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linux-next/drivers/crypto/sunxi-ss/sun4i-ss-prng.c
Corentin LABBE b8ae5c7387 crypto: sun4i-ss - support the Security System PRNG
The Security System has a PRNG, this patch adds support for it via
crypto_rng.

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-07-18 17:50:55 +08:00

57 lines
1.3 KiB
C

#include "sun4i-ss.h"
int sun4i_ss_prng_seed(struct crypto_rng *tfm, const u8 *seed,
unsigned int slen)
{
struct sun4i_ss_alg_template *algt;
struct rng_alg *alg = crypto_rng_alg(tfm);
algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
memcpy(algt->ss->seed, seed, slen);
return 0;
}
int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int dlen)
{
struct sun4i_ss_alg_template *algt;
struct rng_alg *alg = crypto_rng_alg(tfm);
int i;
u32 v;
u32 *data = (u32 *)dst;
const u32 mode = SS_OP_PRNG | SS_PRNG_CONTINUE | SS_ENABLED;
size_t len;
struct sun4i_ss_ctx *ss;
unsigned int todo = (dlen / 4) * 4;
algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
ss = algt->ss;
spin_lock(&ss->slock);
writel(mode, ss->base + SS_CTL);
while (todo > 0) {
/* write the seed */
for (i = 0; i < SS_SEED_LEN / BITS_PER_LONG; i++)
writel(ss->seed[i], ss->base + SS_KEY0 + i * 4);
/* Read the random data */
len = min_t(size_t, SS_DATA_LEN / BITS_PER_BYTE, todo);
readsl(ss->base + SS_TXFIFO, data, len / 4);
data += len / 4;
todo -= len;
/* Update the seed */
for (i = 0; i < SS_SEED_LEN / BITS_PER_LONG; i++) {
v = readl(ss->base + SS_KEY0 + i * 4);
ss->seed[i] = v;
}
}
writel(0, ss->base + SS_CTL);
spin_unlock(&ss->slock);
return dlen;
}