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>

4 files changed, 1 insertions, 187 deletions

diff --git a/drivers/crypto/hisilicon/Kconfig b/drivers/crypto/hisilicon/Kconfig
index e8690c223584..4137a8bf131f 100644
--- a/drivers/crypto/hisilicon/Kconfig
+++ b/drivers/crypto/hisilicon/Kconfig
@@ -82,10 +82,3 @@ config CRYPTO_DEV_HISI_TRNG
 	select CRYPTO_RNG
 	help
 	  Support for HiSilicon TRNG Driver.
-
-config CRYPTO_DEV_HISTB_TRNG
-	tristate "Support for HiSTB TRNG Driver"
-	depends on ARCH_HISI || COMPILE_TEST
-	select HW_RANDOM
-	help
-	  Support for HiSTB TRNG Driver.
diff --git a/drivers/crypto/hisilicon/Makefile b/drivers/crypto/hisilicon/Makefile
index fc51e0edec69..8595a5a5d228 100644
--- a/drivers/crypto/hisilicon/Makefile
+++ b/drivers/crypto/hisilicon/Makefile
@@ -5,4 +5,4 @@ obj-$(CONFIG_CRYPTO_DEV_HISI_SEC2) += sec2/
 obj-$(CONFIG_CRYPTO_DEV_HISI_QM) += hisi_qm.o
 hisi_qm-objs = qm.o sgl.o debugfs.o
 obj-$(CONFIG_CRYPTO_DEV_HISI_ZIP) += zip/
-obj-y += trng/
+obj-$(CONFIG_CRYPTO_DEV_HISI_TRNG) += trng/
diff --git a/drivers/crypto/hisilicon/trng/Makefile b/drivers/crypto/hisilicon/trng/Makefile
index cf20b057c66b..d909079f351c 100644
--- a/drivers/crypto/hisilicon/trng/Makefile
+++ b/drivers/crypto/hisilicon/trng/Makefile
@@ -1,5 +1,2 @@
 obj-$(CONFIG_CRYPTO_DEV_HISI_TRNG) += hisi-trng-v2.o
 hisi-trng-v2-objs = trng.o
-
-obj-$(CONFIG_CRYPTO_DEV_HISTB_TRNG) += histb-trng.o
-histb-trng-objs += trng-stb.o
diff --git a/drivers/crypto/hisilicon/trng/trng-stb.c b/drivers/crypto/hisilicon/trng/trng-stb.c
deleted file mode 100644
index 29200a7d3d81..000000000000
--- a/drivers/crypto/hisilicon/trng/trng-stb.c
+++ /dev/null
@@ -1,176 +0,0 @@
-// 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/module.h>
-#include <linux/mutex.h>
-#include <linux/of_device.h>
-
-#define HISTB_TRNG_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  DATA_COUNT			GENMASK(2, 0)	/* max 4 */
-
-struct histb_trng_priv {
-	struct hwrng rng;
-	void __iomem *base;
-};
-
-/*
- * Observed:
- * depth = 1 -> ~1ms
- * depth = 255 -> ~16ms
- */
-static int histb_trng_wait(void __iomem *base)
-{
-	u32 val;
-
-	return readl_relaxed_poll_timeout(base + HISTB_TRNG_STAT, val,
-					  val & DATA_COUNT, 1000, 30 * 1000);
-}
-
-static void histb_trng_init(void __iomem *base, unsigned int depth)
-{
-	u32 val;
-
-	val = readl_relaxed(base + HISTB_TRNG_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 + HISTB_TRNG_CTRL);
-}
-
-static int histb_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
-{
-	struct histb_trng_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 (!wait)
-				return i;
-			if (histb_trng_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);
-	}
-
-	return max;
-}
-
-static unsigned int histb_trng_get_depth(void __iomem *base)
-{
-	return (readl_relaxed(base + HISTB_TRNG_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);
-	void __iomem *base = priv->base;
-
-	return sprintf(buf, "%d\n", histb_trng_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);
-	void __iomem *base = priv->base;
-	unsigned int depth;
-
-	if (kstrtouint(buf, 0, &depth))
-		return -ERANGE;
-
-	histb_trng_init(base, depth);
-	return count;
-}
-
-static DEVICE_ATTR_RW(depth);
-
-static struct attribute *histb_trng_attrs[] = {
-	&dev_attr_depth.attr,
-	NULL,
-};
-
-ATTRIBUTE_GROUPS(histb_trng);
-
-static int histb_trng_probe(struct platform_device *pdev)
-{
-	struct device *dev = &pdev->dev;
-	struct histb_trng_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 -ENOMEM;
-
-	histb_trng_init(base, 144);
-	if (histb_trng_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;
-	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_trng_of_match[] = {
-	{ .compatible = "hisilicon,histb-trng", },
-	{ }
-};
-
-static struct platform_driver histb_trng_driver = {
-	.probe = histb_trng_probe,
-	.driver = {
-		.name = "histb-trng",
-		.of_match_table = histb_trng_of_match,
-		.dev_groups = histb_trng_groups,
-	},
-};
-
-module_platform_driver(histb_trng_driver);
-
-MODULE_DESCRIPTION("HiSTB True RNG");
-MODULE_LICENSE("Dual MIT/GPL");
-MODULE_AUTHOR("David Yang <mmyangfl@gmail.com>");