drivers/tty/serial/jsm/jsm_neo.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /************************************************************************
   3  * Copyright 2003 Digi International (www.digi.com)
   4  *
   5  * Copyright (C) 2004 IBM Corporation. All rights reserved.
   6  *
   7  * Contact Information:
   8  * Scott H Kilau <Scott_Kilau@digi.com>
   9  * Wendy Xiong   <wendyx@us.ibm.com>
  10  *
  11  ***********************************************************************/
  12 #include <linux/delay.h>        /* For udelay */
  13 #include <linux/serial_reg.h>   /* For the various UART offsets */
  14 #include <linux/tty.h>
  15 #include <linux/pci.h>
  16 #include <asm/io.h>
  17
  18 #include "jsm.h"                /* Driver main header file */
  19
  20 static u32 jsm_offset_table[8] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 };
  21
  22 /*
  23  * This function allows calls to ensure that all outstanding
  24  * PCI writes have been completed, by doing a PCI read against
  25  * a non-destructive, read-only location on the Neo card.
  26  *
  27  * In this case, we are reading the DVID (Read-only Device Identification)
  28  * value of the Neo card.
  29  */
  30 static inline void neo_pci_posting_flush(struct jsm_board *bd)
  31 {
  32       readb(bd->re_map_membase + 0x8D);
  33 }
  34
  35 static void neo_set_cts_flow_control(struct jsm_channel *ch)
  36 {
  37         u8 ier, efr;
  38         ier = readb(&ch->ch_neo_uart->ier);
  39         efr = readb(&ch->ch_neo_uart->efr);
  40
  41         jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting CTSFLOW\n");
  42
  43         /* Turn on auto CTS flow control */
  44         ier |= (UART_17158_IER_CTSDSR);
  45         efr |= (UART_17158_EFR_ECB | UART_17158_EFR_CTSDSR);
  46
  47         /* Turn off auto Xon flow control */
  48         efr &= ~(UART_17158_EFR_IXON);
  49
  50         /* Why? Becuz Exar's spec says we have to zero it out before setting it */
  51         writeb(0, &ch->ch_neo_uart->efr);
  52
  53         /* Turn on UART enhanced bits */
  54         writeb(efr, &ch->ch_neo_uart->efr);
  55
  56         /* Turn on table D, with 8 char hi/low watermarks */
  57         writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
  58
  59         /* Feed the UART our trigger levels */
  60         writeb(8, &ch->ch_neo_uart->tfifo);
  61         ch->ch_t_tlevel = 8;
  62
  63         writeb(ier, &ch->ch_neo_uart->ier);
  64 }
  65
  66 static void neo_set_rts_flow_control(struct jsm_channel *ch)
  67 {
  68         u8 ier, efr;
  69         ier = readb(&ch->ch_neo_uart->ier);
  70         efr = readb(&ch->ch_neo_uart->efr);
  71
  72         jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting RTSFLOW\n");
  73
  74         /* Turn on auto RTS flow control */
  75         ier |= (UART_17158_IER_RTSDTR);
  76         efr |= (UART_17158_EFR_ECB | UART_17158_EFR_RTSDTR);
  77
  78         /* Turn off auto Xoff flow control */
  79         ier &= ~(UART_17158_IER_XOFF);
  80         efr &= ~(UART_17158_EFR_IXOFF);
  81
  82         /* Why? Becuz Exar's spec says we have to zero it out before setting it */
  83         writeb(0, &ch->ch_neo_uart->efr);
  84
  85         /* Turn on UART enhanced bits */
  86         writeb(efr, &ch->ch_neo_uart->efr);
  87
  88         writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
  89         ch->ch_r_watermark = 4;
  90
  91         writeb(56, &ch->ch_neo_uart->rfifo);
  92         ch->ch_r_tlevel = 56;
  93
  94         writeb(ier, &ch->ch_neo_uart->ier);
  95
  96         /*
  97          * From the Neo UART spec sheet:
  98          * The auto RTS/DTR function must be started by asserting
  99          * RTS/DTR# output pin (MCR bit-0 or 1 to logic 1 after
 100          * it is enabled.
 101          */
 102         ch->ch_mostat |= (UART_MCR_RTS);
 103 }
 104
 105
 106 static void neo_set_ixon_flow_control(struct jsm_channel *ch)
 107 {
 108         u8 ier, efr;
 109         ier = readb(&ch->ch_neo_uart->ier);
 110         efr = readb(&ch->ch_neo_uart->efr);
 111
 112         jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting IXON FLOW\n");
 113
 114         /* Turn off auto CTS flow control */
 115         ier &= ~(UART_17158_IER_CTSDSR);
 116         efr &= ~(UART_17158_EFR_CTSDSR);
 117
 118         /* Turn on auto Xon flow control */
 119         efr |= (UART_17158_EFR_ECB | UART_17158_EFR_IXON);
 120
 121         /* Why? Becuz Exar's spec says we have to zero it out before setting it */
 122         writeb(0, &ch->ch_neo_uart->efr);
 123
 124         /* Turn on UART enhanced bits */
 125         writeb(efr, &ch->ch_neo_uart->efr);
 126
 127         writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
 128         ch->ch_r_watermark = 4;
 129
 130         writeb(32, &ch->ch_neo_uart->rfifo);
 131         ch->ch_r_tlevel = 32;
 132
 133         /* Tell UART what start/stop chars it should be looking for */
 134         writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
 135         writeb(0, &ch->ch_neo_uart->xonchar2);
 136
 137         writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
 138         writeb(0, &ch->ch_neo_uart->xoffchar2);
 139
 140         writeb(ier, &ch->ch_neo_uart->ier);
 141 }
 142
 143 static void neo_set_ixoff_flow_control(struct jsm_channel *ch)
 144 {
 145         u8 ier, efr;
 146         ier = readb(&ch->ch_neo_uart->ier);
 147         efr = readb(&ch->ch_neo_uart->efr);
 148
 149         jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting IXOFF FLOW\n");
 150
 151         /* Turn off auto RTS flow control */
 152         ier &= ~(UART_17158_IER_RTSDTR);
 153         efr &= ~(UART_17158_EFR_RTSDTR);
 154
 155         /* Turn on auto Xoff flow control */
 156         ier |= (UART_17158_IER_XOFF);
 157         efr |= (UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
 158
 159         /* Why? Becuz Exar's spec says we have to zero it out before setting it */
 160         writeb(0, &ch->ch_neo_uart->efr);
 161
 162         /* Turn on UART enhanced bits */
 163         writeb(efr, &ch->ch_neo_uart->efr);
 164
 165         /* Turn on table D, with 8 char hi/low watermarks */
 166         writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
