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 "vl.h"
  25
  26 //#define DEBUG_SERIAL
  27
  28 #define UART_LCR_DLAB   0x80    /* Divisor latch access bit */
  29
  30 #define UART_IER_MSI    0x08    /* Enable Modem status interrupt */
  31 #define UART_IER_RLSI   0x04    /* Enable receiver line status interrupt */
  32 #define UART_IER_THRI   0x02    /* Enable Transmitter holding register int. */
  33 #define UART_IER_RDI    0x01    /* Enable receiver data interrupt */
  34
  35 #define UART_IIR_NO_INT 0x01    /* No interrupts pending */
  36 #define UART_IIR_ID     0x06    /* Mask for the interrupt ID */
  37
  38 #define UART_IIR_MSI    0x00    /* Modem status interrupt */
  39 #define UART_IIR_THRI   0x02    /* Transmitter holding register empty */
  40 #define UART_IIR_RDI    0x04    /* Receiver data interrupt */
  41 #define UART_IIR_RLSI   0x06    /* Receiver line status interrupt */
  42
  43 /*
  44  * These are the definitions for the Modem Control Register
  45  */
  46 #define UART_MCR_LOOP   0x10    /* Enable loopback test mode */
  47 #define UART_MCR_OUT2   0x08    /* Out2 complement */
  48 #define UART_MCR_OUT1   0x04    /* Out1 complement */
  49 #define UART_MCR_RTS    0x02    /* RTS complement */
  50 #define UART_MCR_DTR    0x01    /* DTR complement */
  51
  52 /*
  53  * These are the definitions for the Modem Status Register
  54  */
  55 #define UART_MSR_DCD    0x80    /* Data Carrier Detect */
  56 #define UART_MSR_RI     0x40    /* Ring Indicator */
  57 #define UART_MSR_DSR    0x20    /* Data Set Ready */
  58 #define UART_MSR_CTS    0x10    /* Clear to Send */
  59 #define UART_MSR_DDCD   0x08    /* Delta DCD */
  60 #define UART_MSR_TERI   0x04    /* Trailing edge ring indicator */
  61 #define UART_MSR_DDSR   0x02    /* Delta DSR */
  62 #define UART_MSR_DCTS   0x01    /* Delta CTS */
  63 #define UART_MSR_ANY_DELTA 0x0F /* Any of the delta bits! */
  64
  65 #define UART_LSR_TEMT   0x40    /* Transmitter empty */
  66 #define UART_LSR_THRE   0x20    /* Transmit-hold-register empty */
  67 #define UART_LSR_BI     0x10    /* Break interrupt indicator */
  68 #define UART_LSR_FE     0x08    /* Frame error indicator */
  69 #define UART_LSR_PE     0x04    /* Parity error indicator */
  70 #define UART_LSR_OE     0x02    /* Overrun error indicator */
  71 #define UART_LSR_DR     0x01    /* Receiver data ready */
  72
  73 struct SerialState {
  74     uint16_t divider;
  75     uint8_t rbr; /* receive register */
  76     uint8_t ier;
  77     uint8_t iir; /* read only */
  78     uint8_t lcr;
  79     uint8_t mcr;
  80     uint8_t lsr; /* read only */
  81     uint8_t msr; /* read only */
  82     uint8_t scr;
  83     /* NOTE: this hidden state is necessary for tx irq generation as
  84        it can be reset while reading iir */
  85     int thr_ipending;
  86     SetIRQFunc *set_irq;
  87     void *irq_opaque;
  88     int irq;
  89     CharDriverState *chr;
  90     int last_break_enable;
  91     target_ulong base;
  92     int it_shift;
  93 };
  94
  95 static void serial_update_irq(SerialState *s)
  96 {
  97     if ((s->lsr & UART_LSR_DR) && (s->ier & UART_IER_RDI)) {
  98         s->iir = UART_IIR_RDI;
  99     } else if (s->thr_ipending && (s->ier & UART_IER_THRI)) {
 100         s->iir = UART_IIR_THRI;
 101     } else {
 102         s->iir = UART_IIR_NO_INT;
 103     }
 104     if (s->iir != UART_IIR_NO_INT) {
 105         s->set_irq(s->irq_opaque, s->irq, 1);
