[v1] hw/char: Improve RX FIFO depth uses

[PATCH 6/9] hw/char/imx_serial: Really use RX FIFO depth

Posted by Philippe Mathieu-Daudé 3 days, 8 hours ago

While we model a 32-elements RX FIFO since the PL011 model was
introduced in commit 988f2442971 ("hw/char/imx_serial: Implement
receive FIFO and ageing timer") we only read 1 char at a time!

Have the IOCanReadHandler handler return how many elements are
available, and use that in the IOReadHandler handler.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/char/imx_serial.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/char/imx_serial.c b/hw/char/imx_serial.c
index 38b4865157e..6f14f8403a9 100644
--- a/hw/char/imx_serial.c
+++ b/hw/char/imx_serial.c
@@ -386,7 +386,8 @@ static void imx_serial_write(void *opaque, hwaddr offset,
 static int imx_can_receive(void *opaque)
 {
     IMXSerialState *s = (IMXSerialState *)opaque;
-    return s->ucr2 & UCR2_RXEN && fifo32_num_used(&s->rx_fifo) < FIFO_SIZE;
+
+    return s->ucr2 & UCR2_RXEN ? fifo32_num_free(&s->rx_fifo) : 0;
 }
 
 static void imx_put_data(void *opaque, uint32_t value)
@@ -417,7 +418,10 @@ static void imx_receive(void *opaque, const uint8_t *buf, int size)
     IMXSerialState *s = (IMXSerialState *)opaque;
 
     s->usr2 |= USR2_WAKE;
-    imx_put_data(opaque, *buf);
+
+    for (int i = 0; i < size; i++) {
+        imx_put_data(opaque, buf[i]);
+    }
 }
 
 static void imx_event(void *opaque, QEMUChrEvent event)
-- 
2.47.1

Re: [PATCH 6/9] hw/char/imx_serial: Really use RX FIFO depth

Posted by Luc Michel 2 days, 20 hours ago

On 22:08 Wed 19 Feb     , Philippe Mathieu-Daudé wrote:
> While we model a 32-elements RX FIFO since the PL011 model was
> introduced in commit 988f2442971 ("hw/char/imx_serial: Implement
> receive FIFO and ageing timer") we only read 1 char at a time!

"the IMX serial model"?

Reviewed-by: Luc Michel <luc.michel@amd.com>

> 
> Have the IOCanReadHandler handler return how many elements are
> available, and use that in the IOReadHandler handler.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  hw/char/imx_serial.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/char/imx_serial.c b/hw/char/imx_serial.c
> index 38b4865157e..6f14f8403a9 100644
> --- a/hw/char/imx_serial.c
> +++ b/hw/char/imx_serial.c
> @@ -386,7 +386,8 @@ static void imx_serial_write(void *opaque, hwaddr offset,
>  static int imx_can_receive(void *opaque)
>  {
>      IMXSerialState *s = (IMXSerialState *)opaque;
> -    return s->ucr2 & UCR2_RXEN && fifo32_num_used(&s->rx_fifo) < FIFO_SIZE;
> +
> +    return s->ucr2 & UCR2_RXEN ? fifo32_num_free(&s->rx_fifo) : 0;
>  }
> 
>  static void imx_put_data(void *opaque, uint32_t value)
> @@ -417,7 +418,10 @@ static void imx_receive(void *opaque, const uint8_t *buf, int size)
>      IMXSerialState *s = (IMXSerialState *)opaque;
> 
>      s->usr2 |= USR2_WAKE;
> -    imx_put_data(opaque, *buf);
> +
> +    for (int i = 0; i < size; i++) {
> +        imx_put_data(opaque, buf[i]);
> +    }
>  }
> 
>  static void imx_event(void *opaque, QEMUChrEvent event)
> --
> 2.47.1
> 

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