hw/serial.c

   1 /*
   2  * QEMU 16450 UART emulation
   3  *
   4  * Copyright (c) 2003-2004 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "hw.h"
  25 #include "qemu-char.h"
  26 #include "isa.h"
  27 #include "pc.h"
  28
  29 //#define DEBUG_SERIAL
  30
  31 #define UART_LCR_DLAB   0x80    /* Divisor latch access bit */
  32
  33 #define UART_IER_MSI    0x08    /* Enable Modem status interrupt */
  34 #define UART_IER_RLSI   0x04    /* Enable receiver line status interrupt */
  35 #define UART_IER_THRI   0x02    /* Enable Transmitter holding register int. */
  36 #define UART_IER_RDI    0x01    /* Enable receiver data interrupt */
  37
  38 #define UART_IIR_NO_INT 0x01    /* No interrupts pending */
  39 #define UART_IIR_ID     0x06    /* Mask for the interrupt ID */
  40
  41 #define UART_IIR_MSI    0x00    /* Modem status interrupt */
  42 #define UART_IIR_THRI   0x02    /* Transmitter holding register empty */
  43 #define UART_IIR_RDI    0x04    /* Receiver data interrupt */
  44 #define UART_IIR_RLSI   0x06    /* Receiver line status interrupt */
  45
  46 /*
  47  * These are the definitions for the Modem Control Register
  48  */
  49 #define UART_MCR_LOOP   0x10    /* Enable loopback test mode */
  50 #define UART_MCR_OUT2   0x08    /* Out2 complement */
  51 #define UART_MCR_OUT1   0x04    /* Out1 complement */
  52 #define UART_MCR_RTS    0x02    /* RTS complement */
  53 #define UART_MCR_DTR    0x01    /* DTR complement */
  54
  55 /*
  56  * These are the definitions for the Modem Status Register
  57  */
  58 #define UART_MSR_DCD    0x80    /* Data Carrier Detect */
  59 #define UART_MSR_RI     0x40    /* Ring Indicator */
  60 #define UART_MSR_DSR    0x20    /* Data Set Ready */
  61 #define UART_MSR_CTS    0x10    /* Clear to Send */
  62 #define UART_MSR_DDCD   0x08    /* Delta DCD */
  63 #define UART_MSR_TERI   0x04    /* Trailing edge ring indicator */
  64 #define UART_MSR_DDSR   0x02    /* Delta DSR */
  65 #define UART_MSR_DCTS   0x01    /* Delta CTS */
  66 #define UART_MSR_ANY_DELTA 0x0F /* Any of the delta bits! */
  67
  68 #define UART_LSR_TEMT   0x40    /* Transmitter empty */
  69 #define UART_LSR_THRE   0x20    /* Transmit-hold-register empty */
  70 #define UART_LSR_BI     0x10    /* Break interrupt indicator */
  71 #define UART_LSR_FE     0x08    /* Frame error indicator */
  72 #define UART_LSR_PE     0x04    /* Parity error indicator */
  73 #define UART_LSR_OE     0x02    /* Overrun error indicator */
  74 #define UART_LSR_DR     0x01    /* Receiver data ready */
  75
  76 struct SerialState {
  77     uint16_t divider;
  78     uint8_t rbr; /* receive register */
  79     uint8_t ier;
  80     uint8_t iir; /* read only */
  81     uint8_t lcr;
  82     uint8_t mcr;
  83     uint8_t lsr; /* read only */
  84     uint8_t msr; /* read only */
  85     uint8_t scr;
  86     /* NOTE: this hidden state is necessary for tx irq generation as
  87        it can be reset while reading iir */
  88     int thr_ipending;
  89     qemu_irq irq;
  90     CharDriverState *chr;
  91     int last_break_enable;
  92     target_phys_addr_t base;
  93     int it_shift;
  94 };
  95
  96 static void serial_receive_byte(SerialState *s, int ch);
  97
  98 static void serial_update_irq(SerialState *s)
  99 {
 100     if ((s->lsr & UART_LSR_DR) && (s->ier & UART_IER_RDI)) {
 101         s->iir = UART_IIR_RDI;
 102     } else if (s->thr_ipending && (s->ier & UART_IER_THRI)) {
 103         s->iir = UART_IIR_THRI;
 104     } else {
 105         s->iir = UART_IIR_NO_INT;
 106     }
 107     if (s->iir != UART_IIR_NO_INT) {
 108         qemu_irq_raise(s->irq);
 109     } else {
 110         qemu_irq_lower(s->irq);
 111     }
 112 }
 113
 114 static void serial_update_parameters(SerialState *s)
 115 {
 116     int speed, parity, data_bits, stop_bits;
