hw/imx_serial.c

   1 /*
   2  * IMX31 UARTS
   3  *
   4  * Copyright (c) 2008 OKL
   5  * Originally Written by Hans Jiang
   6  * Copyright (c) 2011 NICTA Pty Ltd.
   7  *
   8  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   9  * See the COPYING file in the top-level directory.
  10  *
  11  * This is a `bare-bones' implementation of the IMX series serial ports.
  12  * TODO:
  13  *  -- implement FIFOs.  The real hardware has 32 word transmit
  14  *                       and receive FIFOs; we currently use a 1-char buffer
  15  *  -- implement DMA
  16  *  -- implement BAUD-rate and modem lines, for when the backend
  17  *     is a real serial device.
  18  */
  19
  20 #include "hw.h"
  21 #include "sysbus.h"
  22 #include "sysemu/sysemu.h"
  23 #include "char/char.h"
  24 #include "imx.h"
  25
  26 //#define DEBUG_SERIAL 1
  27 #ifdef DEBUG_SERIAL
  28 #define DPRINTF(fmt, args...) \
  29 do { printf("imx_serial: " fmt , ##args); } while (0)
  30 #else
  31 #define DPRINTF(fmt, args...) do {} while (0)
  32 #endif
  33
  34 /*
  35  * Define to 1 for messages about attempts to
  36  * access unimplemented registers or similar.
  37  */
  38 //#define DEBUG_IMPLEMENTATION 1
  39 #ifdef DEBUG_IMPLEMENTATION
  40 #  define IPRINTF(fmt, args...) \
  41     do  { fprintf(stderr, "imx_serial: " fmt, ##args); } while (0)
  42 #else
  43 #  define IPRINTF(fmt, args...) do {} while (0)
  44 #endif
  45
  46 typedef struct {
  47     SysBusDevice busdev;
  48     MemoryRegion iomem;
  49     int32_t readbuff;
  50
  51     uint32_t usr1;
  52     uint32_t usr2;
  53     uint32_t ucr1;
  54     uint32_t ucr2;
  55     uint32_t uts1;
  56
  57     /*
  58      * The registers below are implemented just so that the
  59      * guest OS sees what it has written
  60      */
  61     uint32_t onems;
  62     uint32_t ufcr;
  63     uint32_t ubmr;
  64     uint32_t ubrc;
  65     uint32_t ucr3;
  66
  67     qemu_irq irq;
  68     CharDriverState *chr;
  69 } IMXSerialState;
  70
  71 static const VMStateDescription vmstate_imx_serial = {
  72     .name = "imx-serial",
  73     .version_id = 1,
  74     .minimum_version_id = 1,
  75     .minimum_version_id_old = 1,
  76     .fields = (VMStateField[]) {
  77         VMSTATE_INT32(readbuff, IMXSerialState),
  78         VMSTATE_UINT32(usr1, IMXSerialState),
  79         VMSTATE_UINT32(usr2, IMXSerialState),
  80         VMSTATE_UINT32(ucr1, IMXSerialState),
  81         VMSTATE_UINT32(uts1, IMXSerialState),
  82         VMSTATE_UINT32(onems, IMXSerialState),
  83         VMSTATE_UINT32(ufcr, IMXSerialState),
  84         VMSTATE_UINT32(ubmr, IMXSerialState),
  85         VMSTATE_UINT32(ubrc, IMXSerialState),
  86         VMSTATE_UINT32(ucr3, IMXSerialState),
  87         VMSTATE_END_OF_LIST()
  88     },
  89 };
  90
  91
  92 #define URXD_CHARRDY    (1<<15)   /* character read is valid */
  93 #define URXD_ERR        (1<<14)   /* Character has error */
  94 #define URXD_BRK        (1<<11)   /* Break received */
  95
  96 #define USR1_PARTYER    (1<<15)   /* Parity Error */
  97 #define USR1_RTSS       (1<<14)   /* RTS pin status */
  98 #define USR1_TRDY       (1<<13)   /* Tx ready */
  99 #define USR1_RTSD       (1<<12)   /* RTS delta: pin changed state */
 100 #define USR1_ESCF       (1<<11)   /* Escape sequence interrupt */
