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[PATCH 7/7] serial: imx: Fix imx_shutdown procedure

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

In some cases, It looks that interrupts can happen after the dma was
disabled and port was not yet shutdown. This will result in interrupts
handled by imx_rxint.

This commits updates the shutdown function to ensure that underlying
components are disabled in the right order. This disables RX and TX
blocks, then it disabled interrupts. In case DMA is enabled, it disables
DMA and free corresponding resources. It disables UART port and stop
clocks.

Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Romain Perier <romain.perier@collabora.com>
---
 drivers/tty/serial/imx.c | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index d5b6e09..7dc6f0c 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1404,44 +1404,44 @@ static void imx_shutdown(struct uart_port *port)
 	unsigned long temp;
 	unsigned long flags;
 
-	if (sport->dma_is_enabled) {
-		sport->dma_is_rxing = 0;
-		sport->dma_is_txing = 0;
-		dmaengine_terminate_sync(sport->dma_chan_tx);
-		dmaengine_terminate_sync(sport->dma_chan_rx);
-
+	if (!sport->port.suspended) {
 		spin_lock_irqsave(&sport->port.lock, flags);
 		imx_stop_tx(port);
 		imx_stop_rx(port);
-		imx_disable_dma(sport);
 		spin_unlock_irqrestore(&sport->port.lock, flags);
-		imx_uart_dma_exit(sport);
 	}
 
-	mctrl_gpio_disable_ms(sport->gpios);
+	if (sport->dma_is_inited) {
+		if (sport->dma_is_enabled) {
+			spin_lock_irqsave(&sport->port.lock, flags);
+			imx_disable_dma(sport);
+			spin_unlock_irqrestore(&sport->port.lock, flags);
+		}
+		imx_uart_dma_exit(sport);
+	}
 
 	spin_lock_irqsave(&sport->port.lock, flags);
 	temp = readl(sport->port.membase + UCR2);
-	temp &= ~(UCR2_TXEN);
+	temp &= ~(UCR2_TXEN | UCR2_RXEN);
 	writel(temp, sport->port.membase + UCR2);
+	temp = readl(sport->port.membase + UCR4);
+	temp &= ~UCR4_OREN;
+	writel(temp, sport->port.membase + UCR4);
 	spin_unlock_irqrestore(&sport->port.lock, flags);
 
-	/*
-	 * Stop our timer.
-	 */
-	del_timer_sync(&sport->timer);
+	mctrl_gpio_disable_ms(sport->gpios);
 
-	/*
-	 * Disable all interrupts, port and break condition.
-	 */
+	/* Stop our timer. */
+	del_timer_sync(&sport->timer);
 
+	/* Disable port. */
 	spin_lock_irqsave(&sport->port.lock, flags);
 	temp = readl(sport->port.membase + UCR1);
-	temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
-
+	temp &= ~UCR1_UARTEN;
 	writel(temp, sport->port.membase + UCR1);
 	spin_unlock_irqrestore(&sport->port.lock, flags);
 
+	/* Disable clocks. */
 	clk_disable_unprepare(sport->clk_per);
 	clk_disable_unprepare(sport->clk_ipg);
 }
-- 
1.8.3.1

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[PATCH 0/7] serial: imx: various improvements Romain Perier <romain.perier@collabora.com> - 2017-06-30 14:10 +0200
  [PATCH 2/7] serial: imx: move log from error to debug type Romain Perier <romain.perier@collabora.com> - 2017-06-30 14:10 +0200
    Re: [PATCH 2/7] serial: imx: move log from error to debug type Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2017-07-03 09:00 +0200
  [PATCH 7/7] serial: imx: Fix imx_shutdown procedure Romain Perier <romain.perier@collabora.com> - 2017-06-30 14:10 +0200
    Re: [PATCH 7/7] serial: imx: Fix imx_shutdown procedure Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2017-07-03 09:10 +0200
  [PATCH 1/7] serial: imx: only set DMA rx-ing when DMA starts Romain Perier <romain.perier@collabora.com> - 2017-06-30 14:10 +0200
    Re: [PATCH 1/7] serial: imx: only set DMA rx-ing when DMA starts Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2017-07-03 08:50 +0200
  [PATCH 3/7] serial: imx: init dma_is_{rx|tx}ing variables Romain Perier <romain.perier@collabora.com> - 2017-06-30 14:10 +0200
    Re: [PATCH 3/7] serial: imx: init dma_is_{rx|tx}ing variables Lothar Waßmann <LW@KARO-electronics.de> - 2017-06-30 14:20 +0200
      Re: [PATCH 3/7] serial: imx: init dma_is_{rx|tx}ing variables Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2017-07-03 09:00 +0200
  [PATCH 5/7] serial: imx: umap sg buffers when DMA channel is released Romain Perier <romain.perier@collabora.com> - 2017-06-30 14:10 +0200
    Re: [PATCH 5/7] serial: imx: umap sg buffers when DMA channel is  released Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2017-07-03 09:10 +0200
  [PATCH 6/7] serial: imx: update the stop rx,tx procedures Romain Perier <romain.perier@collabora.com> - 2017-06-30 14:10 +0200
    Re: [PATCH 6/7] serial: imx: update the stop rx,tx procedures Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2017-07-03 09:10 +0200

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