char/cadence_uart: Fix reset for unattached instances

commit 1db8b5efe0c2b5000e50691eea61264a615f43de introduced an issue
where QEMU would segfault if you have an unattached Cadence UART.

Fix by guarding the flush-on-reset logic on there being a qemu_chr
attachment.

Reported-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Tested-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Message-id: 9009578ee10a50d994b2e10aa2840d73765f5968.1370577272.git.peter.crosthwaite@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index 131370a74bc3afa95c3a9052349be7f7ab812e35..4d457f8c65e9d6afdfa5097093d67f262c122864 100644 (file)
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -157,7 +157,9 @@ static void uart_rx_reset(UartState *s)
 {
     s->rx_wpos = 0;
     s->rx_count = 0;
-    qemu_chr_accept_input(s->chr);
+    if (s->chr) {
+        qemu_chr_accept_input(s->chr);
+    }
 
     s->r[R_SR] |= UART_SR_INTR_REMPTY;
     s->r[R_SR] &= ~UART_SR_INTR_RFUL;