 167
 168         writeb(8, &ch->ch_neo_uart->tfifo);
 169         ch->ch_t_tlevel = 8;
 170
 171         /* Tell UART what start/stop chars it should be looking for */
 172         writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
 173         writeb(0, &ch->ch_neo_uart->xonchar2);
 174
 175         writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
 176         writeb(0, &ch->ch_neo_uart->xoffchar2);
 177
 178         writeb(ier, &ch->ch_neo_uart->ier);
 179 }
 180
 181 static void neo_set_no_input_flow_control(struct jsm_channel *ch)
 182 {
 183         u8 ier, efr;
 184         ier = readb(&ch->ch_neo_uart->ier);
 185         efr = readb(&ch->ch_neo_uart->efr);
 186
 187         jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Unsetting Input FLOW\n");
 188
 189         /* Turn off auto RTS flow control */
 190         ier &= ~(UART_17158_IER_RTSDTR);
 191         efr &= ~(UART_17158_EFR_RTSDTR);
 192
 193         /* Turn off auto Xoff flow control */
 194         ier &= ~(UART_17158_IER_XOFF);
 195         if (ch->ch_c_iflag & IXON)
 196                 efr &= ~(UART_17158_EFR_IXOFF);
 197         else
 198                 efr &= ~(UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
 199
 200         /* Why? Becuz Exar's spec says we have to zero it out before setting it */
 201         writeb(0, &ch->ch_neo_uart->efr);
 202
 203         /* Turn on UART enhanced bits */
 204         writeb(efr, &ch->ch_neo_uart->efr);
 205
 206         /* Turn on table D, with 8 char hi/low watermarks */
 207         writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
 208
 209         ch->ch_r_watermark = 0;
 210
 211         writeb(16, &ch->ch_neo_uart->tfifo);
 212         ch->ch_t_tlevel = 16;
 213
 214         writeb(16, &ch->ch_neo_uart->rfifo);
 215         ch->ch_r_tlevel = 16;
 216
 217         writeb(ier, &ch->ch_neo_uart->ier);
 218 }
 219
 220 static void neo_set_no_output_flow_control(struct jsm_channel *ch)
 221 {
 222         u8 ier, efr;
 223         ier = readb(&ch->ch_neo_uart->ier);
 224         efr = readb(&ch->ch_neo_uart->efr);
 225
 226         jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Unsetting Output FLOW\n");
 227
 228         /* Turn off auto CTS flow control */
 229         ier &= ~(UART_17158_IER_CTSDSR);
 230         efr &= ~(UART_17158_EFR_CTSDSR);
 231
 232         /* Turn off auto Xon flow control */
 233         if (ch->ch_c_iflag & IXOFF)
 234                 efr &= ~(UART_17158_EFR_IXON);
 235         else
 236                 efr &= ~(UART_17158_EFR_ECB | UART_17158_EFR_IXON);
 237
 238         /* Why? Becuz Exar's spec says we have to zero it out before setting it */
 239         writeb(0, &ch->ch_neo_uart->efr);
 240
 241         /* Turn on UART enhanced bits */
 242         writeb(efr, &ch->ch_neo_uart->efr);
 243
 244         /* Turn on table D, with 8 char hi/low watermarks */
 245         writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
 246
 247         ch->ch_r_watermark = 0;
 248
 249         writeb(16, &ch->ch_neo_uart->tfifo);
 250         ch->ch_t_tlevel = 16;
 251
 252         writeb(16, &ch->ch_neo_uart->rfifo);
 253         ch->ch_r_tlevel = 16;
 254
 255         writeb(ier, &ch->ch_neo_uart->ier);
 256 }
 257
 258 static inline void neo_set_new_start_stop_chars(struct jsm_channel *ch)
 259 {
 260
 261         /* if hardware flow control is set, then skip this whole thing */
 262         if (ch->ch_c_cflag & CRTSCTS)
 263                 return;
 264
 265         jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "start\n");
 266
 267         /* Tell UART what start/stop chars it should be looking for */
 268         writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
 269         writeb(0, &ch->ch_neo_uart->xonchar2);
 270
 271         writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
 272         writeb(0, &ch->ch_neo_uart->xoffchar2);
 273 }
 274
 275 static void neo_copy_data_from_uart_to_queue(struct jsm_channel *ch)
 276 {
 277         int qleft = 0;
 278         u8 linestatus = 0;
 279         u8 error_mask = 0;
 280         int n = 0;
 281         int total = 0;
 282         u16 head;
 283         u16 tail;
 284
 285         /* cache head and tail of queue */
 286         head = ch->ch_r_head & RQUEUEMASK;
 287         tail = ch->ch_r_tail & RQUEUEMASK;
 288
 289         /* Get our cached LSR */
 290         linestatus = ch->ch_cached_lsr;
 291         ch->ch_cached_lsr = 0;
 292
 293         /* Store how much space we have left in the queue */
 294         if ((qleft = tail - head - 1) < 0)
 295                 qleft += RQUEUEMASK + 1;
 296
 297         /*
 298          * If the UART is not in FIFO mode, force the FIFO copy to
 299          * NOT be run, by setting total to 0.
 300          *
 301          * On the other hand, if the UART IS in FIFO mode, then ask
 302          * the UART to give us an approximation of data it has RX'ed.
 303          */
 304         if (!(ch->ch_flags & CH_FIFO_ENABLED))
 305                 total = 0;
 306         else {
 307                 total = readb(&ch->ch_neo_uart->rfifo);
 308
 309                 /*
 310                  * EXAR chip bug - RX FIFO COUNT - Fudge factor.
 311                  *
 312                  * This resolves a problem/bug with the Exar chip that sometimes
 313                  * returns a bogus value in the rfifo register.
 314                  * The count can be any where from 0-3 bytes "off".
 315                  * Bizarre, but true.
 316                  */
 317                 total -= 3;
 318         }
 319
 320         /*
 321          * Finally, bound the copy to make sure we don't overflow
 322          * our own queue...
 323          * The byte by byte copy loop below this loop this will
 324          * deal with the queue overflow possibility.
 325          */
 326         total = min(total, qleft);
 327
 328         while (total > 0) {
 329                 /*
 330                  * Grab the linestatus register, we need to check
 331                  * to see if there are any errors in the FIFO.
 332                  */
 333                 linestatus = readb(&ch->ch_neo_uart->lsr);
 334
 335                 /*
 336                  * Break out if there is a FIFO error somewhere.
