Commit fcd09c90 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Kalle Valo
Browse files

ath9k: use hw_random API instead of directly dumping into random.c 



Hardware random number generators are supposed to use the hw_random
framework. This commit turns ath9k's kthread-based design into a proper
hw_random driver.

Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Rui Salvaterra <rsalvaterra@gmail.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Tested-by: default avatarRui Salvaterra <rsalvaterra@gmail.com>
Acked-by: default avatarToke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: default avatarKalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220216113323.53332-1-Jason@zx2c4.com
parent 03e0add7

drivers/net/wireless/ath/ath9k/ath9k.h

+2 −1
Original line number Diff line number Diff line
@@ -1071,8 +1071,9 @@ struct ath_softc { 
#endif



#ifdef CONFIG_ATH9K_HWRNG

	struct hwrng rng_ops;

	u32 rng_last;

	struct task_struct *rng_task;

	char rng_name[sizeof("ath9k_65535")];

#endif

};

drivers/net/wireless/ath/ath9k/rng.c

+31 −41
Original line number Diff line number Diff line
@@ -21,11 +21,6 @@ 
#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;
@@ -71,61 +66,56 @@ static u32 ath9k_rng_delay_get(u32 fail_stats) 
	return delay;

}



static int ath9k_rng_kthread(void *data)

static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)

{

	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;

	struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops);

	u32 fail_stats = 0, word;

	int bytes_read = 0;



	for (;;) {

		if (max & ~3UL)

			bytes_read = ath9k_rng_data_read(sc, buf, max >> 2);

		if ((max & 3UL) && ath9k_rng_data_read(sc, &word, 1)) {

			memcpy(buf + bytes_read, &word, max & 3UL);

			bytes_read += max & 3UL;

			memzero_explicit(&word, sizeof(word));

		}

		if (!wait || !max || likely(bytes_read) || fail_stats > 110)

			break;



		fail_stats = 0;



		/* sleep until entropy bits under write_wakeup_threshold */

		add_hwgenerator_randomness((void *)rng_buf, bytes_read,

					   ATH9K_RNG_ENTROPY(bytes_read));

		msleep_interruptible(ath9k_rng_delay_get(++fail_stats));

	}



	kfree(rng_buf);

out:

	sc->rng_task = NULL;



	return 0;

	if (wait && !bytes_read && max)

		bytes_read = -EIO;

	return bytes_read;

}



void ath9k_rng_start(struct ath_softc *sc)

{

	static atomic_t serial = ATOMIC_INIT(0);

	struct ath_hw *ah = sc->sc_ah;



	if (sc->rng_task)

	if (sc->rng_ops.read)

		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;

	snprintf(sc->rng_name, sizeof(sc->rng_name), "ath9k_%u",

		 (atomic_inc_return(&serial) - 1) & U16_MAX);

	sc->rng_ops.name = sc->rng_name;

	sc->rng_ops.read = ath9k_rng_read;

	sc->rng_ops.quality = 320;



	if (devm_hwrng_register(sc->dev, &sc->rng_ops))

		sc->rng_ops.read = NULL;

}



void ath9k_rng_stop(struct ath_softc *sc)

{

	if (sc->rng_task) {

		kthread_stop(sc->rng_task);

		sc->rng_task = NULL;

	if (sc->rng_ops.read) {

		devm_hwrng_unregister(sc->dev, &sc->rng_ops);

		sc->rng_ops.read = NULL;

	}

}