qemu/hw/dma/bcm2835_dma.c
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   1/*
   2 * Raspberry Pi emulation (c) 2012 Gregory Estrade
   3 * This code is licensed under the GNU GPLv2 and later.
   4 */
   5
   6#include "qemu/osdep.h"
   7#include "qapi/error.h"
   8#include "hw/dma/bcm2835_dma.h"
   9#include "qemu/log.h"
  10
  11/* DMA CS Control and Status bits */
  12#define BCM2708_DMA_ACTIVE      (1 << 0)
  13#define BCM2708_DMA_END         (1 << 1) /* GE */
  14#define BCM2708_DMA_INT         (1 << 2)
  15#define BCM2708_DMA_ISPAUSED    (1 << 4)  /* Pause requested or not active */
  16#define BCM2708_DMA_ISHELD      (1 << 5)  /* Is held by DREQ flow control */
  17#define BCM2708_DMA_ERR         (1 << 8)
  18#define BCM2708_DMA_ABORT       (1 << 30) /* stop current CB, go to next, WO */
  19#define BCM2708_DMA_RESET       (1 << 31) /* WO, self clearing */
  20
  21/* DMA control block "info" field bits */
  22#define BCM2708_DMA_INT_EN      (1 << 0)
  23#define BCM2708_DMA_TDMODE      (1 << 1)
  24#define BCM2708_DMA_WAIT_RESP   (1 << 3)
  25#define BCM2708_DMA_D_INC       (1 << 4)
  26#define BCM2708_DMA_D_WIDTH     (1 << 5)
  27#define BCM2708_DMA_D_DREQ      (1 << 6)
  28#define BCM2708_DMA_D_IGNORE    (1 << 7)
  29#define BCM2708_DMA_S_INC       (1 << 8)
  30#define BCM2708_DMA_S_WIDTH     (1 << 9)
  31#define BCM2708_DMA_S_DREQ      (1 << 10)
  32#define BCM2708_DMA_S_IGNORE    (1 << 11)
  33
  34/* Register offsets */
  35#define BCM2708_DMA_CS          0x00 /* Control and Status */
  36#define BCM2708_DMA_ADDR        0x04 /* Control block address */
  37/* the current control block appears in the following registers - read only */
  38#define BCM2708_DMA_INFO        0x08
  39#define BCM2708_DMA_SOURCE_AD   0x0c
  40#define BCM2708_DMA_DEST_AD     0x10
  41#define BCM2708_DMA_TXFR_LEN    0x14
  42#define BCM2708_DMA_STRIDE      0x18
  43#define BCM2708_DMA_NEXTCB      0x1C
  44#define BCM2708_DMA_DEBUG       0x20
  45
  46#define BCM2708_DMA_INT_STATUS  0xfe0 /* Interrupt status of each channel */
  47#define BCM2708_DMA_ENABLE      0xff0 /* Global enable bits for each channel */
  48
  49#define BCM2708_DMA_CS_RW_MASK  0x30ff0001 /* All RW bits in DMA_CS */
  50
  51static void bcm2835_dma_update(BCM2835DMAState *s, unsigned c)
  52{
  53    BCM2835DMAChan *ch = &s->chan[c];
  54    uint32_t data, xlen, ylen;
  55    int16_t dst_stride, src_stride;
  56
  57    if (!(s->enable & (1 << c))) {
  58        return;
  59    }
  60
  61    while ((s->enable & (1 << c)) && (ch->conblk_ad != 0)) {
  62        /* CB fetch */
  63        ch->ti = ldl_le_phys(&s->dma_as, ch->conblk_ad);
  64        ch->source_ad = ldl_le_phys(&s->dma_as, ch->conblk_ad + 4);
  65        ch->dest_ad = ldl_le_phys(&s->dma_as, ch->conblk_ad + 8);
  66        ch->txfr_len = ldl_le_phys(&s->dma_as, ch->conblk_ad + 12);
  67        ch->stride = ldl_le_phys(&s->dma_as, ch->conblk_ad + 16);
  68        ch->nextconbk = ldl_le_phys(&s->dma_as, ch->conblk_ad + 20);
  69
  70        if (ch->ti & BCM2708_DMA_TDMODE) {
  71            /* 2D transfer mode */
  72            ylen = (ch->txfr_len >> 16) & 0x3fff;
  73            xlen = ch->txfr_len & 0xffff;
  74            dst_stride = ch->stride >> 16;
  75            src_stride = ch->stride & 0xffff;
  76        } else {
  77            ylen = 1;
  78            xlen = ch->txfr_len;
  79            dst_stride = 0;
  80            src_stride = 0;
  81        }
  82
  83        while (ylen != 0) {
  84            /* Normal transfer mode */
