staging: mmal-vchiq: Fix client_component for 64 bit kernel

The MMAL client_component field is used with the event
mechanism to allow the client to identify the component for
which the event is generated.
The field is only 32bits in size, therefore we can't use a
pointer to the component in a 64 bit kernel.

Component handles are already held in an array per VCHI
instance, so use the array index as the client_component handle
to avoid having to create a new IDR for this purpose.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>

drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c

@@ -472,9 +472,9 @@ buffer_from_host(struct vchiq_mmal_instance *instance,
 static void event_to_host_cb(struct vchiq_mmal_instance *instance,
 			     struct mmal_msg *msg, u32 msg_len)
 {
-	/* FIXME: Not going to work on 64 bit */
+	int comp_idx = msg->u.event_to_host.client_component;
 	struct vchiq_mmal_component *component =
-		(struct vchiq_mmal_component *)msg->u.event_to_host.client_component;
+					&instance->component[comp_idx];
 	struct vchiq_mmal_port *port = NULL;
 	struct mmal_msg_context *msg_context;
 	u32 port_num = msg->u.event_to_host.port_num;
@@ -1073,7 +1073,7 @@ static int create_component(struct vchiq_mmal_instance *instance,
 
 	/* build component create message */
 	m.h.type = MMAL_MSG_TYPE_COMPONENT_CREATE;
-	m.u.component_create.client_component = (u32)(unsigned long)component;
+	m.u.component_create.client_component = component->client_component;
 	strncpy(m.u.component_create.name, name,
 		sizeof(m.u.component_create.name));
 
@@ -1868,6 +1868,12 @@ int vchiq_mmal_component_init(struct vchiq_mmal_instance *instance,
 		goto unlock;
 	}
 
+	/* We need a handle to reference back to our component structure.
+	 * Use the array index in instance->component rather than rolling
+	 * another IDR.
+	 */
+	component->client_component = idx;
+
 	ret = create_component(instance, component, name);
 	if (ret < 0) {
 		pr_err("%s: failed to create component %d (Not enough GPU mem?)\n",

drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.h

@@ -97,6 +97,7 @@ struct vchiq_mmal_component {
 	struct vchiq_mmal_port input[MAX_PORT_COUNT]; /* input ports */
 	struct vchiq_mmal_port output[MAX_PORT_COUNT]; /* output ports */
 	struct vchiq_mmal_port clock[MAX_PORT_COUNT]; /* clock ports */
+	u32 client_component;	/* Used to ref back to client struct */
 };
 
 int vchiq_mmal_init(struct vchiq_mmal_instance **out_instance);