 117     QEMUSerialSetParams ssp;
 118
 119     if (s->lcr & 0x08) {
 120         if (s->lcr & 0x10)
 121             parity = 'E';
 122         else
 123             parity = 'O';
 124     } else {
 125             parity = 'N';
 126     }
 127     if (s->lcr & 0x04)
 128         stop_bits = 2;
 129     else
 130         stop_bits = 1;
 131     data_bits = (s->lcr & 0x03) + 5;
 132     if (s->divider == 0)
 133         return;
 134     speed = 115200 / s->divider;
 135     ssp.speed = speed;
 136     ssp.parity = parity;
 137     ssp.data_bits = data_bits;
 138     ssp.stop_bits = stop_bits;
 139     qemu_chr_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
 140 #if 0
 141     printf("speed=%d parity=%c data=%d stop=%d\n",
 142            speed, parity, data_bits, stop_bits);
 143 #endif
 144 }
 145
 146 static void serial_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 147 {
 148     SerialState *s = opaque;
 149     unsigned char ch;
 150
 151     addr &= 7;
 152 #ifdef DEBUG_SERIAL
 153     printf("serial: write addr=0x%02x val=0x%02x\n", addr, val);
 154 #endif
 155     switch(addr) {
 156     default:
 157     case 0:
 158         if (s->lcr & UART_LCR_DLAB) {
 159             s->divider = (s->divider & 0xff00) | val;
 160             serial_update_parameters(s);
 161         } else {
 162             s->thr_ipending = 0;
 163             s->lsr &= ~UART_LSR_THRE;
 164             serial_update_irq(s);
 165             ch = val;
 166             if (!(s->mcr & UART_MCR_LOOP)) {
 167                 /* when not in loopback mode, send the char */
 168                 qemu_chr_write(s->chr, &ch, 1);
 169             }
 170             s->thr_ipending = 1;
 171             s->lsr |= UART_LSR_THRE;
 172             s->lsr |= UART_LSR_TEMT;
 173             serial_update_irq(s);
 174             if (s->mcr & UART_MCR_LOOP) {
 175                 /* in loopback mode, say that we just received a char */
 176                 serial_receive_byte(s, ch);
 177             }
 178         }
 179         break;
 180     case 1:
 181         if (s->lcr & UART_LCR_DLAB) {
 182             s->divider = (s->divider & 0x00ff) | (val << 8);
 183             serial_update_parameters(s);
 184         } else {
 185             s->ier = val & 0x0f;
 186             if (s->lsr & UART_LSR_THRE) {
 187                 s->thr_ipending = 1;
 188             }
 189             serial_update_irq(s);
 190         }
 191         break;
 192     case 2:
 193         break;
 194     case 3:
 195         {
 196             int break_enable;
 197             s->lcr = val;
 198             serial_update_parameters(s);
 199             break_enable = (val >> 6) & 1;
 200             if (break_enable != s->last_break_enable) {
 201                 s->last_break_enable = break_enable;
 202                 qemu_chr_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
 203                                &break_enable);
 204             }
 205         }
 206         break;
 207     case 4:
 208         s->mcr = val & 0x1f;
 209         break;
 210     case 5:
 211         break;
 212     case 6:
 213         break;
 214     case 7:
 215         s->scr = val;
 216         break;
 217     }
 218 }
 219
 220 static uint32_t serial_ioport_read(void *opaque, uint32_t addr)
 221 {
 222     SerialState *s = opaque;
 223     uint32_t ret;
 224
 225     addr &= 7;
 226     switch(addr) {
 227     default:
 228     case 0:
 229         if (s->lcr & UART_LCR_DLAB) {
 230             ret = s->divider & 0xff;
 231         } else {
 232             ret = s->rbr;
 233             s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 234             serial_update_irq(s);
 235             if (!(s->mcr & UART_MCR_LOOP)) {
 236                 /* in loopback mode, don't receive any data */
