_wakeup(&up->port);
 439                 goto ack_tx_int;
 440         }
 441         if (uart_tx_stopped(&up->port))
 442                 goto ack_tx_int;
 443
 444         up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
 445         writeb(xmit->buf[xmit->tail], &channel->data);
 446         ZSDELAY();
 447         ZS_WSYNC(channel);
 448
 449         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 450         up->port.icount.tx++;
 451
 452         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 453                 uart_write_wakeup(&up->port);
 454
 455         return;
 456
 457 ack_tx_int:
 458         writeb(RES_Tx_P, &channel->control);
 459         ZSDELAY();
 460         ZS_WSYNC(channel);
 461 }
 462
 463 static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 464 {
 465         struct uart_ip22zilog_port *up = dev_id;
 466
 467         while (up) {
 468                 struct zilog_channel *channel
 469                         = ZILOG_CHANNEL_FROM_PORT(&up->port);
 470                 unsigned char r3;
 471
 472                 spin_lock(&up->port.lock);
 473                 r3 = read_zsreg(channel, R3);
 474
 475                 /* Channel A */
 476                 if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
 477                         writeb(RES_H_IUS, &channel->control);
 478                         ZSDELAY();
 479                         ZS_WSYNC(channel);
 480
 481                         if (r3 & CHARxIP)
 482                                 ip22zilog_receive_chars(up, channel, regs);
 483                         if (r3 & CHAEXT)
 484                                 ip22zilog_status_handle(up, channel, regs);
 485                         if (r3 & CHATxIP)
 486                                 ip22zilog_transmit_chars(up, channel);
 487                 }
 488                 spin_unlock(&up->port.lock);
 489
 490                 /* Channel B */
 491                 up = up->next;
 492                 channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
 493
 494                 spin_lock(&up->port.lock);
 495                 if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
 496                         writeb(RES_H_IUS, &channel->control);
 497                         ZSDELAY();
 498                         ZS_WSYNC(channel);
 499
 500                         if (r3 & CHBRxIP)
 501                                 ip22zilog_receive_chars(up, channel, regs);
 502                         if (r3 & CHBEXT)
 503                                 ip22zilog_status_handle(up, channel, regs);
 504                         if (r3 & CHBTxIP)
 505                                 ip22zilog_transmit_chars(up, channel);
 506                 }
 507                 spin_unlock(&up->port.lock);
 508
 509                 up = up->next;
 510         }
 511
 512         return IRQ_HANDLED;
 513 }
 514
 515 /* A convenient way to quickly get R0 status.  The caller must _not_ hold the
 516  * port lock, it is acquired here.
 517  */
 518 static __inline__ unsigned char ip22zilog_read_channel_status(struct uart_port *port)
 519 {
 520         struct zilog_channel *channel;
 521         unsigned char status;
 522
 523         channel = ZILOG_CHANNEL_FROM_PORT(port);
 524         status = readb(&channel->control);
 525         ZSDELAY();
 526
 527         return status;
 528 }
 529
 530 /* The port lock is not held.  */
 531 static unsigned int ip22zilog_tx_empty(struct uart_port *port)
 532 {
 533         unsigned long flags;
 534         unsigned char status;
 535         unsigned int ret;
 536
 537         spin_lock_irqsave(&port->lock, flags);
 538
 539         status = ip22zilog_read_channel_status(port);
 540
 541         spin_unlock_irqrestore(&port->lock, flags);
 542
 543         if (status & Tx_BUF_EMP)
 544                 ret = TIOCSER_TEMT;
 545         else
 546                 ret = 0;
 547
 548         return ret;
 549 }
 550
 551 /* The port lock is held and interrupts are disabled.  */
 552 static unsigned int ip22zilog_get_mctrl(struct uart_port *port)
 553 {
 554         unsigned char status;