  85            while (xlen != 0) {
  86                if (ch->ti & BCM2708_DMA_S_IGNORE) {
  87                    /* Ignore reads */
  88                    data = 0;
  89                } else {
  90                    data = ldl_le_phys(&s->dma_as, ch->source_ad);
  91                }
  92                if (ch->ti & BCM2708_DMA_S_INC) {
  93                    ch->source_ad += 4;
  94                }
  95
  96                if (ch->ti & BCM2708_DMA_D_IGNORE) {
  97                    /* Ignore writes */
  98                } else {
  99                    stl_le_phys(&s->dma_as, ch->dest_ad, data);
 100                }
 101                if (ch->ti & BCM2708_DMA_D_INC) {
 102                    ch->dest_ad += 4;
 103                }
 104
 105                /* update remaining transfer length */
 106                xlen -= 4;
 107                if (ch->ti & BCM2708_DMA_TDMODE) {
 108                    ch->txfr_len = (ylen << 16) | xlen;
 109                } else {
 110                    ch->txfr_len = xlen;
 111                }
 112            }
 113
 114            if (--ylen != 0) {
 115                ch->source_ad += src_stride;
 116                ch->dest_ad += dst_stride;
 117            }
 118        }
 119        ch->cs |= BCM2708_DMA_END;
 120        if (ch->ti & BCM2708_DMA_INT_EN) {
 121            ch->cs |= BCM2708_DMA_INT;
 122            s->int_status |= (1 << c);
 123            qemu_set_irq(ch->irq, 1);
 124        }
 125
 126        /* Process next CB */
 127        ch->conblk_ad = ch->nextconbk;
 128    }
 129
 130    ch->cs &= ~BCM2708_DMA_ACTIVE;
 131    ch->cs |= BCM2708_DMA_ISPAUSED;
 132}
 133
 134static void bcm2835_dma_chan_reset(BCM2835DMAChan *ch)
 135{
 136    ch->cs = 0;
 137    ch->conblk_ad = 0;
 138}
 139
 140static uint64_t bcm2835_dma_read(BCM2835DMAState *s, hwaddr offset,
 141                                 unsigned size, unsigned c)
 142{
 143    BCM2835DMAChan *ch;
 144    uint32_t res = 0;
 145
 146    assert(size == 4);
 147    assert(c < BCM2835_DMA_NCHANS);
 148
 149    ch = &s->chan[c];
 150
 151    switch (offset) {
 152    case BCM2708_DMA_CS:
 153        res = ch->cs;
 154        break;
 155    case BCM2708_DMA_ADDR:
 156        res = ch->conblk_ad;
 157        break;
 158    case BCM2708_DMA_INFO:
 159        res = ch->ti;
 160        break;
 161    case BCM2708_DMA_SOURCE_AD:
 162        res = ch->source_ad;
 163        break;
 164    case BCM2708_DMA_DEST_AD:
 165        res = ch->dest_ad;
 166        break;
 167    case BCM2708_DMA_TXFR_LEN:
 168        res = ch->txfr_len;
 169        break;
 170    case BCM2708_DMA_STRIDE:
 171        res = ch->stride;
 172        break;
 173    case BCM2708_DMA_NEXTCB:
 174        res = ch->nextconbk;
 175        break;
 176    case BCM2708_DMA_DEBUG:
 177        res = ch->debug;
 178        break;
 179    default:
 180        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
 181                      __func__, offset);
 182        break;
 183    }
 184    return res;
 185}
 186
 187static void bcm2835_dma_write(BCM2835DMAState *s, hwaddr offset,
 188                              uint64_t value, unsigned size, unsigned c)
 189{
 190    BCM2835DMAChan *ch;
 191    uint32_t oldcs;
 192
 193    assert(size == 4);
 194    assert(c < BCM2835_DMA_NCHANS);
 195
 196    ch = &s->chan[c];
 197
 198    switch (offset) {
 199    case BCM2708_DMA_CS:
 200        oldcs = ch->cs;
 201        if (value & BCM2708_DMA_RESET) {
 202            bcm2835_dma_chan_reset(ch);
