Subject: Don't use hvc_fss if hvc_rtas is available

The latest version of Systemsim does come with HVC_RTAS
support enabled. Use that one instead, since it brings
us one step closer to using no special device drivers
for systemsim.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Index: linus-2.6/drivers/char/hvc_fss.c
===================================================================
--- linus-2.6.orig/drivers/char/hvc_fss.c
+++ linus-2.6/drivers/char/hvc_fss.c
@@ -37,6 +37,7 @@
 
 #include <asm/prom.h>
 #include <asm/irq.h>
+#include <asm/rtas.h>
 #include <asm/systemsim.h>
 
 #include "hvc_console.h"
@@ -97,13 +98,22 @@ module_init(hvc_fss_init);
 static int __init hvc_fss_console_init(void)
 {
 	/* Don't register if we aren't running on the simulator */
-	if (of_find_node_by_path("/mambo")) {
-		/* Tell the driver we know of one console device.  We
-		 * shouldn't get a collision on the index as long as no-one
-		 * else instantiates on hardware they don't have. */
-		hvc_instantiate(hvc_fss_cookie, 0, &hvc_fss_get_put_ops );
-		add_preferred_console("hvc", 0, NULL);
-	}
+	if (!of_find_node_by_path("/mambo"))
+		return -ENODEV;
+
+#ifdef CONFIG_HVC_RTAS
+	/* Also don't register if rtas console is implemented by
+	 * systemsim, so we don't get duplicate output */
+	if (rtas_token("put-term-char") != RTAS_UNKNOWN_SERVICE)
+		return -EBUSY;
+#endif
+
+	/* Tell the driver we know of one console device.  We
+	 * shouldn't get a collision on the index as long as no-one
+	 * else instantiates on hardware they don't have. */
+	hvc_instantiate(hvc_fss_cookie, 0, &hvc_fss_get_put_ops );
+	add_preferred_console("hvc", 0, NULL);
+
 	return 0;
 }
 console_initcall(hvc_fss_console_init);