 555         unsigned int ret;
 556
 557         status = ip22zilog_read_channel_status(port);
 558
 559         ret = 0;
 560         if (status & DCD)
 561                 ret |= TIOCM_CAR;
 562         if (status & SYNC)
 563                 ret |= TIOCM_DSR;
 564         if (status & CTS)
 565                 ret |= TIOCM_CTS;
 566
 567         return ret;
 568 }
 569
 570 /* The port lock is held and interrupts are disabled.  */
 571 static void ip22zilog_set_mctrl(struct uart_port *port, unsigned int mctrl)
 572 {
 573         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
 574         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
 575         unsigned char set_bits, clear_bits;
 576
 577         set_bits = clear_bits = 0;
 578
 579         if (mctrl & TIOCM_RTS)
 580                 set_bits |= RTS;
 581         else
 582                 clear_bits |= RTS;
 583         if (mctrl & TIOCM_DTR)
 584                 set_bits |= DTR;
 585         else
 586                 clear_bits |= DTR;
 587
 588         /* NOTE: Not subject to 'transmitter active' rule.  */
 589         up->curregs[R5] |= set_bits;
 590         up->curregs[R5] &= ~clear_bits;
 591         write_zsreg(channel, R5, up->curregs[R5]);
 592 }
 593
 594 /* The port lock is held and interrupts are disabled.  */
 595 static void ip22zilog_stop_tx(struct uart_port *port)
 596 {
 597         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
 598
 599         up->flags |= IP22ZILOG_FLAG_TX_STOPPED;
 600 }
 601
 602 /* The port lock is held and interrupts are disabled.  */
 603 static void ip22zilog_start_tx(struct uart_port *port)
 604 {
 605         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
 606         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
 607         unsigned char status;
 608
 609         up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
 610         up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
 611
 612         status = readb(&channel->control);
 613         ZSDELAY();
 614
 615         /* TX busy?  Just wait for the TX done interrupt.  */
 616         if (!(status & Tx_BUF_EMP))
 617                 return;
 618
 619         /* Send the first character to jump-start the TX done
 620          * IRQ sending engine.
 621          */
 622         if (port->x_char) {
 623                 writeb(port->x_char, &channel->data);
 624                 ZSDELAY();
 625                 ZS_WSYNC(channel);
 626
 627                 port->icount.tx++;
 628                 port->x_char = 0;
 629         } else {
 630                 struct circ_buf *xmit = &port->info->xmit;
 631
 632                 writeb(xmit->buf[xmit->tail], &channel->data);
 633                 ZSDELAY();
 634                 ZS_WSYNC(channel);
 635
 636                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 637                 port->icount.tx++;
 638
 639                 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 640                         uart_write_wakeup(&up->port);
 641         }
 642 }
 643
 644 /* The port lock is held and interrupts are disabled.  */
 645 static void ip22zilog_stop_rx(struct uart_port *port)
 646 {
 647         struct uart_ip22zilog_port *up = UART_ZILOG(port);
 648         struct zilog_channel *channel;
 649
 650         if (ZS_IS_CONS(up))
 651                 return;
 652
 653         channel = ZILOG_CHANNEL_FROM_PORT(port);
 654
 655         /* Disable all RX interrupts.  */
 656         up->curregs[R1] &= ~RxINT_MASK;
 657         ip22zilog_maybe_update_regs(up, channel);
 658 }
 659
 660 /* The port lock is held.  */
 661 static void ip22zilog_enable_ms(struct uart_port *port)
 662 {
 663         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
 664         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
 665         unsigned char new_reg;
 666
 667         new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
 668         if (new_reg != up->curregs[R15]) {
 669                 up->curregs[R15] = new_reg;
 670
 671                 /* NOTE: Not subject to 'transmitter active' rule.  */
