linux-kernel - [PATCH v3 07/14] serial: liteuart: rx loop should only ack rx events

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Message-Id: <20221112212125.448824-8-gsomlo@gmail.com>
Date:   Sat, 12 Nov 2022 16:21:18 -0500
From:   Gabriel Somlo <gsomlo@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-serial@...r.kernel.org, gregkh@...uxfoundation.org,
        jirislaby@...nel.org, kgugala@...micro.com, mholenko@...micro.com,
        joel@....id.au, david.abdurachmanov@...il.com,
        florent@...oy-digital.fr, geert@...ux-m68k.org
Subject: [PATCH v3 07/14] serial: liteuart: rx loop should only ack rx events

While receiving characters, it is necessary to acknowledge each one
by writing to the EV_PENDING register's EV_RX bit. Ensure we do not
also gratuitously set the EV_TX bit in the process.

Signed-off-by: Gabriel Somlo <gsomlo@...il.com>
---
 drivers/tty/serial/liteuart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
index ff3486860989..b5ab48aa35cf 100644
--- a/drivers/tty/serial/liteuart.c
+++ b/drivers/tty/serial/liteuart.c
@@ -81,7 +81,7 @@ static void liteuart_timer(struct timer_list *t)
 		port->icount.rx++;
 
 		/* necessary for RXEMPTY to refresh its value */
-		litex_write8(membase + OFF_EV_PENDING, EV_TX | EV_RX);
+		litex_write8(membase + OFF_EV_PENDING, EV_RX);
 
 		/* no overflow bits in status */
 		if (!(uart_handle_sysrq_char(port, ch)))
-- 
2.37.3