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Date: Tue, 12 Dec 2017 17:36:05 +0100
From: Łukasz Stelmach <l.stelmach@...sung.com>
To: Krzysztof Kozlowski <krzk@...nel.org>, robh+dt@...nel.org,
Stephan Mueller <smueller@...onox.de>,
Herbert Xu <herbert@...dor.apana.org.au>,
"David S . Miller" <davem@...emloft.net>,
Kukjin Kim <kgene@...nel.org>, linux-crypto@...r.kernel.org,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Łukasz Stelmach <l.stelmach@...sung.com>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: [PATCH v3 2/4] 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@...sung.com>
---
drivers/crypto/exynos-rng.c | 31 ++-----------------------------
1 file 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;
}
--
2.11.0
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