static uint64_t bmdma_read(void *opaque, hwaddr addr, unsigned size)
{
    BMDMAState *bm = opaque;
    uint32_t val;

    if (size != 1) {
        return ((uint64_t)1 << (size * 8)) - 1;
    }

    switch(addr & 3) {
    case 0:
        val = bm->cmd;
        break;
    case 2:
        val = bm->status;
        break;
    default:
        val = 0xff;
        break;
    }
#ifdef DEBUG_IDE
    printf("bmdma: readb 0x%02x : 0x%02x\n", (uint8_t)addr, val);
#endif
    return val;
}