Re: [PATCH v2] hwrng: histb - Move driver to drivers/char/hw_random/histb-rng.c
From: Rob Herring
Date: Wed Jun 07 2023 - 13:29:32 EST
On Sat, Apr 22, 2023 at 12:56:49AM +0800, David Yang wrote:
> Move to drivers/char/hw_random since histb-(t)rng does not provide
> cryptography pseudo rng.
>
> histb-rng is pretty like hisi-rng, but after investigation, we confirm
> there is no RNG_PHY_SEED register on histb-rng so a separate driver is
> needed.
>
> Still we rename relevant function names to match those in hisi-rng.
>
> Link: https://lore.kernel.org/r/20230401164448.1393336-1-mmyangfl@xxxxxxxxx
> Signed-off-by: David Yang <mmyangfl@xxxxxxxxx>
> ---
> v2: drop the dependency on HW_RANDOM
> drivers/char/hw_random/Kconfig | 11 +++
> drivers/char/hw_random/Makefile | 1 +
> .../trng-stb.c => char/hw_random/histb-rng.c} | 83 +++++++++----------
> drivers/crypto/hisilicon/Kconfig | 7 --
> drivers/crypto/hisilicon/Makefile | 2 +-
> drivers/crypto/hisilicon/trng/Makefile | 3 -
> 6 files changed, 53 insertions(+), 54 deletions(-)
> rename drivers/{crypto/hisilicon/trng/trng-stb.c => char/hw_random/histb-rng.c} (53%)
>
> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> index 4fdf07ae3c54..c92f146ee89a 100644
> --- a/drivers/char/hw_random/Kconfig
> +++ b/drivers/char/hw_random/Kconfig
> @@ -335,6 +335,17 @@ config HW_RANDOM_HISI
>
> If unsure, say Y.
>
> +config HW_RANDOM_HISTB
> + tristate "Hisilicon STB Random Number Generator support"
> + depends on ARCH_HISI || COMPILE_TEST
> + default ARCH_HISI
> + help
> + This driver provides kernel-side support for the Random Number
> + Generator hardware found on Hisilicon Hi37xx SoC.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called histb-rng.
> +
> config HW_RANDOM_ST
> tristate "ST Microelectronics HW Random Number Generator support"
> depends on HW_RANDOM && ARCH_STI
> diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
> index 09bde4a0f971..32549a1186dc 100644
> --- a/drivers/char/hw_random/Makefile
> +++ b/drivers/char/hw_random/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
> obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
> obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
> obj-$(CONFIG_HW_RANDOM_HISI) += hisi-rng.o
> +obj-$(CONFIG_HW_RANDOM_HISTB) += histb-rng.o
> obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
> obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
> obj-$(CONFIG_HW_RANDOM_ST) += st-rng.o
> diff --git a/drivers/crypto/hisilicon/trng/trng-stb.c b/drivers/char/hw_random/histb-rng.c
> similarity index 53%
> rename from drivers/crypto/hisilicon/trng/trng-stb.c
> rename to drivers/char/hw_random/histb-rng.c
> index 29200a7d3d81..f652e1135e4b 100644
> --- a/drivers/crypto/hisilicon/trng/trng-stb.c
> +++ b/drivers/char/hw_random/histb-rng.c
> @@ -1,31 +1,27 @@
> // SPDX-License-Identifier: GPL-2.0-or-later OR MIT
> /*
> - * Device driver for True RNG in HiSTB SoCs
> - *
> * Copyright (c) 2023 David Yang
> */
>
> -#include <crypto/internal/rng.h>
> -#include <linux/device.h>
> #include <linux/err.h>
> #include <linux/hw_random.h>
> #include <linux/io.h>
> #include <linux/iopoll.h>
> #include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> #include <linux/module.h>
> -#include <linux/mutex.h>
> -#include <linux/of_device.h>
> +#include <linux/platform_device.h>
>
> -#define HISTB_TRNG_CTRL 0x0
> +#define RNG_CTRL 0x0
> #define RNG_SOURCE GENMASK(1, 0)
> #define DROP_ENABLE BIT(5)
> #define POST_PROCESS_ENABLE BIT(7)
> #define POST_PROCESS_DEPTH GENMASK(15, 8)
> -#define HISTB_TRNG_NUMBER 0x4
> -#define HISTB_TRNG_STAT 0x8
> +#define RNG_NUMBER 0x4
> +#define RNG_STAT 0x8
> #define DATA_COUNT GENMASK(2, 0) /* max 4 */
>
> -struct histb_trng_priv {
> +struct histb_rng_priv {
> struct hwrng rng;
> void __iomem *base;
> };
> @@ -35,19 +31,19 @@ struct histb_trng_priv {
> * depth = 1 -> ~1ms
> * depth = 255 -> ~16ms
> */
> -static int histb_trng_wait(void __iomem *base)
> +static int histb_rng_wait(void __iomem *base)
> {
> u32 val;
>
> - return readl_relaxed_poll_timeout(base + HISTB_TRNG_STAT, val,
> + return readl_relaxed_poll_timeout(base + RNG_STAT, val,
