[RFC/RFT] crypto: rk3288: enable support for TRNG

The rockchip IP has a TRNG which could be used as a hwrng.
Since TRNG is only failling rngtests on rk3328 and does not work on
rk3288, the TRNG is enabled only on rk3399 via a variant.
But this is not a surprise since when vendor tried to add support for TRNG upstream,
rk3288 was not handled, and rk3328 was added "disabled", so I conclude
this is a known problem.
Anyway the quality of rk3399 TRNG is low, so a dedicated kconfig option
is done to not enabled it by default.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
---
Hello

All rk3288 compatible crypto IP have a TRNG and supporting it was awaited for
some time (https://bugzilla.kernel.org/show_bug.cgi?id=216502)

I has some problem with this one, it was the first time I hit so many 100% failure on rngtest.

I finally bisected a RNG_SAMPLE value (1200) which lead to "only" 50-70% failure.
The calcul of fail rate is done with (FIPS 140-2 successes/FIPS 140-2 failures) of rngtest.
Since it is the first time I hit that case, does setting rng_quality to 300 is
what to do (using the worst succes rate of 30%) ?

But I am really puzzled why vendor default is to use RNG_SAMPLE=100 which is total failure (according to rngtest).
Unfortunatly all my try to have more answer from them seems to have been forwarded to /dev/null.

Thanks
Regards
 drivers/crypto/Kconfig                        |  8 ++
 drivers/crypto/rockchip/Makefile              |  1 +
 drivers/crypto/rockchip/rk3288_crypto.c       | 18 +++-
 drivers/crypto/rockchip/rk3288_crypto.h       | 18 ++++
 drivers/crypto/rockchip/rk3288_crypto_ahash.c |  2 +
 .../crypto/rockchip/rk3288_crypto_skcipher.c  |  2 +
 drivers/crypto/rockchip/rk3288_crypto_trng.c  | 92 +++++++++++++++++++
 7 files changed, 140 insertions(+), 1 deletion(-)
 create mode 100644 drivers/crypto/rockchip/rk3288_crypto_trng.c

Hi,

On Fri Jul 7, 2023 at 1:52 PM CEST, Corentin Labbe wrote:
> The rockchip IP has a TRNG which could be used as a hwrng.
> Since TRNG is only failling rngtests on rk3328 and does not work on
> rk3288, the TRNG is enabled only on rk3399 via a variant.
> But this is not a surprise since when vendor tried to add support for TRNG upstream,
> rk3288 was not handled, and rk3328 was added "disabled", so I conclude
> this is a known problem.
> Anyway the quality of rk3399 TRNG is low, so a dedicated kconfig option
> is done to not enabled it by default.
>
> Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
> ---
> Hello
>
> All rk3288 compatible crypto IP have a TRNG and supporting it was awaited for
> some time (https://bugzilla.kernel.org/show_bug.cgi?id=216502)
>
> I has some problem with this one, it was the first time I hit so many 100% failure on rngtest.
>
> I finally bisected a RNG_SAMPLE value (1200) which lead to "only" 50-70% failure.
> The calcul of fail rate is done with (FIPS 140-2 successes/FIPS 140-2 failures) of rngtest.
> Since it is the first time I hit that case, does setting rng_quality to 300 is
> what to do (using the worst succes rate of 30%) ?
>
> But I am really puzzled why vendor default is to use RNG_SAMPLE=100 which is total failure (according to rngtest).
> Unfortunatly all my try to have more answer from them seems to have been forwarded to /dev/null.
>
> Thanks
> Regards

I tested this on a rk3399-rock-pi-4b with the following results:

# uname -a
Linux rockpi-bookworm 6.4.3-dirty #83 SMP PREEMPT Wed Jul 12 09:07:12 CEST 2023 aarch64 GNU/Linux

# sudo ls -l /dev/hwrng
crw------- 1 root root 10, 183 Jan 18 09:52 /dev/hwrng

# cat /sys/devices/virtual/misc/hw_random/rng_current
Rockchip rk3288 TRNG

# sudo dd if=/dev/hwrng count=100 bs=2048 | rngtest
rngtest 5
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

rngtest: starting FIPS tests...
100+0 records in
100+0 records out
204800 bytes (205 kB, 200 KiB) copied, 10.1847 s, 20.1 kB/s
rngtest: entropy source drained
rngtest: bits received from input: 1638400
rngtest: FIPS 140-2 successes: 54
rngtest: FIPS 140-2 failures: 27
rngtest: FIPS 140-2(2001-10-10) Monobit: 27
rngtest: FIPS 140-2(2001-10-10) Poker: 3
rngtest: FIPS 140-2(2001-10-10) Runs: 1
rngtest: FIPS 140-2(2001-10-10) Long run: 0
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=94.195; avg=159.504; max=195.252)Kibits/s
rngtest: FIPS tests speed: (min=17.826; avg=25.180; max=38.377)Mibits/s
rngtest: Program run time: 10221628 microseconds

# sudo dd if=/dev/hwrng count=200 bs=2048 | rngtest
rngtest 5
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

rngtest: starting FIPS tests...
200+0 records in
200+0 records out
409600 bytes (410 kB, 400 KiB) copied, 20.2624 s, 20.2 kB/s
rngtest: entropy source drained
rngtest: bits received from input: 3276800
rngtest: FIPS 140-2 successes: 115
rngtest: FIPS 140-2 failures: 48
rngtest: FIPS 140-2(2001-10-10) Monobit: 48
rngtest: FIPS 140-2(2001-10-10) Poker: 1
rngtest: FIPS 140-2(2001-10-10) Runs: 0
rngtest: FIPS 140-2(2001-10-10) Long run: 0
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=94.636; avg=159.621; max=195.400)Kibits/s
rngtest: FIPS tests speed: (min=25.031; avg=27.258; max=28.639)Mibits/s
rngtest: Program run time: 20297102 microseconds



