All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: miaoqing@codeaurora.org, "Rui Salvaterra" <rsalvaterra@gmail.com>,
	"Toke Høiland-Jørgensen" <toke@toke.dk>,
	"Sepehrdad, Pouyan" <pouyans@qti.qualcomm.com>,
	ath9k-devel <ath9k-devel@qca.qualcomm.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	"Kalle Valo" <kvalo@kernel.org>,
	"Dominik Brodowski" <linux@dominikbrodowski.net>,
	"Linux Crypto Mailing List" <linux-crypto@vger.kernel.org>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	LKML <linux-kernel@vger.kernel.org>,
	Netdev <netdev@vger.kernel.org>,
	"Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Florian Fainelli" <f.fainelli@gmail.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH v3] ath9k: use hw_random API instead of directly dumping into random.c
Date: Wed, 16 Feb 2022 12:33:23 +0100	[thread overview]
Message-ID: <20220216113323.53332-1-Jason@zx2c4.com> (raw)
In-Reply-To: <CAHmME9rkDXbeNbe1uehoVONioy=pa8oBtJEW22Afbp=86A9SUQ@mail.gmail.com>

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: Jason A. Donenfeld <Jason@zx2c4.com>
---
Changes v2->v3:
- Use msleep_interruptable like other hwrng drivers.
- Give up after 110 tries.
- Return -EIO after giving up like other hwrng drivers.
- Use for loop for style nits.
- Append serial number for driver in case of multiple cards.

Changes v1->v2:
- Count in words rather than bytes.

 drivers/net/wireless/ath/ath9k/ath9k.h |  3 +-
 drivers/net/wireless/ath/ath9k/rng.c   | 72 +++++++++++---------------
 2 files changed, 33 insertions(+), 42 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index ef6f5ea06c1f..3ccf8cfc6b63 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -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
 };
 
diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
index f9d3d6eedd3c..cb5414265a9b 100644
--- a/drivers/net/wireless/ath/ath9k/rng.c
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -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;
 	}
 }
-- 
2.35.0


  reply	other threads:[~2022-02-16 11:33 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-08 16:51 ath9k should perhaps use hw_random api? Jason A. Donenfeld
2022-02-15 15:38 ` Jason A. Donenfeld
2022-02-15 16:28   ` [PATCH] ath9k: use hw_random API instead of directly dumping into random.c Jason A. Donenfeld
2022-02-15 22:55     ` Rui Salvaterra
2022-02-15 23:22     ` Toke Høiland-Jørgensen
2022-02-15 23:52       ` Jason A. Donenfeld
2022-02-16  0:02         ` [PATCH v2] " Jason A. Donenfeld
2022-02-16  3:13           ` Florian Fainelli
2022-02-16 10:43             ` Jason A. Donenfeld
2022-02-16 11:33               ` Jason A. Donenfeld [this message]
2022-02-16 13:27                 ` [PATCH v3] " Rui Salvaterra
2022-02-17 13:51                 ` Toke Høiland-Jørgensen
2022-02-21 10:22                 ` Kalle Valo
2022-02-22 10:01                   ` Ard Biesheuvel
2022-02-22 10:13                     ` Jason A. Donenfeld
2022-02-16  5:38           ` [PATCH v2] " Kalle Valo
2022-02-16  7:15           ` Dominik Brodowski
2022-02-16  7:11         ` [PATCH] " Dominik Brodowski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220216113323.53332-1-Jason@zx2c4.com \
    --to=jason@zx2c4.com \
    --cc=ath9k-devel@qca.qualcomm.com \
    --cc=f.fainelli@gmail.com \
    --cc=herbert@gondor.apana.org.au \
    --cc=kvalo@kernel.org \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linux@dominikbrodowski.net \
    --cc=miaoqing@codeaurora.org \
    --cc=netdev@vger.kernel.org \
    --cc=pouyans@qti.qualcomm.com \
    --cc=rsalvaterra@gmail.com \
    --cc=toke@redhat.com \
    --cc=toke@toke.dk \
    --subject='Re: [PATCH v3] ath9k: use hw_random API instead of directly dumping into random.c' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.