drivers/tty/serial/jsm/jsm_cls.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright 2003 Digi International (www.digi.com)
   4  *      Scott H Kilau <Scott_Kilau at digi dot com>
   5  *
   6  *      NOTE TO LINUX KERNEL HACKERS:  DO NOT REFORMAT THIS CODE!
   7  *
   8  *      This is shared code between Digi's CVS archive and the
   9  *      Linux Kernel sources.
  10  *      Changing the source just for reformatting needlessly breaks
  11  *      our CVS diff history.
  12  *
  13  *      Send any bug fixes/changes to:  Eng.Linux at digi dot com.
  14  *      Thank you.
  15  *
  16  */
  17
  18 #include <linux/delay.h>        /* For udelay */
  19 #include <linux/io.h>           /* For read[bwl]/write[bwl] */
  20 #include <linux/serial.h>       /* For struct async_serial */
  21 #include <linux/serial_reg.h>   /* For the various UART offsets */
  22 #include <linux/pci.h>
  23 #include <linux/tty.h>
  24
  25 #include "jsm.h"        /* Driver main header file */
  26
  27 static struct {
  28         unsigned int rate;
  29         unsigned int cflag;
  30 } baud_rates[] = {
  31         { 921600, B921600 },
  32         { 460800, B460800 },
  33         { 230400, B230400 },
  34         { 115200, B115200 },
  35         {  57600, B57600  },
  36         {  38400, B38400  },
  37         {  19200, B19200  },
  38         {   9600, B9600   },
  39         {   4800, B4800   },
  40         {   2400, B2400   },
  41         {   1200, B1200   },
  42         {    600, B600    },
  43         {    300, B300    },
  44         {    200, B200    },
  45         {    150, B150    },
  46         {    134, B134    },
  47         {    110, B110    },
  48         {     75, B75     },
  49         {     50, B50     },
  50 };
  51
  52 static void cls_set_cts_flow_control(struct jsm_channel *ch)
  53 {
  54         u8 lcrb = readb(&ch->ch_cls_uart->lcr);
  55         u8 ier = readb(&ch->ch_cls_uart->ier);
  56         u8 isr_fcr = 0;
  57
  58         /*
  59          * The Enhanced Register Set may only be accessed when
  60          * the Line Control Register is set to 0xBFh.
  61          */
  62         writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
  63
  64         isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
  65
  66         /* Turn on CTS flow control, turn off IXON flow control */
  67         isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_CTSDSR);
  68         isr_fcr &= ~(UART_EXAR654_EFR_IXON);
  69
  70         writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
  71
  72         /* Write old LCR value back out, which turns enhanced access off */
  73         writeb(lcrb, &ch->ch_cls_uart->lcr);
  74
  75         /*
  76          * Enable interrupts for CTS flow, turn off interrupts for
  77          * received XOFF chars
  78          */
  79         ier |= (UART_EXAR654_IER_CTSDSR);
  80         ier &= ~(UART_EXAR654_IER_XOFF);
  81         writeb(ier, &ch->ch_cls_uart->ier);
  82
  83         /* Set the usual FIFO values */
  84         writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
  85
  86         writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_56 |
  87                 UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
  88                 &ch->ch_cls_uart->isr_fcr);
  89
  90         ch->ch_t_tlevel = 16;
  91 }
  92
  93 static void cls_set_ixon_flow_control(struct jsm_channel *ch)
  94 {
  95         u8 lcrb = readb(&ch->ch_cls_uart->lcr);
  96         u8 ier = readb(&ch->ch_cls_uart->ier);
  97         u8 isr_fcr = 0;
  98
  99         /*
 100          * The Enhanced Register Set may only be accessed when
 101          * the Line Control Register is set to 0xBFh.
