tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped
commit 69646d7a3689fbe1a65ae90397d22ac3f1b8d40f upstream. In half-duplex operation, RX should be started after TX completes. If DMA is used, there is a case when the DMA transfer completes but the TX FIFO is not emptied, so the RX cannot be restarted just yet. Use a boolean variable to store this state and rearm TX interrupt mask to be signaled again that the transfer finished. In interrupt transmit handler this variable is used to start RX. A warning message is generated if RX is activated before TX fifo is cleared. Fixes: b389f173 ("tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done") Signed-off-by: NRazvan Stefanescu <razvan.stefanescu@microchip.com> Acked-by: NRichard Genoud <richard.genoud@gmail.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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