| Message ID | 20220913174224.1399480-1-bryan.odonoghue@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | wcn36xx: Add RX frame SNR as a source of system entropy | expand |
diff --git a/drivers/net/wireless/ath/wcn36xx/txrx.c b/drivers/net/wireless/ath/wcn36xx/txrx.c index 8da3955995b6e..f3b77d7ffebe4 100644 --- a/drivers/net/wireless/ath/wcn36xx/txrx.c +++ b/drivers/net/wireless/ath/wcn36xx/txrx.c @@ -16,6 +16,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/random.h> #include "txrx.h" static inline int get_rssi0(struct wcn36xx_rx_bd *bd) @@ -297,6 +298,8 @@ static void wcn36xx_update_survey(struct wcn36xx *wcn, int rssi, int snr, wcn->chan_survey[idx].rssi = rssi; wcn->chan_survey[idx].snr = snr; spin_unlock(&wcn->survey_lock); + + add_device_randomness(&snr, sizeof(int)); } int wcn36xx_rx_skb(struct wcn36xx *wcn, struct sk_buff *skb)
The signal-to-noise-ratio of a received frame is a representation of noise in a given received frame. RSSI - received signal strength indication can appear pretty static frame-to-frame but noise will "bounce around" more depending on the EM environment, temperature or placement of obstacles between the transmitter and receiver. Other WiFi drivers offer up the noise component of the FFT as an entropy source for the random pool i.e. Commit: 2aa56cca3571 ("ath9k: Mix the received FFT bins to the random pool") I attended Jason's talk on sources of randomness at Plumbers and it occured to me that SNR is a reasonable candidate to add. Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> --- drivers/net/wireless/ath/wcn36xx/txrx.c | 3 +++ 1 file changed, 3 insertions(+)