 337                  * This will allow us to go byte by byte down below,
 338                  * finding the exact location of the error.
 339                  */
 340                 if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
 341                         break;
 342
 343                 /* Make sure we don't go over the end of our queue */
 344                 n = min(((u32) total), (RQUEUESIZE - (u32) head));
 345
 346                 /*
 347                  * Cut down n even further if needed, this is to fix
 348                  * a problem with memcpy_fromio() with the Neo on the
 349                  * IBM pSeries platform.
 350                  * 15 bytes max appears to be the magic number.
 351                  */
 352                 n = min((u32) n, (u32) 12);
 353
 354                 /*
 355                  * Since we are grabbing the linestatus register, which
 356                  * will reset some bits after our read, we need to ensure
 357                  * we don't miss our TX FIFO emptys.
 358                  */
 359                 if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR))
 360                         ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 361
 362                 linestatus = 0;
 363
 364                 /* Copy data from uart to the queue */
 365                 memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, n);
 366                 /*
 367                  * Since RX_FIFO_DATA_ERROR was 0, we are guaranteed
 368                  * that all the data currently in the FIFO is free of
 369                  * breaks and parity/frame/orun errors.
 370                  */
 371                 memset(ch->ch_equeue + head, 0, n);
 372
 373                 /* Add to and flip head if needed */
 374                 head = (head + n) & RQUEUEMASK;
 375                 total -= n;
 376                 qleft -= n;
 377                 ch->ch_rxcount += n;
 378         }
 379
 380         /*
 381          * Create a mask to determine whether we should
 382          * insert the character (if any) into our queue.
 383          */
 384         if (ch->ch_c_iflag & IGNBRK)
 385                 error_mask |= UART_LSR_BI;
 386
 387         /*
 388          * Now cleanup any leftover bytes still in the UART.
 389          * Also deal with any possible queue overflow here as well.
 390          */
 391         while (1) {
 392
 393                 /*
 394                  * Its possible we have a linestatus from the loop above
 395                  * this, so we "OR" on any extra bits.
 396                  */
 397                 linestatus |= readb(&ch->ch_neo_uart->lsr);
 398
 399                 /*
 400                  * If the chip tells us there is no more data pending to
 401                  * be read, we can then leave.
 402                  * But before we do, cache the linestatus, just in case.
 403                  */
 404                 if (!(linestatus & UART_LSR_DR)) {
 405                         ch->ch_cached_lsr = linestatus;
 406                         break;
 407                 }
 408
 409                 /* No need to store this bit */
 410                 linestatus &= ~UART_LSR_DR;
 411
 412                 /*
 413                  * Since we are grabbing the linestatus register, which
 414                  * will reset some bits after our read, we need to ensure
 415                  * we don't miss our TX FIFO emptys.
 416                  */
 417                 if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR)) {
 418                         linestatus &= ~(UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR);
 419                         ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 420                 }
 421
 422                 /*
 423                  * Discard character if we are ignoring the error mask.
 424                  */
 425                 if (linestatus & error_mask) {
 426                         u8 discard;
 427                         linestatus = 0;
 428                         memcpy_fromio(&discard, &ch->ch_neo_uart->txrxburst, 1);
 429                         continue;
 430                 }
 431
 432                 /*
 433                  * If our queue is full, we have no choice but to drop some data.
 434                  * The assumption is that HWFLOW or SWFLOW should have stopped
 435                  * things way way before we got to this point.
 436                  *
 437                  * I decided that I wanted to ditch the oldest data first,
 438                  * I hope thats okay with everyone? Yes? Good.
 439                  */
 440                 while (qleft < 1) {
 441                         jsm_dbg(READ, &ch->ch_bd->pci_dev,
 442                                 "Queue full, dropping DATA:%x LSR:%x\n",
 443                                 ch->ch_rqueue[tail], ch->ch_equeue[tail]);
 444
 445                         ch->ch_r_tail = tail = (tail + 1) & RQUEUEMASK;
 446                         ch->ch_err_overrun++;
 447                         qleft++;
 448                 }
 449
 450                 memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, 1);
 451                 ch->ch_equeue[head] = (u8) linestatus;
 452
 453                 jsm_dbg(READ, &ch->ch_bd->pci_dev, "DATA/LSR pair: %x %x\n",
 454                         ch->ch_rqueue[head], ch->ch_equeue[head]);
 455
 456                 /* Ditch any remaining linestatus value. */
 457                 linestatus = 0;
 458
 459                 /* Add to and flip head if needed */
 460                 head = (head + 1) & RQUEUEMASK;
 461
 462                 qleft--;
 463                 ch->ch_rxcount++;
 464         }
 465
 466         /*
 467          * Write new final heads to channel structure.
 468          */
 469         ch->ch_r_head = head & RQUEUEMASK;
 470         ch->ch_e_head = head & EQUEUEMASK;
 471         jsm_input(ch);
 472 }
 473
 474 static void neo_copy_data_from_queue_to_uart(struct jsm_channel *ch)
 475 {
 476         u16 head;
 477         u16 tail;
 478         int n;
 479         int s;
 480         int qlen;
 481         u32 len_written = 0;
 482         struct circ_buf *circ;
 483
 484         if (!ch)
 485                 return;
 486
 487         circ = &ch->uart_port.state->xmit;
 488
 489         /* No data to write to the UART */
 490         if (uart_circ_empty(circ))
 491                 return;
 492
 493         /* If port is "stopped", don't send any data to the UART */
 494         if ((ch->ch_flags & CH_STOP) || (ch->ch_flags & CH_BREAK_SENDING))
 495                 return;
 496         /*
 497          * If FIFOs are disabled. Send data directly to txrx register
 498          */
 499         if (!(ch->ch_flags & CH_FIFO_ENABLED)) {
 500                 u8 lsrbits = readb(&ch->ch_neo_uart->lsr);
 501
 502                 ch->ch_cached_lsr |= lsrbits;
 503                 if (ch->ch_cached_lsr & UART_LSR_THRE) {
 504                         ch->ch_cached_lsr &= ~(UART_LSR_THRE);
 505
 506                         writeb(circ->buf[circ->tail], &ch->ch_neo_uart->txrx);
 507                         jsm_dbg(WRITE, &ch->ch_bd->pci_dev,
 508                                 "Tx data: %x\n", circ->buf[circ->tail]);
 509                         circ->tail = (circ->tail + 1) & (UART_XMIT_SIZE - 1);
 510                         ch->ch_txcount++;
 511                 }
 512                 return;
 513         }
 514
 515         /*
 516          * We have to do it this way, because of the EXAR TXFIFO count bug.