 672                 write_zsreg(channel, R15, up->curregs[R15]);
 673         }
 674 }
 675
 676 /* The port lock is not held.  */
 677 static void ip22zilog_break_ctl(struct uart_port *port, int break_state)
 678 {
 679         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
 680         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
 681         unsigned char set_bits, clear_bits, new_reg;
 682         unsigned long flags;
 683
 684         set_bits = clear_bits = 0;
 685
 686         if (break_state)
 687                 set_bits |= SND_BRK;
 688         else
 689                 clear_bits |= SND_BRK;
 690
 691         spin_lock_irqsave(&port->lock, flags);
 692
 693         new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
 694         if (new_reg != up->curregs[R5]) {
 695                 up->curregs[R5] = new_reg;
 696
 697                 /* NOTE: Not subject to 'transmitter active' rule.  */
 698                 write_zsreg(channel, R5, up->curregs[R5]);
 699         }
 700
 701         spin_unlock_irqrestore(&port->lock, flags);
 702 }
 703
 704 static void __ip22zilog_startup(struct uart_ip22zilog_port *up)
 705 {
 706         struct zilog_channel *channel;
 707
 708         channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
 709         up->prev_status = readb(&channel->control);
 710
 711         /* Enable receiver and transmitter.  */
 712         up->curregs[R3] |= RxENAB;
 713         up->curregs[R5] |= TxENAB;
 714
 715         up->curregs[R1] |= EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
 716         ip22zilog_maybe_update_regs(up, channel);
 717 }
 718
 719 static int ip22zilog_startup(struct uart_port *port)
 720 {
 721         struct uart_ip22zilog_port *up = UART_ZILOG(port);
 722         unsigned long flags;
 723
 724         if (ZS_IS_CONS(up))
 725                 return 0;
 726
 727         spin_lock_irqsave(&port->lock, flags);
 728         __ip22zilog_startup(up);
 729         spin_unlock_irqrestore(&port->lock, flags);
 730         return 0;
 731 }
 732
 733 /*
 734  * The test for ZS_IS_CONS is explained by the following e-mail:
 735  *****
 736  * From: Russell King <rmk@arm.linux.org.uk>
 737  * Date: Sun, 8 Dec 2002 10:18:38 +0000
 738  *
 739  * On Sun, Dec 08, 2002 at 02:43:36AM -0500, Pete Zaitcev wrote:
 740  * > I boot my 2.5 boxes using "console=ttyS0,9600" argument,
 741  * > and I noticed that something is not right with reference
 742  * > counting in this case. It seems that when the console
 743  * > is open by kernel initially, this is not accounted
 744  * > as an open, and uart_startup is not called.
 745  *
 746  * That is correct.  We are unable to call uart_startup when the serial
 747  * console is initialised because it may need to allocate memory (as
 748  * request_irq does) and the memory allocators may not have been
 749  * initialised.
 750  *
 751  * 1. initialise the port into a state where it can send characters in the
 752  *    console write method.
 753  *
 754  * 2. don't do the actual hardware shutdown in your shutdown() method (but
 755  *    do the normal software shutdown - ie, free irqs etc)
 756  *****
 757  */
 758 static void ip22zilog_shutdown(struct uart_port *port)
 759 {
 760         struct uart_ip22zilog_port *up = UART_ZILOG(port);
 761         struct zilog_channel *channel;
 762         unsigned long flags;
 763
 764         if (ZS_IS_CONS(up))
 765                 return;
 766
 767         spin_lock_irqsave(&port->lock, flags);
 768
 769         channel = ZILOG_CHANNEL_FROM_PORT(port);
 770
 771         /* Disable receiver and transmitter.  */
 772         up->curregs[R3] &= ~RxENAB;
 773         up->curregs[R5] &= ~TxENAB;
 774
 775         /* Disable all interrupts and BRK assertion.  */
 776         up->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
 777         up->curregs[R5] &= ~SND_BRK;
 778         ip22zilog_maybe_update_regs(up, channel);
 779
 780         spin_unlock_irqrestore(&port->lock, flags);
 781 }
 782
 783 /* Shared by TTY driver and serial console setup.  The port lock is held
 784  * and local interrupts are disabled.
