[PATCH v2] tty/serial/8250: fix RS485 half-duplex RX

Subsystems: 8250/16?50 (and clone uarts) serial driver, the rest, tty layer and serial drivers

STALE3813d

3 messages, 2 authors, 2016-03-31 · open the first message on its own page

[PATCH v2] tty/serial/8250: fix RS485 half-duplex RX

From: <hidden>
Date: 2016-03-24 08:05:21 

From: Yegor Yefremov <redacted>

When in half-duplex mode RX will be disabled before TX, but not
enabled after deactivating transmitter. This patch enables
UART_IER_RLSI and UART_IER_RDI interrupts after TX is over.

Cc: Matwey V. Kornilov <redacted>
Signed-off-by: Yegor Yefremov <redacted>
Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
---
Changes:
	v2: change subject and add 'Fixes' tag

 drivers/tty/serial/8250/8250_port.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index e213da0..00ad263 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1403,9 +1403,18 @@ static void __do_stop_tx_rs485(struct uart_8250_port *p)
 	/*
 	 * Empty the RX FIFO, we are not interested in anything
 	 * received during the half-duplex transmission.
+	 * Enable previously disabled RX interrupts.
 	 */
-	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX))
+	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
 		serial8250_clear_fifos(p);
+
+		serial8250_rpm_get(p);
+
+		p->ier |= UART_IER_RLSI | UART_IER_RDI;
+		serial_port_out(&p->port, UART_IER, p->ier);
+
+		serial8250_rpm_put(p);
+	}
 }
 
 static void serial8250_em485_handle_stop_tx(unsigned long arg)
-- 
2.1.4

Re: [PATCH v2] tty/serial/8250: fix RS485 half-duplex RX

From: Yegor Yefremov <hidden>
Date: 2016-03-31 05:23:17 

On Thu, Mar 24, 2016 at 9:03 AM,  [off-list ref] wrote:
From: Yegor Yefremov <redacted>

When in half-duplex mode RX will be disabled before TX, but not
enabled after deactivating transmitter. This patch enables
UART_IER_RLSI and UART_IER_RDI interrupts after TX is over.

Cc: Matwey V. Kornilov <redacted>
Signed-off-by: Yegor Yefremov <redacted>
Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
Transferring from Acked-by from v1:

Acked-by: Matwey V. Kornilov <redacted>
quoted hunk
---
Changes:
        v2: change subject and add 'Fixes' tag

 drivers/tty/serial/8250/8250_port.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index e213da0..00ad263 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1403,9 +1403,18 @@ static void __do_stop_tx_rs485(struct uart_8250_port *p)
        /*
         * Empty the RX FIFO, we are not interested in anything
         * received during the half-duplex transmission.
+        * Enable previously disabled RX interrupts.
         */
-       if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX))
+       if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
                serial8250_clear_fifos(p);
+
+               serial8250_rpm_get(p);
+
+               p->ier |= UART_IER_RLSI | UART_IER_RDI;
+               serial_port_out(&p->port, UART_IER, p->ier);
+
+               serial8250_rpm_put(p);
+       }
 }

 static void serial8250_em485_handle_stop_tx(unsigned long arg)
--
2.1.4

Re: [PATCH v2] tty/serial/8250: fix RS485 half-duplex RX

From: Matwey V. Kornilov <hidden>
Date: 2016-03-31 08:10:43 

2016-03-24 11:03 GMT+03:00  [off-list ref]:
From: Yegor Yefremov <redacted>

When in half-duplex mode RX will be disabled before TX, but not
enabled after deactivating transmitter. This patch enables
UART_IER_RLSI and UART_IER_RDI interrupts after TX is over.

Cc: Matwey V. Kornilov <redacted>
Signed-off-by: Yegor Yefremov <redacted>
Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
Acked-by: Matwey V. Kornilov <redacted>
quoted hunk
---
Changes:
        v2: change subject and add 'Fixes' tag

 drivers/tty/serial/8250/8250_port.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index e213da0..00ad263 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1403,9 +1403,18 @@ static void __do_stop_tx_rs485(struct uart_8250_port *p)
        /*
         * Empty the RX FIFO, we are not interested in anything
         * received during the half-duplex transmission.
+        * Enable previously disabled RX interrupts.
         */
-       if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX))
+       if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
                serial8250_clear_fifos(p);
+
+               serial8250_rpm_get(p);
+
+               p->ier |= UART_IER_RLSI | UART_IER_RDI;
+               serial_port_out(&p->port, UART_IER, p->ier);
+
+               serial8250_rpm_put(p);
+       }
 }

 static void serial8250_em485_handle_stop_tx(unsigned long arg)
--
2.1.4


-- 
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382
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