arch/powerpc/platforms/pseries/rng.c

   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);