 785  */
 786 static void
 787 ip22zilog_convert_to_zs(struct uart_ip22zilog_port *up, unsigned int cflag,
 788                        unsigned int iflag, int brg)
 789 {
 790
 791         up->curregs[R10] = NRZ;
 792         up->curregs[R11] = TCBR | RCBR;
 793
 794         /* Program BAUD and clock source. */
 795         up->curregs[R4] &= ~XCLK_MASK;
 796         up->curregs[R4] |= X16CLK;
 797         up->curregs[R12] = brg & 0xff;
 798         up->curregs[R13] = (brg >> 8) & 0xff;
 799         up->curregs[R14] = BRENAB;
 800
 801         /* Character size, stop bits, and parity. */
 802         up->curregs[3] &= ~RxN_MASK;
 803         up->curregs[5] &= ~TxN_MASK;
 804         switch (cflag & CSIZE) {
 805         case CS5:
 806                 up->curregs[3] |= Rx5;
 807                 up->curregs[5] |= Tx5;
 808                 up->parity_mask = 0x1f;
 809                 break;
 810         case CS6:
 811                 up->curregs[3] |= Rx6;
 812                 up->curregs[5] |= Tx6;
 813                 up->parity_mask = 0x3f;
 814                 break;
 815         case CS7:
 816                 up->curregs[3] |= Rx7;
 817                 up->curregs[5] |= Tx7;
 818                 up->parity_mask = 0x7f;
 819                 break;
 820         case CS8:
 821         default:
 822                 up->curregs[3] |= Rx8;
 823                 up->curregs[5] |= Tx8;
 824                 up->parity_mask = 0xff;
 825                 break;
 826         };
 827         up->curregs[4] &= ~0x0c;
 828         if (cflag & CSTOPB)
 829                 up->curregs[4] |= SB2;
 830         else
 831                 up->curregs[4] |= SB1;
 832         if (cflag & PARENB)
 833                 up->curregs[4] |= PAR_ENAB;
 834         else
 835                 up->curregs[4] &= ~PAR_ENAB;
 836         if (!(cflag & PARODD))
 837                 up->curregs[4] |= PAR_EVEN;
 838         else
 839                 up->curregs[4] &= ~PAR_EVEN;
 840
 841         up->port.read_status_mask = Rx_OVR;
 842         if (iflag & INPCK)
 843                 up->port.read_status_mask |= CRC_ERR | PAR_ERR;
 844         if (iflag & (BRKINT | PARMRK))
 845                 up->port.read_status_mask |= BRK_ABRT;
 846
 847         up->port.ignore_status_mask = 0;
 848         if (iflag & IGNPAR)
 849                 up->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
 850         if (iflag & IGNBRK) {
 851                 up->port.ignore_status_mask |= BRK_ABRT;
 852                 if (iflag & IGNPAR)
 853                         up->port.ignore_status_mask |= Rx_OVR;
 854         }
 855
 856         if ((cflag & CREAD) == 0)
 857                 up->port.ignore_status_mask = 0xff;
 858 }
 859
 860 /* The port lock is not held.  */
 861 static void
 862 ip22zilog_set_termios(struct uart_port *port, struct termios *termios,
 863                       struct termios *old)
 864 {
 865         struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
 866         unsigned long flags;
 867         int baud, brg;
 868
 869         baud = uart_get_baud_rate(port, termios, old, 1200, 76800);
 870
 871         spin_lock_irqsave(&up->port.lock, flags);
 872
 873         brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
 874
 875         ip22zilog_convert_to_zs(up, termios->c_cflag, termios->c_iflag, brg);
 876
 877         if (UART_ENABLE_MS(&up->port, termios->c_cflag))
 878                 up->flags |= IP22ZILOG_FLAG_MODEM_STATUS;
 879         else
 880                 up->flags &= ~IP22ZILOG_FLAG_MODEM_STATUS;
 881
 882         up->cflag = termios->c_cflag;
 883
 884         ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));
 885
 886         spin_unlock_irqrestore(&up->port.lock, flags);
 887 }
 888
 889 static const char *ip22zilog_type(struct uart_port *port)
 890 {
 891         return "IP22-Zilog";
 892 }
 893
 894 /* We do not request/release mappings of the registers here, this
 895  * happens at early serial probe time.