 106     } else {
 107         s->set_irq(s->irq_opaque, s->irq, 0);
 108     }
 109 }
 110
 111 static void serial_update_parameters(SerialState *s)
 112 {
 113     int speed, parity, data_bits, stop_bits;
 114     QEMUSerialSetParams ssp;
 115
 116     if (s->lcr & 0x08) {
 117         if (s->lcr & 0x10)
 118             parity = 'E';
 119         else
 120             parity = 'O';
 121     } else {
 122             parity = 'N';
 123     }
 124     if (s->lcr & 0x04)
 125         stop_bits = 2;
 126     else
 127         stop_bits = 1;
 128     data_bits = (s->lcr & 0x03) + 5;
 129     if (s->divider == 0)
 130         return;
 131     speed = 115200 / s->divider;
 132     ssp.speed = speed;
 133     ssp.parity = parity;
 134     ssp.data_bits = data_bits;
 135     ssp.stop_bits = stop_bits;
 136     qemu_chr_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
 137 #if 0
 138     printf("speed=%d parity=%c data=%d stop=%d\n",
 139            speed, parity, data_bits, stop_bits);
 140 #endif
 141 }
 142
 143 static void serial_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 144 {
 145     SerialState *s = opaque;
 146     unsigned char ch;
 147
 148     addr &= 7;
 149 #ifdef DEBUG_SERIAL
 150     printf("serial: write addr=0x%02x val=0x%02x\n", addr, val);
 151 #endif
 152     switch(addr) {
 153     default:
 154     case 0:
 155         if (s->lcr & UART_LCR_DLAB) {
 156             s->divider = (s->divider & 0xff00) | val;
 157             serial_update_parameters(s);
 158         } else {
 159             s->thr_ipending = 0;
 160             s->lsr &= ~UART_LSR_THRE;
 161             serial_update_irq(s);
 162             ch = val;
 163             qemu_chr_write(s->chr, &ch, 1);
 164             s->thr_ipending = 1;
 165             s->lsr |= UART_LSR_THRE;
 166             s->lsr |= UART_LSR_TEMT;
 167             serial_update_irq(s);
 168         }
 169         break;
 170     case 1:
 171         if (s->lcr & UART_LCR_DLAB) {
 172             s->divider = (s->divider & 0x00ff) | (val << 8);
 173             serial_update_parameters(s);
 174         } else {
 175             s->ier = val & 0x0f;
 176             if (s->lsr & UART_LSR_THRE) {
 177                 s->thr_ipending = 1;
 178             }
 179             serial_update_irq(s);
 180         }
 181         break;
 182     case 2:
 183         break;
 184     case 3:
 185         {
 186             int break_enable;
 187             s->lcr = val;
 188             serial_update_parameters(s);
 189             break_enable = (val >> 6) & 1;
 190             if (break_enable != s->last_break_enable) {
 191                 s->last_break_enable = break_enable;
 192                 qemu_chr_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
 193                                &break_enable);
 194             }
 195         }
 196         break;
 197     case 4:
 198         s->mcr = val & 0x1f;
 199         break;
 200     case 5:
 201         break;
 202     case 6:
 203         break;
 204     case 7:
 205         s->scr = val;
 206         break;
 207     }
 208 }
 209
 210 static uint32_t serial_ioport_read(void *opaque, uint32_t addr)
 211 {
 212     SerialState *s = opaque;
 213     uint32_t ret;
 214
 215     addr &= 7;
 216     switch(addr) {
 217     default:
 218     case 0:
 219         if (s->lcr & UART_LCR_DLAB) {
 220             ret = s->divider & 0xff;
 221         } else {
