2015-04-16 14:58:15

by Ludovic Desroches

Subject: [PATCH] tty/serial: at91: maxburst was missing for dma transfers

Maxburst was not set when doing the dma slave configuration. This value
is checked by the recently introduced xdmac. It causes an error when
doing the slave configuration and so prevents from using dma.

Signed-off-by: Ludovic Desroches <[email protected]>
Cc: <[email protected]> # 3.12 and later
---
drivers/tty/serial/atmel_serial.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 4e959c4..6afce7e 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -880,6 +880,7 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
config.direction = DMA_MEM_TO_DEV;
config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
config.dst_addr = port->mapbase + ATMEL_US_THR;
+ config.dst_maxburst = 1;

ret = dmaengine_slave_config(atmel_port->chan_tx,
&config);
@@ -1059,6 +1060,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
config.direction = DMA_DEV_TO_MEM;
config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
config.src_addr = port->mapbase + ATMEL_US_RHR;
+ config.src_maxburst = 1;

ret = dmaengine_slave_config(atmel_port->chan_rx,
&config);
--
2.2.0

2015-04-16 15:08:42

by Nicolas Ferre

Subject: Re: [PATCH] tty/serial: at91: maxburst was missing for dma transfers

Le 16/04/2015 16:58, Ludovic Desroches a ?crit :
> Maxburst was not set when doing the dma slave configuration. This value
> is checked by the recently introduced xdmac. It causes an error when
> doing the slave configuration and so prevents from using dma.
>
> Signed-off-by: Ludovic Desroches <[email protected]>
> Cc: <[email protected]> # 3.12 and later

Indeed, thanks!
Acked-by: Nicolas Ferre <[email protected]>

> ---
> drivers/tty/serial/atmel_serial.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 4e959c4..6afce7e 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -880,6 +880,7 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
> config.direction = DMA_MEM_TO_DEV;
> config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> config.dst_addr = port->mapbase + ATMEL_US_THR;
> + config.dst_maxburst = 1;
>
> ret = dmaengine_slave_config(atmel_port->chan_tx,
> &config);
> @@ -1059,6 +1060,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
> config.direction = DMA_DEV_TO_MEM;
> config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> config.src_addr = port->mapbase + ATMEL_US_RHR;
> + config.src_maxburst = 1;
>
> ret = dmaengine_slave_config(atmel_port->chan_rx,
> &config);
>


--
Nicolas Ferre