Commit 88679739 authored Nov 18, 2015 by Ben Dooks Committed by Greg Kroah-Hartman Dec 13, 2015

ARM: meson: serial: tx_empty fails to check for transmitter busy



The tx_empty() uart_op should only return empty if both the transmit fifo
and the transmit state-machine are both idle. Add a test for the hardware's
XMIT_BUSY flag.

Note, this is possibly related to an issue where the port is being shutdown
with paritally transmitted characters in it.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reported-by: Edward Cragg <edward.cragg@codethink.co.uk>
Tested-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 00661dd8

drivers/tty/serial/meson_uart.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -57,6 +57,7 @@
		#define AML_UART_RX_EMPTY BIT(20)
		#define AML_UART_TX_FULL BIT(21)
		#define AML_UART_TX_EMPTY BIT(22)
		#define AML_UART_XMIT_BUSY BIT(25)
		#define AML_UART_ERR (AML_UART_PARITY_ERR \| \
		AML_UART_FRAME_ERR \| \
		AML_UART_TX_FIFO_WERR)
		@@ -100,7 +101,8 @@ static unsigned int meson_uart_tx_empty(struct uart_port *port)
		u32 val;

		val = readl(port->membase + AML_UART_STATUS);
		return (val & AML_UART_TX_EMPTY) ? TIOCSER_TEMT : 0;
		val &= (AML_UART_TX_EMPTY \| AML_UART_XMIT_BUSY);
		return (val == AML_UART_TX_EMPTY) ? TIOCSER_TEMT : 0;
		}

		static void meson_uart_stop_tx(struct uart_port *port)