From: Alexandre Belloni <alexandre.belloni@free-electrons.com> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Nicolas Ferre <nicolas.ferre@atmel.com> Cc: linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexandre Belloni <alexandre.belloni@free-electrons.com> Subject: [PATCH] tty/serial: atmel: fix RS485 half duplex with DMA Date: Sat, 28 May 2016 00:54:08 +0200 [thread overview] Message-ID: <1464389648-4820-1-git-send-email-alexandre.belloni@free-electrons.com> (raw) When using DMA, half duplex doesn't work properly because rx is not stopped before starting tx. Ensure we call atmel_stop_rx() in the DMA case. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> --- drivers/tty/serial/atmel_serial.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 954941dd8124..f9c798cba83f 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -482,19 +482,21 @@ static void atmel_start_tx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); - if (atmel_use_pdc_tx(port)) { - if (atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN) - /* The transmitter is already running. Yes, we - really need this.*/ - return; + if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR) + & ATMEL_PDC_TXTEN)) + /* The transmitter is already running. Yes, we + really need this.*/ + return; + if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port)) if ((port->rs485.flags & SER_RS485_ENABLED) && !(port->rs485.flags & SER_RS485_RX_DURING_TX)) atmel_stop_rx(port); + if (atmel_use_pdc_tx(port)) /* re-enable PDC transmit */ atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN); - } + /* Enable interrupts */ atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask); } -- 2.8.1
WARNING: multiple messages have this Message-ID (diff)
From: alexandre.belloni@free-electrons.com (Alexandre Belloni) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] tty/serial: atmel: fix RS485 half duplex with DMA Date: Sat, 28 May 2016 00:54:08 +0200 [thread overview] Message-ID: <1464389648-4820-1-git-send-email-alexandre.belloni@free-electrons.com> (raw) When using DMA, half duplex doesn't work properly because rx is not stopped before starting tx. Ensure we call atmel_stop_rx() in the DMA case. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> --- drivers/tty/serial/atmel_serial.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 954941dd8124..f9c798cba83f 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -482,19 +482,21 @@ static void atmel_start_tx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); - if (atmel_use_pdc_tx(port)) { - if (atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN) - /* The transmitter is already running. Yes, we - really need this.*/ - return; + if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR) + & ATMEL_PDC_TXTEN)) + /* The transmitter is already running. Yes, we + really need this.*/ + return; + if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port)) if ((port->rs485.flags & SER_RS485_ENABLED) && !(port->rs485.flags & SER_RS485_RX_DURING_TX)) atmel_stop_rx(port); + if (atmel_use_pdc_tx(port)) /* re-enable PDC transmit */ atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN); - } + /* Enable interrupts */ atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask); } -- 2.8.1
next reply other threads:[~2016-05-27 22:54 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-05-27 22:54 Alexandre Belloni [this message] 2016-05-27 22:54 ` [PATCH] tty/serial: atmel: fix RS485 half duplex with DMA Alexandre Belloni 2016-06-02 10:41 ` Nicolas Ferre 2016-06-02 10:41 ` Nicolas Ferre 2016-06-02 10:41 ` Nicolas Ferre 2016-06-13 9:51 ` Nicolas Ferre 2016-06-13 9:51 ` Nicolas Ferre 2016-06-13 9:51 ` Nicolas Ferre
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