Tested-by: Folker Schwesinger <dev@folker-schwesinger.de>

Kind regards,

Folker


>  drivers/crypto/Kconfig                        |  8 ++
>  drivers/crypto/rockchip/Makefile              |  1 +
>  drivers/crypto/rockchip/rk3288_crypto.c       | 18 +++-
>  drivers/crypto/rockchip/rk3288_crypto.h       | 18 ++++
>  drivers/crypto/rockchip/rk3288_crypto_ahash.c |  2 +
>  .../crypto/rockchip/rk3288_crypto_skcipher.c  |  2 +
>  drivers/crypto/rockchip/rk3288_crypto_trng.c  | 92 +++++++++++++++++++
>  7 files changed, 140 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/crypto/rockchip/rk3288_crypto_trng.c
>
> diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
> index 44e44b8d9ce6..7226d441686c 100644
> --- a/drivers/crypto/Kconfig
> +++ b/drivers/crypto/Kconfig
> @@ -650,6 +650,14 @@ config CRYPTO_DEV_ROCKCHIP
>  	  This driver interfaces with the hardware crypto accelerator.
>  	  Supporting cbc/ecb chainmode, and aes/des/des3_ede cipher mode.
>  
> +config CRYPTO_DEV_ROCKCHIP_TRNG
> +	bool "Support for Rockchip TRNG"
> +	depends on CRYPTO_DEV_ROCKCHIP
> +	select HW_RANDOM
> +	help
> +	  Select this option if you want to provide kernel-side support for
> +	  the True Random Number Generator found in the Crypto IP.
> +
>  config CRYPTO_DEV_ROCKCHIP_DEBUG
>  	bool "Enable Rockchip crypto stats"
>  	depends on CRYPTO_DEV_ROCKCHIP
> diff --git a/drivers/crypto/rockchip/Makefile b/drivers/crypto/rockchip/Makefile
> index 785277aca71e..11910f0e6a62 100644
> --- a/drivers/crypto/rockchip/Makefile
> +++ b/drivers/crypto/rockchip/Makefile
> @@ -3,3 +3,4 @@ obj-$(CONFIG_CRYPTO_DEV_ROCKCHIP) += rk_crypto.o
>  rk_crypto-objs := rk3288_crypto.o \
>  		  rk3288_crypto_skcipher.o \
>  		  rk3288_crypto_ahash.o
> +rk_crypto-$(CONFIG_CRYPTO_DEV_ROCKCHIP_TRNG) += rk3288_crypto_trng.o
> diff --git a/drivers/crypto/rockchip/rk3288_crypto.c b/drivers/crypto/rockchip/rk3288_crypto.c
> index 9f6ba770a90a..880e4db812a2 100644
> --- a/drivers/crypto/rockchip/rk3288_crypto.c
> +++ b/drivers/crypto/rockchip/rk3288_crypto.c
> @@ -40,15 +40,18 @@ static const struct rk_variant rk3288_variant = {
>  	.num_clks = 4,
>  	.rkclks = {
>  		{ "sclk", 150000000},
> -	}
> +	},
> +	.trng = false,
>  };
>  
>  static const struct rk_variant rk3328_variant = {
>  	.num_clks = 3,
> +	.trng = false,
>  };
>  
>  static const struct rk_variant rk3399_variant = {
>  	.num_clks = 3,
> +	.trng = true,
>  };
>  
>  static int rk_crypto_get_clks(struct rk_crypto_info *dev)
> @@ -195,6 +198,10 @@ static int rk_crypto_debugfs_show(struct seq_file *seq, void *v)
>  		seq_printf(seq, "%s %s requests: %lu\n",
>  			   dev_driver_string(dd->dev), dev_name(dd->dev),
>  			   dd->nreq);
> +#ifdef CONFIG_CRYPTO_DEV_ROCKCHIP_TRNG
> +		seq_printf(seq, "HWRNG: %lu %lu\n",
> +			   dd->hwrng_stat_req, dd->hwrng_stat_bytes);
> +#endif
>  	}
>  	spin_unlock(&rocklist.lock);
>  
> @@ -381,6 +388,10 @@ static int rk_crypto_probe(struct platform_device *pdev)
>  			dev_err(dev, "Fail to register crypto algorithms");
>  			goto err_register_alg;
>  		}
> +#ifdef CONFIG_CRYPTO_DEV_ROCKCHIP_TRNG
> +		if (crypto_info->variant->trng)
> +			rk3288_hwrng_register(crypto_info);
> +#endif
>  
>  		register_debugfs(crypto_info);
>  	}
> @@ -411,6 +422,11 @@ static int rk_crypto_remove(struct platform_device *pdev)
>  #ifdef CONFIG_CRYPTO_DEV_ROCKCHIP_DEBUG
>  		debugfs_remove_recursive(rocklist.dbgfs_dir);
>  #endif
> +#ifdef CONFIG_CRYPTO_DEV_ROCKCHIP_TRNG
> +		if (crypto_tmp->variant->trng)
> +			rk3288_hwrng_unregister(crypto_tmp);
> +#endif
> +
>  		rk_crypto_unregister();
>  	}
>  	rk_crypto_pm_exit(crypto_tmp);
> diff --git a/drivers/crypto/rockchip/rk3288_crypto.h b/drivers/crypto/rockchip/rk3288_crypto.h
> index b2695258cade..016c3b72c19c 100644
> --- a/drivers/crypto/rockchip/rk3288_crypto.h
> +++ b/drivers/crypto/rockchip/rk3288_crypto.h
> @@ -9,6 +9,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/debugfs.h>
>  #include <linux/delay.h>
> +#include <linux/hw_random.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/scatterlist.h>
>  #include <crypto/engine.h>
> @@ -183,6 +184,16 @@
>  #define RK_CRYPTO_HASH_DOUT_6		0x01a4
>  #define RK_CRYPTO_HASH_DOUT_7		0x01a8
>  
> +#define RK_CRYPTO_TRNG_CTRL		0x0200
> +#define RK_CRYPTO_OSC_ENABLE		BIT(16)
> +#define RK_CRYPTO_TRNG_DOUT_0		0x0204
> +/* sample < 1000 lead to 100% failure on rngtest,
> + * using more than 1200 does not increase success.
> + */
> +#define RK_CRYPTO_RNG_SAMPLE		1200
> +
> +#define RK_CRYPTO_MAX_TRNG_BYTE		32
> +
>  #define CRYPTO_READ(dev, offset)		  \
>  		readl_relaxed(((dev)->reg + (offset)))
>  #define CRYPTO_WRITE(dev, offset, val)	  \
> @@ -212,6 +223,7 @@ struct rk_clks {
>  struct rk_variant {
>  	int num_clks;
>  	struct rk_clks rkclks[RK_MAX_CLKS];
> +	bool trng;
>  };
>  
>  struct rk_crypto_info {
> @@ -222,11 +234,15 @@ struct rk_crypto_info {
>  	struct reset_control		*rst;
>  	void __iomem			*reg;
>  	int				irq;
> +	struct mutex			lock;
> +	struct hwrng			hwrng;
>  	const struct rk_variant *variant;
>  	unsigned long nreq;
>  	struct crypto_engine *engine;
>  	struct completion complete;
>  	int status;
> +	unsigned long hwrng_stat_req;
> +	unsigned long hwrng_stat_bytes;
>  };
>  
>  /* the private variable of hash */
> @@ -288,3 +304,5 @@ extern struct rk_crypto_tmp rk_ahash_md5;
>  
>  struct rk_crypto_info *get_rk_crypto(void);
>  #endif
> +int rk3288_hwrng_register(struct rk_crypto_info *rk);
> +void rk3288_hwrng_unregister(struct rk_crypto_info *rk);
> diff --git a/drivers/crypto/rockchip/rk3288_crypto_ahash.c b/drivers/crypto/rockchip/rk3288_crypto_ahash.c
> index a78ff3dcd0b1..67ed3a54bc7b 100644
> --- a/drivers/crypto/rockchip/rk3288_crypto_ahash.c
> +++ b/drivers/crypto/rockchip/rk3288_crypto_ahash.c
> @@ -287,6 +287,7 @@ static int rk_hash_run(struct crypto_engine *engine, void *breq)
>  		goto theend;
>  	}
>  
> +	mutex_lock(&rkc->lock);
>  	rk_ahash_reg_init(areq, rkc);
>  
>  	while (sg) {
> @@ -321,6 +322,7 @@ static int rk_hash_run(struct crypto_engine *engine, void *breq)
>  	}
>  
>  theend:
> +	mutex_unlock(&rkc->lock);
>  	pm_runtime_put_autosuspend(rkc->dev);
>  
>  	local_bh_disable();
> diff --git a/drivers/crypto/rockchip/rk3288_crypto_skcipher.c b/drivers/crypto/rockchip/rk3288_crypto_skcipher.c
> index 59069457582b..304c2c44fea0 100644
> --- a/drivers/crypto/rockchip/rk3288_crypto_skcipher.c
> +++ b/drivers/crypto/rockchip/rk3288_crypto_skcipher.c
> @@ -357,6 +357,7 @@ static int rk_cipher_run(struct crypto_engine *engine, void *async_req)
>  			}
>  		}
>  		err = 0;
> +		mutex_unlock(&rkc->lock);
>  		rk_cipher_hw_init(rkc, areq);
>  		if (ivsize) {
>  			if (ivsize == DES_BLOCK_SIZE)
> @@ -372,6 +373,7 @@ static int rk_cipher_run(struct crypto_engine *engine, void *async_req)
>  		crypto_dma_start(rkc, sgs, sgd, todo / 4);
>  		wait_for_completion_interruptible_timeout(&rkc->complete,
>  							  msecs_to_jiffies(2000));
> +		mutex_unlock(&rkc->lock);
>  		if (!rkc->status) {
>  			dev_err(rkc->dev, "DMA timeout\n");
>  			err = -EFAULT;
> diff --git a/drivers/crypto/rockchip/rk3288_crypto_trng.c b/drivers/crypto/rockchip/rk3288_crypto_trng.c
> new file mode 100644
> index 000000000000..7a0e1300d0e8
> --- /dev/null
> +++ b/drivers/crypto/rockchip/rk3288_crypto_trng.c
> @@ -0,0 +1,92 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * rk3288_crypto_trng.c - hardware cryptographic offloader for rockchip
> + *
> + * Copyright (C) 2022-2023 Corentin Labbe <clabbe@baylibre.com>
> + *
> + * This file handle the TRNG
> + */
> +#include "rk3288_crypto.h"
> +#include <linux/hw_random.h>
> +#include <linux/iopoll.h>
> +#include <linux/pm_runtime.h>
> +
> +static int rk3288_trng_read(struct hwrng *hwrng, void *data, size_t max, bool wait)
> +{
> +	struct rk_crypto_info *rk;
> +	unsigned int todo;
> +	int err = 0;
> +	int i;
> +	u32 v;
> +
> +	rk = container_of(hwrng, struct rk_crypto_info, hwrng);
> +
> +	todo = min_t(size_t, max, RK_CRYPTO_MAX_TRNG_BYTE);
> +
> +#ifdef CONFIG_CRYPTO_DEV_ROCKCHIP_DEBUG
> +	rk->hwrng_stat_req++;
> +	rk->hwrng_stat_bytes += todo;
> +#endif
> +
> +	err = pm_runtime_resume_and_get(rk->dev);
> +	if (err < 0)
> +		goto err_pm;
> +
> +	mutex_lock(&rk->lock);
> +
> +#define HIWORD_UPDATE(val, mask, shift) \
> +			((val) << (shift) | (mask) << ((shift) + 16))
> +	v = RK_CRYPTO_OSC_ENABLE | RK_CRYPTO_RNG_SAMPLE;
> +	CRYPTO_WRITE(rk, RK_CRYPTO_TRNG_CTRL, v);
> +
> +	v = HIWORD_UPDATE(RK_CRYPTO_TRNG_START, RK_CRYPTO_TRNG_START, 0);
> +	CRYPTO_WRITE(rk, RK_CRYPTO_CTRL, v);
> +	wmb();
> +
> +	err = readl_poll_timeout(rk->reg + RK_CRYPTO_CTRL, v,
> +				 !(v & RK_CRYPTO_TRNG_START),
> +				 100, 2000);
> +	if (err) {
> +		dev_err(rk->dev, "HWRNG read timeout");
> +		goto readfail;
> +	}
> +
> +	for (i = 0; i < todo / 4; i++) {
> +		v = readl(rk->reg + RK_CRYPTO_TRNG_DOUT_0 + i * 4);
> +		put_unaligned_le32(v, data + i * 4);
> +	}
> +
> +	err = todo;
> +
> +	v = HIWORD_UPDATE(0, RK_CRYPTO_TRNG_START, 0);
> +	CRYPTO_WRITE(rk, RK_CRYPTO_CTRL, v);
> +
> +readfail:
> +	mutex_unlock(&rk->lock);
> +
> +	pm_runtime_put(rk->dev);
> +
> +err_pm:
> +	return err;
> +}
> +
> +int rk3288_hwrng_register(struct rk_crypto_info *rk)
> +{
> +	int ret;
> +
> +	dev_info(rk->dev, "Register TRNG with sample=%d\n", RK_CRYPTO_RNG_SAMPLE);
> +
> +	rk->hwrng.name = "Rockchip rk3288 TRNG";
> +	rk->hwrng.read = rk3288_trng_read;
> +	rk->hwrng.quality = 300;
> +
> +	ret = hwrng_register(&rk->hwrng);
> +	if (ret)
> +		dev_err(rk->dev, "Fail to register the TRNG\n");
> +	return ret;
> +}
> +
> +void rk3288_hwrng_unregister(struct rk_crypto_info *rk)
> +{
> +	hwrng_unregister(&rk->hwrng);
> +}