1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*
* 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 <linux/hw_random.h>
#include <linux/kthread.h>
#include "ath9k.h"
#include "hw.h"
#include "ar9003_phy.h"
#define ATH9K_RNG_BUF_SIZE 320
#define ATH9K_RNG_ENTROPY(x) (((x) * 8 * 10) >> 5) /* quality: 10/32 */
static DECLARE_WAIT_QUEUE_HEAD(rng_queue);
static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
{
int i, j;
u32 v1, v2, rng_last = sc->rng_last;
struct ath_hw *ah = sc->sc_ah;
ath9k_ps_wakeup(sc);
REG_RMW_FIELD(ah, AR_PHY_TEST, AR_PHY_TEST_BBB_OBS_SEL, 1);
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);
for (i = 0, j = 0; i < buf_size; i++) {
v1 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
v2 = REG_READ(ah, AR_PHY_TST_ADC) & 0xffff;
/* wait for data ready */
if (v1 && v2 && rng_last != v1 && v1 != v2 && v1 != 0xffff &&
v2 != 0xffff)
buf[j++] = (v1 << 16) | v2;
rng_last = v2;
}
ath9k_ps_restore(sc);
sc->rng_last = rng_last;
return j << 2;
}
static u32 ath9k_rng_delay_get(u32 fail_stats)
{
u32 delay;
if (fail_stats < 100)
delay = 10;
else if (fail_stats < 105)
delay = 1000;
else
delay = 10000;
return delay;
}
static int ath9k_rng_kthread(void *data)
{
int bytes_read;
struct ath_softc *sc = data;
u32 *rng_buf;
u32 delay, fail_stats = 0;
rng_buf = kmalloc_array(ATH9K_RNG_BUF_SIZE, sizeof(u32), GFP_KERNEL);
if (!rng_buf)
goto out;
while (!kthread_should_stop()) {
bytes_read = ath9k_rng_data_read(sc, rng_buf,
ATH9K_RNG_BUF_SIZE);
if (unlikely(!bytes_read)) {
delay = ath9k_rng_delay_get(++fail_stats);
wait_event_interruptible_timeout(rng_queue,
kthread_should_stop(),
msecs_to_jiffies(delay));
continue;
}
fail_stats = 0;
/* sleep until entropy bits under write_wakeup_threshold */
add_hwgenerator_randomness((void *)rng_buf, bytes_read,
ATH9K_RNG_ENTROPY(bytes_read));
}
kfree(rng_buf);
out:
sc->rng_task = NULL;
return 0;
}
void ath9k_rng_start(struct ath_softc *sc)
{
struct ath_hw *ah = sc->sc_ah;
if (sc->rng_task)
return;
if (!AR_SREV_9300_20_OR_LATER(ah))
return;
sc->rng_task = kthread_run(ath9k_rng_kthread, sc, "ath9k-hwrng");
if (IS_ERR(sc->rng_task))
sc->rng_task = NULL;
}
void ath9k_rng_stop(struct ath_softc *sc)
{
if (sc->rng_task) {
kthread_stop(sc->rng_task);
sc->rng_task = NULL;
}
}
|
