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| author | Krzysztof Kozlowski <krzk@kernel.org> | 2017-04-11 20:08:35 +0200 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2017-04-21 14:30:46 +0200 |
| commit | c46ea13f55b629a26d5dd4a22688a5f88cff0906 (patch) | |
| tree | 9d3136d9f89c9b131ba2ddcfedb109eaefcda5ea /drivers/char/hw_random/Makefile | |
| parent | linux/kernel.h: Add ALIGN_DOWN macro (diff) | |
| download | linux-c46ea13f55b629a26d5dd4a22688a5f88cff0906.tar.xz linux-c46ea13f55b629a26d5dd4a22688a5f88cff0906.zip | |
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/char/hw_random/Makefile')
| -rw-r--r-- | drivers/char/hw_random/Makefile | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index 5f52b1e4e7be..6f1eecc2045c 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -24,7 +24,6 @@ obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o -obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o obj-$(CONFIG_HW_RANDOM_HISI) += hisi-rng.o obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o |