 222             ret = s->rbr;
 223             s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 224             serial_update_irq(s);
 225         }
 226         break;
 227     case 1:
 228         if (s->lcr & UART_LCR_DLAB) {
 229             ret = (s->divider >> 8) & 0xff;
 230         } else {
 231             ret = s->ier;
 232         }
 233         break;
 234     case 2:
 235         ret = s->iir;
 236         /* reset THR pending bit */
 237         if ((ret & 0x7) == UART_IIR_THRI)
 238             s->thr_ipending = 0;
 239         serial_update_irq(s);
 240         break;
 241     case 3:
 242         ret = s->lcr;
 243         break;
 244     case 4:
 245         ret = s->mcr;
 246         break;
 247     case 5:
 248         ret = s->lsr;
 249         break;
 250     case 6:
 251         if (s->mcr & UART_MCR_LOOP) {
 252             /* in loopback, the modem output pins are connected to the
 253                inputs */
 254             ret = (s->mcr & 0x0c) << 4;
 255             ret |= (s->mcr & 0x02) << 3;
 256             ret |= (s->mcr & 0x01) << 5;
 257         } else {
 258             ret = s->msr;
 259         }
 260         break;
 261     case 7:
 262         ret = s->scr;
 263         break;
 264     }
 265 #ifdef DEBUG_SERIAL
 266     printf("serial: read addr=0x%02x val=0x%02x\n", addr, ret);
 267 #endif
 268     return ret;
 269 }
 270
 271 static int serial_can_receive(SerialState *s)
 272 {
 273     return !(s->lsr & UART_LSR_DR);
 274 }
 275
 276 static void serial_receive_byte(SerialState *s, int ch)
 277 {
 278     s->rbr = ch;
 279     s->lsr |= UART_LSR_DR;
 280     serial_update_irq(s);
 281 }
 282
 283 static void serial_receive_break(SerialState *s)
 284 {
 285     s->rbr = 0;
 286     s->lsr |= UART_LSR_BI | UART_LSR_DR;
 287     serial_update_irq(s);
 288 }
 289
 290 static int serial_can_receive1(void *opaque)
 291 {
 292     SerialState *s = opaque;
 293     return serial_can_receive(s);
 294 }
 295
 296 static void serial_receive1(void *opaque, const uint8_t *buf, int size)
 297 {
 298     SerialState *s = opaque;
 299     serial_receive_byte(s, buf[0]);
 300 }
 301
 302 static void serial_event(void *opaque, int event)
 303 {
 304     SerialState *s = opaque;
 305     if (event == CHR_EVENT_BREAK)
 306         serial_receive_break(s);
 307 }
 308
 309 static void serial_save(QEMUFile *f, void *opaque)
 310 {
 311     SerialState *s = opaque;
 312
 313     qemu_put_be16s(f,&s->divider);
 314     qemu_put_8s(f,&s->rbr);
 315     qemu_put_8s(f,&s->ier);
 316     qemu_put_8s(f,&s->iir);
 317     qemu_put_8s(f,&s->lcr);
 318     qemu_put_8s(f,&s->mcr);
 319     qemu_put_8s(f,&s->lsr);
 320     qemu_put_8s(f,&s->msr);
 321     qemu_put_8s(f,&s->scr);
 322 }
 323
 324 static int serial_load(QEMUFile *f, void *opaque, int version_id)
 325 {
 326     SerialState *s = opaque;
 327
 328     if(version_id > 2)
 329         return -EINVAL;
 330
 331     if (version_id >= 2)
 332         qemu_get_be16s(f, &s->divider);
 333     else
 334         s->divider = qemu_get_byte(f);
 335     qemu_get_8s(f,&s->rbr);
 336     qemu_get_8s(f,&s->ier);
 337     qemu_get_8s(f,&s->iir);
 338     qemu_get_8s(f,&s->lcr);
 339     qemu_get_8s(f,&s->mcr);
 340     qemu_get_8s(f,&s->lsr);
 341     qemu_get_8s(f,&s->msr);
 342     qemu_get_8s(f,&s->scr);
 343
 344     return 0;
 345 }
 346
 347 /* If fd is zero, it means that the serial device uses the console */
