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crypto: exynos - Improve performance of PRNG

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Use memcpy_fromio() instead of custom exynos_rng_copy_random() function
to retrieve generated numbers from the registers of PRNG.

Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Łukasz Stelmach 2017-12-12 17:36:05 +01:00 committed by Herbert Xu
parent f76d38b26c
commit 3a5a5e5c07
1 changed files with 2 additions and 29 deletions
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31
drivers/crypto/exynos-rng.c
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@ -130,34 +130,6 @@ static int exynos_rng_set_seed(struct exynos_rng_dev *rng,
return 0;
}
/*
* Read from output registers and put the data under 'dst' array,
* up to dlen bytes.
*
* Returns number of bytes actually stored in 'dst' (dlen
* or EXYNOS_RNG_SEED_SIZE).
*/
static unsigned int exynos_rng_copy_random(struct exynos_rng_dev *rng,
u8 *dst, unsigned int dlen)
{
unsigned int cnt = 0;
int i, j;
u32 val;
for (j = 0; j < EXYNOS_RNG_SEED_REGS; j++) {
val = exynos_rng_readl(rng, EXYNOS_RNG_OUT(j));
for (i = 0; i < 4; i++) {
dst[cnt] = val & 0xff;
val >>= 8;
if (++cnt >= dlen)
return cnt;
}
}
return cnt;
}
/*
* Start the engine and poll for finish. Then read from output registers
* filling the 'dst' buffer up to 'dlen' bytes or up to size of generated
@ -190,7 +162,8 @@ static int exynos_rng_get_random(struct exynos_rng_dev *rng,
/* Clear status bit */
exynos_rng_writel(rng, EXYNOS_RNG_STATUS_RNG_DONE,
EXYNOS_RNG_STATUS);
*read = exynos_rng_copy_random(rng, dst, dlen);
*read = min_t(size_t, dlen, EXYNOS_RNG_SEED_SIZE);
memcpy_fromio(dst, rng->mem + EXYNOS_RNG_OUT_BASE, *read);
return 0;
}