serial: exynos: apply TX MASK scheme in tx irq

When tty circ_buffer go to START from END, circ_buffer has residual tx data from START to HEAD. But tx interrupt handler clears tx irq pending and quits irq handler. So, tx irq handler never called until start_tx function is called by another process. TX MASK scheme is MASKING INTR in front side of tx handler and UNMASK at back side of tx handler. TX UNMASKING can make new tx pending and new tx irq handler is called to flush circ_buffer. Change-Id: I71b476c7546fca25291e0c12ab44c1c1f20cdd7a Signed-off-by: myung-su.cha <[email protected]> Signed-off-by: Hyunki Koo <[email protected]>
celtare21 · May 4, 2021 · d3a5135 · d3a5135
1 parent a67dd5c
commit d3a5135
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/drivers/tty/serial/exynos_tty.c b/drivers/tty/serial/exynos_tty.c
@@ -1201,6 +1201,9 @@ static irqreturn_t exynos_serial_tx_chars(int irq, void *id)
 
 	spin_lock_irqsave(&port->lock, flags);
 
+	exynos_set_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM);
+	wr_regl(port, S3C64XX_UINTP, S3C64XX_UINTM_TXD_MSK);
+
 	count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 
 	if (ourport->dma && ourport->dma->tx_chan &&
@@ -1265,7 +1268,9 @@ static irqreturn_t exynos_serial_tx_chars(int irq, void *id)
 		exynos_serial_stop_tx(port);
 
 out:
-	wr_regl(port, S3C64XX_UINTP, S3C64XX_UINTM_TXD_MSK);
+	if (ourport->tx_enabled)
+		exynos_clear_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM);
+
 	if (ourport->uart_logging && trace_cnt)
 		uart_copy_to_local_buf(0, &ourport->uart_local_buf, trace_buf,
 				       trace_cnt);