> val & DATA_COUNT, 1000, 30 * 1000);
> }
>
> -static void histb_trng_init(void __iomem *base, unsigned int depth)
> +static void histb_rng_init(void __iomem *base, unsigned int depth)
> {
> u32 val;
>
> - val = readl_relaxed(base + HISTB_TRNG_CTRL);
> + val = readl_relaxed(base + RNG_CTRL);
>
> val &= ~RNG_SOURCE;
> val |= 2;
> @@ -58,72 +54,72 @@ static void histb_trng_init(void __iomem *base, unsigned int depth)
> val |= POST_PROCESS_ENABLE;
> val |= DROP_ENABLE;
>
> - writel_relaxed(val, base + HISTB_TRNG_CTRL);
> + writel_relaxed(val, base + RNG_CTRL);
> }
>
> -static int histb_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
> +static int histb_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
> {
> - struct histb_trng_priv *priv = container_of(rng, typeof(*priv), rng);
> + struct histb_rng_priv *priv = container_of(rng, typeof(*priv), rng);
> void __iomem *base = priv->base;
>
> for (int i = 0; i < max; i += sizeof(u32)) {
> - if (!(readl_relaxed(base + HISTB_TRNG_STAT) & DATA_COUNT)) {
> + if (!(readl_relaxed(base + RNG_STAT) & DATA_COUNT)) {
> if (!wait)
> return i;
> - if (histb_trng_wait(base)) {
> + if (histb_rng_wait(base)) {
> pr_err("failed to generate random number, generated %d\n",
> i);
> return i ? i : -ETIMEDOUT;
> }
> }
> - *(u32 *) (data + i) = readl_relaxed(base + HISTB_TRNG_NUMBER);
> + *(u32 *) (data + i) = readl_relaxed(base + RNG_NUMBER);
> }
>
> return max;
> }
>
> -static unsigned int histb_trng_get_depth(void __iomem *base)
> +static unsigned int histb_rng_get_depth(void __iomem *base)
> {
> - return (readl_relaxed(base + HISTB_TRNG_CTRL) & POST_PROCESS_DEPTH) >> 8;
> + return (readl_relaxed(base + RNG_CTRL) & POST_PROCESS_DEPTH) >> 8;
> }
>
> static ssize_t
> depth_show(struct device *dev, struct device_attribute *attr, char *buf)
> {
> - struct histb_trng_priv *priv = dev_get_drvdata(dev);
> + struct histb_rng_priv *priv = dev_get_drvdata(dev);
> void __iomem *base = priv->base;
>
> - return sprintf(buf, "%d\n", histb_trng_get_depth(base));
> + return sprintf(buf, "%d\n", histb_rng_get_depth(base));
> }
>
> static ssize_t
> depth_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t count)
> {
> - struct histb_trng_priv *priv = dev_get_drvdata(dev);
> + struct histb_rng_priv *priv = dev_get_drvdata(dev);
> void __iomem *base = priv->base;
> unsigned int depth;
>
> if (kstrtouint(buf, 0, &depth))
> return -ERANGE;
>
> - histb_trng_init(base, depth);
> + histb_rng_init(base, depth);
> return count;
> }
>
> static DEVICE_ATTR_RW(depth);
>
> -static struct attribute *histb_trng_attrs[] = {
> +static struct attribute *histb_rng_attrs[] = {
> &dev_attr_depth.attr,
> NULL,
> };
>
> -ATTRIBUTE_GROUPS(histb_trng);
> +ATTRIBUTE_GROUPS(histb_rng);
>
> -static int histb_trng_probe(struct platform_device *pdev)
> +static int histb_rng_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> - struct histb_trng_priv *priv;
> + struct histb_rng_priv *priv;
> void __iomem *base;
> int ret;
>
> @@ -133,17 +129,17 @@ static int histb_trng_probe(struct platform_device *pdev)
>
> base = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(base))
> - return -ENOMEM;
> + return PTR_ERR(base);
>
> - histb_trng_init(base, 144);
> - if (histb_trng_wait(base)) {
> + histb_rng_init(base, 144);
> + if (histb_rng_wait(base)) {
> dev_err(dev, "cannot bring up device\n");
> return -ENODEV;
> }
>
> priv->base = base;
> priv->rng.name = pdev->name;
> - priv->rng.read = histb_trng_read;
> + priv->rng.read = histb_rng_read;
> ret = devm_hwrng_register(dev, &priv->rng);
> if (ret) {
> dev_err(dev, "failed to register hwrng: %d\n", ret);
> @@ -155,22 +151,23 @@ static int histb_trng_probe(struct platform_device *pdev)
> return 0;
> }
>
> -static const struct of_device_id histb_trng_of_match[] = {
> - { .compatible = "hisilicon,histb-trng", },
> +static const struct of_device_id histb_rng_of_match[] = {
> + { .compatible = "hisilicon,histb-rng", },
You can't just change compatible strings as they are an ABI. Seems this
is a newly added driver though, so I guess it's okay. However, neither
string was documented with a DT schema and that must be fixed.
Rob