READAHEAD_RING_LEN
static int imxuart_readahead[READAHEAD_RING_LEN];
(((imxuart_readahead_in+1) & (READAHEAD_RING_LEN-1)) ==imxuart_readahead_out)
(READAHEAD_RING_LEN-1);
(READAHEAD_RING_LEN-1);
static int zynquart_readahead[READAHEAD_RING_LEN];
(((zynquart_readahead_in+1) & (READAHEAD_RING_LEN-1)) ==zynquart_readahead_out)
(READAHEAD_RING_LEN-1);
(READAHEAD_RING_LEN-1);