Fixes missing characters on kernel console at low baud rates (i.e.9600).
The driver should poll TX_RDY or TX_FIFO_EMP instead of TX_EMP to ensure
that the transmitter holding register (THR) is ready to receive a new byte.
TX_EMP tells us when it is possible to send a break sequence via
SND_BRK_SEQ. While this also indicates that both the THR and the TSR are
empty, it does not guarantee that a new byte can be written just yet.
Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port")
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Gabriel Matni <gabriel.matni@exfo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
u32 val;
readl_poll_timeout_atomic(port->membase + UART_STAT, val,
- (val & STAT_TX_EMP), 1, 10000);
+ (val & STAT_TX_RDY(port)), 1, 10000);
}
static void mvebu_uart_console_putchar(struct uart_port *port, int ch)