 517          */
 518         if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
 519                 return;
 520
 521         n = UART_17158_TX_FIFOSIZE - ch->ch_t_tlevel;
 522
 523         /* cache head and tail of queue */
 524         head = circ->head & (UART_XMIT_SIZE - 1);
 525         tail = circ->tail & (UART_XMIT_SIZE - 1);
 526         qlen = uart_circ_chars_pending(circ);
 527
 528         /* Find minimum of the FIFO space, versus queue length */
 529         n = min(n, qlen);
 530
 531         while (n > 0) {
 532
 533                 s = ((head >= tail) ? head : UART_XMIT_SIZE) - tail;
 534                 s = min(s, n);
 535
 536                 if (s <= 0)
 537                         break;
 538
 539                 memcpy_toio(&ch->ch_neo_uart->txrxburst, circ->buf + tail, s);
 540                 /* Add and flip queue if needed */
 541                 tail = (tail + s) & (UART_XMIT_SIZE - 1);
 542                 n -= s;
 543                 ch->ch_txcount += s;
 544                 len_written += s;
 545         }
 546
 547         /* Update the final tail */
 548         circ->tail = tail & (UART_XMIT_SIZE - 1);
 549
 550         if (len_written >= ch->ch_t_tlevel)
 551                 ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 552
 553         if (uart_circ_empty(circ))
 554                 uart_write_wakeup(&ch->uart_port);
 555 }
 556
 557 static void neo_parse_modem(struct jsm_channel *ch, u8 signals)
 558 {
 559         u8 msignals = signals;
 560
 561         jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
 562                 "neo_parse_modem: port: %d msignals: %x\n",
 563                 ch->ch_portnum, msignals);
 564
 565         /* Scrub off lower bits. They signify delta's, which I don't care about */
 566         /* Keep DDCD and DDSR though */
 567         msignals &= 0xf8;
 568
 569         if (msignals & UART_MSR_DDCD)
 570                 uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_DCD);
 571         if (msignals & UART_MSR_DDSR)
 572                 uart_handle_cts_change(&ch->uart_port, msignals & UART_MSR_CTS);
 573         if (msignals & UART_MSR_DCD)
 574                 ch->ch_mistat |= UART_MSR_DCD;
 575         else
 576                 ch->ch_mistat &= ~UART_MSR_DCD;
 577
 578         if (msignals & UART_MSR_DSR)
 579                 ch->ch_mistat |= UART_MSR_DSR;
 580         else
 581                 ch->ch_mistat &= ~UART_MSR_DSR;
 582
 583         if (msignals & UART_MSR_RI)
 584                 ch->ch_mistat |= UART_MSR_RI;
 585         else
 586                 ch->ch_mistat &= ~UART_MSR_RI;
 587
 588         if (msignals & UART_MSR_CTS)
 589                 ch->ch_mistat |= UART_MSR_CTS;
 590         else
 591                 ch->ch_mistat &= ~UART_MSR_CTS;
 592
 593         jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
 594                 "Port: %d DTR: %d RTS: %d CTS: %d DSR: %d " "RI: %d CD: %d\n",
 595                 ch->ch_portnum,
 596                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_DTR),
 597                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_RTS),
 598                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_CTS),
 599                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DSR),
 600                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_RI),
 601                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DCD));
 602 }
 603
 604 /* Make the UART raise any of the output signals we want up */
 605 static void neo_assert_modem_signals(struct jsm_channel *ch)
 606 {
 607         if (!ch)
 608                 return;
 609
 610         writeb(ch->ch_mostat, &ch->ch_neo_uart->mcr);
 611
 612         /* flush write operation */
 613         neo_pci_posting_flush(ch->ch_bd);
 614 }
 615
 616 /*
 617  * Flush the WRITE FIFO on the Neo.
 618  *
 619  * NOTE: Channel lock MUST be held before calling this function!
 620  */
 621 static void neo_flush_uart_write(struct jsm_channel *ch)
 622 {
 623         u8 tmp = 0;
 624         int i = 0;
 625
 626         if (!ch)
 627                 return;
 628
 629         writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT), &ch->ch_neo_uart->isr_fcr);
 630
 631         for (i = 0; i < 10; i++) {
 632
 633                 /* Check to see if the UART feels it completely flushed the FIFO. */
 634                 tmp = readb(&ch->ch_neo_uart->isr_fcr);
 635                 if (tmp & UART_FCR_CLEAR_XMIT) {
 636                         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
 637                                 "Still flushing TX UART... i: %d\n", i);
 638                         udelay(10);
 639                 }
 640                 else
 641                         break;
 642         }
 643
 644         ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 645 }
 646
 647
 648 /*
 649  * Flush the READ FIFO on the Neo.
 650  *
 651  * NOTE: Channel lock MUST be held before calling this function!
 652  */
 653 static void neo_flush_uart_read(struct jsm_channel *ch)
 654 {
 655         u8 tmp = 0;
 656         int i = 0;
 657
 658         if (!ch)
 659                 return;
 660
 661         writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR), &ch->ch_neo_uart->isr_fcr);
 662
 663         for (i = 0; i < 10; i++) {
 664
 665                 /* Check to see if the UART feels it completely flushed the FIFO. */
 666                 tmp = readb(&ch->ch_neo_uart->isr_fcr);
 667                 if (tmp & 2) {
 668                         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
 669                                 "Still flushing RX UART... i: %d\n", i);
 670                         udelay(10);
 671                 }
 672                 else
 673                         break;
 674         }
 675 }
 676
 677 /*
 678  * No locks are assumed to be held when calling this function.
 679  */
 680 static void neo_clear_break(struct jsm_channel *ch)
 681 {
 682         unsigned long lock_flags;
 683
 684         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 685
 686         /* Turn break off, and unset some variables */
 687         if (ch->ch_flags & CH_BREAK_SENDING) {
 688                 u8 temp = readb(&ch->ch_neo_uart->lcr);
 689                 writeb((temp & ~UART_LCR_SBC), &ch->ch_neo_uart->lcr);
 690
 691                 ch->ch_flags &= ~(CH_BREAK_SENDING);
 692                 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
 693                         "clear break Finishing UART_LCR_SBC! finished: %lx\n",
 694                         jiffies);
 695
 696                 /* flush write operation */
 697                 neo_pci_posting_flush(ch->ch_bd);
 698         }
 699         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 700 }
 701
 702 /*
 703  * Parse the ISR register.
