[PATCH v2] hwrng: histb - Move driver to drivers/char/hw_random/histb-rng.c

[David Yang <mmyangfl@gmail.com>]

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>
---
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", },
 	{ }
 };
+MODULE_DEVICE_TABLE(of, histb_rng_of_match);
 
-static struct platform_driver histb_trng_driver = {
-	.probe = histb_trng_probe,
+static struct platform_driver histb_rng_driver = {
+	.probe = histb_rng_probe,
 	.driver = {
-		.name = "histb-trng",
-		.of_match_table = histb_trng_of_match,
-		.dev_groups = histb_trng_groups,
+		.name = "histb-rng",
+		.of_match_table = histb_rng_of_match,
+		.dev_groups = histb_rng_groups,
 	},
 };
 
-module_platform_driver(histb_trng_driver);
+module_platform_driver(histb_rng_driver);
 
-MODULE_DESCRIPTION("HiSTB True RNG");
+MODULE_DESCRIPTION("Hisilicon STB random number generator driver");
 MODULE_LICENSE("Dual MIT/GPL");
 MODULE_AUTHOR("David Yang <mmyangfl@gmail.com>");
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
-- 
2.39.2