 102          */
 103         writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
 104
 105         isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
 106
 107         /* Turn on IXON flow control, turn off CTS flow control */
 108         isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_IXON);
 109         isr_fcr &= ~(UART_EXAR654_EFR_CTSDSR);
 110
 111         writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
 112
 113         /* Now set our current start/stop chars while in enhanced mode */
 114         writeb(ch->ch_startc, &ch->ch_cls_uart->mcr);
 115         writeb(0, &ch->ch_cls_uart->lsr);
 116         writeb(ch->ch_stopc, &ch->ch_cls_uart->msr);
 117         writeb(0, &ch->ch_cls_uart->spr);
 118
 119         /* Write old LCR value back out, which turns enhanced access off */
 120         writeb(lcrb, &ch->ch_cls_uart->lcr);
 121
 122         /*
 123          * Disable interrupts for CTS flow, turn on interrupts for
 124          * received XOFF chars
 125          */
 126         ier &= ~(UART_EXAR654_IER_CTSDSR);
 127         ier |= (UART_EXAR654_IER_XOFF);
 128         writeb(ier, &ch->ch_cls_uart->ier);
 129
 130         /* Set the usual FIFO values */
 131         writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
 132
 133         writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
 134                 UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
 135                 &ch->ch_cls_uart->isr_fcr);
 136 }
 137
 138 static void cls_set_no_output_flow_control(struct jsm_channel *ch)
 139 {
 140         u8 lcrb = readb(&ch->ch_cls_uart->lcr);
 141         u8 ier = readb(&ch->ch_cls_uart->ier);
 142         u8 isr_fcr = 0;
 143
 144         /*
 145          * The Enhanced Register Set may only be accessed when
 146          * the Line Control Register is set to 0xBFh.
 147          */
 148         writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
 149
 150         isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
 151
 152         /* Turn off IXON flow control, turn off CTS flow control */
 153         isr_fcr |= (UART_EXAR654_EFR_ECB);
 154         isr_fcr &= ~(UART_EXAR654_EFR_CTSDSR | UART_EXAR654_EFR_IXON);
 155
 156         writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
 157
 158         /* Write old LCR value back out, which turns enhanced access off */
 159         writeb(lcrb, &ch->ch_cls_uart->lcr);
 160
 161         /*
 162          * Disable interrupts for CTS flow, turn off interrupts for
 163          * received XOFF chars
 164          */
 165         ier &= ~(UART_EXAR654_IER_CTSDSR);
 166         ier &= ~(UART_EXAR654_IER_XOFF);
 167         writeb(ier, &ch->ch_cls_uart->ier);
 168
 169         /* Set the usual FIFO values */
 170         writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
 171
 172         writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
 173                 UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
 174                 &ch->ch_cls_uart->isr_fcr);
 175
 176         ch->ch_r_watermark = 0;
 177         ch->ch_t_tlevel = 16;
 178         ch->ch_r_tlevel = 16;
 179 }
 180
 181 static void cls_set_rts_flow_control(struct jsm_channel *ch)
 182 {
 183         u8 lcrb = readb(&ch->ch_cls_uart->lcr);
 184         u8 ier = readb(&ch->ch_cls_uart->ier);
 185         u8 isr_fcr = 0;
 186
 187         /*
 188          * The Enhanced Register Set may only be accessed when
 189          * the Line Control Register is set to 0xBFh.
 190          */
 191         writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
 192
 193         isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
 194
 195         /* Turn on RTS flow control, turn off IXOFF flow control */
 196         isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_RTSDTR);
 197         isr_fcr &= ~(UART_EXAR654_EFR_IXOFF);
 198
 199         writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
 200
 201         /* Write old LCR value back out, which turns enhanced access off */
 202         writeb(lcrb, &ch->ch_cls_uart->lcr);
 203
 204         /* Enable interrupts for RTS flow */
 205         ier |= (UART_EXAR654_IER_RTSDTR);
 206         writeb(ier, &ch->ch_cls_uart->ier);
 207
 208         /* Set the usual FIFO values */
 209         writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
 210
 211         writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_56 |
 212                 UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
 213                 &ch->ch_cls_uart->isr_fcr);
 214
 215         ch->ch_r_watermark = 4;
 216         ch->ch_r_tlevel = 8;
 217 }
 218
 219 static void cls_set_ixoff_flow_control(struct jsm_channel *ch)
 220 {
 221         u8 lcrb = readb(&ch->ch_cls_uart->lcr);
 222         u8 ier = readb(&ch->ch_cls_uart->ier);
 223         u8 isr_fcr = 0;
 224
 225         /*
 226          * The Enhanced Register Set may only be accessed when
 227          * the Line Control Register is set to 0xBFh.
