VFF_RING_SIZE 171 drivers/dma/mediatek/mtk-uart-apdma.c if ((wpt & VFF_RING_SIZE) == vff_sz) VFF_RING_SIZE 237 drivers/dma/mediatek/mtk-uart-apdma.c cnt = (wg & VFF_RING_SIZE) - (rg & VFF_RING_SIZE);