Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1400163 > unrolled thread

[PATCH 1/3] tty/serial: atmel: re-integrate status check in irq handler

Back to article view | Back to linux.kernel

Contents

  [PATCH 1/3] tty/serial: atmel: re-integrate status check in irq handler Ludovic Desroches <ludovic.desroches@atmel.com> - 2016-05-12 17:40 +0200
    [PATCH 3/3] tty/serial: atmel: add comment for the ring buffer size macro Ludovic Desroches <ludovic.desroches@atmel.com> - 2016-05-12 17:40 +0200
      Re: [PATCH 3/3] tty/serial: atmel: add comment for the ring buffer  size macro Nicolas Ferre <nicolas.ferre@atmel.com> - 2016-05-12 18:00 +0200

#1400163 — [PATCH 1/3] tty/serial: atmel: re-integrate status check in irq handler

From: Nicolas Ferre <nicolas.ferre@atmel.com>

The IRQ status check and related actions was done in the tasklet without
benefit. So, move it back to the IRQ context to simplify IRQ handling and
having the possibility to split the tasklet in two separated ones for
receive and transmit actions.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++-----------------------
 1 file changed, 17 insertions(+), 26 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 954941d..8854ac6 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -146,9 +146,7 @@ struct atmel_uart_port {
 	struct scatterlist		sg_tx;
 	struct scatterlist		sg_rx;
 	struct tasklet_struct	tasklet;
-	unsigned int		irq_status;
 	unsigned int		irq_status_prev;
-	unsigned int		status_change;
 	unsigned int		tx_len;
 
 	struct circ_buf		rx_ring;
@@ -1237,14 +1235,27 @@ atmel_handle_status(struct uart_port *port, unsigned int pending,
 		    unsigned int status)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	unsigned int status_change;
 
 	if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC
 				| ATMEL_US_CTSIC)) {
-		atmel_port->irq_status = status;
-		atmel_port->status_change = atmel_port->irq_status ^
-					    atmel_port->irq_status_prev;
+		status_change = status ^ atmel_port->irq_status_prev;
 		atmel_port->irq_status_prev = status;
-		tasklet_schedule(&atmel_port->tasklet);
+
+		if (status_change & (ATMEL_US_RI | ATMEL_US_DSR
+					| ATMEL_US_DCD | ATMEL_US_CTS)) {
+			/* TODO: All reads to CSR will clear these interrupts! */
+			if (status_change & ATMEL_US_RI)
+				port->icount.rng++;
+			if (status_change & ATMEL_US_DSR)
+				port->icount.dsr++;
+			if (status_change & ATMEL_US_DCD)
+				uart_handle_dcd_change(port, !(status & ATMEL_US_DCD));
+			if (status_change & ATMEL_US_CTS)
+				uart_handle_cts_change(port, !(status & ATMEL_US_CTS));
+
+			wake_up_interruptible(&port->state->port.delta_msr_wait);
+		}
 	}
 }
 
@@ -1575,31 +1586,12 @@ static void atmel_tasklet_func(unsigned long data)
 {
 	struct uart_port *port = (struct uart_port *)data;
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
-	unsigned int status = atmel_port->irq_status;
-	unsigned int status_change = atmel_port->status_change;
 
 	/* The interrupt handler does not take the lock */
 	spin_lock(&port->lock);
 
 	atmel_port->schedule_tx(port);
 
-	if (status_change & (ATMEL_US_RI | ATMEL_US_DSR
-				| ATMEL_US_DCD | ATMEL_US_CTS)) {
-		/* TODO: All reads to CSR will clear these interrupts! */
-		if (status_change & ATMEL_US_RI)
-			port->icount.rng++;
-		if (status_change & ATMEL_US_DSR)
-			port->icount.dsr++;
-		if (status_change & ATMEL_US_DCD)
-			uart_handle_dcd_change(port, !(status & ATMEL_US_DCD));
-		if (status_change & ATMEL_US_CTS)
-			uart_handle_cts_change(port, !(status & ATMEL_US_CTS));
-
-		wake_up_interruptible(&port->state->port.delta_msr_wait);
-
-		atmel_port->status_change = 0;
-	}
-
 	atmel_port->schedule_rx(port);
 
 	spin_unlock(&port->lock);
@@ -1833,7 +1825,6 @@ static int atmel_startup(struct uart_port *port)
 
 	/* Save current CSR for comparison in atmel_tasklet_func() */
 	atmel_port->irq_status_prev = atmel_get_lines_status(port);
-	atmel_port->irq_status = atmel_port->irq_status_prev;
 
 	/*
 	 * Finally, enable the serial port
-- 
2.5.0

[toc] | [next] | [standalone]

#1400164 — [PATCH 3/3] tty/serial: atmel: add comment for the ring buffer size macro

There is a macro named ATMEL_SERIAL_RINGSIZE which suggesting that it
corresponds to the real size of the ring buffer. Let warn people that
there is a factor of four since allocation size is
sizeof(struct atmel_uart_char) * ATMEL_SERIAL_RINGSIZE.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
---
 drivers/tty/serial/atmel_serial.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 6c1ec7d..8570163 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -108,6 +108,12 @@ struct atmel_uart_char {
 	u16		ch;
 };
 
+/*
+ * Be careful, the real size of the ring buffer is
+ * sizeof(atmel_uart_char) * ATMEL_SERIAL_RINGSIZE. It means that ring buffer
+ * can contain up to 1024 characters in PIO mode and up to 4096 characters in
+ * DMA mode.
+ */
 #define ATMEL_SERIAL_RINGSIZE 1024
 
 /*
-- 
2.5.0

[toc] | [prev] | [next] | [standalone]

#1400197 — Re: [PATCH 3/3] tty/serial: atmel: add comment for the ring buffer size macro

Le 12/05/2016 17:37, Ludovic Desroches a écrit :
> There is a macro named ATMEL_SERIAL_RINGSIZE which suggesting that it
> corresponds to the real size of the ring buffer. Let warn people that
> there is a factor of four since allocation size is
> sizeof(struct atmel_uart_char) * ATMEL_SERIAL_RINGSIZE.
> 
> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>

Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>

Thanks!

> ---
>  drivers/tty/serial/atmel_serial.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 6c1ec7d..8570163 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -108,6 +108,12 @@ struct atmel_uart_char {
>  	u16		ch;
>  };
>  
> +/*
> + * Be careful, the real size of the ring buffer is
> + * sizeof(atmel_uart_char) * ATMEL_SERIAL_RINGSIZE. It means that ring buffer
> + * can contain up to 1024 characters in PIO mode and up to 4096 characters in
> + * DMA mode.
> + */
>  #define ATMEL_SERIAL_RINGSIZE 1024
>  
>  /*
> 


-- 
Nicolas Ferre

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web