hwrng: npcm: add NPCM RNG driver support

Added device tree binding documentation for Nuvoton BMC NPCM Random Number Generator (RNG).

Signed-off-by Tomer Maimon <[email protected]>

---
 .../devicetree/bindings/rng/nuvoton,npcm-rng.txt     | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rng/nuvoton,npcm-rng.txt

Add Nuvoton NPCM BMC Random Number Generator(RNG) driver.

Signed-off-by Tomer Maimon <[email protected]>

---
 drivers/char/hw_random/Kconfig    |  13 +++
 drivers/char/hw_random/Makefile   |   1 +
 drivers/char/hw_random/npcm-rng.c | 186 ++++++++++++++++++++++++++++++
 3 files changed, 200 insertions(+)
 create mode 100644 drivers/char/hw_random/npcm-rng.c

drivers/char/hw_random/Kconfig +13 -0

index 59f25286befe..87a1c30e7958 100644
@@ -440,6 +440,19 @@ config HW_RANDOM_OPTEE
 
 	  If unsure, say Y.
 
+config HW_RANDOM_NPCM
+	tristate "NPCM Random Number Generator support"
+	depends on ARCH_NPCM || COMPILE_TEST
+	default HW_RANDOM
+	help
+ 	  This driver provides support for the Random Number
+	  Generator hardware available in Nuvoton NPCM SoCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called npcm-rng.
+
+ 	  If unsure, say Y.
+
 endif # HW_RANDOM
 
 config UML_RANDOM

drivers/char/hw_random/Makefile +1 -0

index 7c9ef4a7667f..17b6d4e6d591 100644
@@ -39,3 +39,4 @@ obj-$(CONFIG_HW_RANDOM_MTK)	+= mtk-rng.o
 obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
 obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
 obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
+obj-$(CONFIG_HW_RANDOM_NPCM) += npcm-rng.o

