[PATCH 1/1] drivers/rng: add Amlogic hardware RNG driver

[Neil Armstrong]

Hi,

Le 24/02/2020 à 23:21, Heinrich Schuchardt a écrit :
> Add support for the hardware random number generator of Amlogic SOCs.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>  drivers/rng/Kconfig     |   8 +++
>  drivers/rng/Makefile    |   1 +
>  drivers/rng/meson-rng.c | 120 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 129 insertions(+)
>  create mode 100644 drivers/rng/meson-rng.c
> 
> diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
> index c1aa43b823..edb6152bb9 100644
> --- a/drivers/rng/Kconfig
> +++ b/drivers/rng/Kconfig
> @@ -8,6 +8,14 @@ config DM_RNG
> 
>  if DM_RNG
> 
> +config RNG_MESON
> +	bool "Amlogic Meson Random Number Generator support"
> +	depends on ARCH_MESON
> +	default y
> +	help
> +	  Enable support for hardware random number generator
> +	  of Amlogic Meson SoCs.
> +
>  config RNG_SANDBOX
>  	bool "Sandbox random number generator"
>  	depends on SANDBOX
> diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
> index 3517005541..6a8a66779b 100644
> --- a/drivers/rng/Makefile
> +++ b/drivers/rng/Makefile
> @@ -4,5 +4,6 @@
>  #
> 
>  obj-$(CONFIG_DM_RNG) += rng-uclass.o
> +obj-$(CONFIG_RNG_MESON) += meson-rng.o
>  obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
>  obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
> diff --git a/drivers/rng/meson-rng.c b/drivers/rng/meson-rng.c
> new file mode 100644
> index 0000000000..4b81a62353
> --- /dev/null
> +++ b/drivers/rng/meson-rng.c
> @@ -0,0 +1,120 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright 2020, Heinrich Schuchardt <xypron.glpk at gmx.de>
> + *
> + * Driver for Amlogic hardware random number generator
> + */
> +
> +#include <common.h>
> +#include <clk.h>
> +#include <dm.h>
> +#include <rng.h>
> +#include <asm/io.h>
> +
> +struct meson_rng_platdata {
> +	fdt_addr_t base;
> +	struct clk clk;
> +};
> +
> +/**
> + * meson_rng_read() - fill buffer with random bytes
> + *
> + * @buffer:	buffer to receive data
> + * @size:	size of buffer
> + *
> + * Return:	0
> + */
> +static int meson_rng_read(struct udevice *dev, void *data, size_t len)
> +{
> +	struct meson_rng_platdata *pdata = dev_get_platdata(dev);
> +	char *buffer = (char *)data;
> +
> +	while (len) {
> +		u32 rand = readl(pdata->base);
> +		size_t step;
> +
> +		if (len >= 4)
> +			step = 4;
> +		else
> +			step = len;
> +		memcpy(buffer, &rand, step);
> +		buffer += step;
> +		len -= step;
> +	}
> +	return 0;
> +}
> +
> +/**
> + * meson_rng_probe() - probe rng device
> + *
> + * @dev:	device
> + * Return:	0 if ok
> + */
> +static int meson_rng_probe(struct udevice *dev)
> +{
> +	struct meson_rng_platdata *pdata = dev_get_platdata(dev);
> +	int err;
> +
> +	err = clk_enable(&pdata->clk);
> +	if (err)
> +		return err;
> +
> +	return 0;
> +}
> +
> +/**
> + * meson_rng_remove() - deinitialize rng device
> + *
> + * @dev:	device
> + * Return:	0 if ok
> + */
> +static int meson_rng_remove(struct udevice *dev)
> +{
> +	struct meson_rng_platdata *pdata = dev_get_platdata(dev);
> +
> +	return clk_disable(&pdata->clk);
> +}
> +
> +/**
> + * meson_rng_ofdata_to_platdata() - transfer device tree data to plaform data
> + *
> + * @dev:	device
> + * Return:	0 if ok
> + */
> +static int meson_rng_ofdata_to_platdata(struct udevice *dev)
> +{
> +	struct meson_rng_platdata *pdata = dev_get_platdata(dev);
> +	int err;
> +
> +	pdata->base = dev_read_addr(dev);
> +	if (!pdata->base)
> +		return -ENODEV;
> +
> +	err = clk_get_by_name(dev, "core", &pdata->clk);
> +	if (err)
> +		return err;
> +
> +	return 0;
> +}
> +
> +static const struct dm_rng_ops meson_rng_ops = {
> +	.read = meson_rng_read,
> +};
> +
> +static const struct udevice_id meson_rng_match[] = {
> +	{
> +		.compatible = "amlogic,meson-rng",
> +	},
> +	{},
> +};
> +
> +U_BOOT_DRIVER(meson_rng) = {
> +	.name = "meson-rng",
> +	.id = UCLASS_RNG,
> +	.of_match = meson_rng_match,
> +	.ops = &meson_rng_ops,
> +	.probe = meson_rng_probe,
> +	.remove = meson_rng_remove,
> +	.platdata_auto_alloc_size = sizeof(struct meson_rng_platdata),
> +	.ofdata_to_platdata = meson_rng_ofdata_to_platdata,
> +};
> --
> 2.20.1
> 

Reviewed-by: Neil Armstrong <narmstrong at baylibre.com>

Thanks, looks fine.

I suspect this will help adding EFI RNG data for Linux early random seed, right ?

Is there a RNG maintainer or should I apply it myself ?

Neil