From 9c12d739d69b80847e99d24692ff20de993bf172 Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Tue, 14 May 2019 13:14:15 +0300 Subject: [PATCH] tty: max310x: Split uart characters insertion loop Batch read mode doesn't check any conditions or flags except the Rx overflow one. But it may only happen after the last character is pushed into the RHR register. In this case we shouldn't push all the read characters with overrun flag set, but only the last one caused the FIFO overflow. This commit splits the characters retrieval loop into two parts. First one is ordinary intsert-chars procedure without taking the overrun status into account. Second part inserts the last character checking whether the overrun happened and pushing a '\0' character with TTY_OVERRUN flag to a flip-buffer. If we left the loop the way it was the '\0' character would be inserted after each character retrieved at the overrun occasion. Signed-off-by: Serge Semin Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/max310x.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index 36943f6..81b2413 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -680,10 +680,16 @@ static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen) port->icount.overrun++; } - for (i = 0; i < rxlen; ++i) { - uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, - one->rx_buf[i], flag); - } + for (i = 0; i < (rxlen - 1); ++i) + uart_insert_char(port, sts, 0, one->rx_buf[i], flag); + + /* + * Handle the overrun case for the last character only, since + * the RxFIFO overflow happens after it is pushed to the FIFO + * tail. + */ + uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, + one->rx_buf[rxlen], flag); } else { if (unlikely(rxlen >= port->fifosize)) { -- 2.7.4