The of node for the rng must be created much later in boot. Otherwise it
tries to connect to a parent that doesn't yet exist, resulting on this
splat:

[    0.000478] kobject: '(null)' ((____ptrval____)): is not initialized, yet kobject_get() is being called.
[    0.002925] [c000000002a0fb30] [c00000000073b0bc] kobject_get+0x8c/0x100 (unreliable)
[    0.003071] [c000000002a0fba0] [c00000000087e464] device_add+0xf4/0xb00
[    0.003194] [c000000002a0fc80] [c000000000a7f6e4] of_device_add+0x64/0x80
[    0.003321] [c000000002a0fcb0] [c000000000a800d0] of_platform_device_create_pdata+0xd0/0x1b0
[    0.003476] [c000000002a0fd00] [c00000000201fa44] pnv_get_random_long_early+0x240/0x2e4
[    0.003623] [c000000002a0fe20] [c000000002060c38] random_init+0xc0/0x214

This patch fixes the issue by doing the of node creation inside of
machine_subsys_initcall.

Fixes: f3eac426657d ("powerpc/powernv: wire up rng during setup_arch")
Cc: stable@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Sachin Sant <redacted>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 arch/powerpc/platforms/powernv/rng.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
index 463c78c52cc5..bd5ad5f351c2 100644
--- a/arch/powerpc/platforms/powernv/rng.c
+++ b/arch/powerpc/platforms/powernv/rng.c

@@ -176,12 +176,8 @@ static int __init pnv_get_random_long_early(unsigned long *v)
 		    NULL) != pnv_get_random_long_early)
 		return 0;
 
-	for_each_compatible_node(dn, NULL, "ibm,power-rng") {
-		if (rng_create(dn))
-			continue;
-		/* Create devices for hwrng driver */
-		of_platform_device_create(dn, NULL, NULL);
-	}
+	for_each_compatible_node(dn, NULL, "ibm,power-rng")
+		rng_create(dn);
 
 	if (!ppc_md.get_random_seed)
 		return 0;

@@ -205,10 +201,16 @@ void __init pnv_rng_init(void)
 
 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, pnv_rng_late_init);

-- 
2.35.1