[PATCH 1/7] serial: imx: only set DMA rx-ing when DMA starts
From: Romain Perier <hidden>
Date: 2017-06-30 12:05:37
Also in:
linux-serial, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
From: Nandor Han <redacted> 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 <redacted> Signed-off-by: Romain Perier <redacted> --- 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