 237                 qemu_chr_accept_input(s->chr);
 238             }
 239         }
 240         break;
 241     case 1:
 242         if (s->lcr & UART_LCR_DLAB) {
 243             ret = (s->divider >> 8) & 0xff;
 244         } else {
 245             ret = s->ier;
 246         }
 247         break;
 248     case 2:
 249         ret = s->iir;
 250         /* reset THR pending bit */
 251         if ((ret & 0x7) == UART_IIR_THRI)
 252             s->thr_ipending = 0;
 253         serial_update_irq(s);
 254         break;
 255     case 3:
 256         ret = s->lcr;
 257         break;
 258     case 4:
 259         ret = s->mcr;
 260         break;
 261     case 5:
 262         ret = s->lsr;
 263         break;
 264     case 6:
 265         if (s->mcr & UART_MCR_LOOP) {
 266             /* in loopback, the modem output pins are connected to the
 267                inputs */
 268             ret = (s->mcr & 0x0c) << 4;
 269             ret |= (s->mcr & 0x02) << 3;
 270             ret |= (s->mcr & 0x01) << 5;
 271         } else {
 272             ret = s->msr;
 273         }
 274         break;
 275     case 7:
 276         ret = s->scr;
 277         break;
 278     }
 279 #ifdef DEBUG_SERIAL
 280     printf("serial: read addr=0x%02x val=0x%02x\n", addr, ret);
 281 #endif
 282     return ret;
 283 }
 284
 285 static int serial_can_receive(SerialState *s)
 286 {
 287     return !(s->lsr & UART_LSR_DR);
 288 }
 289
 290 static void serial_receive_byte(SerialState *s, int ch)
 291 {
 292     s->rbr = ch;
 293     s->lsr |= UART_LSR_DR;
 294     serial_update_irq(s);
 295 }
 296
 297 static void serial_receive_break(SerialState *s)
 298 {
 299     s->rbr = 0;
 300     s->lsr |= UART_LSR_BI | UART_LSR_DR;
 301     serial_update_irq(s);
 302 }
 303
 304 static int serial_can_receive1(void *opaque)
 305 {
 306     SerialState *s = opaque;
 307     return serial_can_receive(s);
 308 }
 309
 310 static void serial_receive1(void *opaque, const uint8_t *buf, int size)
 311 {
 312     SerialState *s = opaque;
 313     serial_receive_byte(s, buf[0]);
 314 }
 315
 316 static void serial_event(void *opaque, int event)
 317 {
 318     SerialState *s = opaque;
 319     if (event == CHR_EVENT_BREAK)
 320         serial_receive_break(s);
 321 }
 322
 323 static void serial_save(QEMUFile *f, void *opaque)
 324 {
 325     SerialState *s = opaque;
 326
 327     qemu_put_be16s(f,&s->divider);
 328     qemu_put_8s(f,&s->rbr);
 329     qemu_put_8s(f,&s->ier);
 330     qemu_put_8s(f,&s->iir);
 331     qemu_put_8s(f,&s->lcr);
 332     qemu_put_8s(f,&s->mcr);
 333     qemu_put_8s(f,&s->lsr);
 334     qemu_put_8s(f,&s->msr);
 335     qemu_put_8s(f,&s->scr);
 336 }
 337
 338 static int serial_load(QEMUFile *f, void *opaque, int version_id)
 339 {
 340     SerialState *s = opaque;
 341
 342     if(version_id > 2)
 343         return -EINVAL;
 344
 345     if (version_id >= 2)
 346         qemu_get_be16s(f, &s->divider);
 347     else
 348         s->divider = qemu_get_byte(f);
 349     qemu_get_8s(f,&s->rbr);
 350     qemu_get_8s(f,&s->ier);
 351     qemu_get_8s(f,&s->iir);
 352     qemu_get_8s(f,&s->lcr);
 353     qemu_get_8s(f,&s->mcr);
 354     qemu_get_8s(f,&s->lsr);
 355     qemu_get_8s(f,&s->msr);
 356     qemu_get_8s(f,&s->scr);
 357
 358     return 0;
 359 }
 360
 361 static void serial_reset(void *opaque)
 362 {
 363     SerialState *s = opaque;
 364
 365     s->divider = 0;
 366     s->rbr = 0;
 367     s->ier = 0;
 368     s->iir = UART_IIR_NO_INT;
 369     s->lcr = 0;
 370     s->mcr = 0;
 371     s->lsr = UART_LSR_TEMT | UART_LSR_THRE;
 372     s->msr = UART_MSR_DCD | UART_MSR_DSR | UART_MSR_CTS;
 373     s->scr = 0;
 374
 375     s->thr_ipending = 0;
 376     s->last_break_enable = 0;
 377     qemu_irq_lower(s->irq);
 378 }
 379
