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.
This compiles, but I have no hardware or other ability to determine
whether it works. I'll leave further development up to the ath9k
and hw_random maintainers.
Cc: Toke Høiland-Jørgensen <[email protected]>
Cc: Kalle Valo <[email protected]>
Cc: Dominik Brodowski <[email protected]>
Cc: Herbert Xu <[email protected]>
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/net/wireless/ath/ath9k/ath9k.h | 2 +-
drivers/net/wireless/ath/ath9k/rng.c | 62 +++++++++-----------------
2 files changed, 23 insertions(+), 41 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index ef6f5ea06c1f..142f472903dc 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -1072,7 +1072,7 @@ struct ath_softc {
#ifdef CONFIG_ATH9K_HWRNG
u32 rng_last;
- struct task_struct *rng_task;
+ struct hwrng rng_ops;
#endif
};
diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
index aae2bd3cac69..369b222908ba 100644
--- a/drivers/net/wireless/ath/ath9k/rng.c
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -22,9 +22,6 @@
#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)
@@ -72,61 +69,46 @@ 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)
{
+ struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops);
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;
- }
-
- fail_stats = 0;
-
- /* sleep until entropy bits under write_wakeup_threshold */
- add_hwgenerator_randomness((void *)rng_buf, bytes_read,
- ATH9K_RNG_ENTROPY(bytes_read));
- }
+ u32 fail_stats = 0;
- kfree(rng_buf);
-out:
- sc->rng_task = NULL;
+retry:
+ bytes_read = ath9k_rng_data_read(sc, buf, max);
+ if (unlikely(!bytes_read) && wait) {
+ msleep(ath9k_rng_delay_get(++fail_stats));
+ goto retry;
+ }
- return 0;
+ return bytes_read;
}
void ath9k_rng_start(struct ath_softc *sc)
{
struct ath_hw *ah = sc->sc_ah;
+ int ret;
- 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;
+ sc->rng_ops.name = "ath9k";
+ sc->rng_ops.read = ath9k_rng_read;
+ sc->rng_ops.quality = 320;
+
+ ret = devm_hwrng_register(sc->dev, &sc->rng_ops);
+ if (ret)
+ 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
"Jason A. Donenfeld" <[email protected]> writes:
> 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.
>
> This compiles, but I have no hardware or other ability to determine
> whether it works. I'll leave further development up to the ath9k
> and hw_random maintainers.
>
> Cc: Toke Høiland-Jørgensen <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: Dominik Brodowski <[email protected]>
> Cc: Herbert Xu <[email protected]>
> Signed-off-by: Jason A. Donenfeld <[email protected]>
> ---
> drivers/net/wireless/ath/ath9k/ath9k.h | 2 +-
> drivers/net/wireless/ath/ath9k/rng.c | 62 +++++++++-----------------
> 2 files changed, 23 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
> index ef6f5ea06c1f..142f472903dc 100644
> --- a/drivers/net/wireless/ath/ath9k/ath9k.h
> +++ b/drivers/net/wireless/ath/ath9k/ath9k.h
> @@ -1072,7 +1072,7 @@ struct ath_softc {
>
> #ifdef CONFIG_ATH9K_HWRNG
> u32 rng_last;
> - struct task_struct *rng_task;
> + struct hwrng rng_ops;
> #endif
> };
>
> diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
> index aae2bd3cac69..369b222908ba 100644
> --- a/drivers/net/wireless/ath/ath9k/rng.c
> +++ b/drivers/net/wireless/ath/ath9k/rng.c
> @@ -22,9 +22,6 @@
> #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 */
So this comment says "quality: 10/32" but below you're setting "quality"
as 320. No idea what the units are supposed to be, but is this right?
> static DECLARE_WAIT_QUEUE_HEAD(rng_queue);
>
> static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
This function takes buf as a *u32, and interprets buf_size as a number
of u32s...
> @@ -72,61 +69,46 @@ 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)
> {
> + struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops);
> 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;
> - }
> -
> - fail_stats = 0;
> -
> - /* sleep until entropy bits under write_wakeup_threshold */
> - add_hwgenerator_randomness((void *)rng_buf, bytes_read,
> - ATH9K_RNG_ENTROPY(bytes_read));
> - }
> + u32 fail_stats = 0;
>
> - kfree(rng_buf);
> -out:
> - sc->rng_task = NULL;
> +retry:
> + bytes_read = ath9k_rng_data_read(sc, buf, max);
... but AFAICT here you're calling it with a buffer size from hw_random
that's in bytes?
-Toke
Hi, Jason,
On Tue, 15 Feb 2022 at 22:44, Jason A. Donenfeld <[email protected]> wrote:
>
> 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.
>
> This compiles, but I have no hardware or other ability to determine
> whether it works. I'll leave further development up to the ath9k
> and hw_random maintainers.
>
> Cc: Toke Høiland-Jørgensen <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: Dominik Brodowski <[email protected]>
> Cc: Herbert Xu <[email protected]>
> Signed-off-by: Jason A. Donenfeld <[email protected]>
[patch snipped]
On my laptop, with a…
02:00.0 Network controller: Qualcomm Atheros AR9462 Wireless Network
Adapter (rev 01)
… I have the following…
rui@arrandale:~$ cat /sys/devices/virtual/misc/hw_random/rng_available
ath9k
rui@arrandale:~$ cat /sys/devices/virtual/misc/hw_random/rng_current
ath9k
rui@arrandale:~$
… and sure enough, /dev/hwrng is created and outputs a stream of
random data, as expected. I haven't done any serious randomness
quality testing, but it should be the same as the one produced by the
original code. I consider this patch thus
Tested-by: Rui Salvaterra <[email protected]>
Thanks,
Rui