[PATCH 07/15] tty: serial: 8250_dma: enqueue RX dma again on completion.
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2014-08-15 17:43:32
Also in:
linux-arm-kernel, linux-omap, lkml
Subsystem:
8250/16?50 (and clone uarts) serial driver, the rest, tty layer and serial drivers · Maintainers:
Greg Kroah-Hartman, Linus Torvalds, Jiri Slaby
The omap needs a DMA request pending right away. If it is enqueued once the bytes are in the FIFO then nothing will happen and the FIFO will be later purged via RX-timeout interrupt. This patch enqueues RX-DMA request on completion but not if it was aborted on error. The first enqueue will happen in the driver in startup. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/tty/serial/8250/8250_core.c | 3 +++ drivers/tty/serial/8250/8250_dma.c | 12 +++++++++--- 2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 7498ce1..ab2de27 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c@@ -1598,6 +1598,9 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) if (!up->dma || dma_err) status = serial8250_rx_chars(up, status); + + if (dma_err && port->type == PORT_OMAP_16750) + serial8250_rx_dma(up, 0); } serial8250_modem_status(up); if ((!up->dma || up->dma_tx_err) && (status & UART_LSR_THRE))
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 5c59b15..7417ed5 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c@@ -50,9 +50,8 @@ static void __dma_tx_complete(void *param) spin_unlock_irqrestore(&p->port.lock, flags); } -static void __dma_rx_complete(void *param) +static void __dma_rx_do_complete(struct uart_8250_port *p, bool error) { - struct uart_8250_port *p = param; struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state;
@@ -68,10 +67,17 @@ static void __dma_rx_complete(void *param) tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + if (!error && p->port.type == PORT_OMAP_16750) + serial8250_rx_dma(p, 0); tty_flip_buffer_push(tty_port); } +static void __dma_rx_complete(void *param) +{ + __dma_rx_do_complete(param, false); +} + int serial8250_tx_dma(struct uart_8250_port *p) { struct uart_8250_dma *dma = p->dma;
@@ -139,7 +145,7 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir) */ if (dma_status == DMA_IN_PROGRESS) { dmaengine_pause(dma->rxchan); - __dma_rx_complete(p); + __dma_rx_do_complete(p, true); } return -ETIMEDOUT; default:
--
2.0.1