linux-kernel - [PATCH 6/7] serial: imx: update the stop rx,tx procedures

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Message-Id: <20170630120446.13994-7-romain.perier@collabora.com>
Date:   Fri, 30 Jun 2017 14:04:45 +0200
From:   Romain Perier <romain.perier@...labora.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-serial@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Nandor Han <nandor.han@...com>,
        Romain Perier <romain.perier@...labora.com>
Subject: [PATCH 6/7] serial: imx: update the stop rx,tx procedures

From: Nandor Han <nandor.han@...com>

According to "Documentation/serial/driver" both procedures should stop
receiving or sending data. Based on this the procedures should stop the
activity regardless if DMA is enabled or not.

This commit updates both imx_stop_{rx|tx} procedures to stop the
activity and disable the interrupts related to that. In case DMA is used
the sg buffers are also un-maped.

Signed-off-by: Nandor Han <nandor.han@...com>
Signed-off-by: Romain Perier <romain.perier@...labora.com>
---
 drivers/tty/serial/imx.c | 39 ++++++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 58d6b1c..d5b6e09 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -360,6 +360,9 @@ static void imx_port_rts_auto(struct imx_port *sport, unsigned long *ucr2)
 	*ucr2 |= UCR2_CTSC;
 }
 
+static void imx_stop_rx_dma(struct imx_port *sport);
+static void imx_stop_tx_dma(struct imx_port *sport);
+
 /*
  * interrupts disabled on entry
  */
@@ -368,15 +371,14 @@ static void imx_stop_tx(struct uart_port *port)
 	struct imx_port *sport = (struct imx_port *)port;
 	unsigned long temp;
 
-	/*
-	 * We are maybe in the SMP context, so if the DMA TX thread is running
-	 * on other cpu, we have to wait for it to finish.
-	 */
-	if (sport->dma_is_enabled && sport->dma_is_txing)
-		return;
+	sport->tx_bytes = 0;
+
+	if (sport->dma_is_enabled)
+		imx_stop_tx_dma(sport);
 
 	temp = readl(port->membase + UCR1);
-	writel(temp & ~UCR1_TXMPTYEN, port->membase + UCR1);
+	temp &= ~(UCR1_TXMPTYEN | UCR1_TRDYEN | UCR1_RTSDEN);
+	writel(temp, port->membase + UCR1);
 
 	/* in rs485 mode disable transmitter if shifter is empty */
 	if (port->rs485.flags & SER_RS485_ENABLED &&
@@ -403,21 +405,20 @@ static void imx_stop_rx(struct uart_port *port)
 	struct imx_port *sport = (struct imx_port *)port;
 	unsigned long temp;
 
-	if (sport->dma_is_enabled && sport->dma_is_rxing) {
-		if (sport->port.suspended) {
-			dmaengine_terminate_all(sport->dma_chan_rx);
-			sport->dma_is_rxing = 0;
-		} else {
-			return;
-		}
-	}
+	if (sport->dma_is_enabled)
+		imx_stop_rx_dma(sport);
+
+	temp = readl(sport->port.membase + UCR1);
+	temp &= ~UCR1_RRDYEN;
+	writel(temp, sport->port.membase + UCR1);
 
 	temp = readl(sport->port.membase + UCR2);
-	writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2);
+	temp &= ~UCR2_ATEN;
+	writel(temp, sport->port.membase + UCR2);
 
-	/* disable the `Receiver Ready Interrrupt` */
-	temp = readl(sport->port.membase + UCR1);
-	writel(temp & ~UCR1_RRDYEN, sport->port.membase + UCR1);
+	temp = readl(sport->port.membase + UCR3);
+	temp &= ~UCR3_AWAKEN;
+	writel(temp, sport->port.membase + UCR3);
 }
 
 /*
-- 
1.8.3.1