 228          */
 229         writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
 230
 231         isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
 232
 233         /* Turn on IXOFF flow control, turn off RTS flow control */
 234         isr_fcr |= (UART_EXAR654_EFR_ECB | UART_EXAR654_EFR_IXOFF);
 235         isr_fcr &= ~(UART_EXAR654_EFR_RTSDTR);
 236
 237         writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
 238
 239         /* Now set our current start/stop chars while in enhanced mode */
 240         writeb(ch->ch_startc, &ch->ch_cls_uart->mcr);
 241         writeb(0, &ch->ch_cls_uart->lsr);
 242         writeb(ch->ch_stopc, &ch->ch_cls_uart->msr);
 243         writeb(0, &ch->ch_cls_uart->spr);
 244
 245         /* Write old LCR value back out, which turns enhanced access off */
 246         writeb(lcrb, &ch->ch_cls_uart->lcr);
 247
 248         /* Disable interrupts for RTS flow */
 249         ier &= ~(UART_EXAR654_IER_RTSDTR);
 250         writeb(ier, &ch->ch_cls_uart->ier);
 251
 252         /* Set the usual FIFO values */
 253         writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
 254
 255         writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
 256                 UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
 257                 &ch->ch_cls_uart->isr_fcr);
 258 }
 259
 260 static void cls_set_no_input_flow_control(struct jsm_channel *ch)
 261 {
 262         u8 lcrb = readb(&ch->ch_cls_uart->lcr);
 263         u8 ier = readb(&ch->ch_cls_uart->ier);
 264         u8 isr_fcr = 0;
 265
 266         /*
 267          * The Enhanced Register Set may only be accessed when
 268          * the Line Control Register is set to 0xBFh.
 269          */
 270         writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
 271
 272         isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
 273
 274         /* Turn off IXOFF flow control, turn off RTS flow control */
 275         isr_fcr |= (UART_EXAR654_EFR_ECB);
 276         isr_fcr &= ~(UART_EXAR654_EFR_RTSDTR | UART_EXAR654_EFR_IXOFF);
 277
 278         writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
 279
 280         /* Write old LCR value back out, which turns enhanced access off */
 281         writeb(lcrb, &ch->ch_cls_uart->lcr);
 282
 283         /* Disable interrupts for RTS flow */
 284         ier &= ~(UART_EXAR654_IER_RTSDTR);
 285         writeb(ier, &ch->ch_cls_uart->ier);
 286
 287         /* Set the usual FIFO values */
 288         writeb((UART_FCR_ENABLE_FIFO), &ch->ch_cls_uart->isr_fcr);
 289
 290         writeb((UART_FCR_ENABLE_FIFO | UART_16654_FCR_RXTRIGGER_16 |
 291                 UART_16654_FCR_TXTRIGGER_16 | UART_FCR_CLEAR_RCVR),
 292                 &ch->ch_cls_uart->isr_fcr);
 293
 294         ch->ch_t_tlevel = 16;
 295         ch->ch_r_tlevel = 16;
 296 }
 297
 298 /*
 299  * cls_clear_break.
 300  * Determines whether its time to shut off break condition.
 301  *
 302  * No locks are assumed to be held when calling this function.
 303  * channel lock is held and released in this function.
 304  */
 305 static void cls_clear_break(struct jsm_channel *ch)
 306 {
 307         unsigned long lock_flags;
 308
 309         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 310
 311         /* Turn break off, and unset some variables */
 312         if (ch->ch_flags & CH_BREAK_SENDING) {
 313                 u8 temp = readb(&ch->ch_cls_uart->lcr);
 314
 315                 writeb((temp & ~UART_LCR_SBC), &ch->ch_cls_uart->lcr);
 316
 317                 ch->ch_flags &= ~(CH_BREAK_SENDING);
 318                 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
 319                         "clear break Finishing UART_LCR_SBC! finished: %lx\n",
 320                         jiffies);
 321         }
 322         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 323 }
 324
 325 static void cls_disable_receiver(struct jsm_channel *ch)
 326 {
 327         u8 tmp = readb(&ch->ch_cls_uart->ier);
 328
 329         tmp &= ~(UART_IER_RDI);
 330         writeb(tmp, &ch->ch_cls_uart->ier);
 331 }
 332
 333 static void cls_enable_receiver(struct jsm_channel *ch)
 334 {
 335         u8 tmp = readb(&ch->ch_cls_uart->ier);
 336
 337         tmp |= (UART_IER_RDI);
 338         writeb(tmp, &ch->ch_cls_uart->ier);
 339 }
 340
 341 /* Make the UART raise any of the output signals we want up */
 342 static void cls_assert_modem_signals(struct jsm_channel *ch)
 343 {
 344         if (!ch)
 345                 return;
 346
 347         writeb(ch->ch_mostat, &ch->ch_cls_uart->mcr);
 348 }
 349
 350 static void cls_copy_data_from_uart_to_queue(struct jsm_channel *ch)
 351 {
 352         int qleft = 0;
 353         u8 linestatus = 0;
 354         u8 error_mask = 0;
 355         u16 head;
 356         u16 tail;
 357         unsigned long flags;
 358
 359         if (!ch)
 360                 return;
 361
 362         spin_lock_irqsave(&ch->ch_lock, flags);
 363
 364         /* cache head and tail of queue */
 365         head = ch->ch_r_head & RQUEUEMASK;
 366         tail = ch->ch_r_tail & RQUEUEMASK;
 367
 368         /* Get our cached LSR */
 369         linestatus = ch->ch_cached_lsr;
 370         ch->ch_cached_lsr = 0;
 371
 372         /* Store how much space we have left in the queue */
 373         qleft = tail - head - 1;
 374         if (qleft < 0)
 375                 qleft += RQUEUEMASK + 1;
 376
 377         /*
 378          * Create a mask to determine whether we should
 379          * insert the character (if any) into our queue.
