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ath9k: fix rng high cpu load

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If no valid ADC randomness output, ath9k rng will continuously
reading ADC, which will cause high CPU load. So increase the
delay to wait for ADC ready.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=114261
Signed-off-by: Miaoqing Pan <miaoqing@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
This commit is contained in:
Miaoqing Pan 2016-03-18 17:54:56 +08:00 committed by Kalle Valo
parent 69218a4800
commit a2cb3d5f04
1 changed files with 19 additions and 1 deletions
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20
drivers/net/wireless/ath/ath9k/rng.c
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@ -55,11 +55,26 @@ static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
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)
@ -69,10 +84,13 @@ static int ath9k_rng_kthread(void *data)
bytes_read = ath9k_rng_data_read(sc, rng_buf,
ATH9K_RNG_BUF_SIZE);
if (unlikely(!bytes_read)) {
msleep_interruptible(10);
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));