 704  */
 705 static void neo_parse_isr(struct jsm_board *brd, u32 port)
 706 {
 707         struct jsm_channel *ch;
 708         u8 isr;
 709         u8 cause;
 710         unsigned long lock_flags;
 711
 712         if (!brd)
 713                 return;
 714
 715         if (port >= brd->maxports)
 716                 return;
 717
 718         ch = brd->channels[port];
 719         if (!ch)
 720                 return;
 721
 722         /* Here we try to figure out what caused the interrupt to happen */
 723         while (1) {
 724
 725                 isr = readb(&ch->ch_neo_uart->isr_fcr);
 726
 727                 /* Bail if no pending interrupt */
 728                 if (isr & UART_IIR_NO_INT)
 729                         break;
 730
 731                 /*
 732                  * Yank off the upper 2 bits, which just show that the FIFO's are enabled.
 733                  */
 734                 isr &= ~(UART_17158_IIR_FIFO_ENABLED);
 735
 736                 jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d isr: %x\n",
 737                         __FILE__, __LINE__, isr);
 738
 739                 if (isr & (UART_17158_IIR_RDI_TIMEOUT | UART_IIR_RDI)) {
 740                         /* Read data from uart -> queue */
 741                         neo_copy_data_from_uart_to_queue(ch);
 742
 743                         /* Call our tty layer to enforce queue flow control if needed. */
 744                         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 745                         jsm_check_queue_flow_control(ch);
 746                         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 747                 }
 748
 749                 if (isr & UART_IIR_THRI) {
 750                         /* Transfer data (if any) from Write Queue -> UART. */
 751                         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 752                         ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 753                         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 754                         neo_copy_data_from_queue_to_uart(ch);
 755                 }
 756
 757                 if (isr & UART_17158_IIR_XONXOFF) {
 758                         cause = readb(&ch->ch_neo_uart->xoffchar1);
 759
 760                         jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 761                                 "Port %d. Got ISR_XONXOFF: cause:%x\n",
 762                                 port, cause);
 763
 764                         /*
 765                          * Since the UART detected either an XON or
 766                          * XOFF match, we need to figure out which
 767                          * one it was, so we can suspend or resume data flow.
 768                          */
 769                         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 770                         if (cause == UART_17158_XON_DETECT) {
 771                                 /* Is output stopped right now, if so, resume it */
 772                                 if (brd->channels[port]->ch_flags & CH_STOP) {
 773                                         ch->ch_flags &= ~(CH_STOP);
 774                                 }
 775                                 jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 776                                         "Port %d. XON detected in incoming data\n",
 777                                         port);
 778                         }
 779                         else if (cause == UART_17158_XOFF_DETECT) {
 780                                 if (!(brd->channels[port]->ch_flags & CH_STOP)) {
 781                                         ch->ch_flags |= CH_STOP;
 782                                         jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 783                                                 "Setting CH_STOP\n");
 784                                 }
 785                                 jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 786                                         "Port: %d. XOFF detected in incoming data\n",
 787                                         port);
 788                         }
 789                         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 790                 }
 791
 792                 if (isr & UART_17158_IIR_HWFLOW_STATE_CHANGE) {
 793                         /*
 794                          * If we get here, this means the hardware is doing auto flow control.
 795                          * Check to see whether RTS/DTR or CTS/DSR caused this interrupt.
 796                          */
 797                         cause = readb(&ch->ch_neo_uart->mcr);
 798
 799                         /* Which pin is doing auto flow? RTS or DTR? */
 800                         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 801                         if ((cause & 0x4) == 0) {
 802                                 if (cause & UART_MCR_RTS)
 803                                         ch->ch_mostat |= UART_MCR_RTS;
 804                                 else
 805                                         ch->ch_mostat &= ~(UART_MCR_RTS);
 806                         } else {
 807                                 if (cause & UART_MCR_DTR)
 808                                         ch->ch_mostat |= UART_MCR_DTR;
 809                                 else
 810                                         ch->ch_mostat &= ~(UART_MCR_DTR);
 811                         }
 812                         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 813                 }
 814
 815                 /* Parse any modem signal changes */
 816                 jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 817                         "MOD_STAT: sending to parse_modem_sigs\n");
 818                 spin_lock_irqsave(&ch->uart_port.lock, lock_flags);
 819                 neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
 820                 spin_unlock_irqrestore(&ch->uart_port.lock, lock_flags);
 821         }
 822 }
 823
 824 static inline void neo_parse_lsr(struct jsm_board *brd, u32 port)
 825 {
 826         struct jsm_channel *ch;
 827         int linestatus;
 828         unsigned long lock_flags;
 829
 830         if (!brd)
 831                 return;
 832
 833         if (port >= brd->maxports)
 834                 return;
 835
 836         ch = brd->channels[port];
 837         if (!ch)
 838                 return;
 839
 840         linestatus = readb(&ch->ch_neo_uart->lsr);
 841
 842         jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d port: %d linestatus: %x\n",
 843                 __FILE__, __LINE__, port, linestatus);
 844
 845         ch->ch_cached_lsr |= linestatus;
 846
 847         if (ch->ch_cached_lsr & UART_LSR_DR) {
 848                 /* Read data from uart -> queue */
 849                 neo_copy_data_from_uart_to_queue(ch);
 850                 spin_lock_irqsave(&ch->ch_lock, lock_flags);
 851                 jsm_check_queue_flow_control(ch);
 852                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 853         }
 854
 855         /*
 856          * This is a special flag. It indicates that at least 1
 857          * RX error (parity, framing, or break) has happened.
 858          * Mark this in our struct, which will tell me that I have
 859          *to do the special RX+LSR read for this FIFO load.
 860          */
 861         if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
 862                 jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 863                         "%s:%d Port: %d Got an RX error, need to parse LSR\n",
 864                         __FILE__, __LINE__, port);
 865
 866         /*
 867          * The next 3 tests should *NOT* happen, as the above test
 868          * should encapsulate all 3... At least, thats what Exar says.
 869          */
 870
 871         if (linestatus & UART_LSR_PE) {
 872                 ch->ch_err_parity++;
 873                 jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. PAR ERR!\n",
 874                         __FILE__, __LINE__, port);
 875         }
 876
 877         if (linestatus & UART_LSR_FE) {
 878                 ch->ch_err_frame++;
 879                 jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. FRM ERR!\n",
 880                         __FILE__, __LINE__, port);
 881         }
 882
 883         if (linestatus & UART_LSR_BI) {
 884                 ch->ch_err_break++;
 885                 jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 886                         "%s:%d Port: %d. BRK INTR!\n",
 887                         __FILE__, __LINE__, port);
 888         }
 889
 890         if (linestatus & UART_LSR_OE) {
 891                 /*
 892                  * Rx Oruns. Exar says that an orun will NOT corrupt
 893                  * the FIFO. It will just replace the holding register
 894                  * with this new data byte. So basically just ignore this.
