[PATCH v3 4/6] serial: imx: unmap sg buffers when DMA channel is released

From: Martyn Welch
Date: Thu Sep 21 2017 - 12:19:31 EST


From: Nandor Han <nandor.han@xxxxxx>

This commits unmaps sg buffers when the DMA channel is released. It also
sets to zero `dma_is_rxing` and `dma_is_txing` to state that the
corresponding channels cannot transmit/receive data, as these are
disabled.

Signed-off-by: Nandor Han <nandor.han@xxxxxx>
Signed-off-by: Romain Perier <romain.perier@xxxxxxxxxxxxx>
Signed-off-by: Martyn Welch <martyn.welch@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/imx.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 2fb3210..ed02783 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -357,6 +357,12 @@ static void imx_stop_tx_dma(struct imx_port *sport)
temp = readl(sport->port.membase + UCR1);
temp &= ~UCR1_TDMAEN;
writel(temp, sport->port.membase + UCR1);
+
+ if (sport->dma_is_txing) {
+ dma_unmap_sg(sport->port.dev, &sport->tx_sgl[0],
+ sport->dma_tx_nents, DMA_TO_DEVICE);
+ sport->dma_is_txing = 0;
+ }
}

static void imx_stop_rx_dma(struct imx_port *sport)
@@ -366,6 +372,12 @@ static void imx_stop_rx_dma(struct imx_port *sport)
temp = readl(sport->port.membase + UCR1);
temp &= ~(UCR1_RDMAEN | UCR1_ATDMAEN);
writel(temp, sport->port.membase + UCR1);
+
+ if (sport->dma_is_rxing) {
+ dma_unmap_sg(sport->port.dev, &sport->rx_sgl, 1,
+ DMA_FROM_DEVICE);
+ sport->dma_is_rxing = 0;
+ }
}

/*
--
1.8.3.1