 380          */
 381         if (ch->ch_c_iflag & IGNBRK)
 382                 error_mask |= UART_LSR_BI;
 383
 384         while (1) {
 385                 /*
 386                  * Grab the linestatus register, we need to
 387                  * check to see if there is any data to read
 388                  */
 389                 linestatus = readb(&ch->ch_cls_uart->lsr);
 390
 391                 /* Break out if there is no data to fetch */
 392                 if (!(linestatus & UART_LSR_DR))
 393                         break;
 394
 395                 /*
 396                  * Discard character if we are ignoring the error mask
 397                  * which in this case is the break signal.
 398                  */
 399                 if (linestatus & error_mask)  {
 400                         u8 discard;
 401
 402                         linestatus = 0;
 403                         discard = readb(&ch->ch_cls_uart->txrx);
 404                         continue;
 405                 }
 406
 407                 /*
 408                  * If our queue is full, we have no choice but to drop some
 409                  * data. The assumption is that HWFLOW or SWFLOW should have
 410                  * stopped things way way before we got to this point.
 411                  *
 412                  * I decided that I wanted to ditch the oldest data first,
 413                  * I hope thats okay with everyone? Yes? Good.
 414                  */
 415                 while (qleft < 1) {
 416                         tail = (tail + 1) & RQUEUEMASK;
 417                         ch->ch_r_tail = tail;
 418                         ch->ch_err_overrun++;
 419                         qleft++;
 420                 }
 421
 422                 ch->ch_equeue[head] = linestatus & (UART_LSR_BI | UART_LSR_PE
 423                                                                  | UART_LSR_FE);
 424                 ch->ch_rqueue[head] = readb(&ch->ch_cls_uart->txrx);
 425
 426                 qleft--;
 427
 428                 if (ch->ch_equeue[head] & UART_LSR_PE)
 429                         ch->ch_err_parity++;
 430                 if (ch->ch_equeue[head] & UART_LSR_BI)
 431                         ch->ch_err_break++;
 432                 if (ch->ch_equeue[head] & UART_LSR_FE)
 433                         ch->ch_err_frame++;
 434
 435                 /* Add to, and flip head if needed */
 436                 head = (head + 1) & RQUEUEMASK;
 437                 ch->ch_rxcount++;
 438         }
 439
 440         /*
 441          * Write new final heads to channel structure.
 442          */
 443         ch->ch_r_head = head & RQUEUEMASK;
 444         ch->ch_e_head = head & EQUEUEMASK;
 445
 446         spin_unlock_irqrestore(&ch->ch_lock, flags);
 447 }
 448
 449 static void cls_copy_data_from_queue_to_uart(struct jsm_channel *ch)
 450 {
 451         u16 tail;
 452         int n;
 453         int qlen;
 454         u32 len_written = 0;
 455         struct circ_buf *circ;
 456
 457         if (!ch)
 458                 return;
 459
 460         circ = &ch->uart_port.state->xmit;
 461
 462         /* No data to write to the UART */
 463         if (uart_circ_empty(circ))
 464                 return;
 465
 466         /* If port is "stopped", don't send any data to the UART */
 467         if ((ch->ch_flags & CH_STOP) || (ch->ch_flags & CH_BREAK_SENDING))
 468                 return;
 469
 470         /* We have to do it this way, because of the EXAR TXFIFO count bug. */
 471         if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
 472                 return;
 473
 474         n = 32;
 475
 476         /* cache tail of queue */
 477         tail = circ->tail & (UART_XMIT_SIZE - 1);
 478         qlen = uart_circ_chars_pending(circ);
 479
 480         /* Find minimum of the FIFO space, versus queue length */
 481         n = min(n, qlen);
 482
 483         while (n > 0) {
 484                 writeb(circ->buf[tail], &ch->ch_cls_uart->txrx);
 485                 tail = (tail + 1) & (UART_XMIT_SIZE - 1);
 486                 n--;
 487                 ch->ch_txcount++;
 488                 len_written++;
 489         }
 490
 491         /* Update the final tail */
 492         circ->tail = tail & (UART_XMIT_SIZE - 1);
 493
 494         if (len_written > ch->ch_t_tlevel)
 495                 ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 496
 497         if (uart_circ_empty(circ))
 498                 uart_write_wakeup(&ch->uart_port);
 499 }
 500
 501 static void cls_parse_modem(struct jsm_channel *ch, u8 signals)
 502 {
 503         u8 msignals = signals;
 504
 505         jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
 506                 "neo_parse_modem: port: %d msignals: %x\n",
 507                 ch->ch_portnum, msignals);
 508
 509         /*
 510          * Scrub off lower bits.