 895                  * Probably we should eventually have an orun stat in our driver...
 896                  */
 897                 ch->ch_err_overrun++;
 898                 jsm_dbg(INTR, &ch->ch_bd->pci_dev,
 899                         "%s:%d Port: %d. Rx Overrun!\n",
 900                         __FILE__, __LINE__, port);
 901         }
 902
 903         if (linestatus & UART_LSR_THRE) {
 904                 spin_lock_irqsave(&ch->ch_lock, lock_flags);
 905                 ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 906                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 907
 908                 /* Transfer data (if any) from Write Queue -> UART. */
 909                 neo_copy_data_from_queue_to_uart(ch);
 910         }
 911         else if (linestatus & UART_17158_TX_AND_FIFO_CLR) {
 912                 spin_lock_irqsave(&ch->ch_lock, lock_flags);
 913                 ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 914                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 915
 916                 /* Transfer data (if any) from Write Queue -> UART. */
 917                 neo_copy_data_from_queue_to_uart(ch);
 918         }
 919 }
 920
 921 /*
 922  * neo_param()
 923  * Send any/all changes to the line to the UART.
 924  */
 925 static void neo_param(struct jsm_channel *ch)
 926 {
 927         u8 lcr = 0;
 928         u8 uart_lcr, ier;
 929         u32 baud;
 930         int quot;
 931         struct jsm_board *bd;
 932
 933         bd = ch->ch_bd;
 934         if (!bd)
 935                 return;
 936
 937         /*
 938          * If baud rate is zero, flush queues, and set mval to drop DTR.
 939          */
 940         if ((ch->ch_c_cflag & (CBAUD)) == 0) {
 941                 ch->ch_r_head = ch->ch_r_tail = 0;
 942                 ch->ch_e_head = ch->ch_e_tail = 0;
 943
 944                 neo_flush_uart_write(ch);
 945                 neo_flush_uart_read(ch);
 946
 947                 ch->ch_flags |= (CH_BAUD0);
 948                 ch->ch_mostat &= ~(UART_MCR_RTS | UART_MCR_DTR);
 949                 neo_assert_modem_signals(ch);
 950                 return;
 951
 952         } else {
 953                 int i;
 954                 unsigned int cflag;
 955                 static struct {
 956                         unsigned int rate;
 957                         unsigned int cflag;
 958                 } baud_rates[] = {
 959                         { 921600, B921600 },
 960                         { 460800, B460800 },
 961                         { 230400, B230400 },
 962                         { 115200, B115200 },
 963                         {  57600, B57600  },
 964                         {  38400, B38400  },
 965                         {  19200, B19200  },
 966                         {   9600, B9600   },
 967                         {   4800, B4800   },
 968                         {   2400, B2400   },
 969                         {   1200, B1200   },
 970                         {    600, B600    },
 971                         {    300, B300    },
 972                         {    200, B200    },
 973                         {    150, B150    },
 974                         {    134, B134    },
 975                         {    110, B110    },
 976                         {     75, B75     },
 977                         {     50, B50     },
 978                 };
 979
 980                 cflag = C_BAUD(ch->uart_port.state->port.tty);
 981                 baud = 9600;
 982                 for (i = 0; i < ARRAY_SIZE(baud_rates); i++) {
 983                         if (baud_rates[i].cflag == cflag) {
 984                                 baud = baud_rates[i].rate;
 985                                 break;
 986                         }
 987                 }
 988
 989                 if (ch->ch_flags & CH_BAUD0)
 990                         ch->ch_flags &= ~(CH_BAUD0);
 991         }
 992
 993         if (ch->ch_c_cflag & PARENB)
 994                 lcr |= UART_LCR_PARITY;
 995
 996         if (!(ch->ch_c_cflag & PARODD))
 997                 lcr |= UART_LCR_EPAR;
 998
 999         /*
1000          * Not all platforms support mark/space parity,
1001          * so this will hide behind an ifdef.
1002          */
1003 #ifdef CMSPAR
1004         if (ch->ch_c_cflag & CMSPAR)
1005                 lcr |= UART_LCR_SPAR;
1006 #endif
1007
1008         if (ch->ch_c_cflag & CSTOPB)
1009                 lcr |= UART_LCR_STOP;
1010
1011         switch (ch->ch_c_cflag & CSIZE) {
1012         case CS5:
1013                 lcr |= UART_LCR_WLEN5;
1014                 break;
1015         case CS6:
1016                 lcr |= UART_LCR_WLEN6;
1017                 break;
1018         case CS7:
1019                 lcr |= UART_LCR_WLEN7;
1020                 break;
1021         case CS8:
1022         default:
1023                 lcr |= UART_LCR_WLEN8;
1024         break;
1025         }
1026
1027         ier = readb(&ch->ch_neo_uart->ier);
1028         uart_lcr = readb(&ch->ch_neo_uart->lcr);
1029
1030         quot = ch->ch_bd->bd_dividend / baud;
1031
1032         if (quot != 0) {
1033                 writeb(UART_LCR_DLAB, &ch->ch_neo_uart->lcr);
1034                 writeb((quot & 0xff), &ch->ch_neo_uart->txrx);
1035                 writeb((quot >> 8), &ch->ch_neo_uart->ier);
1036                 writeb(lcr, &ch->ch_neo_uart->lcr);
1037         }
1038
1039         if (uart_lcr != lcr)
1040                 writeb(lcr, &ch->ch_neo_uart->lcr);
1041
1042         if (ch->ch_c_cflag & CREAD)
1043                 ier |= (UART_IER_RDI | UART_IER_RLSI);
1044
1045         ier |= (UART_IER_THRI | UART_IER_MSI);
1046
1047         writeb(ier, &ch->ch_neo_uart->ier);
1048
1049         /* Set new start/stop chars */
1050         neo_set_new_start_stop_chars(ch);
1051
1052         if (ch->ch_c_cflag & CRTSCTS)
1053                 neo_set_cts_flow_control(ch);
1054         else if (ch->ch_c_iflag & IXON) {
1055                 /* If start/stop is set to disable, then we should disable flow control */
1056                 if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
1057                         neo_set_no_output_flow_control(ch);
1058                 else
1059                         neo_set_ixon_flow_control(ch);
1060         }
1061         else
1062                 neo_set_no_output_flow_control(ch);
1063
1064         if (ch->ch_c_cflag & CRTSCTS)
1065                 neo_set_rts_flow_control(ch);
1066         else if (ch->ch_c_iflag & IXOFF) {
1067                 /* If start/stop is set to disable, then we should disable flow control */
1068                 if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
1069                         neo_set_no_input_flow_control(ch);
1070                 else
1071                         neo_set_ixoff_flow_control(ch);
1072         }
1073         else
1074                 neo_set_no_input_flow_control(ch);
1075         /*
1076          * Adjust the RX FIFO Trigger level if baud is less than 9600.
