[PATCH v2 1/2] rng: Add iProc RNG200 driver
Heinrich Schuchardt
xypron.glpk at gmx.de
Tue Dec 15 21:04:31 CET 2020
On 12/15/20 10:49 AM, matthias.bgg at kernel.org wrote:
> From: Matthias Brugger <mbrugger at suse.com>
>
> Add support for random number generator RNG200.
> This is for example found on RPi4.
>
> Signed-off-by: Matthias Brugger <mbrugger at suse.com>
The rng command shows random data:
U-Boot> rng
00000000: 25 50 2d a3 c2 9b 1e ac a7 be 01 aa e5 05 f7 09 %P-.............
00000010: d7 e9 ae 88 b0 e6 dc 8c ae dd 74 53 1f 33 5c b5 ..........tS.3\.
00000020: 5d 1b 12 95 17 88 34 7d 6f 88 90 cc 49 de 57 65 ].....4}o...I.We
00000030: 21 5e 3b 97 a2 e3 18 07 77 82 4d 9a 72 db 0f ed !^;.....w.M.r...
Tested-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>
> Changes in v2: None
>
> drivers/rng/Kconfig | 6 ++
> drivers/rng/Makefile | 1 +
> drivers/rng/iproc_rng200.c | 186 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 193 insertions(+)
> create mode 100644 drivers/rng/iproc_rng200.c
>
> diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
> index 11001c8ae7..94915d45b3 100644
> --- a/drivers/rng/Kconfig
> +++ b/drivers/rng/Kconfig
> @@ -46,4 +46,10 @@ config RNG_ROCKCHIP
> Enable random number generator for rockchip.This driver is
> support rng module of crypto v1 and crypto v2.
>
> +config RNG_IPROC200
> + bool "Broadcom iProc RNG200 random number generator"
> + depends on DM_RNG
> + default n
> + help
> + Enable random number generator for RPI4.
> endif
> diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
> index 8953406882..39f7ee3f03 100644
> --- a/drivers/rng/Makefile
> +++ b/drivers/rng/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
> obj-$(CONFIG_RNG_MSM) += msm_rng.o
> obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
> obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o
> +obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o
> diff --git a/drivers/rng/iproc_rng200.c b/drivers/rng/iproc_rng200.c
> new file mode 100644
> index 0000000000..1063f43953
> --- /dev/null
> +++ b/drivers/rng/iproc_rng200.c
> @@ -0,0 +1,186 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright 2020, Matthias Brugger <mbrugger at suse.com>
> + *
> + * Driver for Raspberry Pi hardware random number generator
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <linux/delay.h>
> +#include <rng.h>
> +#include <asm/io.h>
> +
> +#define usleep_range(a, b) udelay((b))
> +
> +#define RNG_CTRL_OFFSET 0x00
> +#define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF
> +#define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001
> +#define RNG_CTRL_RNG_RBGEN_DISABLE 0x00000000
> +
> +#define RNG_SOFT_RESET_OFFSET 0x04
> +#define RNG_SOFT_RESET 0x00000001
> +
> +#define RBG_SOFT_RESET_OFFSET 0x08
> +#define RBG_SOFT_RESET 0x00000001
> +
> +#define RNG_INT_STATUS_OFFSET 0x18
> +#define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK 0x80000000
> +#define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK 0x00000020
> +
> +#define RNG_FIFO_DATA_OFFSET 0x20
> +
> +#define RNG_FIFO_COUNT_OFFSET 0x24
> +#define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK 0x000000FF
> +
> +struct iproc_rng200_platdata {
> + fdt_addr_t base;
> +};
> +
> +static void iproc_rng200_enable(struct iproc_rng200_platdata *pdata, bool enable)
> +{
> + fdt_addr_t rng_base = pdata->base;
> + u32 val;
> +
> + val = readl(rng_base + RNG_CTRL_OFFSET);
> + val &= ~RNG_CTRL_RNG_RBGEN_MASK;
> + if (enable)
> + val |= RNG_CTRL_RNG_RBGEN_ENABLE;
> + else
> + val &= ~RNG_CTRL_RNG_RBGEN_ENABLE;
> +
> + writel(val, rng_base + RNG_CTRL_OFFSET);
> +
> +}
> +
