hw/ssi: Check for duplicate CS indexes

This to avoid indexes conflicts on the same SSI bus. Adapt machines
using multiple devices on the same bus to avoid breakage.

Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
Cc: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/hw/ssi/ssi.c b/hw/ssi/ssi.c
index 54ca3c34e9..1f3e540ab8 100644
--- a/hw/ssi/ssi.c
+++ b/hw/ssi/ssi.c
@@ -42,10 +42,31 @@ DeviceState *ssi_get_cs(SSIBus *bus, uint8_t cs_index)
     return NULL;
 }
 
+static bool ssi_bus_check_address(BusState *b, DeviceState *dev, Error **errp)
+{
+    SSIPeripheral *s = SSI_PERIPHERAL(dev);
+
+    if (ssi_get_cs(SSI_BUS(b), s->cs_index)) {
+        error_setg(errp, "CS index '0x%x' in use by a %s device", s->cs_index,
+                   object_get_typename(OBJECT(dev)));
+        return false;
+    }
+
+    return true;
+}
+
+static void ssi_bus_class_init(ObjectClass *klass, void *data)
+{
+    BusClass *k = BUS_CLASS(klass);
+
+    k->check_address = ssi_bus_check_address;
+}
+
 static const TypeInfo ssi_bus_info = {
     .name = TYPE_SSI_BUS,
     .parent = TYPE_BUS,
     .instance_size = sizeof(SSIBus),
+    .class_init = ssi_bus_class_init,
 };
 
 static void ssi_cs_default(void *opaque, int n, int level)