drivers/char/hw_random/npcm-rng.c new file +186 -0

new file mode 100644
index 000000000000..b7c8c7e13a49
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation.
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/of_irq.h>
+#include <linux/pm_runtime.h>
+
+#define NPCM_RNGCS_REG		0x00	/* Control and status register */
+#define NPCM_RNGD_REG		0x04	/* Data register */
+#define NPCM_RNGMODE_REG	0x08	/* Mode register */
+
+#define NPCM_RNG_CLK_SET_25MHZ	GENMASK(4, 3) /* 20-25 MHz */
+#define NPCM_RNG_DATA_VALID	BIT(1)
+#define NPCM_RNG_ENABLE		BIT(0)
+#define NPCM_RNG_M1ROSEL	BIT(1)
+
+#define NPCM_RNG_TIMEOUT_USEC	20000
+#define NPCM_RNG_POLL_USEC	1000
+
+#define to_npcm_rng(p)	container_of(p, struct npcm_rng, rng)
+
+struct npcm_rng {
+	void __iomem *base;
+	struct hwrng rng;
+};
+
+static int npcm_rng_init(struct hwrng *rng)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+
+	writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE,
+	       priv->base + NPCM_RNGCS_REG);
+
+	return 0;
+}
+
+static void npcm_rng_cleanup(struct hwrng *rng)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+
+	writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG);
+}
+
+static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+	int retval = 0;
+	int ready;
+
+	pm_runtime_get_sync((struct device *)priv->rng.priv);
+
+	while (max >= sizeof(u32)) {
+		if (wait) {
+			if (readl_poll_timeout(priv->base + NPCM_RNGCS_REG,
+					       ready,
+					       ready & NPCM_RNG_DATA_VALID,
+					       NPCM_RNG_POLL_USEC,
+					       NPCM_RNG_TIMEOUT_USEC))
+				break;
+		} else {
+			if ((readl(priv->base + NPCM_RNGCS_REG) &
+			    NPCM_RNG_DATA_VALID) == 0)
+				break;
+		}
+
+		*(u32 *)buf = readl(priv->base + NPCM_RNGD_REG);
+		retval += sizeof(u32);
+		buf += sizeof(u32);
+		max -= sizeof(u32);
+	}
+
+	pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
+	pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);
+
+	return retval || !wait ? retval : -EIO;
+}
+
+static int npcm_rng_probe(struct platform_device *pdev)
+{
+	struct npcm_rng *priv;
+	struct resource *res;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	dev_set_drvdata(&pdev->dev, priv);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+#ifndef CONFIG_PM
+	priv->rng.init = npcm_rng_init;
+	priv->rng.cleanup = npcm_rng_cleanup;
+#endif
+	priv->rng.name = pdev->name;
+	priv->rng.read = npcm_rng_read;
+	priv->rng.priv = (unsigned long)&pdev->dev;
+	priv->rng.quality = 1000;
+
+	writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);
+
+	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register rng device: %d\n",
+			ret);
+		pm_runtime_disable(&pdev->dev);
+		pm_runtime_set_suspended(&pdev->dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int npcm_rng_remove(struct platform_device *pdev)
+{
+	struct npcm_rng *priv = platform_get_drvdata(pdev);
+
+	devm_hwrng_unregister(&pdev->dev, &priv->rng);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int npcm_rng_runtime_suspend(struct device *dev)
+{
+	struct npcm_rng *priv = dev_get_drvdata(dev);
+
+	npcm_rng_cleanup(&priv->rng);
+
+	return 0;
+}
+
+static int npcm_rng_runtime_resume(struct device *dev)
+{
+	struct npcm_rng *priv = dev_get_drvdata(dev);
+
+	return npcm_rng_init(&priv->rng);
+}
+#endif
+
+static const struct dev_pm_ops npcm_rng_pm_ops = {
+	SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend,
+			   npcm_rng_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+};
+
+static const struct of_device_id rng_dt_id[] = {
+	{ .compatible = "nuvoton,npcm750-rng",  },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rng_dt_id);
+
+static struct platform_driver npcm_rng_driver = {
+	.driver = {
+		.name		= "npcm-rng",
+		.pm		= &npcm_rng_pm_ops,
+		.of_match_table = of_match_ptr(rng_dt_id),
+	},
+	.probe		= npcm_rng_probe,
+	.remove		= npcm_rng_remove,
+};
+
+module_platform_driver(npcm_rng_driver);
+
+MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver");
+MODULE_AUTHOR("Tomer Maimon <[email protected]>");
+MODULE_LICENSE("GPL v2");

Signature · 1 line

2.18.0

Quoted 1 line · Tomer Maimon

Add Nuvoton NPCM BMC Random Number Generator(RNG) driver.

Is this a true RNG or a psedo RNG, in case of latter it should be added in drivers/crypto/. See crypto_register_rng()

Review

Quoted 10 lines

Signed-off-by Tomer Maimon <[email protected]>

---
 drivers/char/hw_random/Kconfig    |  13 +++
 drivers/char/hw_random/Makefile   |   1 +
 drivers/char/hw_random/npcm-rng.c | 186 ++++++++++++++++++++++++++++++
 3 files changed, 200 insertions(+)
 create mode 100644 drivers/char/hw_random/npcm-rng.c

(quoted diff) +0 -0

b/drivers/char/hw_random/Kconfig

Review

Quoted 24 lines

index 59f25286befe..87a1c30e7958 100644

drivers/char/hw_random/Kconfig +13 -0

@@ -440,6 +440,19 @@ config HW_RANDOM_OPTEE
 
        If unsure, say Y.
 
