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@xxxxxxxxxx>
Cc: Kalle Valo <kvalo@xxxxxxxxxx>
Cc: Rui Salvaterra <rsalvaterra@xxxxxxxxx>
Cc: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
---
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
