VPDMA_DESC_ALIGN
WARN_ON(((unsigned long)buf->addr & VPDMA_DESC_ALIGN) != 0);
WARN_ON(blk->dma_addr & VPDMA_DESC_ALIGN);
WARN_ON(adb->dma_addr & VPDMA_DESC_ALIGN);
w_align = roundup_pow_of_two(VPDMA_DESC_ALIGN / depth_bytes);