1077          * Not exactly elegant, but this is needed because of the Exar chip's
1078          * delay on firing off the RX FIFO interrupt on slower baud rates.
1079          */
1080         if (baud < 9600) {
1081                 writeb(1, &ch->ch_neo_uart->rfifo);
1082                 ch->ch_r_tlevel = 1;
1083         }
1084
1085         neo_assert_modem_signals(ch);
1086
1087         /* Get current status of the modem signals now */
1088         neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
1089         return;
1090 }
1091
1092 /*
1093  * jsm_neo_intr()
1094  *
1095  * Neo specific interrupt handler.
1096  */
1097 static irqreturn_t neo_intr(int irq, void *voidbrd)
1098 {
1099         struct jsm_board *brd = voidbrd;
1100         struct jsm_channel *ch;
1101         int port = 0;
1102         int type = 0;
1103         int current_port;
1104         u32 tmp;
1105         u32 uart_poll;
1106         unsigned long lock_flags;
1107         unsigned long lock_flags2;
1108         int outofloop_count = 0;
1109
1110         /* Lock out the slow poller from running on this board. */
1111         spin_lock_irqsave(&brd->bd_intr_lock, lock_flags);
1112
1113         /*
1114          * Read in "extended" IRQ information from the 32bit Neo register.
1115          * Bits 0-7: What port triggered the interrupt.
1116          * Bits 8-31: Each 3bits indicate what type of interrupt occurred.
1117          */
1118         uart_poll = readl(brd->re_map_membase + UART_17158_POLL_ADDR_OFFSET);
1119
1120         jsm_dbg(INTR, &brd->pci_dev, "%s:%d uart_poll: %x\n",
1121                 __FILE__, __LINE__, uart_poll);
1122
1123         if (!uart_poll) {
1124                 jsm_dbg(INTR, &brd->pci_dev,
1125                         "Kernel interrupted to me, but no pending interrupts...\n");
1126                 spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
1127                 return IRQ_NONE;
1128         }
1129
1130         /* At this point, we have at least SOMETHING to service, dig further... */
1131
1132         current_port = 0;
1133
1134         /* Loop on each port */
1135         while (((uart_poll & 0xff) != 0) && (outofloop_count < 0xff)){
1136
1137                 tmp = uart_poll;
1138                 outofloop_count++;
1139
1140                 /* Check current port to see if it has interrupt pending */
1141                 if ((tmp & jsm_offset_table[current_port]) != 0) {
1142                         port = current_port;
1143                         type = tmp >> (8 + (port * 3));
1144                         type &= 0x7;
1145                 } else {
1146                         current_port++;
1147                         continue;
1148                 }
1149
1150                 jsm_dbg(INTR, &brd->pci_dev, "%s:%d port: %x type: %x\n",
1151                         __FILE__, __LINE__, port, type);
1152
1153                 /* Remove this port + type from uart_poll */
1154                 uart_poll &= ~(jsm_offset_table[port]);
1155
1156                 if (!type) {
1157                         /* If no type, just ignore it, and move onto next port */
1158                         jsm_dbg(INTR, &brd->pci_dev,
1159                                 "Interrupt with no type! port: %d\n", port);
1160                         continue;
1161                 }
1162
1163                 /* Switch on type of interrupt we have */
1164                 switch (type) {
1165
1166                 case UART_17158_RXRDY_TIMEOUT:
1167                         /*
1168                          * RXRDY Time-out is cleared by reading data in the
1169                         * RX FIFO until it falls below the trigger level.
1170                          */
1171
1172                         /* Verify the port is in range. */
1173                         if (port >= brd->nasync)
1174                                 continue;
1175
1176                         ch = brd->channels[port];
1177                         if (!ch)
1178                                 continue;
1179
1180                         neo_copy_data_from_uart_to_queue(ch);
1181
1182                         /* Call our tty layer to enforce queue flow control if needed. */
1183                         spin_lock_irqsave(&ch->ch_lock, lock_flags2);
1184                         jsm_check_queue_flow_control(ch);
1185                         spin_unlock_irqrestore(&ch->ch_lock, lock_flags2);
1186
1187                         continue;
1188
1189                 case UART_17158_RX_LINE_STATUS:
1190                         /*
1191                          * RXRDY and RX LINE Status (logic OR of LSR[4:1])
1192                          */
1193                         neo_parse_lsr(brd, port);
1194                         continue;
1195
1196                 case UART_17158_TXRDY:
1197                         /*
1198                          * TXRDY interrupt clears after reading ISR register for the UART channel.
1199                          */
1200
1201                         /*
1202                          * Yes, this is odd...
1203                          * Why would I check EVERY possibility of type of
1204                          * interrupt, when we know its TXRDY???
1205                          * Becuz for some reason, even tho we got triggered for TXRDY,
1206                          * it seems to be occasionally wrong. Instead of TX, which
1207                          * it should be, I was getting things like RXDY too. Weird.
1208                          */
1209                         neo_parse_isr(brd, port);
1210                         continue;
1211
1212                 case UART_17158_MSR:
1213                         /*
1214                          * MSR or flow control was seen.
1215                          */
1216                         neo_parse_isr(brd, port);
1217                         continue;
1218
1219                 default:
1220                         /*
1221                          * The UART triggered us with a bogus interrupt type.
1222                          * It appears the Exar chip, when REALLY bogged down, will throw
1223                          * these once and awhile.
1224                          * Its harmless, just ignore it and move on.
1225                          */
1226                         jsm_dbg(INTR, &brd->pci_dev,
1227                                 "%s:%d Unknown Interrupt type: %x\n",
1228                                 __FILE__, __LINE__, type);
1229                         continue;
1230                 }
1231         }
1232
1233         spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
1234
1235         jsm_dbg(INTR, &brd->pci_dev, "finish\n");
1236         return IRQ_HANDLED;
1237 }
1238
1239 /*
1240  * Neo specific way of turning off the receiver.