 101 #define USR1_FRAMERR    (1<<10)   /* Framing error  */
 102 #define USR1_RRDY       (1<<9)    /* receiver ready */
 103 #define USR1_AGTIM      (1<<8)    /* Aging timer interrupt */
 104 #define USR1_DTRD       (1<<7)    /* DTR changed */
 105 #define USR1_RXDS       (1<<6)    /* Receiver is idle */
 106 #define USR1_AIRINT     (1<<5)    /* Aysnch IR interrupt */
 107 #define USR1_AWAKE      (1<<4)    /* Falling edge detected on RXd pin */
 108
 109 #define USR2_ADET       (1<<15)   /* Autobaud complete */
 110 #define USR2_TXFE       (1<<14)   /* Transmit FIFO empty */
 111 #define USR2_DTRF       (1<<13)   /* DTR/DSR transition */
 112 #define USR2_IDLE       (1<<12)   /* UART has been idle for too long */
 113 #define USR2_ACST       (1<<11)   /* Autobaud counter stopped */
 114 #define USR2_RIDELT     (1<<10)   /* Ring Indicator delta */
 115 #define USR2_RIIN       (1<<9)    /* Ring Indicator Input */
 116 #define USR2_IRINT      (1<<8)    /* Serial Infrared Interrupt */
 117 #define USR2_WAKE       (1<<7)    /* Start bit detected */
 118 #define USR2_DCDDELT    (1<<6)    /* Data Carrier Detect delta */
 119 #define USR2_DCDIN      (1<<5)    /* Data Carrier Detect Input */
 120 #define USR2_RTSF       (1<<4)    /* RTS transition */
 121 #define USR2_TXDC       (1<<3)    /* Transmission complete */
 122 #define USR2_BRCD       (1<<2)    /* Break condition detected */
 123 #define USR2_ORE        (1<<1)    /* Overrun error */
 124 #define USR2_RDR        (1<<0)    /* Receive data ready */
 125
 126 #define UCR1_TRDYEN     (1<<13)   /* Tx Ready Interrupt Enable */
 127 #define UCR1_RRDYEN     (1<<9)    /* Rx Ready Interrupt Enable */
 128 #define UCR1_TXMPTYEN   (1<<6)    /* Tx Empty Interrupt Enable */
 129 #define UCR1_UARTEN     (1<<0)    /* UART Enable */
 130
 131 #define UCR2_TXEN       (1<<2)    /* Transmitter enable */
 132 #define UCR2_RXEN       (1<<1)    /* Receiver enable */
 133 #define UCR2_SRST       (1<<0)    /* Reset complete */
 134
 135 #define UTS1_TXEMPTY    (1<<6)
 136 #define UTS1_RXEMPTY    (1<<5)
 137 #define UTS1_TXFULL     (1<<4)
 138 #define UTS1_RXFULL     (1<<3)
 139
 140 static void imx_update(IMXSerialState *s)
 141 {
 142     uint32_t flags;
 143
 144     flags = (s->usr1 & s->ucr1) & (USR1_TRDY|USR1_RRDY);
 145     if (!(s->ucr1 & UCR1_TXMPTYEN)) {
 146         flags &= ~USR1_TRDY;
 147     }
 148
 149     qemu_set_irq(s->irq, !!flags);
 150 }
 151
 152 static void imx_serial_reset(IMXSerialState *s)
 153 {
 154
 155     s->usr1 = USR1_TRDY | USR1_RXDS;
 156     /*
 157      * Fake attachment of a terminal: assert RTS.
 158      */
 159     s->usr1 |= USR1_RTSS;
 160     s->usr2 = USR2_TXFE | USR2_TXDC | USR2_DCDIN;
 161     s->uts1 = UTS1_RXEMPTY | UTS1_TXEMPTY;
 162     s->ucr1 = 0;
 163     s->ucr2 = UCR2_SRST;
 164     s->ucr3 = 0x700;
 165     s->ubmr = 0;
 166     s->ubrc = 4;
 167     s->readbuff = URXD_ERR;
 168 }
 169
 170 static void imx_serial_reset_at_boot(DeviceState *dev)
 171 {
 172     IMXSerialState *s = container_of(dev, IMXSerialState, busdev.qdev);
 173
 174     imx_serial_reset(s);
 175
 176     /*
 177      * enable the uart on boot, so messages from the linux decompresser
 178      * are visible.  On real hardware this is done by the boot rom
 179      * before anything else is loaded.
