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Commit 3a5a5e5c authored by Łukasz Stelmach's avatar Łukasz Stelmach Committed by Herbert Xu
Browse files

crypto: exynos - Improve performance of PRNG 



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

Signed-off-by: default avatarŁukasz Stelmach <l.stelmach@samsung.com>
Reviewed-by: default avatarKrzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent f76d38b2

drivers/crypto/exynos-rng.c

+2 −29
Original line number Diff line number Diff line
@@ -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;

}