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| author | Krzysztof Kozlowski <krzk@kernel.org> | 2017-04-11 21:08:35 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2017-04-21 15:30:46 +0300 |
| commit | c46ea13f55b629a26d5dd4a22688a5f88cff0906 (patch) | |
| tree | 9d3136d9f89c9b131ba2ddcfedb109eaefcda5ea /drivers/crypto/Kconfig | |
| parent | ed067d4a859ff696373324c5061392e013a7561a (diff) | |
| download | linux-c46ea13f55b629a26d5dd4a22688a5f88cff0906.tar.xz | |
crypto: exynos - Add new Exynos RNG driver
Replace existing hw_ranndom/exynos-rng driver with a new, reworked one.
This is a driver for pseudo random number generator block which on
Exynos4 chipsets must be seeded with some value. On newer Exynos5420
chipsets it might seed itself from true random number generator block
but this is not implemented yet.
New driver is a complete rework to use the crypto ALGAPI instead of
hw_random API. Rationale for the change:
1. hw_random interface is for true RNG devices.
2. The old driver was seeding itself with jiffies which is not a
reliable source for randomness.
3. Device generates five random 32-bit numbers in each pass but old
driver was returning only one 32-bit number thus its performance was
reduced.
Compatibility with DeviceTree bindings is preserved.
New driver does not use runtime power management but manually enables
and disables the clock when needed. This is preferred approach because
using runtime PM just to toggle clock is huge overhead.
Another difference is reseeding itself with generated random data
periodically and during resuming from system suspend (previously driver
was re-seeding itself again with jiffies).
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/crypto/Kconfig')
| -rw-r--r-- | drivers/crypto/Kconfig | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig index 3cd234052775..fb1e60f5002e 100644 --- a/drivers/crypto/Kconfig +++ b/drivers/crypto/Kconfig @@ -388,6 +388,21 @@ config CRYPTO_DEV_MXC_SCC This option enables support for the Security Controller (SCC) found in Freescale i.MX25 chips. +config CRYPTO_DEV_EXYNOS_RNG + tristate "EXYNOS HW pseudo random number generator support" + depends on ARCH_EXYNOS || COMPILE_TEST + depends on HAS_IOMEM + select CRYPTO_RNG + ---help--- + This driver provides kernel-side support through the + cryptographic API for the pseudo random number generator hardware + found on Exynos SoCs. + + To compile this driver as a module, choose M here: the + module will be called exynos-rng. + + If unsure, say Y. + config CRYPTO_DEV_S5P tristate "Support for Samsung S5PV210/Exynos crypto accelerator" depends on ARCH_S5PV210 || ARCH_EXYNOS || COMPILE_TEST |