 180      */
 181     s->ucr1 = UCR1_UARTEN;
 182     s->ucr2 = UCR2_TXEN;
 183
 184 }
 185
 186 static uint64_t imx_serial_read(void *opaque, hwaddr offset,
 187                                 unsigned size)
 188 {
 189     IMXSerialState *s = (IMXSerialState *)opaque;
 190     uint32_t c;
 191
 192     DPRINTF("read(offset=%x)\n", offset >> 2);
 193     switch (offset >> 2) {
 194     case 0x0: /* URXD */
 195         c = s->readbuff;
 196         if (!(s->uts1 & UTS1_RXEMPTY)) {
 197             /* Character is valid */
 198             c |= URXD_CHARRDY;
 199             s->usr1 &= ~USR1_RRDY;
 200             s->usr2 &= ~USR2_RDR;
 201             s->uts1 |= UTS1_RXEMPTY;
 202             imx_update(s);
 203             qemu_chr_accept_input(s->chr);
 204         }
 205         return c;
 206
 207     case 0x20: /* UCR1 */
 208         return s->ucr1;
 209
 210     case 0x21: /* UCR2 */
 211         return s->ucr2;
 212
 213     case 0x25: /* USR1 */
 214         return s->usr1;
 215
 216     case 0x26: /* USR2 */
 217         return s->usr2;
 218
 219     case 0x2A: /* BRM Modulator */
 220         return s->ubmr;
 221
 222     case 0x2B: /* Baud Rate Count */
 223         return s->ubrc;
 224
 225     case 0x2d: /* Test register */
 226         return s->uts1;
 227
 228     case 0x24: /* UFCR */
 229         return s->ufcr;
 230
 231     case 0x2c:
 232         return s->onems;
 233
 234     case 0x22: /* UCR3 */
 235         return s->ucr3;
 236
 237     case 0x23: /* UCR4 */
 238     case 0x29: /* BRM Incremental */
 239         return 0x0; /* TODO */
 240
 241     default:
 242         IPRINTF("imx_serial_read: bad offset: 0x%x\n", (int)offset);
 243         return 0;
 244     }
 245 }
 246
 247 static void imx_serial_write(void *opaque, hwaddr offset,
 248                       uint64_t value, unsigned size)
 249 {
 250     IMXSerialState *s = (IMXSerialState *)opaque;
 251     unsigned char ch;
 252
 253     DPRINTF("write(offset=%x, value = %x) to %s\n",
 254             offset >> 2,
 255             (unsigned int)value, s->chr ? s->chr->label : "NODEV");
 256
 257     switch (offset >> 2) {
 258     case 0x10: /* UTXD */
 259         ch = value;
 260         if (s->ucr2 & UCR2_TXEN) {
 261             if (s->chr) {
 262                 qemu_chr_fe_write(s->chr, &ch, 1);
 263             }
 264             s->usr1 &= ~USR1_TRDY;
 265             imx_update(s);
 266             s->usr1 |= USR1_TRDY;
 267             imx_update(s);
 268         }
 269         break;
 270
 271     case 0x20: /* UCR1 */
 272         s->ucr1 = value & 0xffff;
 273         DPRINTF("write(ucr1=%x)\n", (unsigned int)value);
 274         imx_update(s);
 275         break;
 276
 277     case 0x21: /* UCR2 */
 278         /*
 279          * Only a few bits in control register 2 are implemented as yet.
 280          * If it's intended to use a real serial device as a back-end, this
 281          * register will have to be implemented more fully.
 282          */
 283         if (!(value & UCR2_SRST)) {
 284             imx_serial_reset(s);
 285             imx_update(s);
 286             value |= UCR2_SRST;
 287         }
 288         if (value & UCR2_RXEN) {
 289             if (!(s->ucr2 & UCR2_RXEN)) {
 290                 qemu_chr_accept_input(s->chr);
 291             }
 292         }
 293         s->ucr2 = value & 0xffff;
 294         break;
 295
 296     case 0x25: /* USR1 */
 297         value &= USR1_AWAKE | USR1_AIRINT | USR1_DTRD | USR1_AGTIM |
 298             USR1_FRAMERR | USR1_ESCF | USR1_RTSD | USR1_PARTYER;
 299         s->usr1 &= ~value;
 300         break;
 301
 302     case 0x26: /* USR2 */
 303        /*
 304         * Writing 1 to some bits clears them; all other
 305         * values are ignored
 306         */
 307         value &= USR2_ADET | USR2_DTRF | USR2_IDLE | USR2_ACST |
 308             USR2_RIDELT | USR2_IRINT | USR2_WAKE |
 309             USR2_DCDDELT | USR2_RTSF | USR2_BRCD | USR2_ORE;
 310         s->usr2 &= ~value;
 311         break;
 312
 313         /*
 314          * Linux expects to see what it writes to these registers
 315          * We don't currently alter the baud rate
 316          */
 317     case 0x29: /* UBIR */
 318         s->ubrc = value & 0xffff;
 319         break;
 320
 321     case 0x2a: /* UBMR */
