1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright 2013, Michael Ellerman, IBM Corporation.
4  */
5 
6 #define pr_fmt(fmt)	"pseries-rng: " fmt
7 
8 #include <linux/kernel.h>
9 #include <linux/of.h>
10 #include <asm/archrandom.h>
11 #include <asm/machdep.h>
12 #include <asm/plpar_wrappers.h>
13 
14 
15 static int pseries_get_random_long(unsigned long *v)
16 {
17 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
18 
19 	if (plpar_hcall(H_RANDOM, retbuf) == H_SUCCESS) {
20 		*v = retbuf[0];
21 		return 1;
22 	}
23 
24 	return 0;
25 }
26 
27 static __init int rng_init(void)
28 {
29 	struct device_node *dn;
30 
31 	dn = of_find_compatible_node(NULL, NULL, "ibm,random");
32 	if (!dn)
33 		return -ENODEV;
34 
35 	pr_info("Registering arch random hook.\n");
36 
37 	ppc_md.get_random_seed = pseries_get_random_long;
38 
39 	of_node_put(dn);
40 	return 0;
41 }
42 machine_subsys_initcall(pseries, rng_init);
43