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Subject[PATCH v2 2/2] hwrng: npcm: add NPCM RNG driver
Date
Add Nuvoton NPCM BMC Random Number Generator(RNG) driver.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
drivers/char/hw_random/Kconfig | 13 ++
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/npcm-rng.c | 203 ++++++++++++++++++++++++++++++
3 files changed, 217 insertions(+)
create mode 100644 drivers/char/hw_random/npcm-rng.c

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 59f25286befe..87a1c30e7958 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -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
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 7c9ef4a7667f..17b6d4e6d591 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -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
diff --git a/drivers/char/hw_random/npcm-rng.c b/drivers/char/hw_random/npcm-rng.c
new file mode 100644
index 000000000000..3ed396474563
--- /dev/null
+++ b/drivers/char/hw_random/npcm-rng.c
@@ -0,0 +1,203 @@
+// 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);
+ u32 val;
+
+ val = readl(priv->base + NPCM_RNGCS_REG);
+ val |= NPCM_RNG_ENABLE;
+ writel(val, priv->base + NPCM_RNGCS_REG);
+
+ return 0;
+}
+
+static void npcm_rng_cleanup(struct hwrng *rng)
+{
+ struct npcm_rng *priv = to_npcm_rng(rng);
+ u32 val;
+
+ val = readl(priv->base + NPCM_RNGCS_REG);
+ val &= ~NPCM_RNG_ENABLE;
+ writel(val, 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)) {
+ ready = readl(priv->base + NPCM_RNGCS_REG) &
+ NPCM_RNG_DATA_VALID;
+ if (!ready) {
+ 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 {
+ 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;
+ bool pm_dis = false;
+ u32 quality;
+ 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);
+
+ priv->rng.name = pdev->name;
+#ifndef CONFIG_PM
+ pm_dis = true;
+ priv->rng.init = npcm_rng_init;
+ priv->rng.cleanup = npcm_rng_cleanup;
+#endif
+ priv->rng.read = npcm_rng_read;
+ priv->rng.priv = (unsigned long)&pdev->dev;
+ if (of_property_read_u32(pdev->dev.of_node, "quality", &quality))
+ priv->rng.quality = 1000;
+ else
+ priv->rng.quality = quality;
+
+ writel(NPCM_RNG_M1ROSEL, priv->base + NPCM_RNGMODE_REG);
+ if (pm_dis)
+ writel(NPCM_RNG_CLK_SET_25MHZ, priv->base + NPCM_RNGCS_REG);
+ else
+ writel(NPCM_RNG_CLK_SET_25MHZ | NPCM_RNG_ENABLE,
+ priv->base + NPCM_RNGCS_REG);
+
+ ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to register rng device: %d\n",
+ ret);
+ return ret;
+ }
+
+ 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);
+
+ return 0;
+}
+
+static int npcm_rng_remove(struct platform_device *pdev)
+{
+ struct npcm_rng *priv = platform_get_drvdata(pdev);
+
+ hwrng_unregister(&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,
+ .owner = THIS_MODULE,
+ .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 <tomer.maimon@nuvoton.com>");
+MODULE_LICENSE("GPL v2");
--
2.18.0
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