 896  */
 897 static void ip22zilog_release_port(struct uart_port *port)
 898 {
 899 }
 900
 901 static int ip22zilog_request_port(struct uart_port *port)
 902 {
 903         return 0;
 904 }
 905
 906 /* These do not need to do anything interesting either.  */
 907 static void ip22zilog_config_port(struct uart_port *port, int flags)
 908 {
 909 }
 910
 911 /* We do not support letting the user mess with the divisor, IRQ, etc. */
 912 static int ip22zilog_verify_port(struct uart_port *port, struct serial_struct *ser)
 913 {
 914         return -EINVAL;
 915 }
 916
 917 static struct uart_ops ip22zilog_pops = {
 918         .tx_empty       =       ip22zilog_tx_empty,
 919         .set_mctrl      =       ip22zilog_set_mctrl,
 920         .get_mctrl      =       ip22zilog_get_mctrl,
 921         .stop_tx        =       ip22zilog_stop_tx,
 922         .start_tx       =       ip22zilog_start_tx,
 923         .stop_rx        =       ip22zilog_stop_rx,
 924         .enable_ms      =       ip22zilog_enable_ms,
 925         .break_ctl      =       ip22zilog_break_ctl,
 926         .startup        =       ip22zilog_startup,
 927         .shutdown       =       ip22zilog_shutdown,
 928         .set_termios    =       ip22zilog_set_termios,
 929         .type           =       ip22zilog_type,
 930         .release_port   =       ip22zilog_release_port,
 931         .request_port   =       ip22zilog_request_port,
 932         .config_port    =       ip22zilog_config_port,
 933         .verify_port    =       ip22zilog_verify_port,
 934 };
 935
 936 static struct uart_ip22zilog_port *ip22zilog_port_table;
 937 static struct zilog_layout **ip22zilog_chip_regs;
 938
 939 static struct uart_ip22zilog_port *ip22zilog_irq_chain;
 940 static int zilog_irq = -1;
 941
 942 static void * __init alloc_one_table(unsigned long size)
 943 {
 944         void *ret;
 945
 946         ret = kmalloc(size, GFP_KERNEL);
 947         if (ret != NULL)
 948                 memset(ret, 0, size);
 949
 950         return ret;
 951 }
 952
 953 static void __init ip22zilog_alloc_tables(void)
 954 {
 955         ip22zilog_port_table = (struct uart_ip22zilog_port *)
 956                 alloc_one_table(NUM_CHANNELS * sizeof(struct uart_ip22zilog_port));
 957         ip22zilog_chip_regs = (struct zilog_layout **)
 958                 alloc_one_table(NUM_IP22ZILOG * sizeof(struct zilog_layout *));
 959
 960         if (ip22zilog_port_table == NULL || ip22zilog_chip_regs == NULL) {
 961                 panic("IP22-Zilog: Cannot allocate IP22-Zilog tables.");
 962         }
 963 }
 964
 965 /* Get the address of the registers for IP22-Zilog instance CHIP.  */
 966 static struct zilog_layout * __init get_zs(int chip)
 967 {
 968         unsigned long base;
 969
 970         if (chip < 0 || chip >= NUM_IP22ZILOG) {
 971                 panic("IP22-Zilog: Illegal chip number %d in get_zs.", chip);
 972         }
 973
 974         /* Not probe-able, hard code it. */
 975         base = (unsigned long) &sgioc->uart;
 976
 977         zilog_irq = SGI_SERIAL_IRQ;
 978         request_mem_region(base, 8, "IP22-Zilog");
 979