 348 SerialState *serial_init(SetIRQFunc *set_irq, void *opaque,
 349                          int base, int irq, CharDriverState *chr)
 350 {
 351     SerialState *s;
 352
 353     s = qemu_mallocz(sizeof(SerialState));
 354     if (!s)
 355         return NULL;
 356     s->set_irq = set_irq;
 357     s->irq_opaque = opaque;
 358     s->irq = irq;
 359     s->lsr = UART_LSR_TEMT | UART_LSR_THRE;
 360     s->iir = UART_IIR_NO_INT;
 361     s->msr = UART_MSR_DCD | UART_MSR_DSR | UART_MSR_CTS;
 362
 363     register_savevm("serial", base, 2, serial_save, serial_load, s);
 364
 365     register_ioport_write(base, 8, 1, serial_ioport_write, s);
 366     register_ioport_read(base, 8, 1, serial_ioport_read, s);
 367     s->chr = chr;
 368     qemu_chr_add_handlers(chr, serial_can_receive1, serial_receive1,
 369                           serial_event, s);
 370     return s;
 371 }
 372
 373 /* Memory mapped interface */
 374 static uint32_t serial_mm_readb (void *opaque, target_phys_addr_t addr)
 375 {
 376     SerialState *s = opaque;
 377
 378     return serial_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFF;
 379 }
 380
 381 static void serial_mm_writeb (void *opaque,
 382                               target_phys_addr_t addr, uint32_t value)
 383 {
 384     SerialState *s = opaque;
 385
 386     serial_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFF);
 387 }
 388
 389 static uint32_t serial_mm_readw (void *opaque, target_phys_addr_t addr)
 390 {
 391     SerialState *s = opaque;
 392
 393     return serial_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFFFF;
 394 }
 395
 396 static void serial_mm_writew (void *opaque,
 397                               target_phys_addr_t addr, uint32_t value)
 398 {
 399     SerialState *s = opaque;
 400
 401     serial_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFFFF);
 402 }
 403
 404 static uint32_t serial_mm_readl (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);
 409 }
 410
 411 static void serial_mm_writel (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);
 417 }
 418
 419 static CPUReadMemoryFunc *serial_mm_read[] = {
 420     &serial_mm_readb,
 421     &serial_mm_readw,
 422     &serial_mm_readl,
 423 };
 424
 425 static CPUWriteMemoryFunc *serial_mm_write[] = {
 426     &serial_mm_writeb,
 427     &serial_mm_writew,
 428     &serial_mm_writel,
 429 };
 430
 431 SerialState *serial_mm_init (SetIRQFunc *set_irq, void *opaque,
 432                              target_ulong base, int it_shift,
 433                              int irq, CharDriverState *chr)
 434 {
 435     SerialState *s;
 436     int s_io_memory;
 437
 438     s = qemu_mallocz(sizeof(SerialState));
 439     if (!s)
 440         return NULL;
 441     s->set_irq = set_irq;
 442     s->irq_opaque = opaque;
 443     s->irq = irq;
 444     s->lsr = UART_LSR_TEMT | UART_LSR_THRE;
 445     s->iir = UART_IIR_NO_INT;
 446     s->msr = UART_MSR_DCD | UART_MSR_DSR | UART_MSR_CTS;
 447     s->base = base;
 448     s->it_shift = it_shift;
 449
 450     register_savevm("serial", base, 2, serial_save, serial_load, s);
 451
 452     s_io_memory = cpu_register_io_memory(0, serial_mm_read,
 453                                          serial_mm_write, s);
 454     cpu_register_physical_memory(base, 8 << it_shift, s_io_memory);
 455     s->chr = chr;
 456     qemu_chr_add_handlers(chr, serial_can_receive1, serial_receive1,
 457                           serial_event, s);
 458     return s;
 459 }