xiongyu cf3b2df4a4 bugfix(uart): fix esp32 fifo_cnt bug
When using DPort to read fifo, fifo_cnt is not credible, we need to calculate the real cnt based on the fifo read and write pointer. When using AHB to read FIFO, we can use fifo_cnt to indicate the data length in fifo.
2020-06-16 14:48:02 +08:00
..
2019-06-11 13:06:32 +08:00