 203        }
 204        if (value & BCM2708_DMA_ABORT) {
 205            /* abort is a no-op, since we always run to completion */
 206        }
 207        if (value & BCM2708_DMA_END) {
 208            ch->cs &= ~BCM2708_DMA_END;
 209        }
 210        if (value & BCM2708_DMA_INT) {
 211            ch->cs &= ~BCM2708_DMA_INT;
 212            s->int_status &= ~(1 << c);
 213            qemu_set_irq(ch->irq, 0);
 214        }
 215        ch->cs &= ~BCM2708_DMA_CS_RW_MASK;
 216        ch->cs |= (value & BCM2708_DMA_CS_RW_MASK);
 217        if (!(oldcs & BCM2708_DMA_ACTIVE) && (ch->cs & BCM2708_DMA_ACTIVE)) {
 218            bcm2835_dma_update(s, c);
 219        }
 220        break;
 221    case BCM2708_DMA_ADDR:
 222        ch->conblk_ad = value;
 223        break;
 224    case BCM2708_DMA_DEBUG:
 225        ch->debug = value;
 226        break;
 227    default:
 228        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
 229                      __func__, offset);
 230        break;
 231    }
 232}
 233
 234static uint64_t bcm2835_dma0_read(void *opaque, hwaddr offset, unsigned size)
 235{
 236    BCM2835DMAState *s = opaque;
 237
 238    if (offset < 0xf00) {
 239        return bcm2835_dma_read(s, (offset & 0xff), size, (offset >> 8) & 0xf);
 240    } else {
 241        switch (offset) {
 242        case BCM2708_DMA_INT_STATUS:
 243            return s->int_status;
 244        case BCM2708_DMA_ENABLE:
 245            return s->enable;
 246        default:
 247            qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
 248                          __func__, offset);
 249            return 0;
 250        }
 251    }
 252}
 253
 254static uint64_t bcm2835_dma15_read(void *opaque, hwaddr offset, unsigned size)
 255{
 256    return bcm2835_dma_read(opaque, (offset & 0xff), size, 15);
 257}
 258
 259static void bcm2835_dma0_write(void *opaque, hwaddr offset, uint64_t value,
 260                               unsigned size)
 261{
 262    BCM2835DMAState *s = opaque;
 263
 264    if (offset < 0xf00) {
 265        bcm2835_dma_write(s, (offset & 0xff), value, size, (offset >> 8) & 0xf);
 266    } else {
 267        switch (offset) {
 268        case BCM2708_DMA_INT_STATUS:
 269            break;
 270        case BCM2708_DMA_ENABLE:
 271            s->enable = (value & 0xffff);
 272            break;
 273        default:
 274            qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
 275                          __func__, offset);
 276        }
 277    }
 278
 279}
 280
 281static void bcm2835_dma15_write(void *opaque, hwaddr offset, uint64_t value,
 282                                unsigned size)
 283{
 284    bcm2835_dma_write(opaque, (offset & 0xff), value, size, 15);
 285}
 286
 287static const MemoryRegionOps bcm2835_dma0_ops = {
 288    .read = bcm2835_dma0_read,
 289    .write = bcm2835_dma0_write,
 290    .endianness = DEVICE_NATIVE_ENDIAN,
 291    .valid.min_access_size = 4,
 292    .valid.max_access_size = 4,
 293};
 294
 295static const MemoryRegionOps bcm2835_dma15_ops = {
 296    .read = bcm2835_dma15_read,
 297    .write = bcm2835_dma15_write,
 298    .endianness = DEVICE_NATIVE_ENDIAN,
 299    .valid.min_access_size = 4,
 300    .valid.max_access_size = 4,
 301};
 302
 303static const VMStateDescription vmstate_bcm2835_dma_chan = {
 304    .name = TYPE_BCM2835_DMA "-chan",
 305    .version_id = 1,
 306    .minimum_version_id = 1,
 307    .fields = (VMStateField[]) {
 308        VMSTATE_UINT32(cs, BCM2835DMAChan),
