[PATCH v3 7/10] hw/char/pl011: Check if receiver is enabled

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Do not receive characters when UART or receiver are disabled.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
TODO: Understand Richard comment from v2:

  this doesn't fall under "my first assembly program" because
  it isn't part of "Hello, World"?
---
 hw/char/pl011.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hw/char/pl011.c b/hw/char/pl011.c
index 9c43cb47bf..ca931be139 100644
--- a/hw/char/pl011.c
+++ b/hw/char/pl011.c
@@ -77,6 +77,7 @@ DeviceState *pl011_create(hwaddr addr, qemu_irq irq, Chardev *chr)
 #define LCR_BRK     (1 << 0)
 
 /* Control Register, UARTCR */
+#define CR_RXE      (1 << 9)
 #define CR_TXE      (1 << 8)
 #define CR_UARTEN   (1 << 0)
 
@@ -359,9 +360,11 @@ static void pl011_write(void *opaque, hwaddr offset,
 static int pl011_can_receive(void *opaque)
 {
     PL011State *s = (PL011State *)opaque;
-    int r;
+    int r = 0;
 
-    r = s->read_count < pl011_get_fifo_depth(s);
+    if ((s->cr & CR_UARTEN) && (s->cr & CR_RXE)) {
+        r = s->read_count < pl011_get_fifo_depth(s);
+    }
     trace_pl011_can_receive(s->lcr, s->read_count, r);
     return r;
 }
-- 
2.41.0