 511          * They signify delta's, which I don't care about
 512          * Keep DDCD and DDSR though
 513          */
 514         msignals &= 0xf8;
 515
 516         if (msignals & UART_MSR_DDCD)
 517                 uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_DCD);
 518         if (msignals & UART_MSR_DDSR)
 519                 uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_CTS);
 520
 521         if (msignals & UART_MSR_DCD)
 522                 ch->ch_mistat |= UART_MSR_DCD;
 523         else
 524                 ch->ch_mistat &= ~UART_MSR_DCD;
 525
 526         if (msignals & UART_MSR_DSR)
 527                 ch->ch_mistat |= UART_MSR_DSR;
 528         else
 529                 ch->ch_mistat &= ~UART_MSR_DSR;
 530
 531         if (msignals & UART_MSR_RI)
 532                 ch->ch_mistat |= UART_MSR_RI;
 533         else
 534                 ch->ch_mistat &= ~UART_MSR_RI;
 535
 536         if (msignals & UART_MSR_CTS)
 537                 ch->ch_mistat |= UART_MSR_CTS;
 538         else
 539                 ch->ch_mistat &= ~UART_MSR_CTS;
 540
 541         jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
 542                 "Port: %d DTR: %d RTS: %d CTS: %d DSR: %d " "RI: %d CD: %d\n",
 543                 ch->ch_portnum,
 544                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_DTR),
 545                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_RTS),
 546                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_CTS),
 547                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DSR),
 548                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_RI),
 549                 !!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DCD));
 550 }
 551
 552 /* Parse the ISR register for the specific port */
 553 static inline void cls_parse_isr(struct jsm_board *brd, uint port)
 554 {
 555         struct jsm_channel *ch;
 556         u8 isr = 0;
 557         unsigned long flags;
 558
 559         /*
 560          * No need to verify board pointer, it was already
 561          * verified in the interrupt routine.
 562          */
 563
 564         if (port >= brd->nasync)
 565                 return;
 566
 567         ch = brd->channels[port];
 568         if (!ch)
 569                 return;
 570
 571         /* Here we try to figure out what caused the interrupt to happen */
 572         while (1) {
 573                 isr = readb(&ch->ch_cls_uart->isr_fcr);
 574
 575                 /* Bail if no pending interrupt on port */
 576                 if (isr & UART_IIR_NO_INT)
 577                         break;
 578
 579                 /* Receive Interrupt pending */
 580                 if (isr & (UART_IIR_RDI | UART_IIR_RDI_TIMEOUT)) {
 581                         /* Read data from uart -> queue */
 582                         cls_copy_data_from_uart_to_queue(ch);
 583                         jsm_check_queue_flow_control(ch);
 584                 }
 585
 586                 /* Transmit Hold register empty pending */
 587                 if (isr & UART_IIR_THRI) {
 588                         /* Transfer data (if any) from Write Queue -> UART. */
 589                         spin_lock_irqsave(&ch->ch_lock, flags);
 590                         ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 591                         spin_unlock_irqrestore(&ch->ch_lock, flags);
 592                         cls_copy_data_from_queue_to_uart(ch);
 593                 }
 594
 595                 /*
 596                  * CTS/RTS change of state:
 597                  * Don't need to do anything, the cls_parse_modem
 598                  * below will grab the updated modem signals.
