diff options
author | David Yang <mmyangfl@gmail.com> | 2023-04-21 19:56:49 +0300 |
---|---|---|
committer | Herbert Xu <herbert@gondor.apana.org.au> | 2023-05-12 13:48:01 +0300 |
commit | 903e6ada01f305eb6c82a27f48bf1ea18eb38a99 (patch) | |
tree | 089538ade3c681c045725bed5973697812799665 /drivers/char/hw_random | |
parent | 69f1c387ba700f69e9fdad6d6ce44a3bb774dbff (diff) | |
download | linux-903e6ada01f305eb6c82a27f48bf1ea18eb38a99.tar.xz |
hwrng: histb - Move driver to drivers/char/hw_random/histb-rng.c
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@gmail.com
Signed-off-by: David Yang <mmyangfl@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/char/hw_random')
-rw-r--r-- | drivers/char/hw_random/Kconfig | 11 | ||||
-rw-r--r-- | drivers/char/hw_random/Makefile | 1 | ||||
-rw-r--r-- | drivers/char/hw_random/histb-rng.c | 173 |
3 files changed, 185 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index dbad0c57e54a..baefa2e0edbc 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/char/hw_random/histb-rng.c b/drivers/char/hw_random/histb-rng.c new file mode 100644 index 000000000000..f652e1135e4b --- /dev/null +++ b/drivers/char/hw_random/histb-rng.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0-or-later OR MIT +/* + * Copyright (c) 2023 David Yang + */ + +#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/platform_device.h> + +#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 RNG_NUMBER 0x4 +#define RNG_STAT 0x8 +#define DATA_COUNT GENMASK(2, 0) /* max 4 */ + +struct histb_rng_priv { + struct hwrng rng; + void __iomem *base; +}; + +/* + * Observed: + * depth = 1 -> ~1ms + * depth = 255 -> ~16ms + */ +static int histb_rng_wait(void __iomem *base) +{ + u32 val; + + return readl_relaxed_poll_timeout(base + RNG_STAT, val, + val & DATA_COUNT, 1000, 30 * 1000); +} + +static void histb_rng_init(void __iomem *base, unsigned int depth) +{ + u32 val; + + val = readl_relaxed(base + RNG_CTRL); + + val &= ~RNG_SOURCE; + val |= 2; + + val &= ~POST_PROCESS_DEPTH; + val |= min(depth, 0xffu) << 8; + + val |= POST_PROCESS_ENABLE; + val |= DROP_ENABLE; + + writel_relaxed(val, base + RNG_CTRL); +} + +static int histb_rng_read(struct hwrng *rng, void *data, size_t max, bool wait) +{ + 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 + RNG_STAT) & DATA_COUNT)) { + if (!wait) + return i; + 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 + RNG_NUMBER); + } + + return max; +} + +static unsigned int histb_rng_get_depth(void __iomem *base) +{ + 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_rng_priv *priv = dev_get_drvdata(dev); + void __iomem *base = priv->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_rng_priv *priv = dev_get_drvdata(dev); + void __iomem *base = priv->base; + unsigned int depth; + + if (kstrtouint(buf, 0, &depth)) + return -ERANGE; + + histb_rng_init(base, depth); + return count; +} + +static DEVICE_ATTR_RW(depth); + +static struct attribute *histb_rng_attrs[] = { + &dev_attr_depth.attr, + NULL, +}; + +ATTRIBUTE_GROUPS(histb_rng); + +static int histb_rng_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct histb_rng_priv *priv; + void __iomem *base; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(base)) + return PTR_ERR(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_rng_read; + ret = devm_hwrng_register(dev, &priv->rng); + if (ret) { + dev_err(dev, "failed to register hwrng: %d\n", ret); + return ret; + } + + platform_set_drvdata(pdev, priv); + dev_set_drvdata(dev, priv); + return 0; +} + +static const struct of_device_id histb_rng_of_match[] = { + { .compatible = "hisilicon,histb-rng", }, + { } +}; +MODULE_DEVICE_TABLE(of, histb_rng_of_match); + +static struct platform_driver histb_rng_driver = { + .probe = histb_rng_probe, + .driver = { + .name = "histb-rng", + .of_match_table = histb_rng_of_match, + .dev_groups = histb_rng_groups, + }, +}; + +module_platform_driver(histb_rng_driver); + +MODULE_DESCRIPTION("Hisilicon STB random number generator driver"); +MODULE_LICENSE("Dual MIT/GPL"); +MODULE_AUTHOR("David Yang <mmyangfl@gmail.com>"); |