From 6301566e0b2dafa7d6779598621bca867962a0a2 Mon Sep 17 00:00:00 2001 From: Miaoqing Pan Date: Wed, 15 Jul 2015 15:54:07 +0800 Subject: [PATCH] ath9k: export HW random number generator We measured the FFT-based entropy in 3 ways, Shannon entropy, collision entropy, and directly measured min-entropy. Just to be conservative, we recommend the estimated min-Entropy to be 10 bits per 16-bit value. Analysis was done by Jacobson,David(djacobso@qti.qualcomm.com). Signed-off-by: Miaoqing Pan Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath9k/Kconfig | 7 +++ drivers/net/wireless/ath/ath9k/Makefile | 1 + drivers/net/wireless/ath/ath9k/ath9k.h | 23 ++++++++ drivers/net/wireless/ath/ath9k/main.c | 4 ++ drivers/net/wireless/ath/ath9k/rng.c | 75 +++++++++++++++++++++++++ 5 files changed, 110 insertions(+) create mode 100644 drivers/net/wireless/ath/ath9k/rng.c diff --git a/drivers/net/wireless/ath/ath9k/Kconfig b/drivers/net/wireless/ath/ath9k/Kconfig index fee0cadb0f5e..bde62ec98bc7 100644 --- a/drivers/net/wireless/ath/ath9k/Kconfig +++ b/drivers/net/wireless/ath/ath9k/Kconfig @@ -176,3 +176,10 @@ config ATH9K_HTC_DEBUGFS depends on ATH9K_HTC && DEBUG_FS ---help--- Say Y, if you need access to ath9k_htc's statistics. + +config ATH9K_HWRNG + bool "Random number generator support" + depends on ATH9K && (HW_RANDOM = y || HW_RANDOM = ATH9K) + default y + ---help--- + Provides a hardware random number generator to the kernel. diff --git a/drivers/net/wireless/ath/ath9k/Makefile b/drivers/net/wireless/ath/ath9k/Makefile index ecda613c2d54..76f9dc37500b 100644 --- a/drivers/net/wireless/ath/ath9k/Makefile +++ b/drivers/net/wireless/ath/ath9k/Makefile @@ -15,6 +15,7 @@ ath9k-$(CONFIG_ATH9K_DFS_DEBUGFS) += dfs_debug.o ath9k-$(CONFIG_ATH9K_DFS_CERTIFIED) += dfs.o ath9k-$(CONFIG_ATH9K_TX99) += tx99.o ath9k-$(CONFIG_ATH9K_WOW) += wow.o +ath9k-$(CONFIG_ATH9K_HWRNG) += rng.o ath9k-$(CONFIG_ATH9K_DEBUGFS) += debug.o diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h index a7a81b3969ce..45596e5ae4db 100644 --- a/drivers/net/wireless/ath/ath9k/ath9k.h +++ b/drivers/net/wireless/ath/ath9k/ath9k.h @@ -23,6 +23,7 @@ #include #include #include +#include #include "common.h" #include "debug.h" @@ -1041,6 +1042,12 @@ struct ath_softc { u32 wow_intr_before_sleep; bool force_wow; #endif + +#ifdef CONFIG_ATH9K_HWRNG + struct hwrng rng; + bool rng_initialized; + u32 rng_last; +#endif }; /********/ @@ -1063,6 +1070,22 @@ static inline int ath9k_tx99_send(struct ath_softc *sc, } #endif /* CONFIG_ATH9K_TX99 */ +/***************************/ +/* Random Number Generator */ +/***************************/ +#ifdef CONFIG_ATH9K_HWRNG +void ath9k_rng_register(struct ath_softc *sc); +void ath9k_rng_unregister(struct ath_softc *sc); +#else +static inline void ath9k_rng_register(struct ath_softc *sc) +{ +} + +static inline void ath9k_rng_unregister(struct ath_softc *sc) +{ +} +#endif + static inline void ath_read_cachesize(struct ath_common *common, int *csz) { common->bus_ops->read_cachesize(common, csz); diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index cfd45cb8ccfc..5916ab2f4a3d 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -739,6 +739,8 @@ static int ath9k_start(struct ieee80211_hw *hw) ath9k_ps_restore(sc); + ath9k_rng_register(sc); + return 0; } @@ -828,6 +830,8 @@ static void ath9k_stop(struct ieee80211_hw *hw) ath9k_deinit_channel_context(sc); + ath9k_rng_unregister(sc); + mutex_lock(&sc->mutex); ath_cancel_work(sc); diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c new file mode 100644 index 000000000000..d8fa7a535ab8 --- /dev/null +++ b/drivers/net/wireless/ath/ath9k/rng.c @@ -0,0 +1,75 @@ +/* + * Copyright (c) 2015 Qualcomm Atheros, Inc. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include "ath9k.h" +#include "hw.h" +#include "ar9003_phy.h" + +static int ath9k_rng_data_read(struct hwrng *rng, u32 *data) +{ + u32 v1, v2; + struct ath_softc *sc = (struct ath_softc *)rng->priv; + struct ath_hw *ah = sc->sc_ah; + + ath9k_ps_wakeup(sc); + + REG_RMW_FIELD(ah, AR_PHY_TEST, AR_PHY_TEST_BBB_OBS_SEL, 5); + REG_CLR_BIT(ah, AR_PHY_TEST, AR_PHY_TEST_RX_OBS_SEL_BIT5); + REG_RMW_FIELD(ah, AR_PHY_TEST_CTL_STATUS, AR_PHY_TEST_CTL_RX_OBS_SEL, 0); + + v1 = REG_READ(ah, AR_PHY_TST_ADC); + v2 = REG_READ(ah, AR_PHY_TST_ADC); + + ath9k_ps_restore(sc); + + /* wait for data ready */ + if (v1 && v2 && sc->rng_last != v1 && v1 != v2) { + *data = (v1 & 0xffff) | (v2 << 16); + sc->rng_last = v2; + + return sizeof(u32); + } + + sc->rng_last = v2; + + return 0; +} + +void ath9k_rng_register(struct ath_softc *sc) +{ + struct ath_hw *ah = sc->sc_ah; + + if (WARN_ON(sc->rng_initialized)) + return; + + if (!AR_SREV_9300_20_OR_LATER(ah)) + return; + + sc->rng.name = "ath9k"; + sc->rng.data_read = ath9k_rng_data_read; + sc->rng.priv = (unsigned long)sc; + + if (!hwrng_register(&sc->rng)) + sc->rng_initialized = true; +} + +void ath9k_rng_unregister(struct ath_softc *sc) +{ + if (sc->rng_initialized) { + hwrng_unregister(&sc->rng); + sc->rng_initialized = false; + } +}