[PATCH 3/7] serial: 8250_dma: continue TX dma on dma error
From: bigeasy@linutronix.de (Sebastian Andrzej Siewior)
Date: 2014-07-29 19:01:31
Also in:
linux-omap, linux-serial, 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
After TX dma completes the code will queue another DMA transfer. If serial8250_tx_dma() fails then there is no plan B to continue the transfer manually. This patch enables the TX-fifo empty event so it can be tried again via DMA or use the manual fallback in case it fails. Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/tty/serial/8250/8250_dma.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 148ffe4..f9ef69f 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c@@ -36,8 +36,15 @@ static void __dma_tx_complete(void *param) if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&p->port); - if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) - serial8250_tx_dma(p); + if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) { + int ret; + + ret = serial8250_tx_dma(p); + if (ret && !(p->ier & UART_IER_THRI)) { + p->ier |= UART_IER_THRI; + serial_port_out(&p->port, UART_IER, p->ier); + } + } spin_unlock_irqrestore(&p->port.lock, flags); }
--
2.0.1