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Subject[PATCH 1/7] serial: imx: only set DMA rx-ing when DMA starts
Date
From: Nandor Han <nandor.han@ge.com>

Avoid the situation when `dma_is_rxing` could incorrectly signal that
DMA RX channel is receiving data in case DMA preparation or sg mapping
fails.

Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Romain Perier <romain.perier@collabora.com>
---
drivers/tty/serial/imx.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 5437b34..1d35293 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -725,11 +725,11 @@ static irqreturn_t imx_rxint(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static void imx_disable_rx_int(struct imx_port *sport)
+static void imx_disable_rx_int(struct imx_port *sport, bool is_rxing)
{
unsigned long temp;

- sport->dma_is_rxing = 1;
+ sport->dma_is_rxing = is_rxing;

/* disable the receiver ready and aging timer interrupts */
temp = readl(sport->port.membase + UCR1);
@@ -762,7 +762,7 @@ static void imx_dma_rxint(struct imx_port *sport)
temp = readl(sport->port.membase + USR2);
if ((temp & USR2_RDR) && !sport->dma_is_rxing) {

- imx_disable_rx_int(sport);
+ imx_disable_rx_int(sport, false);

/* tell the DMA to receive the data. */
start_rx_dma(sport);
@@ -1083,6 +1083,7 @@ static int start_rx_dma(struct imx_port *sport)
desc->callback_param = sport;

dev_dbg(dev, "RX: prepare for the DMA.\n");
+ sport->dma_is_rxing = 1;
sport->rx_cookie = dmaengine_submit(desc);
dma_async_issue_pending(chan);
return 0;
@@ -1362,7 +1363,7 @@ static int imx_startup(struct uart_port *port)
spin_unlock(&tty->files_lock);

if (readcnt > 0) {
- imx_disable_rx_int(sport);
+ imx_disable_rx_int(sport, true);
start_rx_dma(sport);
}
}
--
1.8.3.1
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