+config HW_RANDOM_NPCM
+     tristate "NPCM Random Number Generator support"
+     depends on ARCH_NPCM || COMPILE_TEST
+     default HW_RANDOM
+     help
+       This driver provides support for the Random Number
+       Generator hardware available in Nuvoton NPCM SoCs.
+
+       To compile this driver as a module, choose M here: the
+       module will be called npcm-rng.
+
+       If unsure, say Y.
+
 endif # HW_RANDOM
 
 config UML_RANDOM

(quoted diff) +0 -0

b/drivers/char/hw_random/Makefile

Review

Quoted 9 lines

index 7c9ef4a7667f..17b6d4e6d591 100644

drivers/char/hw_random/Makefile +1 -0

@@ -39,3 +39,4 @@ obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o
 obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
 obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
 obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
+obj-$(CONFIG_HW_RANDOM_NPCM) += npcm-rng.o

(quoted diff) +0 -0

b/drivers/char/hw_random/npcm-rng.c

Quoted 12 lines

new file mode 100644
index 000000000000..b7c8c7e13a49

drivers/char/hw_random/npcm-rng.c new file +7 -0

@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation.
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>

drivers/char/hw_random/npcm-rng.c line 17

Quoted 10 lines

drivers/char/hw_random/npcm-rng.c new file +10 -0

+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/of_irq.h>
+#include <linux/pm_runtime.h>
+
+#define NPCM_RNGCS_REG               0x00    /* Control and status

register */

Quoted 26 lines

drivers/char/hw_random/npcm-rng.c new file +26 -0

+#define NPCM_RNGD_REG                0x04    /* Data register */
+#define NPCM_RNGMODE_REG     0x08    /* Mode register */
+
+#define NPCM_RNG_CLK_SET_25MHZ       GENMASK(4, 3) /* 20-25 MHz */
+#define NPCM_RNG_DATA_VALID  BIT(1)
+#define NPCM_RNG_ENABLE              BIT(0)
+#define NPCM_RNG_M1ROSEL     BIT(1)
+
+#define NPCM_RNG_TIMEOUT_USEC        20000
+#define NPCM_RNG_POLL_USEC   1000
+
+#define to_npcm_rng(p)       container_of(p, struct npcm_rng, rng)
+
+struct npcm_rng {
+     void __iomem *base;
+     struct hwrng rng;
+};
+
+static int npcm_rng_init(struct hwrng *rng)
+{
+     struct npcm_rng *priv = to_npcm_rng(rng);
+
+     writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE,
+            priv->base + NPCM_RNGCS_REG);
+
+     return 0;

drivers/char/hw_random/npcm-rng.c

Quoted 10 lines

drivers/char/hw_random/npcm-rng.c new file +10 -0

+}
+
+static void npcm_rng_cleanup(struct hwrng *rng)
+{
+     struct npcm_rng *priv = to_npcm_rng(rng);
+
+     writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG);
+}
+
+static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool

wait)

