9 files changed, 73 insertions, 36 deletions

diff --git a/arch/powerpc/platforms/microwatt/microwatt.h b/arch/powerpc/platforms/microwatt/microwatt.h
new file mode 100644
index 000000000000..335417e95e66
--- /dev/null
+++ b/arch/powerpc/platforms/microwatt/microwatt.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _MICROWATT_H
+#define _MICROWATT_H
+
+void microwatt_rng_init(void);
+
+#endif /* _MICROWATT_H */
diff --git a/arch/powerpc/platforms/microwatt/rng.c b/arch/powerpc/platforms/microwatt/rng.c
index 7bc4d1cbfaf0..8ece87d005c8 100644
--- a/arch/powerpc/platforms/microwatt/rng.c
+++ b/arch/powerpc/platforms/microwatt/rng.c
@@ -11,6 +11,7 @@
 #include <asm/archrandom.h>
 #include <asm/cputable.h>
 #include <asm/machdep.h>
+#include "microwatt.h"
 
 #define DARN_ERR 0xFFFFFFFFFFFFFFFFul
 
@@ -29,7 +30,7 @@ static int microwatt_get_random_darn(unsigned long *v)
 	return 1;
 }
 
-static __init int rng_init(void)
+void __init microwatt_rng_init(void)
 {
 	unsigned long val;
 	int i;
@@ -37,12 +38,7 @@ static __init int rng_init(void)
 	for (i = 0; i < 10; i++) {
 		if (microwatt_get_random_darn(&val)) {
 			ppc_md.get_random_seed = microwatt_get_random_darn;
-			return 0;
+			return;
 		}
 	}
-
-	pr_warn("Unable to use DARN for get_random_seed()\n");
-
-	return -EIO;
 }
-machine_subsys_initcall(, rng_init);
diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
index 0b02603bdb74..6b32539395a4 100644
--- a/arch/powerpc/platforms/microwatt/setup.c
+++ b/arch/powerpc/platforms/microwatt/setup.c
@@ -16,6 +16,8 @@
 #include <asm/xics.h>
 #include <asm/udbg.h>
 
+#include "microwatt.h"
+
 static void __init microwatt_init_IRQ(void)
 {
 	xics_init();
@@ -32,10 +34,16 @@ static int __init microwatt_populate(void)
 }
 machine_arch_initcall(microwatt, microwatt_populate);
 
+static void __init microwatt_setup_arch(void)
+{
+	microwatt_rng_init();
+}
+
 define_machine(microwatt) {
 	.name			= "microwatt",
 	.probe			= microwatt_probe,
 	.init_IRQ		= microwatt_init_IRQ,
+	.setup_arch		= microwatt_setup_arch,
 	.progress		= udbg_progress,
 	.calibrate_decr		= generic_calibrate_decr,
 };
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)
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index f5c916c839c9..1d75b7742ef0 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -122,4 +122,6 @@ void pseries_lpar_read_hblkrm_characteristics(void);
 static inline void pseries_lpar_read_hblkrm_characteristics(void) { }
 #endif
 
+void pseries_rng_init(void);
+
 #endif /* _PSERIES_PSERIES_H */
diff --git a/arch/powerpc/platforms/pseries/rng.c b/arch/powerpc/platforms/pseries/rng.c
index 6268545947b8..6ddfdeaace9e 100644
--- a/arch/powerpc/platforms/pseries/rng.c
+++ b/arch/powerpc/platforms/pseries/rng.c
@@ -10,6 +10,7 @@
 #include <asm/archrandom.h>
 #include <asm/machdep.h>
 #include <asm/plpar_wrappers.h>
+#include "pseries.h"
 
 
 static int pseries_get_random_long(unsigned long *v)
@@ -24,19 +25,13 @@ static int pseries_get_random_long(unsigned long *v)
 	return 0;
 }
 
-static __init int rng_init(void)
+void __init pseries_rng_init(void)
 {
 	struct device_node *dn;
 
 	dn = of_find_compatible_node(NULL, NULL, "ibm,random");
 	if (!dn)
-		return -ENODEV;
-
-	pr_info("Registering arch random hook.\n");
-
+		return;
 	ppc_md.get_random_seed = pseries_get_random_long;
-
 	of_node_put(dn);
-	return 0;
 }
-machine_subsys_initcall(pseries, rng_init);
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 4f08161f09b9..a74c425be624 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -839,6 +839,7 @@ static void __init pSeries_setup_arch(void)
 	}
 
 	ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
+	pseries_rng_init();
 }
 
 static void pseries_panic(char *str)