Commit d0e7600b authored by Michael Walle's avatar Michael Walle Committed by Greg Kroah-Hartman
Browse files

tty: serial: fsl_lpuart: move dma_request_chan() 



Move dma_request_chan() out of the atomic context. First this call
should not be in the atomic context at all and second the
dev_info_once() may cause a hang because because the console takes this
spinlock, too.

Fixes: 159381df ("tty: serial: fsl_lpuart: fix DMA operation when using IOMMU")
Reported-by: default avatarLeonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: default avatarMichael Walle <michael@walle.cc>
Reviewed-by: default avatarFugang Duan <fugang.duan@nxp.com>
Tested-by: default avatarLeonard Crestez <leonard.crestez@nxp.com>
Link: https://lore.kernel.org/r/20200325090658.25967-1-michael@walle.cc


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a0c4adee

drivers/tty/serial/fsl_lpuart.c

+23 −13
Original line number Diff line number Diff line
@@ -1510,20 +1510,33 @@ static void rx_dma_timer_init(struct lpuart_port *sport) 
	add_timer(&sport->lpuart_timer);

}



static void lpuart_tx_dma_startup(struct lpuart_port *sport)

static void lpuart_request_dma(struct lpuart_port *sport)

{

	u32 uartbaud;

	int ret;



	sport->dma_tx_chan = dma_request_chan(sport->port.dev, "tx");

	if (IS_ERR(sport->dma_tx_chan)) {

		dev_info_once(sport->port.dev,

			      "DMA tx channel request failed, operating without tx DMA (%ld)\n",

			      PTR_ERR(sport->dma_tx_chan));

		sport->dma_tx_chan = NULL;

		goto err;

	}



	sport->dma_rx_chan = dma_request_chan(sport->port.dev, "rx");

	if (IS_ERR(sport->dma_rx_chan)) {

		dev_info_once(sport->port.dev,

			      "DMA rx channel request failed, operating without rx DMA (%ld)\n",

			      PTR_ERR(sport->dma_rx_chan));

		sport->dma_rx_chan = NULL;

	}

}



static void lpuart_tx_dma_startup(struct lpuart_port *sport)

{

	u32 uartbaud;

	int ret;



	if (!sport->dma_tx_chan)

		goto err;



	ret = lpuart_dma_tx_request(&sport->port);

	if (!ret)

		goto err;
@@ -1549,14 +1562,8 @@ static void lpuart_rx_dma_startup(struct lpuart_port *sport) 
{

	int ret;



	sport->dma_rx_chan = dma_request_chan(sport->port.dev, "rx");

	if (IS_ERR(sport->dma_rx_chan)) {

		dev_info_once(sport->port.dev,

			      "DMA rx channel request failed, operating without rx DMA (%ld)\n",

			      PTR_ERR(sport->dma_rx_chan));

		sport->dma_rx_chan = NULL;

	if (!sport->dma_rx_chan)

		goto err;

	}



	ret = lpuart_start_rx_dma(sport);

	if (ret)
@@ -1592,6 +1599,8 @@ static int lpuart_startup(struct uart_port *port) 
	sport->rxfifo_size = UARTFIFO_DEPTH((temp >> UARTPFIFO_RXSIZE_OFF) &

					    UARTPFIFO_FIFOSIZE_MASK);



	lpuart_request_dma(sport);



	spin_lock_irqsave(&sport->port.lock, flags);



	lpuart_setup_watermark_enable(sport);
@@ -1649,11 +1658,12 @@ static int lpuart32_startup(struct uart_port *port) 
		sport->port.fifosize = sport->txfifo_size;

	}



	lpuart_request_dma(sport);



	spin_lock_irqsave(&sport->port.lock, flags);



	lpuart32_setup_watermark_enable(sport);





	lpuart_rx_dma_startup(sport);

	lpuart_tx_dma_startup(sport);

CRA Git | Maintained and supported by SUSTech CRA and CCSE