[3/3] serial: 8250: omap: restore registers on shutdown
diff mbox

Message ID 87egjp2r4a.fsf@linutronix.de
State New
Headers show

Commit Message

John Ogness July 30, 2015, 10:54 p.m. UTC
If DMA is active during a shutdown, a delayed restore of the
registers may be pending. The restore must be performed after
the DMA is stopped, otherwise the delayed restore remains
pending and will fire upon the first DMA TX complete of a
totally different serial session.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
 drivers/tty/serial/8250/8250_omap.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Peter Hurley July 31, 2015, 12:51 a.m. UTC | #1
Hi John,

On 07/30/2015 06:54 PM, John Ogness wrote:
> If DMA is active during a shutdown, a delayed restore of the
> registers may be pending. The restore must be performed after
> the DMA is stopped, otherwise the delayed restore remains
> pending and will fire upon the first DMA TX complete of a
> totally different serial session.
> 
> Signed-off-by: John Ogness <john.ogness@linutronix.de>
> ---
>  drivers/tty/serial/8250/8250_omap.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
> index 5b39892..25f6255 100644
> --- a/drivers/tty/serial/8250/8250_omap.c
> +++ b/drivers/tty/serial/8250/8250_omap.c
> @@ -657,9 +657,15 @@ static void omap_8250_shutdown(struct uart_port *port)
>  	up->ier = 0;
>  	serial_out(up, UART_IER, 0);
>  
> -	if (up->dma)
> +	if (up->dma) {
>  		serial8250_release_dma(up);
>  
> +		if (priv->delayed_restore) {
> +			priv->delayed_restore = 0;
> +			omap8250_restore_regs(up);
> +		}

I was never really a fan of the deferred set_termios();
I think it's more appropriate to wait for tx dma to
complete in omap_8250_set_termios().

Regards,
Peter Hurley


> +	}
> +
>  	/*
>  	 * Disable break condition and FIFOs
>  	 */
> 

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Patch
diff mbox

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 5b39892..25f6255 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -657,9 +657,15 @@  static void omap_8250_shutdown(struct uart_port *port)
 	up->ier = 0;
 	serial_out(up, UART_IER, 0);
 
-	if (up->dma)
+	if (up->dma) {
 		serial8250_release_dma(up);
 
+		if (priv->delayed_restore) {
+			priv->delayed_restore = 0;
+			omap8250_restore_regs(up);
+		}
+	}
+
 	/*
 	 * Disable break condition and FIFOs
 	 */