 599                  */
 600
 601                 /* Parse any modem signal changes */
 602                 cls_parse_modem(ch, readb(&ch->ch_cls_uart->msr));
 603         }
 604 }
 605
 606 /* Channel lock MUST be held before calling this function! */
 607 static void cls_flush_uart_write(struct jsm_channel *ch)
 608 {
 609         u8 tmp = 0;
 610         u8 i = 0;
 611
 612         if (!ch)
 613                 return;
 614
 615         writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT),
 616                                                 &ch->ch_cls_uart->isr_fcr);
 617
 618         for (i = 0; i < 10; i++) {
 619                 /* Check to see if the UART feels it completely flushed FIFO */
 620                 tmp = readb(&ch->ch_cls_uart->isr_fcr);
 621                 if (tmp & UART_FCR_CLEAR_XMIT) {
 622                         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
 623                                 "Still flushing TX UART... i: %d\n", i);
 624                         udelay(10);
 625                 } else
 626                         break;
 627         }
 628
 629         ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 630 }
 631
 632 /* Channel lock MUST be held before calling this function! */
 633 static void cls_flush_uart_read(struct jsm_channel *ch)
 634 {
 635         if (!ch)
 636                 return;
 637
 638         /*
 639          * For complete POSIX compatibility, we should be purging the
 640          * read FIFO in the UART here.
 641          *
 642          * However, clearing the read FIFO (UART_FCR_CLEAR_RCVR) also
 643          * incorrectly flushes write data as well as just basically trashing the
 644          * FIFO.
 645          *
 646          * Presumably, this is a bug in this UART.
 647          */
 648
 649         udelay(10);
 650 }
 651
 652 static void cls_send_start_character(struct jsm_channel *ch)
 653 {
 654         if (!ch)
 655                 return;
 656
 657         if (ch->ch_startc != __DISABLED_CHAR) {
 658                 ch->ch_xon_sends++;
 659                 writeb(ch->ch_startc, &ch->ch_cls_uart->txrx);
 660         }
 661 }
 662
 663 static void cls_send_stop_character(struct jsm_channel *ch)
 664 {
 665         if (!ch)
 666                 return;
 667
 668         if (ch->ch_stopc != __DISABLED_CHAR) {
 669                 ch->ch_xoff_sends++;
 670                 writeb(ch->ch_stopc, &ch->ch_cls_uart->txrx);
 671         }
 672 }
 673
 674 /*
 675  * cls_param()
 676  * Send any/all changes to the line to the UART.
 677  */
 678 static void cls_param(struct jsm_channel *ch)
 679 {
 680         u8 lcr = 0;
 681         u8 uart_lcr = 0;
 682         u8 ier = 0;
 683         u32 baud = 9600;
 684         int quot = 0;
 685         struct jsm_board *bd;
 686         int i;
 687         unsigned int cflag;
 688
 689         bd = ch->ch_bd;
 690         if (!bd)
 691                 return;
 692
 693         /*
 694          * If baud rate is zero, flush queues, and set mval to drop DTR.
 695          */
 696         if ((ch->ch_c_cflag & (CBAUD)) == 0) {
 697                 ch->ch_r_head = 0;
 698                 ch->ch_r_tail = 0;
 699                 ch->ch_e_head = 0;
 700                 ch->ch_e_tail = 0;
 701
 702                 cls_flush_uart_write(ch);
 703                 cls_flush_uart_read(ch);
 704
 705                 /* The baudrate is B0 so all modem lines are to be dropped. */
 706                 ch->ch_flags |= (CH_BAUD0);
 707                 ch->ch_mostat &= ~(UART_MCR_RTS | UART_MCR_DTR);
 708                 cls_assert_modem_signals(ch);
 709                 return;
 710         }
 711
 712         cflag = C_BAUD(ch->uart_port.state->port.tty);
 713         baud = 9600;
 714         for (i = 0; i < ARRAY_SIZE(baud_rates); i++) {
 715                 if (baud_rates[i].cflag == cflag) {
 716                         baud = baud_rates[i].rate;
 717                         break;
 718                 }
 719         }
 720
 721         if (ch->ch_flags & CH_BAUD0)
 722                 ch->ch_flags &= ~(CH_BAUD0);
 723
 724         if (ch->ch_c_cflag & PARENB)
 725                 lcr |= UART_LCR_PARITY;
 726
 727         if (!(ch->ch_c_cflag & PARODD))
 728                 lcr |= UART_LCR_EPAR;
 729
 730         /*
 731          * Not all platforms support mark/space parity,
 732          * so this will hide behind an ifdef.
