3 files changed, 49 insertions, 21 deletions

diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h
index e297bf4abfcb..866efdc103fd 100644
--- a/arch/powerpc/platforms/powernv/powernv.h
+++ b/arch/powerpc/platforms/powernv/powernv.h
@@ -42,4 +42,6 @@ ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count);
 u32 __init memcons_get_size(struct memcons *mc);
 struct memcons *__init memcons_init(struct device_node *node, const char *mc_prop_name);
 
+void pnv_rng_init(void);
+
 #endif /* _POWERNV_H */
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
index e3d44b36ae98..3805ad13b8f3 100644
--- a/arch/powerpc/platforms/powernv/rng.c
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -17,6 +17,7 @@
 #include <asm/prom.h>
 #include <asm/machdep.h>
 #include <asm/smp.h>
+#include "powernv.h"
 
 #define DARN_ERR 0xFFFFFFFFFFFFFFFFul
 
@@ -28,7 +29,6 @@ struct powernv_rng {
 
 static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);
 
-
 int powernv_hwrng_present(void)
 {
 	struct powernv_rng *rng;
@@ -98,9 +98,6 @@ static int __init initialise_darn(void)
 			return 0;
 		}
 	}
-
-	pr_warn("Unable to use DARN for get_random_seed()\n");
-
 	return -EIO;
 }
 
@@ -163,32 +160,59 @@ static __init int rng_create(struct device_node *dn)
 
 	rng_init_per_cpu(rng, dn);
 
-	pr_info_once("Registering arch random hook.\n");
-
 	ppc_md.get_random_seed = powernv_get_random_long;
 
 	return 0;
 }
 
-static __init int rng_init(void)
+static int __init pnv_get_random_long_early(unsigned long *v)
 {
 	struct device_node *dn;
-	int rc;
-
-	for_each_compatible_node(dn, NULL, "ibm,power-rng") {
-		rc = rng_create(dn);
-		if (rc) {
-			pr_err("Failed creating rng for %pOF (%d).\n",
-				dn, rc);
-			continue;
-		}
 
-		/* Create devices for hwrng driver */
-		of_platform_device_create(dn, NULL, NULL);
-	}
+	if (!slab_is_available())
+		return 0;
+
+	if (cmpxchg(&ppc_md.get_random_seed, pnv_get_random_long_early,
+		    NULL) != pnv_get_random_long_early)
+		return 0;
+
+	for_each_compatible_node(dn, NULL, "ibm,power-rng")
+		rng_create(dn);
+
+	if (!ppc_md.get_random_seed)
+		return 0;
+	return ppc_md.get_random_seed(v);
+}
 
-	initialise_darn();
+void __init pnv_rng_init(void)
+{
+	struct device_node *dn;
+
+	/* Prefer darn over the rest. */
+	if (!initialise_darn())
+		return;
+
+	dn = of_find_compatible_node(NULL, NULL, "ibm,power-rng");
+	if (dn)
+		ppc_md.get_random_seed = pnv_get_random_long_early;
+
+	of_node_put(dn);
+}
+
+static int __init pnv_rng_late_init(void)
+{
+	struct device_node *dn;
+	unsigned long v;
+
+	/* In case it wasn't called during init for some other reason. */
+	if (ppc_md.get_random_seed == pnv_get_random_long_early)
+		pnv_get_random_long_early(&v);
+
+	if (ppc_md.get_random_seed == powernv_get_random_long) {
+		for_each_compatible_node(dn, NULL, "ibm,power-rng")
+			of_platform_device_create(dn, NULL, NULL);
+	}
 
 	return 0;
 }
-machine_subsys_initcall(powernv, rng_init);
+machine_subsys_initcall(powernv, pnv_rng_late_init);
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 824c3ad7a0fa..dac545aa0308 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -203,6 +203,8 @@ static void __init pnv_setup_arch(void)
 	pnv_check_guarded_cores();
 
 	/* XXX PMCS */
+
+	pnv_rng_init();
 }
 
 static void __init pnv_init(void)