Quoted 134 lines

drivers/char/hw_random/npcm-rng.c new file +133 -1

+{
+     struct npcm_rng *priv = to_npcm_rng(rng);
+     int retval = 0;
+     int ready;
+
+     pm_runtime_get_sync((struct device *)priv->rng.priv);
+
+     while (max >= sizeof(u32)) {
+             if (wait) {
+                     if (readl_poll_timeout(priv->base + NPCM_RNGCS_REG,
+                                            ready,
+                                            ready & NPCM_RNG_DATA_VALID,
+                                            NPCM_RNG_POLL_USEC,
+                                            NPCM_RNG_TIMEOUT_USEC))
+                             break;
+             } else {
+                     if ((readl(priv->base + NPCM_RNGCS_REG) &
+                         NPCM_RNG_DATA_VALID) == 0)
+                             break;
+             }
+
+             *(u32 *)buf = readl(priv->base + NPCM_RNGD_REG);
+             retval += sizeof(u32);
+             buf += sizeof(u32);
+             max -= sizeof(u32);
+     }
+
+     pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
+     pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);
+
+     return retval || !wait ? retval : -EIO;
+}
+
+static int npcm_rng_probe(struct platform_device *pdev)
+{
+     struct npcm_rng *priv;
+     struct resource *res;
+     int ret;
+
+     priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+     if (!priv)
+             return -ENOMEM;
+
+     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+     priv->base = devm_ioremap_resource(&pdev->dev, res);
+     if (IS_ERR(priv->base))
+             return PTR_ERR(priv->base);
+
+     dev_set_drvdata(&pdev->dev, priv);
+     pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
+     pm_runtime_use_autosuspend(&pdev->dev);
+     pm_runtime_enable(&pdev->dev);
+
+#ifndef CONFIG_PM
+     priv->rng.init = npcm_rng_init;
+     priv->rng.cleanup = npcm_rng_cleanup;
+#endif
+     priv->rng.name = pdev->name;
+     priv->rng.read = npcm_rng_read;
+     priv->rng.priv = (unsigned long)&pdev->dev;
+     priv->rng.quality = 1000;
+
+     writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);
+
+     ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+     if (ret) {
+             dev_err(&pdev->dev, "Failed to register rng device: %d\n",
+                     ret);
+             pm_runtime_disable(&pdev->dev);
+             pm_runtime_set_suspended(&pdev->dev);
+             return ret;
+     }
+
+     return 0;
+}
+
+static int npcm_rng_remove(struct platform_device *pdev)
+{
+     struct npcm_rng *priv = platform_get_drvdata(pdev);
+
+     devm_hwrng_unregister(&pdev->dev, &priv->rng);
+     pm_runtime_disable(&pdev->dev);
+     pm_runtime_set_suspended(&pdev->dev);
+
+     return 0;
+}
+
+#ifdef CONFIG_PM
+static int npcm_rng_runtime_suspend(struct device *dev)
+{
+     struct npcm_rng *priv = dev_get_drvdata(dev);
+
+     npcm_rng_cleanup(&priv->rng);
+
+     return 0;
+}
+
+static int npcm_rng_runtime_resume(struct device *dev)
+{
+     struct npcm_rng *priv = dev_get_drvdata(dev);
+
+     return npcm_rng_init(&priv->rng);
+}
+#endif
+
+static const struct dev_pm_ops npcm_rng_pm_ops = {
+     SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend,
+                        npcm_rng_runtime_resume, NULL)
+     SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+                             pm_runtime_force_resume)
+};
+
+static const struct of_device_id rng_dt_id[] = {
+     { .compatible = "nuvoton,npcm750-rng",  },
+     {},
+};
+MODULE_DEVICE_TABLE(of, rng_dt_id);
+
+static struct platform_driver npcm_rng_driver = {
+     .driver = {
+             .name           = "npcm-rng",
+             .pm             = &npcm_rng_pm_ops,
+             .of_match_table = of_match_ptr(rng_dt_id),
+     },
+     .probe          = npcm_rng_probe,
+     .remove         = npcm_rng_remove,
+};
+
+module_platform_driver(npcm_rng_driver);
+
+MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver");
+MODULE_AUTHOR("Tomer Maimon <[email protected]>");
+MODULE_LICENSE("GPL v2");
--

Quoted 1 line

2.18.0

--
~Vinod

Hi Vinod,

Thanks for your notification.

NPCM Hardware RNG is true RNG.

Tomer

Quoted 253 lines · Vinod Koul

Quoted 1 line · Tomer Maimon

Add Nuvoton NPCM BMC Random Number Generator(RNG) driver.

Is this a true RNG or a psedo RNG, in case of latter it should be added in drivers/crypto/. See crypto_register_rng()

Review

Quoted 10 lines

Signed-off-by Tomer Maimon <[email protected]>

---
 drivers/char/hw_random/Kconfig    |  13 +++
 drivers/char/hw_random/Makefile   |   1 +
 drivers/char/hw_random/npcm-rng.c | 186 ++++++++++++++++++++++++++++++
 3 files changed, 200 insertions(+)
 create mode 100644 drivers/char/hw_random/npcm-rng.c

(quoted diff) +0 -0

b/drivers/char/hw_random/Kconfig

Review

Quoted 24 lines

index 59f25286befe..87a1c30e7958 100644

drivers/char/hw_random/Kconfig +13 -0

@@ -440,6 +440,19 @@ config HW_RANDOM_OPTEE
 
        If unsure, say Y.
 
