On Tue, 13 Feb 2024 10:49:43 +0100
Heinrich Schuchardt <xypron.g...@gmx.de> wrote:
> On 2/13/24 10:16, Stefan Roese wrote:
> > Hi Max,
> >
> > mostly some nitpicking comments below.
> >
> > On 2/11/24 14:04, Max Resch 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 v4:
> >> - wrongful/missing git rebase
> >>
> >> Changes in v3:
> >> - More meaningful variable names in accordance with review
> >>
> >> 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..ec2cb0bca3
> >> --- /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 };
>
> On a device with memory above 4 GiB this (u32) conversion may point to a
> different location than rwtm_rng_priv.
>
> Is the Armada 3700 family restricted to below 4 GiB?
Indeed it is. Only virtual memory can be mapped to higher locations,
all physical resources (DDR, registers, PCIe, DMA, rWTM) can only be
confiured with 32 bits.
> Should we add a check in the probe function?
No need.
