123 lines
3.1 KiB
C
123 lines
3.1 KiB
C
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/*
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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 <linux/hw_random.h>
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#include <linux/kthread.h>
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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 ath_softc *sc, u32 *buf, u32 buf_size)
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{
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int i, j;
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u32 v1, v2, rng_last = sc->rng_last;
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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, 1);
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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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for (i = 0, j = 0; i < buf_size; i++) {
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v1 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
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v2 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
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/* wait for data ready */
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if (v1 && v2 && rng_last != v1 && v1 != v2 && v1 != 0xffff &&
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v2 != 0xffff)
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buf[j++] = (v1 << 16) | v2;
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rng_last = v2;
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}
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ath9k_ps_restore(sc);
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sc->rng_last = rng_last;
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return j << 2;
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}
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static u32 ath9k_rng_delay_get(u32 fail_stats)
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{
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u32 delay;
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if (fail_stats < 100)
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delay = 10;
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else if (fail_stats < 105)
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delay = 1000;
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else
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delay = 10000;
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return delay;
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}
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static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops);
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u32 fail_stats = 0, word;
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int bytes_read = 0;
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for (;;) {
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if (max & ~3UL)
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bytes_read = ath9k_rng_data_read(sc, buf, max >> 2);
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if ((max & 3UL) && ath9k_rng_data_read(sc, &word, 1)) {
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memcpy(buf + bytes_read, &word, max & 3UL);
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bytes_read += max & 3UL;
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memzero_explicit(&word, sizeof(word));
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}
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if (!wait || !max || likely(bytes_read) || fail_stats > 110)
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break;
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if (hwrng_msleep(rng, ath9k_rng_delay_get(++fail_stats)))
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break;
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}
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if (wait && !bytes_read && max)
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bytes_read = -EIO;
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return bytes_read;
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}
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void ath9k_rng_start(struct ath_softc *sc)
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{
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static atomic_t serial = ATOMIC_INIT(0);
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struct ath_hw *ah = sc->sc_ah;
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if (sc->rng_ops.read)
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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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snprintf(sc->rng_name, sizeof(sc->rng_name), "ath9k_%u",
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(atomic_inc_return(&serial) - 1) & U16_MAX);
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sc->rng_ops.name = sc->rng_name;
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sc->rng_ops.read = ath9k_rng_read;
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sc->rng_ops.quality = 320;
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if (devm_hwrng_register(sc->dev, &sc->rng_ops))
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sc->rng_ops.read = NULL;
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}
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void ath9k_rng_stop(struct ath_softc *sc)
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{
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if (sc->rng_ops.read) {
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devm_hwrng_unregister(sc->dev, &sc->rng_ops);
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sc->rng_ops.read = NULL;
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}
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}
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