 980         return (struct zilog_layout *) base;
 981 }
 982
 983 #define ZS_PUT_CHAR_MAX_DELAY   2000    /* 10 ms */
 984
 985 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
 986 static void ip22zilog_put_char(struct zilog_channel *channel, unsigned char ch)
 987 {
 988         int loops = ZS_PUT_CHAR_MAX_DELAY;
 989
 990         /* This is a timed polling loop so do not switch the explicit
 991          * udelay with ZSDELAY as that is a NOP on some platforms.  -DaveM
 992          */
 993         do {
 994                 unsigned char val = readb(&channel->control);
 995                 if (val & Tx_BUF_EMP) {
 996                         ZSDELAY();
 997                         break;
 998                 }
 999                 udelay(5);
1000         } while (--loops);
1001
1002         writeb(ch, &channel->data);
1003         ZSDELAY();
1004         ZS_WSYNC(channel);
1005 }
1006
1007 static void
1008 ip22zilog_console_write(struct console *con, const char *s, unsigned int count)
1009 {
1010         struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
1011         struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
1012         unsigned long flags;
1013         int i;
1014
1015         spin_lock_irqsave(&up->port.lock, flags);
1016         for (i = 0; i < count; i++, s++) {
1017                 ip22zilog_put_char(channel, *s);
1018                 if (*s == 10)
1019                         ip22zilog_put_char(channel, 13);
1020         }
1021         udelay(2);
1022         spin_unlock_irqrestore(&up->port.lock, flags);
1023 }
1024
1025 void
1026 ip22serial_console_termios(struct console *con, char *options)
1027 {
1028         int baud = 9600, bits = 8, cflag;
1029         int parity = 'n';
1030         int flow = 'n';
1031
1032         if (options)
1033                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1034
1035         cflag = CREAD | HUPCL | CLOCAL;
1036
1037         switch (baud) {
1038                 case 150: cflag |= B150; break;
1039                 case 300: cflag |= B300; break;
1040                 case 600: cflag |= B600; break;
1041                 case 1200: cflag |= B1200; break;
1042                 case 2400: cflag |= B2400; break;
1043                 case 4800: cflag |= B4800; break;
1044                 case 9600: cflag |= B9600; break;
1045                 case 19200: cflag |= B19200; break;
1046                 case 38400: cflag |= B38400; break;
1047                 default: baud = 9600; cflag |= B9600; break;
1048         }
1049
1050         con->cflag = cflag | CS8;                       /* 8N1 */
1051 }
1052
1053 static int __init ip22zilog_console_setup(struct console *con, char *options)
1054 {
1055         struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
1056         unsigned long flags;
1057         int baud, brg;
1058
1059         printk("Console: ttyS%d (IP22-Zilog)\n", con->index);
1060
1061         /* Get firmware console settings.  */
1062         ip22serial_console_termios(con, options);
1063
1064         /* Firmware console speed is limited to 150-->38400 baud so
1065          * this hackish cflag thing is OK.
