126 lines
3.0 KiB
C
126 lines
3.0 KiB
C
/*
|
|
* 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 * 320) >> 10) /* quality: 320/1024 */
|
|
|
|
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);
|
|
msleep_interruptible(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);
|
|
}
|