V3D_SLOT_SIZE
#define V3D_VRAM_MMAP_OFF ((off_t)V3D_RING_SLOTS * V3D_SLOT_SIZE)
error = bus_dmamem_alloc(sc->sc_dmat, V3D_SLOT_SIZE,
1, V3D_SLOT_SIZE, (void **)&sc->sc_v3d_slot[s],
error = bus_dmamap_create(sc->sc_dmat, V3D_SLOT_SIZE, 1,
V3D_SLOT_SIZE, 0, BUS_DMA_WAITOK,
sc->sc_v3d_slot[s], V3D_SLOT_SIZE, NULL, BUS_DMA_WAITOK);
s = (int)(off / V3D_SLOT_SIZE);
off % V3D_SLOT_SIZE, prot, 0);
vs->vs_len == 0 || vs->vs_len > V3D_SLOT_SIZE ||