> +static void iproc_rng200_restart(struct iproc_rng200_platdata *pdata)
> +{
> + fdt_addr_t rng_base = pdata->base;
> + u32 val;
> +
> + iproc_rng200_enable(pdata, false);
> +
> + /* Clear all interrupt status */
> + writel(0xFFFFFFFFUL, rng_base + RNG_INT_STATUS_OFFSET);
> +
> + /* Reset RNG and RBG */
> + val = readl(rng_base + RBG_SOFT_RESET_OFFSET);
> + val |= RBG_SOFT_RESET;
> + writel(val, rng_base + RBG_SOFT_RESET_OFFSET);
> +
> + val = readl(rng_base + RNG_SOFT_RESET_OFFSET);
> + val |= RNG_SOFT_RESET;
> + writel(val, rng_base + RNG_SOFT_RESET_OFFSET);
> +
> + val = readl(rng_base + RNG_SOFT_RESET_OFFSET);
> + val &= ~RNG_SOFT_RESET;
> + writel(val, rng_base + RNG_SOFT_RESET_OFFSET);
> +
> + val = readl(rng_base + RBG_SOFT_RESET_OFFSET);
> + val &= ~RBG_SOFT_RESET;
> + writel(val, rng_base + RBG_SOFT_RESET_OFFSET);
> +
> + iproc_rng200_enable(pdata, true);
> +}
> +
> +static int iproc_rng200_read(struct udevice *dev, void *data, size_t len)
> +{
> + struct iproc_rng200_platdata *priv = dev_get_platdata(dev);
> + char *buf = (char *)data;
> + u32 num_remaining = len;
> + u32 status;
> +
> + #define MAX_RESETS_PER_READ 1
> + u32 num_resets = 0;
> +
> + while (num_remaining > 0) {
> +
> + /* Is RNG sane? If not, reset it. */
> + status = readl(priv->base + RNG_INT_STATUS_OFFSET);
> + if ((status & (RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK |
> + RNG_INT_STATUS_NIST_FAIL_IRQ_MASK)) != 0) {
> +
> + if (num_resets >= MAX_RESETS_PER_READ)
> + return len - num_remaining;
> +
> + iproc_rng200_restart(priv);
> + num_resets++;
> + }
> +
> + /* Are there any random numbers available? */
> + if ((readl(priv->base + RNG_FIFO_COUNT_OFFSET) &
> + RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK) > 0) {
> +
> + if (num_remaining >= sizeof(u32)) {
> + /* Buffer has room to store entire word */
> + *(u32 *)buf = readl(priv->base +
> + RNG_FIFO_DATA_OFFSET);
> + buf += sizeof(u32);
> + num_remaining -= sizeof(u32);
> + } else {
> + /* Buffer can only store partial word */
> + u32 rnd_number = readl(priv->base +
> + RNG_FIFO_DATA_OFFSET);
> + memcpy(buf, &rnd_number, num_remaining);
> + buf += num_remaining;
> + num_remaining = 0;
> + }
> +
> + } else {
> + /* Can wait, give others chance to run */
> + usleep_range(min(num_remaining * 10, 500U), 500);
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int iproc_rng200_probe(struct udevice *dev)
> +{
> + struct iproc_rng200_platdata *priv = dev_get_platdata(dev);
> +
> + iproc_rng200_enable(priv, true);
> +
> + return 0;
> +}
> +
> +static int iproc_rng200_remove(struct udevice *dev)
> +{
> + struct iproc_rng200_platdata *priv = dev_get_platdata(dev);
> +
> + iproc_rng200_enable(priv, false);
> +
> + return 0;
> +}
> +
> +static int iproc_rng200_ofdata_to_platdata(struct udevice *dev)
> +{
> + struct iproc_rng200_platdata *pdata = dev_get_platdata(dev);
> +
> + pdata->base = dev_read_addr(dev);
> + if (!pdata->base)
> + return -ENODEV;
> +
> + return 0;
> +}
> +
> +static const struct dm_rng_ops iproc_rng200_ops = {
> + .read = iproc_rng200_read,
> +};
> +
> +static const struct udevice_id iproc_rng200_rng_match[] = {
> + { .compatible = "brcm,bcm2711-rng200", },
> + { .compatible = "brcm,iproc-rng200", },
> + {},
> +};
> +
> +U_BOOT_DRIVER(iproc_rng200_rng) = {
> + .name = "iproc_rng200-rng",
> + .id = UCLASS_RNG,
> + .of_match = iproc_rng200_rng_match,
> + .ops = &iproc_rng200_ops,
> + .probe = iproc_rng200_probe,
> + .remove = iproc_rng200_remove,
> + .platdata_auto_alloc_size = sizeof(struct iproc_rng200_platdata),
> + .ofdata_to_platdata = iproc_rng200_ofdata_to_platdata,
> +};
>
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