Hello Max,
Out of curiousity, what is your use case for having these random
numbers on this platform in U-Boot?
Below are a few more things to change and then you I'll give my
Reviewed-by tag.
On Sun, 21 Jan 2024 21:17:16 +0100
Max Resch <resch....@gmail.com> wrote:
> A RNG driver for Armada 3720 boards running the Turris Mox rWTM firmware
> from CZ.NIC in the secure processor.
>
> Signed-off-by: Max Resch <resch....@gmail.com>
> ---
>
> Changes in v2:
> - Removed ring buffer implementation
>
> drivers/rng/Kconfig | 8 +++
> drivers/rng/Makefile | 1 +
> drivers/rng/turris_rwtm_rng.c | 122 ++++++++++++++++++++++++++++++++++
> 3 files changed, 131 insertions(+)
> create mode 100644 drivers/rng/turris_rwtm_rng.c
>
> diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
> index a89c899568..cd72852a47 100644
> --- a/drivers/rng/Kconfig
> +++ b/drivers/rng/Kconfig
> @@ -105,4 +105,12 @@ config RNG_JH7110
> help
> Enable True Random Number Generator in StarFive JH7110 SoCs.
>
> +config RNG_TURRIS_RWTM
> + bool "Turris Mox TRNG in Secure Processor"
> + depends on DM_RNG && ARMADA_3700
> + help
> + Use TRNG in Turris Mox Secure Processor Firmware. Can be used
> + on other Armada-3700 devices (like EspressoBin) if Secure
> + Firmware from CZ.NIC is used.
> +
> endif
> diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
> index 7e64c4cdfc..ecae1a3da3 100644
> --- a/drivers/rng/Makefile
> +++ b/drivers/rng/Makefile
> @@ -17,3 +17,4 @@ obj-$(CONFIG_RNG_SMCCC_TRNG) += smccc_trng.o
> obj-$(CONFIG_RNG_ARM_RNDR) += arm_rndr.o
> obj-$(CONFIG_TPM_RNG) += tpm_rng.o
> obj-$(CONFIG_RNG_JH7110) += jh7110_rng.o
> +obj-$(CONFIG_RNG_TURRIS_RWTM) += turris_rwtm_rng.o
> diff --git a/drivers/rng/turris_rwtm_rng.c b/drivers/rng/turris_rwtm_rng.c
> new file mode 100644
> index 0000000000..143fe0b47f
> --- /dev/null
> +++ b/drivers/rng/turris_rwtm_rng.c
> @@ -0,0 +1,122 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause
> +/*
> + * Copyright (c) 2024, Max Resch
> + */
> +
> +#include <dm.h>
> +#include <malloc.h>
> +#include <rng.h>
> +#include <asm/dma-mapping.h>
> +#include <asm/types.h>
> +#include <mach/mbox.h>
> +
> +/* size of entropy buffer */
> +#define RNG_BUFFER_SIZE 128U
> +
> +struct turris_rwtm_rng_priv {
> + phys_addr_t buffer;
> +};
> +
> +static int turris_rwtm_rng_fill_entropy(phys_addr_t entropy, size_t size)
> +{
> + u32 args[3] = { 1, (u32)entropy, size };
> + int ret;
> +
> + /* flush data cache */
> + flush_dcache_range(entropy, entropy + size);
> +
> + /*
> + * get entropy
> + * args[0] = 1 copies BYTES array in args[1] of length args[2]
> + */
> + ret = mbox_do_cmd(MBOX_CMD_GET_RANDOM, args, 3, NULL, 0);
> + if (ret < 0)
> + return ret;
> +
> + /* invalidate data cache */
> + invalidate_dcache_range(entropy, entropy + size);
> +
> + return 0;
> +}
> +
> +static int turris_rwtm_rng_random_read(struct udevice *dev, void *data,
> size_t count)
> +{
> + phys_addr_t p;
> + size_t size;
> + int ret;
> +
> + p = ((struct turris_rwtm_rng_priv *)dev_get_priv(dev))->buffer;
Please declare
struct turris_rwtm_rng_priv *priv = dev_get_priv(dev);
phys_addr_t phys;
size_t size;
int ret;
and then do
phys = priv->buffer;
> + while (count) {
> + size = min_t(size_t, RNG_BUFFER_SIZE, count);
> +
> + ret = turris_rwtm_rng_fill_entropy(p, size);
> +
> + memcpy(data, (void *)p, size);
> + count -= size;
> + data = (u8 *)data + size;
> + }
> +
> + return 0;
> +}
> +
> +static int turris_rwtm_rng_probe(struct udevice *dev)
> +{
> + struct turris_rwtm_rng_priv *priv;
= dev_get_priv(dev);
> + u32 args[] = { 0 };
> + int ret;
> +
> + /*
> + * check if the random command is supported
> + * args[0] = 0 would copy 16 DWORDS entropy to out but we ignore them
> + */
> + ret = mbox_do_cmd(MBOX_CMD_GET_RANDOM, args, ARRAY_SIZE(args), NULL, 0);
> +
> + if (ret < 0)
> + return ret;
> +
> + /* entropy buffer */
> + priv = (struct turris_rwtm_rng_priv *)dev_get_priv(dev);
no need here, do it at the beginning
> + priv->buffer = 0;
> +
> + /* buffer address need to be aligned */
> + dma_alloc_coherent(RNG_BUFFER_SIZE, (unsigned long *)&priv->buffer);
> + if (!priv->buffer)
> + return -ENOMEM;
> +
> + return 0;
> +}
> +
> +static int turris_rwtm_rng_remove(struct udevice *dev)
> +{
> + phys_addr_t p;
rename this to phys, and please do it as I described above.
> +
> + p = ((struct turris_rwtm_rng_priv *)dev_get_priv(dev))->buffer;
> + dma_free_coherent((void *)p);
> +
> + return 0;
Marek
