diff mbox

[07/15] tty: serial: 8250_dma: enqueue RX dma again on completion.

Message ID 1408124563-31541-8-git-send-email-bigeasy@linutronix.de (mailing list archive)
State New, archived
Headers show

Commit Message

Sebastian Andrzej Siewior Aug. 15, 2014, 5:42 p.m. UTC 
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(-)

Comments

Alan Cox Aug. 18, 2014, 10:52 a.m. UTC | #1 
>  		if (!up->dma || dma_err)
>  			status = serial8250_rx_chars(up, status);
> +
> +		if (dma_err && port->type == PORT_OMAP_16750)
> +			serial8250_rx_dma(up, 0);

Can we stick to a 'has dma' flag and port->rx_dma() type usages so that
we don't have to rewrite it again to add them the next slightly odd DMA
user we add 8)
Sebastian Andrzej Siewior Aug. 29, 2014, 3:52 p.m. UTC | #2 
On 08/18/2014 12:52 PM, One Thousand Gnomes wrote:
> 
>>  		if (!up->dma || dma_err)
>>  			status = serial8250_rx_chars(up, status);
>> +
>> +		if (dma_err && port->type == PORT_OMAP_16750)
>> +			serial8250_rx_dma(up, 0);
> 
> Can we stick to a 'has dma' flag and port->rx_dma() type usages so that
> we don't have to rewrite it again to add them the next slightly odd DMA
> user we add 8)

I hide this behind a bug flag, something like UART_NEEDS_DMA_RX_PENDING.

Sebastian
diff mbox

Patch

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: