At least the D1 variant requires a separate clock for the TRNG.
Without this clock enabled, reading from /dev/hwrng reports:

   sun8i-ce 3040000.crypto: DMA timeout for TRNG (tm=96) on flow 3

Experimentation shows that the necessary clock is the SoC's internal
RC oscillator. This makes sense, as noise from the oscillator can be
used as a source of entropy.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

Changes in v2:
 - New patch for v2

 drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c | 1 +
 drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h      | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
index 9f6594699835..a6865ff4d400 100644
--- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
@@ -118,6 +118,7 @@ static const struct ce_variant ce_d1_variant = {
 		{ "bus", 0, 200000000 },
 		{ "mod", 300000000, 0 },
 		{ "ram", 0, 400000000 },
+		{ "trng", 0, 0 },
 		},
 	.esr = ESR_D1,
 	.prng = CE_ALG_PRNG,
diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
index 8177aaba4434..27029fb77e29 100644
--- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
@@ -105,7 +105,7 @@
 
 #define MAX_SG 8
 
-#define CE_MAX_CLOCKS 3
+#define CE_MAX_CLOCKS 4
 
 #define MAXFLOW 4
 
-- 
2.37.4

Le Sat, Dec 31, 2022 at 04:01:44PM -0600, Samuel Holland a écrit :
> At least the D1 variant requires a separate clock for the TRNG.
> Without this clock enabled, reading from /dev/hwrng reports:
> 
>    sun8i-ce 3040000.crypto: DMA timeout for TRNG (tm=96) on flow 3
> 
> Experimentation shows that the necessary clock is the SoC's internal
> RC oscillator. This makes sense, as noise from the oscillator can be
> used as a source of entropy.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
> 

Acked-by: Corentin Labbe <clabbe.montjoie@gmail.com>

Thanks

Dne sobota, 31. december 2022 ob 23:01:44 CET je Samuel Holland napisal(a):
> At least the D1 variant requires a separate clock for the TRNG.
> Without this clock enabled, reading from /dev/hwrng reports:
> 
>    sun8i-ce 3040000.crypto: DMA timeout for TRNG (tm=96) on flow 3
> 
> Experimentation shows that the necessary clock is the SoC's internal
> RC oscillator. This makes sense, as noise from the oscillator can be
> used as a source of entropy.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>

Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Best regards,
Jernej