From a2c718ce6a61f759fc47d632bcc3d8cf6b244581 Mon Sep 17 00:00:00 2001 From: Dirk Behme Date: Tue, 9 Dec 2014 18:11:31 +0900 Subject: [PATCH] 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 Signed-off-by: Dirk Behme Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 0e64f18f8c42..d097169e85d1 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -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; } } -- 2.20.1