1241  * Used as a way to enforce queue flow control when in
1242  * hardware flow control mode.
1243  */
1244 static void neo_disable_receiver(struct jsm_channel *ch)
1245 {
1246         u8 tmp = readb(&ch->ch_neo_uart->ier);
1247         tmp &= ~(UART_IER_RDI);
1248         writeb(tmp, &ch->ch_neo_uart->ier);
1249
1250         /* flush write operation */
1251         neo_pci_posting_flush(ch->ch_bd);
1252 }
1253
1254
1255 /*
1256  * Neo specific way of turning on the receiver.
1257  * Used as a way to un-enforce queue flow control when in
1258  * hardware flow control mode.
1259  */
1260 static void neo_enable_receiver(struct jsm_channel *ch)
1261 {
1262         u8 tmp = readb(&ch->ch_neo_uart->ier);
1263         tmp |= (UART_IER_RDI);
1264         writeb(tmp, &ch->ch_neo_uart->ier);
1265
1266         /* flush write operation */
1267         neo_pci_posting_flush(ch->ch_bd);
1268 }
1269
1270 static void neo_send_start_character(struct jsm_channel *ch)
1271 {
1272         if (!ch)
1273                 return;
1274
1275         if (ch->ch_startc != __DISABLED_CHAR) {
1276                 ch->ch_xon_sends++;
1277                 writeb(ch->ch_startc, &ch->ch_neo_uart->txrx);
1278
1279                 /* flush write operation */
1280                 neo_pci_posting_flush(ch->ch_bd);
1281         }
1282 }
1283
1284 static void neo_send_stop_character(struct jsm_channel *ch)
1285 {
1286         if (!ch)
1287                 return;
1288
1289         if (ch->ch_stopc != __DISABLED_CHAR) {
1290                 ch->ch_xoff_sends++;
1291                 writeb(ch->ch_stopc, &ch->ch_neo_uart->txrx);
1292
1293                 /* flush write operation */
1294                 neo_pci_posting_flush(ch->ch_bd);
1295         }
1296 }
1297
1298 /*
1299  * neo_uart_init
1300  */
1301 static void neo_uart_init(struct jsm_channel *ch)
1302 {
1303         writeb(0, &ch->ch_neo_uart->ier);
1304         writeb(0, &ch->ch_neo_uart->efr);
1305         writeb(UART_EFR_ECB, &ch->ch_neo_uart->efr);
1306
1307         /* Clear out UART and FIFO */
1308         readb(&ch->ch_neo_uart->txrx);
1309         writeb((UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|UART_FCR_CLEAR_XMIT), &ch->ch_neo_uart->isr_fcr);
1310         readb(&ch->ch_neo_uart->lsr);
1311         readb(&ch->ch_neo_uart->msr);
1312
1313         ch->ch_flags |= CH_FIFO_ENABLED;
1314
1315         /* Assert any signals we want up */
1316         writeb(ch->ch_mostat, &ch->ch_neo_uart->mcr);
1317 }
1318
1319 /*
1320  * Make the UART completely turn off.
1321  */
1322 static void neo_uart_off(struct jsm_channel *ch)
1323 {
1324         /* Turn off UART enhanced bits */
1325         writeb(0, &ch->ch_neo_uart->efr);
1326
1327         /* Stop all interrupts from occurring. */
1328         writeb(0, &ch->ch_neo_uart->ier);
1329 }
1330
1331 static u32 neo_get_uart_bytes_left(struct jsm_channel *ch)
1332 {
1333         u8 left = 0;
1334         u8 lsr = readb(&ch->ch_neo_uart->lsr);
1335
1336         /* We must cache the LSR as some of the bits get reset once read... */
1337         ch->ch_cached_lsr |= lsr;
1338
1339         /* Determine whether the Transmitter is empty or not */
1340         if (!(lsr & UART_LSR_TEMT))
1341                 left = 1;
1342         else {
1343                 ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
1344                 left = 0;
1345         }
1346
1347         return left;
1348 }
1349
1350 /* Channel lock MUST be held by the calling function! */
1351 static void neo_send_break(struct jsm_channel *ch)
1352 {
1353         /*
1354          * Set the time we should stop sending the break.
1355          * If we are already sending a break, toss away the existing
1356          * time to stop, and use this new value instead.
1357          */
1358
1359         /* Tell the UART to start sending the break */
1360         if (!(ch->ch_flags & CH_BREAK_SENDING)) {
1361                 u8 temp = readb(&ch->ch_neo_uart->lcr);
1362                 writeb((temp | UART_LCR_SBC), &ch->ch_neo_uart->lcr);
1363                 ch->ch_flags |= (CH_BREAK_SENDING);
1364
1365                 /* flush write operation */
1366                 neo_pci_posting_flush(ch->ch_bd);
1367         }
1368 }
1369
1370 /*
1371  * neo_send_immediate_char.
1372  *
1373  * Sends a specific character as soon as possible to the UART,
1374  * jumping over any bytes that might be in the write queue.
1375  *
1376  * The channel lock MUST be held by the calling function.
1377  */
1378 static void neo_send_immediate_char(struct jsm_channel *ch, unsigned char c)
1379 {
1380         if (!ch)
1381                 return;
1382
1383         writeb(c, &ch->ch_neo_uart->txrx);
1384
1385         /* flush write operation */
1386         neo_pci_posting_flush(ch->ch_bd);
1387 }
1388
1389 struct board_ops jsm_neo_ops = {
1390         .intr                           = neo_intr,
1391         .uart_init                      = neo_uart_init,
1392         .uart_off                       = neo_uart_off,
1393         .param                          = neo_param,
1394         .assert_modem_signals           = neo_assert_modem_signals,
1395         .flush_uart_write               = neo_flush_uart_write,
1396         .flush_uart_read                = neo_flush_uart_read,
1397         .disable_receiver               = neo_disable_receiver,
1398         .enable_receiver                = neo_enable_receiver,
1399         .send_break                     = neo_send_break,
1400         .clear_break                    = neo_clear_break,
1401         .send_start_character           = neo_send_start_character,
1402         .send_stop_character            = neo_send_stop_character,
1403         .copy_data_from_queue_to_uart   = neo_copy_data_from_queue_to_uart,
1404         .get_uart_bytes_left            = neo_get_uart_bytes_left,
1405         .send_immediate_char            = neo_send_immediate_char
1406 };