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serial: imx: disable TDMAEN in imx_flush_buffer() 

Terminating the DMA, make sure the interrupt is disabled, too.
This fixes random kernel Oops due to dma_tx_call() called for
invalid transmissions.

If we disable the TDMAEN, make sure it's enabled again if a TX
DMA is started.

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dirk Behme 2014-12-09 18:11:31 +09:00 committed by Greg Kroah-Hartman
parent 0bbc9b81c1
commit a2c718ce6a
1 changed files with 15 additions and 0 deletions
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15
drivers/tty/serial/imx.c
View File

@ -502,11 +502,16 @@ static void dma_tx_callback(void *data)
struct scatterlist *sgl = &sport->tx_sgl[0];
struct circ_buf *xmit = &sport->port.state->xmit;
unsigned long flags;
unsigned long temp;
spin_lock_irqsave(&sport->port.lock, flags);
dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE);
temp = readl(sport->port.membase + UCR1);
temp &= ~UCR1_TDMAEN;
writel(temp, sport->port.membase + UCR1);
/* update the stat */
xmit->tail = (xmit->tail + sport->tx_bytes) & (UART_XMIT_SIZE - 1);
sport->port.icount.tx += sport->tx_bytes;
@ -539,6 +544,7 @@ static void imx_dma_tx(struct imx_port *sport)
struct dma_async_tx_descriptor *desc;
struct dma_chan *chan = sport->dma_chan_tx;
struct device *dev = sport->port.dev;
unsigned long temp;
int ret;
if (sport->dma_is_txing)
@ -575,6 +581,11 @@ static void imx_dma_tx(struct imx_port *sport)
dev_dbg(dev, "TX: prepare to send %lu bytes by DMA.\n",
uart_circ_chars_pending(xmit));
temp = readl(sport->port.membase + UCR1);
temp |= UCR1_TDMAEN;
writel(temp, sport->port.membase + UCR1);
/* fire it */
sport->dma_is_txing = 1;
dmaengine_submit(desc);
@ -1258,6 +1269,7 @@ static void imx_flush_buffer(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
struct scatterlist *sgl = &sport->tx_sgl[0];
unsigned long temp;
if (!sport->dma_chan_tx)
return;
@ -1267,6 +1279,9 @@ static void imx_flush_buffer(struct uart_port *port)
if (sport->dma_is_txing) {
dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents,
DMA_TO_DEVICE);
temp = readl(sport->port.membase + UCR1);
temp &= ~UCR1_TDMAEN;
writel(temp, sport->port.membase + UCR1);
sport->dma_is_txing = false;
}
}