hw/char/imx_serial: Really use RX FIFO depth

While we model a 32-elements RX FIFO since the IMX serial
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>
Reviewed-by: Luc Michel <luc.michel@amd.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Bernhard Beschow <shentey@gmail.com>
Message-Id: <20250220092903.3726-7-philmd@linaro.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/hw/char/imx_serial.c b/hw/char/imx_serial.c
index 38b4865..6f14f84 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)