From fcd09c90c3c5254b18ef34e30c57c65d34290a84 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 16 Feb 2022 12:33:23 +0100 Subject: ath9k: use hw_random API instead of directly dumping into random.c MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Kalle Valo Cc: Rui Salvaterra Cc: Dominik Brodowski Cc: Herbert Xu Signed-off-by: Jason A. Donenfeld Tested-by: Rui Salvaterra Acked-by: Toke Høiland-Jørgensen Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20220216113323.53332-1-Jason@zx2c4.com --- 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; } } -- cgit v1.2.3