+config HW_RANDOM_NPCM
+     tristate "NPCM Random Number Generator support"
+     depends on ARCH_NPCM || COMPILE_TEST
+     default HW_RANDOM
+     help
+       This driver provides support for the Random Number
+       Generator hardware available in Nuvoton NPCM SoCs.
+
+       To compile this driver as a module, choose M here: the
+       module will be called npcm-rng.
+
+       If unsure, say Y.
+
 endif # HW_RANDOM
 
 config UML_RANDOM

(quoted diff) +0 -0

b/drivers/char/hw_random/Makefile

Review

Quoted 9 lines

index 7c9ef4a7667f..17b6d4e6d591 100644

drivers/char/hw_random/Makefile +1 -0

@@ -39,3 +39,4 @@ obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o
 obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
 obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
 obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
+obj-$(CONFIG_HW_RANDOM_NPCM) += npcm-rng.o

(quoted diff) +0 -0

b/drivers/char/hw_random/npcm-rng.c

Quoted 12 lines

new file mode 100644
index 000000000000..b7c8c7e13a49

drivers/char/hw_random/npcm-rng.c new file +7 -0

@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation.
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>

drivers/char/hw_random/npcm-rng.c line 17

Quoted 10 lines

drivers/char/hw_random/npcm-rng.c new file +10 -0

+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/of_irq.h>
+#include <linux/pm_runtime.h>
+
+#define NPCM_RNGCS_REG               0x00    /* Control and status

register */

Quoted 26 lines

drivers/char/hw_random/npcm-rng.c new file +26 -0

+#define NPCM_RNGD_REG                0x04    /* Data register */
+#define NPCM_RNGMODE_REG     0x08    /* Mode register */
+
+#define NPCM_RNG_CLK_SET_25MHZ       GENMASK(4, 3) /* 20-25 MHz */
+#define NPCM_RNG_DATA_VALID  BIT(1)
+#define NPCM_RNG_ENABLE              BIT(0)
+#define NPCM_RNG_M1ROSEL     BIT(1)
+
+#define NPCM_RNG_TIMEOUT_USEC        20000
+#define NPCM_RNG_POLL_USEC   1000
+
+#define to_npcm_rng(p)       container_of(p, struct npcm_rng, rng)
+
+struct npcm_rng {
+     void __iomem *base;
+     struct hwrng rng;
+};
+
+static int npcm_rng_init(struct hwrng *rng)
+{
+     struct npcm_rng *priv = to_npcm_rng(rng);
+
+     writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE,
+            priv->base + NPCM_RNGCS_REG);
+
+     return 0;

drivers/char/hw_random/npcm-rng.c

Quoted 10 lines

drivers/char/hw_random/npcm-rng.c new file +10 -0

+}
+
+static void npcm_rng_cleanup(struct hwrng *rng)
+{
+     struct npcm_rng *priv = to_npcm_rng(rng);
+
+     writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG);
+}
+
+static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max,

bool wait)

drivers/char/hw_random/npcm-rng.c

Quoted 10 lines

drivers/char/hw_random/npcm-rng.c new file +10 -0

+{
+     struct npcm_rng *priv = to_npcm_rng(rng);
+     int retval = 0;
+     int ready;
+
+     pm_runtime_get_sync((struct device *)priv->rng.priv);
+
+     while (max >= sizeof(u32)) {
+             if (wait) {
+                     if (readl_poll_timeout(priv->base +

NPCM_RNGCS_REG,

drivers/char/hw_random/npcm-rng.c line 65

Quoted 2 lines

drivers/char/hw_random/npcm-rng.c new file +2 -0

+                                            ready,
+                                            ready &