1066          */
1067         switch (con->cflag & CBAUD) {
1068         case B150: baud = 150; break;
1069         case B300: baud = 300; break;
1070         case B600: baud = 600; break;
1071         case B1200: baud = 1200; break;
1072         case B2400: baud = 2400; break;
1073         case B4800: baud = 4800; break;
1074         default: case B9600: baud = 9600; break;
1075         case B19200: baud = 19200; break;
1076         case B38400: baud = 38400; break;
1077         };
1078
1079         brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
1080
1081         spin_lock_irqsave(&up->port.lock, flags);
1082
1083         up->curregs[R15] = BRKIE;
1084         ip22zilog_convert_to_zs(up, con->cflag, 0, brg);
1085
1086         __ip22zilog_startup(up);
1087
1088         spin_unlock_irqrestore(&up->port.lock, flags);
1089
1090         return 0;
1091 }
1092
1093 static struct uart_driver ip22zilog_reg;
1094
1095 static struct console ip22zilog_console = {
1096         .name   =       "ttyS",
1097         .write  =       ip22zilog_console_write,
1098         .device =       uart_console_device,
1099         .setup  =       ip22zilog_console_setup,
1100         .flags  =       CON_PRINTBUFFER,
1101         .index  =       -1,
1102         .data   =       &ip22zilog_reg,
1103 };
1104 #endif /* CONFIG_SERIAL_IP22_ZILOG_CONSOLE */
1105
1106 static struct uart_driver ip22zilog_reg = {
1107         .owner          = THIS_MODULE,
1108         .driver_name    = "serial",
1109         .devfs_name     = "tts/",
1110         .dev_name       = "ttyS",
1111         .major          = TTY_MAJOR,
1112         .minor          = 64,
1113         .nr             = NUM_CHANNELS,
1114 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
1115         .cons           = &ip22zilog_console,
1116 #endif
1117 };
1118
1119 static void __init ip22zilog_prepare(void)
1120 {
1121         struct uart_ip22zilog_port *up;
1122         struct zilog_layout *rp;
1123         int channel, chip;
1124
1125         /*
1126          * Temporary fix.
1127          */
1128         for (channel = 0; channel < NUM_CHANNELS; channel++)
1129                 spin_lock_init(&ip22zilog_port_table[channel].port.lock);
1130
1131         ip22zilog_irq_chain = &ip22zilog_port_table[NUM_CHANNELS - 1];
1132         up = &ip22zilog_port_table[0];
1133         for (channel = NUM_CHANNELS - 1 ; channel > 0; channel--)
1134                 up[channel].next = &up[channel - 1];
1135         up[channel].next = NULL;
1136
1137         for (chip = 0; chip < NUM_IP22ZILOG; chip++) {
1138                 if (!ip22zilog_chip_regs[chip]) {
1139                         ip22zilog_chip_regs[chip] = rp = get_zs(chip);
1140
1141                         up[(chip * 2) + 0].port.membase = (char *) &rp->channelB;
1142                         up[(chip * 2) + 1].port.membase = (char *) &rp->channelA;
1143
1144                         /* In theory mapbase is the physical address ...  */
1145                         up[(chip * 2) + 0].port.mapbase =
1146                                 (unsigned long) ioremap((unsigned long) &rp->channelB, 8);
1147                         up[(chip * 2) + 1].port.mapbase =
1148                                 (unsigned long) ioremap((unsigned long) &rp->channelA, 8);
1149                 }
1150
1151                 /* Channel A */
1152                 up[(chip * 2) + 0].port.iotype = UPIO_MEM;
1153                 up[(chip * 2) + 0].port.irq = zilog_irq;
1154                 up[(chip * 2) + 0].port.uartclk = ZS_CLOCK;
1155                 up[(chip * 2) + 0].port.fifosize = 1;
1156                 up[(chip * 2) + 0].port.ops = &ip22zilog_pops;
1157                 up[(chip * 2) + 0].port.type = PORT_IP22ZILOG;
1158                 up[(chip * 2) + 0].port.flags = 0;
1159                 up[(chip * 2) + 0].port.line = (chip * 2) + 0;
1160                 up[(chip * 2) + 0].flags = 0;
1161
1162                 /* Channel B */
1163                 up[(chip * 2) + 1].port.iotype = UPIO_MEM;
1164                 up[(chip * 2) + 1].port.irq = zilog_irq;
