Commit | Line | Data |
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ed14dc0a MP |
1 | /* |
2 | * Copyright (c) 2015 Qualcomm Atheros, Inc. | |
3 | * | |
4 | * Permission to use, copy, modify, and/or distribute this software for any | |
5 | * purpose with or without fee is hereby granted, provided that the above | |
6 | * copyright notice and this permission notice appear in all copies. | |
7 | * | |
8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
15 | */ | |
16 | ||
17 | #include <linux/hw_random.h> | |
18 | #include <linux/kthread.h> | |
19 | ||
20 | #include "ath9k.h" | |
21 | #include "hw.h" | |
22 | #include "ar9003_phy.h" | |
23 | ||
ed14dc0a MP |
24 | static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size) |
25 | { | |
26 | int i, j; | |
27 | u32 v1, v2, rng_last = sc->rng_last; | |
28 | struct ath_hw *ah = sc->sc_ah; | |
29 | ||
30 | ath9k_ps_wakeup(sc); | |
31 | ||
32 | REG_RMW_FIELD(ah, AR_PHY_TEST, AR_PHY_TEST_BBB_OBS_SEL, 1); | |
33 | REG_CLR_BIT(ah, AR_PHY_TEST, AR_PHY_TEST_RX_OBS_SEL_BIT5); | |
34 | REG_RMW_FIELD(ah, AR_PHY_TEST_CTL_STATUS, AR_PHY_TEST_CTL_RX_OBS_SEL, 0); | |
35 | ||
36 | for (i = 0, j = 0; i < buf_size; i++) { | |
37 | v1 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff; | |
38 | v2 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff; | |
39 | ||
40 | /* wait for data ready */ | |
41 | if (v1 && v2 && rng_last != v1 && v1 != v2 && v1 != 0xffff && | |
42 | v2 != 0xffff) | |
43 | buf[j++] = (v1 << 16) | v2; | |
44 | ||
45 | rng_last = v2; | |
46 | } | |
47 | ||
48 | ath9k_ps_restore(sc); | |
49 | ||
50 | sc->rng_last = rng_last; | |
51 | ||
52 | return j << 2; | |
53 | } | |
54 | ||
a2cb3d5f MP |
55 | static u32 ath9k_rng_delay_get(u32 fail_stats) |
56 | { | |
57 | u32 delay; | |
58 | ||
59 | if (fail_stats < 100) | |
60 | delay = 10; | |
61 | else if (fail_stats < 105) | |
62 | delay = 1000; | |
63 | else | |
64 | delay = 10000; | |
65 | ||
66 | return delay; | |
67 | } | |
68 | ||
fcd09c90 | 69 | static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
ed14dc0a | 70 | { |
fcd09c90 JD |
71 | struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops); |
72 | u32 fail_stats = 0, word; | |
73 | int bytes_read = 0; | |
74 | ||
75 | for (;;) { | |
76 | if (max & ~3UL) | |
77 | bytes_read = ath9k_rng_data_read(sc, buf, max >> 2); | |
78 | if ((max & 3UL) && ath9k_rng_data_read(sc, &word, 1)) { | |
79 | memcpy(buf + bytes_read, &word, max & 3UL); | |
80 | bytes_read += max & 3UL; | |
81 | memzero_explicit(&word, sizeof(word)); | |
ed14dc0a | 82 | } |
fcd09c90 JD |
83 | if (!wait || !max || likely(bytes_read) || fail_stats > 110) |
84 | break; | |
ed14dc0a | 85 | |
36cb6494 JD |
86 | if (hwrng_msleep(rng, ath9k_rng_delay_get(++fail_stats))) |
87 | break; | |
ed14dc0a MP |
88 | } |
89 | ||
fcd09c90 JD |
90 | if (wait && !bytes_read && max) |
91 | bytes_read = -EIO; | |
92 | return bytes_read; | |
ed14dc0a MP |
93 | } |
94 | ||
95 | void ath9k_rng_start(struct ath_softc *sc) | |
96 | { | |
fcd09c90 | 97 | static atomic_t serial = ATOMIC_INIT(0); |
ed14dc0a MP |
98 | struct ath_hw *ah = sc->sc_ah; |
99 | ||
fcd09c90 | 100 | if (sc->rng_ops.read) |
ed14dc0a MP |
101 | return; |
102 | ||
103 | if (!AR_SREV_9300_20_OR_LATER(ah)) | |
104 | return; | |
105 | ||
fcd09c90 JD |
106 | snprintf(sc->rng_name, sizeof(sc->rng_name), "ath9k_%u", |
107 | (atomic_inc_return(&serial) - 1) & U16_MAX); | |
108 | sc->rng_ops.name = sc->rng_name; | |
109 | sc->rng_ops.read = ath9k_rng_read; | |
110 | sc->rng_ops.quality = 320; | |
111 | ||
112 | if (devm_hwrng_register(sc->dev, &sc->rng_ops)) | |
113 | sc->rng_ops.read = NULL; | |
ed14dc0a MP |
114 | } |
115 | ||
116 | void ath9k_rng_stop(struct ath_softc *sc) | |
117 | { | |
fcd09c90 JD |
118 | if (sc->rng_ops.read) { |
119 | devm_hwrng_unregister(sc->dev, &sc->rng_ops); | |
120 | sc->rng_ops.read = NULL; | |
07246c11 | 121 | } |
ed14dc0a | 122 | } |