 733          */
 734 #ifdef CMSPAR
 735         if (ch->ch_c_cflag & CMSPAR)
 736                 lcr |= UART_LCR_SPAR;
 737 #endif
 738
 739         if (ch->ch_c_cflag & CSTOPB)
 740                 lcr |= UART_LCR_STOP;
 741
 742         switch (ch->ch_c_cflag & CSIZE) {
 743         case CS5:
 744                 lcr |= UART_LCR_WLEN5;
 745                 break;
 746         case CS6:
 747                 lcr |= UART_LCR_WLEN6;
 748                 break;
 749         case CS7:
 750                 lcr |= UART_LCR_WLEN7;
 751                 break;
 752         case CS8:
 753         default:
 754                 lcr |= UART_LCR_WLEN8;
 755                 break;
 756         }
 757
 758         ier = readb(&ch->ch_cls_uart->ier);
 759         uart_lcr = readb(&ch->ch_cls_uart->lcr);
 760
 761         quot = ch->ch_bd->bd_dividend / baud;
 762
 763         if (quot != 0) {
 764                 writeb(UART_LCR_DLAB, &ch->ch_cls_uart->lcr);
 765                 writeb((quot & 0xff), &ch->ch_cls_uart->txrx);
 766                 writeb((quot >> 8), &ch->ch_cls_uart->ier);
 767                 writeb(lcr, &ch->ch_cls_uart->lcr);
 768         }
 769
 770         if (uart_lcr != lcr)
 771                 writeb(lcr, &ch->ch_cls_uart->lcr);
 772
 773         if (ch->ch_c_cflag & CREAD)
 774                 ier |= (UART_IER_RDI | UART_IER_RLSI);
 775
 776         ier |= (UART_IER_THRI | UART_IER_MSI);
 777
 778         writeb(ier, &ch->ch_cls_uart->ier);
 779
 780         if (ch->ch_c_cflag & CRTSCTS)
 781                 cls_set_cts_flow_control(ch);
 782         else if (ch->ch_c_iflag & IXON) {
 783                 /*
 784                  * If start/stop is set to disable,
 785                  * then we should disable flow control.
 786                  */
 787                 if ((ch->ch_startc == __DISABLED_CHAR) ||
 788                         (ch->ch_stopc == __DISABLED_CHAR))
 789                         cls_set_no_output_flow_control(ch);
 790                 else
 791                         cls_set_ixon_flow_control(ch);
 792         } else
 793                 cls_set_no_output_flow_control(ch);
 794
 795         if (ch->ch_c_cflag & CRTSCTS)
 796                 cls_set_rts_flow_control(ch);
 797         else if (ch->ch_c_iflag & IXOFF) {
 798                 /*
 799                  * If start/stop is set to disable,
 800                  * then we should disable flow control.
 801                  */
 802                 if ((ch->ch_startc == __DISABLED_CHAR) ||
 803                         (ch->ch_stopc == __DISABLED_CHAR))
 804                         cls_set_no_input_flow_control(ch);
 805                 else
 806                         cls_set_ixoff_flow_control(ch);
 807         } else
 808                 cls_set_no_input_flow_control(ch);
 809
 810         cls_assert_modem_signals(ch);
 811
 812         /* get current status of the modem signals now */
 813         cls_parse_modem(ch, readb(&ch->ch_cls_uart->msr));
 814 }
 815
 816 /*
 817  * cls_intr()
 818  *
 819  * Classic specific interrupt handler.
 820  */
 821 static irqreturn_t cls_intr(int irq, void *voidbrd)
 822 {
 823         struct jsm_board *brd = voidbrd;
 824         unsigned long lock_flags;
 825         unsigned char uart_poll;
 826         uint i = 0;
 827
 828         /* Lock out the slow poller from running on this board. */
 829         spin_lock_irqsave(&brd->bd_intr_lock, lock_flags);
 830
 831         /*
 832          * Check the board's global interrupt offset to see if we
 833          * acctually do have an interrupt pending on us.
 834          */
 835         uart_poll = readb(brd->re_map_membase + UART_CLASSIC_POLL_ADDR_OFFSET);
 836
 837         jsm_dbg(INTR, &brd->pci_dev, "%s:%d uart_poll: %x\n",
 838                 __FILE__, __LINE__, uart_poll);
 839
 840         if (!uart_poll) {
 841                 jsm_dbg(INTR, &brd->pci_dev,
 842                         "Kernel interrupted to me, but no pending interrupts...\n");
 843                 spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
 844                 return IRQ_NONE;
 845         }
 846
 847         /* At this point, we have at least SOMETHING to service, dig further. */
 848
 849         /* Parse each port to find out what caused the interrupt */
 850         for (i = 0; i < brd->nasync; i++)
 851                 cls_parse_isr(brd, i);
 852
 853         spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
 854
 855         return IRQ_HANDLED;
 856 }
 857
 858 /* Inits UART */
 859 static void cls_uart_init(struct jsm_channel *ch)
 860 {
 861         unsigned char lcrb = readb(&ch->ch_cls_uart->lcr);
 862         unsigned char isr_fcr = 0;
 863
 864         writeb(0, &ch->ch_cls_uart->ier);
 865
 866         /*
 867          * The Enhanced Register Set may only be accessed when
 868          * the Line Control Register is set to 0xBFh.
