We use the IMX6 processor for some time now. But recently, we need use one uart port at 460800 baud, and then, we found some system error message said Rx FIFO overrun. We check the drivers code repeatedly, and make some test for it, but we have no idea for this issue. Anyway, if the baud is larger than 115200, like 230400, the Rx FIFO always overrun. We attempt to disable all function unused, just remain some necessities about uart, but it not worked.
By the way, we have a platform used the IMX535 processor run same baud on uart, but it seemed everything is OK.
On the other side, we update some later driver code, it also can not fix this. Our Linux kernel is 3.10.7.