1 /*
2  * Copyright 2013, Michael Ellerman, IBM Corporation.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version
7  * 2 of the License, or (at your option) any later version.
8  */
9 
10 #define pr_fmt(fmt)	"pseries-rng: " fmt
11 
12 #include <linux/kernel.h>
13 #include <linux/of.h>
14 #include <asm/archrandom.h>
15 #include <asm/machdep.h>
16 #include <asm/plpar_wrappers.h>
17 
18 
19 static int pseries_get_random_long(unsigned long *v)
20 {
21 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
22 
23 	if (plpar_hcall(H_RANDOM, retbuf) == H_SUCCESS) {
24 		*v = retbuf[0];
25 		return 1;
26 	}
27 
28 	return 0;
29 }
30 
31 static __init int rng_init(void)
32 {
33 	struct device_node *dn;
34 
35 	dn = of_find_compatible_node(NULL, NULL, "ibm,random");
36 	if (!dn)
37 		return -ENODEV;
38 
39 	pr_info("Registering arch random hook.\n");
40 
41 	ppc_md.get_random_long = pseries_get_random_long;
42 
43 	return 0;
44 }
45 subsys_initcall(rng_init);
46