 322         s->ubmr = value & 0xffff;
 323         break;
 324
 325     case 0x2c: /* One ms reg */
 326         s->onems = value & 0xffff;
 327         break;
 328
 329     case 0x24: /* FIFO control register */
 330         s->ufcr = value & 0xffff;
 331         break;
 332
 333     case 0x22: /* UCR3 */
 334         s->ucr3 = value & 0xffff;
 335         break;
 336
 337     case 0x2d: /* UTS1 */
 338     case 0x23: /* UCR4 */
 339         IPRINTF("Unimplemented Register %x written to\n", offset >> 2);
 340         /* TODO */
 341         break;
 342
 343     default:
 344         IPRINTF("imx_serial_write: Bad offset 0x%x\n", (int)offset);
 345     }
 346 }
 347
 348 static int imx_can_receive(void *opaque)
 349 {
 350     IMXSerialState *s = (IMXSerialState *)opaque;
 351     return !(s->usr1 & USR1_RRDY);
 352 }
 353
 354 static void imx_put_data(void *opaque, uint32_t value)
 355 {
 356     IMXSerialState *s = (IMXSerialState *)opaque;
 357     DPRINTF("received char\n");
 358     s->usr1 |= USR1_RRDY;
 359     s->usr2 |= USR2_RDR;
 360     s->uts1 &= ~UTS1_RXEMPTY;
 361     s->readbuff = value;
 362     imx_update(s);
 363 }
 364
 365 static void imx_receive(void *opaque, const uint8_t *buf, int size)
 366 {
 367     imx_put_data(opaque, *buf);
 368 }
 369
 370 static void imx_event(void *opaque, int event)
 371 {
 372     if (event == CHR_EVENT_BREAK) {
 373         imx_put_data(opaque, URXD_BRK);
 374     }
 375 }
 376
 377
 378 static const struct MemoryRegionOps imx_serial_ops = {
 379     .read = imx_serial_read,
 380     .write = imx_serial_write,
 381     .endianness = DEVICE_NATIVE_ENDIAN,
 382 };
 383
 384 static int imx_serial_init(SysBusDevice *dev)
 385 {
 386     IMXSerialState *s = FROM_SYSBUS(IMXSerialState, dev);
 387
 388
 389     memory_region_init_io(&s->iomem, &imx_serial_ops, s, "imx-serial", 0x1000);
 390     sysbus_init_mmio(dev, &s->iomem);
 391     sysbus_init_irq(dev, &s->irq);
 392
 393     if (s->chr) {
 394         qemu_chr_add_handlers(s->chr, imx_can_receive, imx_receive,
 395                               imx_event, s);
 396     } else {
 397         DPRINTF("No char dev for uart at 0x%lx\n",
 398                 (unsigned long)s->iomem.ram_addr);
 399     }
 400
 401     return 0;
 402 }
 403
 404 void imx_serial_create(int uart, const hwaddr addr, qemu_irq irq)
 405 {
 406     DeviceState *dev;
 407     SysBusDevice *bus;
 408     CharDriverState *chr;
 409     const char chr_name[] = "serial";
 410     char label[ARRAY_SIZE(chr_name) + 1];
 411
 412     dev = qdev_create(NULL, "imx-serial");
 413
 414     if (uart >= MAX_SERIAL_PORTS) {
 415         hw_error("Cannot assign uart %d: QEMU supports only %d ports\n",
 416                  uart, MAX_SERIAL_PORTS);
 417     }
 418     chr = serial_hds[uart];
 419     if (!chr) {
 420         snprintf(label, ARRAY_SIZE(label), "%s%d", chr_name, uart);
 421         chr = qemu_chr_new(label, "null", NULL);
 422         if (!(chr)) {
 423             hw_error("Can't assign serial port to imx-uart%d.\n", uart);
 424         }
 425     }
 426
 427     qdev_prop_set_chr(dev, "chardev", chr);
 428     bus = SYS_BUS_DEVICE(dev);
 429     qdev_init_nofail(dev);
 430     if (addr != (hwaddr)-1) {
 431         sysbus_mmio_map(bus, 0, addr);
 432     }
 433     sysbus_connect_irq(bus, 0, irq);
 434
 435 }
 436
 437
 438 static Property imx32_serial_properties[] = {
 439     DEFINE_PROP_CHR("chardev", IMXSerialState, chr),
 440     DEFINE_PROP_END_OF_LIST(),
 441 };
 442
 443 static void imx_serial_class_init(ObjectClass *klass, void *data)
 444 {
 445     DeviceClass *dc = DEVICE_CLASS(klass);
 446     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 447
 448     k->init = imx_serial_init;
 449     dc->vmsd = &vmstate_imx_serial;
 450     dc->reset = imx_serial_reset_at_boot;
 451     dc->desc = "i.MX series UART";
 452     dc->props = imx32_serial_properties;
 453 }
 454
 455 static const TypeInfo imx_serial_info = {
 456     .name = "imx-serial",
 457     .parent = TYPE_SYS_BUS_DEVICE,
 458     .instance_size = sizeof(IMXSerialState),
 459     .class_init = imx_serial_class_init,
 460 };
 461
 462 static void imx_serial_register_types(void)
 463 {
 464     type_register_static(&imx_serial_info);
 465 }
 466
 467 type_init(imx_serial_register_types)