DMA_BUF_SYNC_WRITE
usage = dma_resv_usage_rw(arg.flags & DMA_BUF_SYNC_WRITE);
usage = (arg.flags & DMA_BUF_SYNC_WRITE) ? DMA_RESV_USAGE_WRITE :
case DMA_BUF_SYNC_WRITE:
#define DMA_BUF_SYNC_RW (DMA_BUF_SYNC_READ | DMA_BUF_SYNC_WRITE)
sync.flags = DMA_BUF_SYNC_START | DMA_BUF_SYNC_WRITE;
sync.flags = DMA_BUF_SYNC_END | DMA_BUF_SYNC_WRITE;