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authorŁukasz Stelmach <l.stelmach@samsung.com>2017-12-12 17:36:05 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2017-12-22 19:52:43 +1100
commit3a5a5e5c07e35366f313a5301fe3568349ab8655 (patch)
treedec183303aff7ff09fb0a89ae3a9e5bc521237e8 /drivers/crypto/exynos-rng.c
parentf76d38b26c114c5e6c8252f3c7dac42bbd69c2c3 (diff)
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: Łukasz Stelmach <l.stelmach@samsung.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/crypto/exynos-rng.c')
-rw-r--r--drivers/crypto/exynos-rng.c31
1 files changed, 2 insertions, 29 deletions
diff --git a/drivers/crypto/exynos-rng.c b/drivers/crypto/exynos-rng.c
index 825c09619eb8..dcdd444d0b3b 100644
--- a/drivers/crypto/exynos-rng.c
+++ b/drivers/crypto/exynos-rng.c
@@ -131,34 +131,6 @@ static int exynos_rng_set_seed(struct exynos_rng_dev *rng,
}
/*
- * 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
* random data (EXYNOS_RNG_SEED_SIZE).
@@ -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;
}