1165                 up[(chip * 2) + 1].port.uartclk = ZS_CLOCK;
1166                 up[(chip * 2) + 1].port.fifosize = 1;
1167                 up[(chip * 2) + 1].port.ops = &ip22zilog_pops;
1168                 up[(chip * 2) + 1].port.type = PORT_IP22ZILOG;
1169                 up[(chip * 2) + 1].port.flags |= IP22ZILOG_FLAG_IS_CHANNEL_A;
1170                 up[(chip * 2) + 1].port.line = (chip * 2) + 1;
1171                 up[(chip * 2) + 1].flags = 0;
1172         }
1173 }
1174
1175 static void __init ip22zilog_init_hw(void)
1176 {
1177         int i;
1178
1179         for (i = 0; i < NUM_CHANNELS; i++) {
1180                 struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
1181                 struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
1182                 unsigned long flags;
1183                 int baud, brg;
1184
1185                 spin_lock_irqsave(&up->port.lock, flags);
1186
1187                 if (ZS_IS_CHANNEL_A(up)) {
1188                         write_zsreg(channel, R9, FHWRES);
1189                         ZSDELAY_LONG();
1190                         (void) read_zsreg(channel, R0);
1191                 }
1192
1193                 /* Normal serial TTY. */
1194                 up->parity_mask = 0xff;
1195                 up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
1196                 up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
1197                 up->curregs[R3] = RxENAB | Rx8;
1198                 up->curregs[R5] = TxENAB | Tx8;
1199                 up->curregs[R9] = NV | MIE;
1200                 up->curregs[R10] = NRZ;
1201                 up->curregs[R11] = TCBR | RCBR;
1202                 baud = 9600;
1203                 brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
1204                 up->curregs[R12] = (brg & 0xff);
1205                 up->curregs[R13] = (brg >> 8) & 0xff;
1206                 up->curregs[R14] = BRENAB;
1207                 __load_zsregs(channel, up->curregs);
1208                 /* set master interrupt enable */
1209                 write_zsreg(channel, R9, up->curregs[R9]);
1210
1211                 spin_unlock_irqrestore(&up->port.lock, flags);
1212         }
1213 }
1214
1215 static int __init ip22zilog_ports_init(void)
1216 {
1217         int ret;
1218
1219         printk(KERN_INFO "Serial: IP22 Zilog driver (%d chips).\n", NUM_IP22ZILOG);
1220
1221         ip22zilog_prepare();
1222
1223         if (request_irq(zilog_irq, ip22zilog_interrupt, 0,
1224                         "IP22-Zilog", ip22zilog_irq_chain)) {
1225                 panic("IP22-Zilog: Unable to register zs interrupt handler.\n");
1226         }
1227
1228         ip22zilog_init_hw();
1229
1230         ret = uart_register_driver(&ip22zilog_reg);
1231         if (ret == 0) {
1232                 int i;
1233
1234                 for (i = 0; i < NUM_CHANNELS; i++) {
1235                         struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
1236
1237                         uart_add_one_port(&ip22zilog_reg, &up->port);
1238                 }
1239         }
1240
1241         return ret;
1242 }
1243
1244 static int __init ip22zilog_init(void)
1245 {
1246         /* IP22 Zilog setup is hard coded, no probing to do.  */
1247         ip22zilog_alloc_tables();
1248         ip22zilog_ports_init();
1249
1250         return 0;
1251 }
1252
1253 static void __exit ip22zilog_exit(void)
1254 {
1255         int i;
1256
1257         for (i = 0; i < NUM_CHANNELS; i++) {
1258                 struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
1259
1260                 uart_remove_one_port(&ip22zilog_reg, &up->port);
1261         }
1262
1263         uart_unregister_driver(&ip22zilog_reg);
1264 }
1265
1266 module_init(ip22zilog_init);
1267 module_exit(ip22zilog_exit);
1268
1269 /* David wrote it but I'm to blame for the bugs ...  */
1270 MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
1271 MODULE_DESCRIPTION("SGI Zilog serial port driver");
1272 MODULE_LICENSE("GPL");