drivers/crypto/sunxi-ss/sun4i-ss-prng.c

   1 #include "sun4i-ss.h"
   2
   3 int sun4i_ss_prng_seed(struct crypto_rng *tfm, const u8 *seed,
   4                        unsigned int slen)
   5 {
   6         struct sun4i_ss_alg_template *algt;
   7         struct rng_alg *alg = crypto_rng_alg(tfm);
   8
   9         algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
  10         memcpy(algt->ss->seed, seed, slen);
  11
  12         return 0;
  13 }
  14
  15 int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
  16                            unsigned int slen, u8 *dst, unsigned int dlen)
  17 {
  18         struct sun4i_ss_alg_template *algt;
  19         struct rng_alg *alg = crypto_rng_alg(tfm);
  20         int i;
  21         u32 v;
  22         u32 *data = (u32 *)dst;
  23         const u32 mode = SS_OP_PRNG | SS_PRNG_CONTINUE | SS_ENABLED;
  24         size_t len;
  25         struct sun4i_ss_ctx *ss;
  26         unsigned int todo = (dlen / 4) * 4;
  27
  28         algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
  29         ss = algt->ss;
  30
  31         spin_lock_bh(&ss->slock);
  32
  33         writel(mode, ss->base + SS_CTL);
  34
  35         while (todo > 0) {
  36                 /* write the seed */
  37                 for (i = 0; i < SS_SEED_LEN / BITS_PER_LONG; i++)
  38                         writel(ss->seed[i], ss->base + SS_KEY0 + i * 4);
  39
  40                 /* Read the random data */
  41                 len = min_t(size_t, SS_DATA_LEN / BITS_PER_BYTE, todo);
  42                 readsl(ss->base + SS_TXFIFO, data, len / 4);
  43                 data += len / 4;
  44                 todo -= len;
  45
  46                 /* Update the seed */
  47                 for (i = 0; i < SS_SEED_LEN / BITS_PER_LONG; i++) {
  48                         v = readl(ss->base + SS_KEY0 + i * 4);
  49                         ss->seed[i] = v;
  50                 }
  51         }
  52
  53         writel(0, ss->base + SS_CTL);
  54         spin_unlock_bh(&ss->slock);
  55         return 0;
  56 }