 380 /* If fd is zero, it means that the serial device uses the console */
 381 SerialState *serial_init(int base, qemu_irq irq, CharDriverState *chr)
 382 {
 383     SerialState *s;
 384
 385     s = qemu_mallocz(sizeof(SerialState));
 386     if (!s)
 387         return NULL;
 388     s->irq = irq;
 389
 390     qemu_register_reset(serial_reset, s);
 391     serial_reset(s);
 392
 393     register_savevm("serial", base, 2, serial_save, serial_load, s);
 394
 395     register_ioport_write(base, 8, 1, serial_ioport_write, s);
 396     register_ioport_read(base, 8, 1, serial_ioport_read, s);
 397     s->chr = chr;
 398     qemu_chr_add_handlers(chr, serial_can_receive1, serial_receive1,
 399                           serial_event, s);
 400     return s;
 401 }
 402
 403 /* Memory mapped interface */
 404 uint32_t serial_mm_readb (void *opaque, target_phys_addr_t addr)
 405 {
 406     SerialState *s = opaque;
 407
 408     return serial_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFF;
 409 }
 410
 411 void serial_mm_writeb (void *opaque,
 412                        target_phys_addr_t addr, uint32_t value)
 413 {
 414     SerialState *s = opaque;
 415
 416     serial_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFF);
 417 }
 418
 419 uint32_t serial_mm_readw (void *opaque, target_phys_addr_t addr)
 420 {
 421     SerialState *s = opaque;
 422     uint32_t val;
 423
 424     val = serial_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFFFF;
 425 #ifdef TARGET_WORDS_BIGENDIAN
 426     val = bswap16(val);
 427 #endif
 428     return val;
 429 }
 430
 431 void serial_mm_writew (void *opaque,
 432                        target_phys_addr_t addr, uint32_t value)
 433 {
 434     SerialState *s = opaque;
 435 #ifdef TARGET_WORDS_BIGENDIAN
 436     value = bswap16(value);
 437 #endif
 438     serial_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFFFF);
 439 }
 440
 441 uint32_t serial_mm_readl (void *opaque, target_phys_addr_t addr)
 442 {
 443     SerialState *s = opaque;
 444     uint32_t val;
 445
 446     val = serial_ioport_read(s, (addr - s->base) >> s->it_shift);
 447 #ifdef TARGET_WORDS_BIGENDIAN
 448     val = bswap32(val);
 449 #endif
 450     return val;
 451 }
 452
 453 void serial_mm_writel (void *opaque,
 454                        target_phys_addr_t addr, uint32_t value)
 455 {
 456     SerialState *s = opaque;
 457 #ifdef TARGET_WORDS_BIGENDIAN
 458     value = bswap32(value);
 459 #endif
 460     serial_ioport_write(s, (addr - s->base) >> s->it_shift, value);
 461 }
 462
 463 static CPUReadMemoryFunc *serial_mm_read[] = {
 464     &serial_mm_readb,
 465     &serial_mm_readw,
 466     &serial_mm_readl,
 467 };
 468
 469 static CPUWriteMemoryFunc *serial_mm_write[] = {
 470     &serial_mm_writeb,
 471     &serial_mm_writew,
 472     &serial_mm_writel,
 473 };
 474
 475 SerialState *serial_mm_init (target_phys_addr_t base, int it_shift,
 476                              qemu_irq irq, CharDriverState *chr,
 477                              int ioregister)
 478 {
 479     SerialState *s;
 480     int s_io_memory;
 481
 482     s = qemu_mallocz(sizeof(SerialState));
 483     if (!s)
 484         return NULL;
 485     s->irq = irq;
 486     s->base = base;
 487     s->it_shift = it_shift;
 488
 489     qemu_register_reset(serial_reset, s);
 490     serial_reset(s);
 491
 492     register_savevm("serial", base, 2, serial_save, serial_load, s);
 493
 494     if (ioregister) {
 495         s_io_memory = cpu_register_io_memory(0, serial_mm_read,
 496                                              serial_mm_write, s);
 497         cpu_register_physical_memory(base, 8 << it_shift, s_io_memory);
 498     }
 499     s->chr = chr;
 500     qemu_chr_add_handlers(chr, serial_can_receive1, serial_receive1,
 501                           serial_event, s);
 502     return s;
 503 }