NPCM_RNG_DATA_VALID,

Quoted 122 lines

drivers/char/hw_random/npcm-rng.c new file +121 -1

+                                            NPCM_RNG_POLL_USEC,
+                                            NPCM_RNG_TIMEOUT_USEC))
+                             break;
+             } else {
+                     if ((readl(priv->base + NPCM_RNGCS_REG) &
+                         NPCM_RNG_DATA_VALID) == 0)
+                             break;
+             }
+
+             *(u32 *)buf = readl(priv->base + NPCM_RNGD_REG);
+             retval += sizeof(u32);
+             buf += sizeof(u32);
+             max -= sizeof(u32);
+     }
+
+     pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
+     pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);
+
+     return retval || !wait ? retval : -EIO;
+}
+
+static int npcm_rng_probe(struct platform_device *pdev)
+{
+     struct npcm_rng *priv;
+     struct resource *res;
+     int ret;
+
+     priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+     if (!priv)
+             return -ENOMEM;
+
+     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+     priv->base = devm_ioremap_resource(&pdev->dev, res);
+     if (IS_ERR(priv->base))
+             return PTR_ERR(priv->base);
+
+     dev_set_drvdata(&pdev->dev, priv);
+     pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
+     pm_runtime_use_autosuspend(&pdev->dev);
+     pm_runtime_enable(&pdev->dev);
+
+#ifndef CONFIG_PM
+     priv->rng.init = npcm_rng_init;
+     priv->rng.cleanup = npcm_rng_cleanup;
+#endif
+     priv->rng.name = pdev->name;
+     priv->rng.read = npcm_rng_read;
+     priv->rng.priv = (unsigned long)&pdev->dev;
+     priv->rng.quality = 1000;
+
+     writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);
+
+     ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+     if (ret) {
+             dev_err(&pdev->dev, "Failed to register rng device: %d\n",
+                     ret);
+             pm_runtime_disable(&pdev->dev);
+             pm_runtime_set_suspended(&pdev->dev);
+             return ret;
+     }
+
+     return 0;
+}
+
+static int npcm_rng_remove(struct platform_device *pdev)
+{
+     struct npcm_rng *priv = platform_get_drvdata(pdev);
+
+     devm_hwrng_unregister(&pdev->dev, &priv->rng);
+     pm_runtime_disable(&pdev->dev);
+     pm_runtime_set_suspended(&pdev->dev);
+
+     return 0;
+}
+
+#ifdef CONFIG_PM
+static int npcm_rng_runtime_suspend(struct device *dev)
+{
+     struct npcm_rng *priv = dev_get_drvdata(dev);
+
+     npcm_rng_cleanup(&priv->rng);
+
+     return 0;
+}
+
+static int npcm_rng_runtime_resume(struct device *dev)
+{
+     struct npcm_rng *priv = dev_get_drvdata(dev);
+
+     return npcm_rng_init(&priv->rng);
+}
+#endif
+
+static const struct dev_pm_ops npcm_rng_pm_ops = {
+     SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend,
+                        npcm_rng_runtime_resume, NULL)
+     SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+                             pm_runtime_force_resume)
+};
+
+static const struct of_device_id rng_dt_id[] = {
+     { .compatible = "nuvoton,npcm750-rng",  },
+     {},
+};
+MODULE_DEVICE_TABLE(of, rng_dt_id);
+
+static struct platform_driver npcm_rng_driver = {
+     .driver = {
+             .name           = "npcm-rng",
+             .pm             = &npcm_rng_pm_ops,
+             .of_match_table = of_match_ptr(rng_dt_id),
+     },
+     .probe          = npcm_rng_probe,
+     .remove         = npcm_rng_remove,
+};
+
+module_platform_driver(npcm_rng_driver);
+
+MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver");
+MODULE_AUTHOR("Tomer Maimon <[email protected]>");
+MODULE_LICENSE("GPL v2");
--

Quoted 1 line

2.18.0

--
~Vinod

Add Nuvoton NPCM BMC Random Number Generator(RNG) driver.

