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131 lines
3.1 KiB
131 lines
3.1 KiB
/* |
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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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#define ATH9K_RNG_BUF_SIZE 320 |
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#define ATH9K_RNG_ENTROPY(x) (((x) * 8 * 10) >> 5) /* quality: 10/32 */ |
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static DECLARE_WAIT_QUEUE_HEAD(rng_queue); |
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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_kthread(void *data) |
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{ |
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int bytes_read; |
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struct ath_softc *sc = data; |
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u32 *rng_buf; |
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u32 delay, fail_stats = 0; |
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rng_buf = kmalloc_array(ATH9K_RNG_BUF_SIZE, sizeof(u32), GFP_KERNEL); |
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if (!rng_buf) |
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goto out; |
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while (!kthread_should_stop()) { |
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bytes_read = ath9k_rng_data_read(sc, rng_buf, |
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ATH9K_RNG_BUF_SIZE); |
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if (unlikely(!bytes_read)) { |
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delay = ath9k_rng_delay_get(++fail_stats); |
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wait_event_interruptible_timeout(rng_queue, |
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kthread_should_stop(), |
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msecs_to_jiffies(delay)); |
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continue; |
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} |
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fail_stats = 0; |
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/* sleep until entropy bits under write_wakeup_threshold */ |
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add_hwgenerator_randomness((void *)rng_buf, bytes_read, |
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ATH9K_RNG_ENTROPY(bytes_read)); |
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} |
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kfree(rng_buf); |
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out: |
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sc->rng_task = NULL; |
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return 0; |
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} |
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void ath9k_rng_start(struct ath_softc *sc) |
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{ |
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struct ath_hw *ah = sc->sc_ah; |
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if (sc->rng_task) |
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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_task = kthread_run(ath9k_rng_kthread, sc, "ath9k-hwrng"); |
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if (IS_ERR(sc->rng_task)) |
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sc->rng_task = 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_task) { |
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kthread_stop(sc->rng_task); |
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sc->rng_task = NULL; |
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} |
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}
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