 869          */
 870         writeb(UART_EXAR654_ENHANCED_REGISTER_SET, &ch->ch_cls_uart->lcr);
 871
 872         isr_fcr = readb(&ch->ch_cls_uart->isr_fcr);
 873
 874         /* Turn on Enhanced/Extended controls */
 875         isr_fcr |= (UART_EXAR654_EFR_ECB);
 876
 877         writeb(isr_fcr, &ch->ch_cls_uart->isr_fcr);
 878
 879         /* Write old LCR value back out, which turns enhanced access off */
 880         writeb(lcrb, &ch->ch_cls_uart->lcr);
 881
 882         /* Clear out UART and FIFO */
 883         readb(&ch->ch_cls_uart->txrx);
 884
 885         writeb((UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|UART_FCR_CLEAR_XMIT),
 886                                                  &ch->ch_cls_uart->isr_fcr);
 887         udelay(10);
 888
 889         ch->ch_flags |= (CH_FIFO_ENABLED | CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 890
 891         readb(&ch->ch_cls_uart->lsr);
 892         readb(&ch->ch_cls_uart->msr);
 893 }
 894
 895 /*
 896  * Turns off UART.
 897  */
 898 static void cls_uart_off(struct jsm_channel *ch)
 899 {
 900         /* Stop all interrupts from accurring. */
 901         writeb(0, &ch->ch_cls_uart->ier);
 902 }
 903
 904 /*
 905  * cls_get_uarts_bytes_left.
 906  * Returns 0 is nothing left in the FIFO, returns 1 otherwise.
 907  *
 908  * The channel lock MUST be held by the calling function.
 909  */
 910 static u32 cls_get_uart_bytes_left(struct jsm_channel *ch)
 911 {
 912         u8 left = 0;
 913         u8 lsr = readb(&ch->ch_cls_uart->lsr);
 914
 915         /* Determine whether the Transmitter is empty or not */
 916         if (!(lsr & UART_LSR_TEMT))
 917                 left = 1;
 918         else {
 919                 ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
 920                 left = 0;
 921         }
 922
 923         return left;
 924 }
 925
 926 /*
 927  * cls_send_break.
 928  * Starts sending a break thru the UART.
 929  *
 930  * The channel lock MUST be held by the calling function.
 931  */
 932 static void cls_send_break(struct jsm_channel *ch)
 933 {
 934         /* Tell the UART to start sending the break */
 935         if (!(ch->ch_flags & CH_BREAK_SENDING)) {
 936                 u8 temp = readb(&ch->ch_cls_uart->lcr);
 937
 938                 writeb((temp | UART_LCR_SBC), &ch->ch_cls_uart->lcr);
 939                 ch->ch_flags |= (CH_BREAK_SENDING);
 940         }
 941 }
 942
 943 /*
 944  * cls_send_immediate_char.
 945  * Sends a specific character as soon as possible to the UART,
 946  * jumping over any bytes that might be in the write queue.
 947  *
 948  * The channel lock MUST be held by the calling function.
 949  */
 950 static void cls_send_immediate_char(struct jsm_channel *ch, unsigned char c)
 951 {
 952         writeb(c, &ch->ch_cls_uart->txrx);
 953 }
 954
 955 struct board_ops jsm_cls_ops = {
 956         .intr =                         cls_intr,
 957         .uart_init =                    cls_uart_init,
 958         .uart_off =                     cls_uart_off,
 959         .param =                        cls_param,
 960         .assert_modem_signals =         cls_assert_modem_signals,
 961         .flush_uart_write =             cls_flush_uart_write,
 962         .flush_uart_read =              cls_flush_uart_read,
 963         .disable_receiver =             cls_disable_receiver,
 964         .enable_receiver =              cls_enable_receiver,
 965         .send_break =                   cls_send_break,
 966         .clear_break =                  cls_clear_break,
 967         .send_start_character =         cls_send_start_character,
 968         .send_stop_character =          cls_send_stop_character,
 969         .copy_data_from_queue_to_uart = cls_copy_data_from_queue_to_uart,
 970         .get_uart_bytes_left =          cls_get_uart_bytes_left,
 971         .send_immediate_char =          cls_send_immediate_char
 972 };
 973