Signed-off-by Tomer Maimon <[email protected]>

---
 drivers/char/hw_random/Kconfig    |  13 +++
 drivers/char/hw_random/Makefile   |   1 +
 drivers/char/hw_random/npcm-rng.c | 186 ++++++++++++++++++++++++++++++
 3 files changed, 200 insertions(+)
 create mode 100644 drivers/char/hw_random/npcm-rng.c

drivers/char/hw_random/Kconfig +13 -0

index 59f25286befe..87a1c30e7958 100644
@@ -440,6 +440,19 @@ config HW_RANDOM_OPTEE
 
 	  If unsure, say Y.
 
+config HW_RANDOM_NPCM
+	tristate "NPCM Random Number Generator support"
+	depends on ARCH_NPCM || COMPILE_TEST
+	default HW_RANDOM
+	help
+ 	  This driver provides support for the Random Number
+	  Generator hardware available in Nuvoton NPCM SoCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called npcm-rng.
+
+ 	  If unsure, say Y.
+
 endif # HW_RANDOM
 
 config UML_RANDOM

drivers/char/hw_random/Makefile +1 -0

index 7c9ef4a7667f..17b6d4e6d591 100644
@@ -39,3 +39,4 @@ obj-$(CONFIG_HW_RANDOM_MTK)	+= mtk-rng.o
 obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o
 obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o
 obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o
+obj-$(CONFIG_HW_RANDOM_NPCM) += npcm-rng.o

drivers/char/hw_random/npcm-rng.c new file +186 -0

new file mode 100644
index 000000000000..b7c8c7e13a49
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation.
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/of_irq.h>
+#include <linux/pm_runtime.h>
+
+#define NPCM_RNGCS_REG		0x00	/* Control and status register */
+#define NPCM_RNGD_REG		0x04	/* Data register */
+#define NPCM_RNGMODE_REG	0x08	/* Mode register */
+
+#define NPCM_RNG_CLK_SET_25MHZ	GENMASK(4, 3) /* 20-25 MHz */
+#define NPCM_RNG_DATA_VALID	BIT(1)
+#define NPCM_RNG_ENABLE		BIT(0)
+#define NPCM_RNG_M1ROSEL	BIT(1)
+
+#define NPCM_RNG_TIMEOUT_USEC	20000
+#define NPCM_RNG_POLL_USEC	1000
+
+#define to_npcm_rng(p)	container_of(p, struct npcm_rng, rng)
+
+struct npcm_rng {
+	void __iomem *base;
+	struct hwrng rng;
+};
+
+static int npcm_rng_init(struct hwrng *rng)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+
+	writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE,
+	       priv->base + NPCM_RNGCS_REG);
+
+	return 0;
+}
+
+static void npcm_rng_cleanup(struct hwrng *rng)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+
+	writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG);
+}
+
+static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct npcm_rng *priv = to_npcm_rng(rng);
+	int retval = 0;
+	int ready;
+
+	pm_runtime_get_sync((struct device *)priv->rng.priv);
+
+	while (max >= sizeof(u32)) {
+		if (wait) {
+			if (readl_poll_timeout(priv->base + NPCM_RNGCS_REG,
+					       ready,
+					       ready & NPCM_RNG_DATA_VALID,
+					       NPCM_RNG_POLL_USEC,
+					       NPCM_RNG_TIMEOUT_USEC))
+				break;
+		} else {
+			if ((readl(priv->base + NPCM_RNGCS_REG) &
+			    NPCM_RNG_DATA_VALID) == 0)
+				break;
+		}
+
+		*(u32 *)buf = readl(priv->base + NPCM_RNGD_REG);
+		retval += sizeof(u32);
+		buf += sizeof(u32);
+		max -= sizeof(u32);
+	}
+
+	pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
+	pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);
+
+	return retval || !wait ? retval : -EIO;
+}
+
+static int npcm_rng_probe(struct platform_device *pdev)
+{
+	struct npcm_rng *priv;
+	struct resource *res;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	dev_set_drvdata(&pdev->dev, priv);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+#ifndef CONFIG_PM
+	priv->rng.init = npcm_rng_init;
+	priv->rng.cleanup = npcm_rng_cleanup;
+#endif
+	priv->rng.name = pdev->name;
+	priv->rng.read = npcm_rng_read;
+	priv->rng.priv = (unsigned long)&pdev->dev;
+	priv->rng.quality = 1000;
+
+	writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);
+
+	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register rng device: %d\n",
+			ret);
+		pm_runtime_disable(&pdev->dev);
+		pm_runtime_set_suspended(&pdev->dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int npcm_rng_remove(struct platform_device *pdev)
+{
+	struct npcm_rng *priv = platform_get_drvdata(pdev);
+
+	devm_hwrng_unregister(&pdev->dev, &priv->rng);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int npcm_rng_runtime_suspend(struct device *dev)
+{
+	struct npcm_rng *priv = dev_get_drvdata(dev);
+
+	npcm_rng_cleanup(&priv->rng);
+
+	return 0;
+}
+
+static int npcm_rng_runtime_resume(struct device *dev)
+{
+	struct npcm_rng *priv = dev_get_drvdata(dev);
+
+	return npcm_rng_init(&priv->rng);
+}
+#endif
+
+static const struct dev_pm_ops npcm_rng_pm_ops = {
+	SET_RUNTIME_PM_OPS(npcm_rng_runtime_suspend,
+			   npcm_rng_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+};
+
+static const struct of_device_id rng_dt_id[] = {
+	{ .compatible = "nuvoton,npcm750-rng",  },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rng_dt_id);
+
+static struct platform_driver npcm_rng_driver = {
+	.driver = {
+		.name		= "npcm-rng",
+		.pm		= &npcm_rng_pm_ops,
+		.of_match_table = of_match_ptr(rng_dt_id),
+	},
+	.probe		= npcm_rng_probe,
+	.remove		= npcm_rng_remove,
+};
+
+module_platform_driver(npcm_rng_driver);
+
+MODULE_DESCRIPTION("Nuvoton NPCM Random Number Generator Driver");
+MODULE_AUTHOR("Tomer Maimon <[email protected]>");
+MODULE_LICENSE("GPL v2");

