ARM: meson: serial: ensure tx irq on if more work to do

The tx_stop() call turns the interrupt off, but the tx_start() does not
check if the interrupt is enabled. Switch it back on if there is more
work to do.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
index 12436cceebb7..6c365267e26a 100644
--- a/drivers/tty/serial/meson_uart.c
+++ b/drivers/tty/serial/meson_uart.c
@@ -144,6 +144,7 @@ static void meson_uart_start_tx(struct uart_port *port)
 {
         struct circ_buf *xmit = &port->state->xmit;
         unsigned int ch;
+        u32 val;
 
         if (uart_tx_stopped(port)) {
                 meson_uart_stop_tx(port);
@@ -167,6 +168,12 @@ static void meson_uart_start_tx(struct uart_port *port)
                 port->icount.tx++;
         }
 
+        if (!uart_circ_empty(xmit)) {
+                val = readl(port->membase + AML_UART_CONTROL);
+                val |= AML_UART_TX_INT_EN;
+                writel(val, port->membase + AML_UART_CONTROL);
+        }
+
         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                 uart_write_wakeup(port);
 }