6301566e0b
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 <miaoqing@qca.qualcomm.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
76 lines
2.0 KiB
C
76 lines
2.0 KiB
C
/*
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* Copyright (c) 2015 Qualcomm Atheros, Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "ath9k.h"
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#include "hw.h"
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#include "ar9003_phy.h"
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static int ath9k_rng_data_read(struct hwrng *rng, u32 *data)
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{
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u32 v1, v2;
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struct ath_softc *sc = (struct ath_softc *)rng->priv;
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struct ath_hw *ah = sc->sc_ah;
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ath9k_ps_wakeup(sc);
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REG_RMW_FIELD(ah, AR_PHY_TEST, AR_PHY_TEST_BBB_OBS_SEL, 5);
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REG_CLR_BIT(ah, AR_PHY_TEST, AR_PHY_TEST_RX_OBS_SEL_BIT5);
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REG_RMW_FIELD(ah, AR_PHY_TEST_CTL_STATUS, AR_PHY_TEST_CTL_RX_OBS_SEL, 0);
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v1 = REG_READ(ah, AR_PHY_TST_ADC);
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v2 = REG_READ(ah, AR_PHY_TST_ADC);
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ath9k_ps_restore(sc);
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/* wait for data ready */
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if (v1 && v2 && sc->rng_last != v1 && v1 != v2) {
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*data = (v1 & 0xffff) | (v2 << 16);
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sc->rng_last = v2;
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return sizeof(u32);
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}
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sc->rng_last = v2;
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return 0;
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}
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void ath9k_rng_register(struct ath_softc *sc)
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{
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struct ath_hw *ah = sc->sc_ah;
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if (WARN_ON(sc->rng_initialized))
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return;
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if (!AR_SREV_9300_20_OR_LATER(ah))
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return;
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sc->rng.name = "ath9k";
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sc->rng.data_read = ath9k_rng_data_read;
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sc->rng.priv = (unsigned long)sc;
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if (!hwrng_register(&sc->rng))
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sc->rng_initialized = true;
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}
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void ath9k_rng_unregister(struct ath_softc *sc)
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{
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if (sc->rng_initialized) {
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hwrng_unregister(&sc->rng);
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sc->rng_initialized = false;
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}
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}
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