Signature · 1 line

2.18.0

This patch set adds Random Number Generator (RNG) support for the Nuvoton NPCM Baseboard Management Controller (BMC).

The RNG driver we use power consumption when the RNG is not required.

The NPCM RNG driver tested on NPCM750 evaluation board.

Addressed comments from:.
- Daniel Thompson: https://lkml.org/lkml/2019/9/10/352
- Milton Miller II : https://lkml.org/lkml/2019/9/10/847
- Daniel Thompson: https://lkml.org/lkml/2019/9/10/294

Changes since version 2:
- Rearrange wait parameter in npcm_rng_read function.
- Calling pm_runtime_enable function before hwrng_register function called to enable the hwrng before add_early_randomness called.
- Remove quality dt-binding parameter in the driver and documentation.
- Disable CONFIG_PM if devm_hwrng_register failed.
- Remove owner setting in the driver struct.

Changes since version 1:
- Define timout in real-world units.
- Using readl_poll_timeout in rng_read function.
- Honor wait parameter in rng_read function.
- Using local variable instead of #ifndef.
- Remove probe print.

Tomer Maimon (2):
dt-binding: hwrng: add NPCM RNG documentation
hwrng: npcm: add NPCM RNG driver

 .../bindings/rng/nuvoton,npcm-rng.txt         |  12 ++
 drivers/char/hw_random/Kconfig                |  13 ++
 drivers/char/hw_random/Makefile               |   1 +
 drivers/char/hw_random/npcm-rng.c             | 186 ++++++++++++++++++
 4 files changed, 212 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rng/nuvoton,npcm-rng.txt
 create mode 100644 drivers/char/hw_random/npcm-rng.c