LXR linux/arch/powerpc/platforms/pseries/rng.c

   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
  19static 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
  31static __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}
  45subsys_initcall(rng_init);
  46