 309        VMSTATE_UINT32(conblk_ad, BCM2835DMAChan),
 310        VMSTATE_UINT32(ti, BCM2835DMAChan),
 311        VMSTATE_UINT32(source_ad, BCM2835DMAChan),
 312        VMSTATE_UINT32(dest_ad, BCM2835DMAChan),
 313        VMSTATE_UINT32(txfr_len, BCM2835DMAChan),
 314        VMSTATE_UINT32(stride, BCM2835DMAChan),
 315        VMSTATE_UINT32(nextconbk, BCM2835DMAChan),
 316        VMSTATE_UINT32(debug, BCM2835DMAChan),
 317        VMSTATE_END_OF_LIST()
 318    }
 319};
 320
 321static const VMStateDescription vmstate_bcm2835_dma = {
 322    .name = TYPE_BCM2835_DMA,
 323    .version_id = 1,
 324    .minimum_version_id = 1,
 325    .fields = (VMStateField[]) {
 326        VMSTATE_STRUCT_ARRAY(chan, BCM2835DMAState, BCM2835_DMA_NCHANS, 1,
 327                             vmstate_bcm2835_dma_chan, BCM2835DMAChan),
 328        VMSTATE_UINT32(int_status, BCM2835DMAState),
 329        VMSTATE_UINT32(enable, BCM2835DMAState),
 330        VMSTATE_END_OF_LIST()
 331    }
 332};
 333
 334static void bcm2835_dma_init(Object *obj)
 335{
 336    BCM2835DMAState *s = BCM2835_DMA(obj);
 337    int n;
 338
 339    /* DMA channels 0-14 occupy a contiguous block of IO memory, along
 340     * with the global enable and interrupt status bits. Channel 15
 341     * has the same register map, but is mapped at a discontiguous
 342     * address in a separate IO block.
 343     */
 344    memory_region_init_io(&s->iomem0, OBJECT(s), &bcm2835_dma0_ops, s,
 345                          TYPE_BCM2835_DMA, 0x1000);
 346    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem0);
 347
 348    memory_region_init_io(&s->iomem15, OBJECT(s), &bcm2835_dma15_ops, s,
 349                          TYPE_BCM2835_DMA "-chan15", 0x100);
 350    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem15);
 351
 352    for (n = 0; n < 16; n++) {
 353        sysbus_init_irq(SYS_BUS_DEVICE(s), &s->chan[n].irq);
 354    }
 355}
 356
 357static void bcm2835_dma_reset(DeviceState *dev)
 358{
 359    BCM2835DMAState *s = BCM2835_DMA(dev);
 360    int n;
 361
 362    s->enable = 0xffff;
 363    s->int_status = 0;
 364    for (n = 0; n < BCM2835_DMA_NCHANS; n++) {
 365        bcm2835_dma_chan_reset(&s->chan[n]);
 366    }
 367}
 368
 369static void bcm2835_dma_realize(DeviceState *dev, Error **errp)
 370{
 371    BCM2835DMAState *s = BCM2835_DMA(dev);
 372    Error *err = NULL;
 373    Object *obj;
 374
 375    obj = object_property_get_link(OBJECT(dev), "dma-mr", &err);
 376    if (obj == NULL) {
 377        error_setg(errp, "%s: required dma-mr link not found: %s",
 378                   __func__, error_get_pretty(err));
 379        return;
 380    }
 381
 382    s->dma_mr = MEMORY_REGION(obj);
 383    address_space_init(&s->dma_as, s->dma_mr, NULL);
 384
 385    bcm2835_dma_reset(dev);
 386}
 387
 388static void bcm2835_dma_class_init(ObjectClass *klass, void *data)
 389{
 390    DeviceClass *dc = DEVICE_CLASS(klass);
 391
 392    dc->realize = bcm2835_dma_realize;
 393    dc->reset = bcm2835_dma_reset;
 394    dc->vmsd = &vmstate_bcm2835_dma;
 395}
 396
 397static TypeInfo bcm2835_dma_info = {
 398    .name          = TYPE_BCM2835_DMA,
 399    .parent        = TYPE_SYS_BUS_DEVICE,
 400    .instance_size = sizeof(BCM2835DMAState),
 401    .class_init    = bcm2835_dma_class_init,
 402    .instance_init = bcm2835_dma_init,
 403};
 404
 405static void bcm2835_dma_register_types(void)
 406{
 407    type_register_static(&bcm2835_dma_info);
 408}
 409
 410type_init(bcm2835_dma_register_types)
 411