drivers/hw_random: Add StarFive JH7100 Random Number Generator driver

drivers/char/hw_random/Kconfig

@@ -322,6 +322,19 @@ config HW_RANDOM_POWERNV
 
 	  If unsure, say Y.
 
+config HW_RANDOM_STARFIVE_VIC
+	tristate "Starfive VIC Random Number Generator support"
+	depends on HW_RANDOM && (SOC_STARFIVE || COMPILE_TEST)
+	default SOC_STARFIVE
+	help
+	  This driver provides kernel-side support for the Random Number
+	  Generator hardware found on Starfive VIC SoC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called starfive-vic-rng.
+
+	  If unsure, say Y.
+
 config HW_RANDOM_HISI
 	tristate "Hisilicon Random Number Generator support"
 	depends on HW_RANDOM && ARCH_HISI

drivers/char/hw_random/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o
 obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
 obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
 obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
+obj-$(CONFIG_HW_RANDOM_STARFIVE_VIC)	+= starfive-vic-rng.o
 obj-$(CONFIG_HW_RANDOM_HISI)	+= hisi-rng.o
 obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
 obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o

drivers/char/hw_random/starfive-vic-rng.c

@@ -0,0 +1,256 @@
+/*
+ ******************************************************************************
+ * @file  starfive-vic-rng.c
+ * @author  StarFive Technology
+ * @version  V1.0
+ * @date  08/13/2020
+ * @brief
+ ******************************************************************************
+ * @copy
+ *
+ * THE PRESENT SOFTWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
+ * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
+ * TIME. AS A RESULT, STARFIVE SHALL NOT BE HELD LIABLE FOR ANY
+ * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
+ * FROM THE CONTENT OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
+ * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
+ *
+ * COPYRIGHT 2020 Shanghai StarFive Technology Co., Ltd.
+ */
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/random.h>
+
+#include "starfive-vic-rng.h"
+
+#define to_vic_rng(p)	container_of(p, struct vic_rng, rng)
+
+struct vic_rng {
+	struct device	*dev;
+	void __iomem	*base;
+	struct hwrng	rng;
+};
+
+static inline void vic_wait_till_idle(struct vic_rng *hrng)
+{
+	while(readl(hrng->base + VIC_STAT) & VIC_STAT_BUSY)
+		;
+}
+
+static inline void vic_rng_irq_mask_clear(struct vic_rng *hrng)
+{
+	// clear register: ISTAT
+	u32 data = readl(hrng->base + VIC_ISTAT);
+	writel(data, hrng->base + VIC_ISTAT);
+	writel(0, hrng->base + VIC_ALARM);
+}
+
+static int vic_trng_cmd(struct vic_rng *hrng, u32 cmd) {
+	int res = 0;
+	// wait till idle
+	vic_wait_till_idle(hrng);
+	switch (cmd) {
+	case VIC_CTRL_CMD_NOP:
+	case VIC_CTRL_CMD_GEN_NOISE:
+	case VIC_CTRL_CMD_GEN_NONCE:
+	case VIC_CTRL_CMD_CREATE_STATE:
+	case VIC_CTRL_CMD_RENEW_STATE:
+	case VIC_CTRL_CMD_REFRESH_ADDIN:
+	case VIC_CTRL_CMD_GEN_RANDOM:
+	case VIC_CTRL_CMD_ADVANCE_STATE:
+	case VIC_CTRL_CMD_KAT:
+	case VIC_CTRL_CMD_ZEROIZE:
+		writel(cmd, hrng->base + VIC_CTRL);
+		break;
+	default:
+		res = -1;
+		break;
+	}
+
+	return res;
+}
+
+static int vic_rng_init(struct hwrng *rng)
+{
+	struct vic_rng *hrng = to_vic_rng(rng);
+
+	// wait till idle
+
+	// clear register: ISTAT
+	vic_rng_irq_mask_clear(hrng);
+
+	// set mission mode
+	writel(VIC_SMODE_SECURE_EN(1), hrng->base + VIC_SMODE);
+
+	vic_trng_cmd(hrng, VIC_CTRL_CMD_GEN_NOISE);
+	vic_wait_till_idle(hrng);
+
+	// set interrupt
+	writel(VIC_IE_ALL, hrng->base + VIC_IE);
+
+	// zeroize
+	vic_trng_cmd(hrng, VIC_CTRL_CMD_ZEROIZE);
+
+	vic_wait_till_idle(hrng);
+
+	return 0;
+}
+
+static irqreturn_t vic_rng_irq(int irq, void *priv)
+{
+	u32 status, val;
+	struct vic_rng *hrng = (struct vic_rng *)priv;
+
+	/*
+	 * clearing the interrupt will also clear the error register
+	 * read error and status before clearing
+	 */
+	status = readl(hrng->base + VIC_ISTAT);
+
+	if (status & VIC_ISTAT_ALARMS) {
+		writel(VIC_ISTAT_ALARMS, hrng->base + VIC_ISTAT);
+		val = readl(hrng->base + VIC_ALARM);
+		if (val & VIC_ALARM_ILLEGAL_CMD_SEQ) {
+			writel(VIC_ALARM_ILLEGAL_CMD_SEQ, hrng->base + VIC_ALARM);
+			//dev_info(hrng->dev, "ILLEGAL CMD SEQ: LAST_CMD=0x%x\r\n",
+			//VIC_STAT_LAST_CMD(readl(hrng->base + VIC_STAT)));
+		} else {
+			dev_info(hrng->dev, "Failed test: %x\r\n", val);
+		}
+	}
+
+	if (status & VIC_ISTAT_ZEROIZE) {
+		writel(VIC_ISTAT_ZEROIZE, hrng->base + VIC_ISTAT);
+		//dev_info(hrng->dev, "zeroized\r\n");
+	}
+
+	if (status & VIC_ISTAT_KAT_COMPLETE) {
+		writel(VIC_ISTAT_KAT_COMPLETE, hrng->base + VIC_ISTAT);
+		//dev_info(hrng->dev, "kat_completed\r\n");
+	}
+
+	if (status & VIC_ISTAT_NOISE_RDY) {
+		writel(VIC_ISTAT_NOISE_RDY, hrng->base + VIC_ISTAT);
+		//dev_info(hrng->dev, "noise_rdy\r\n");
+	}
+
+	if (status & VIC_ISTAT_DONE) {
+		writel(VIC_ISTAT_DONE, hrng->base + VIC_ISTAT);
+		//dev_info(hrng->dev, "done\r\n");
+		/*
+		if (VIC_STAT_LAST_CMD(readl(hrng->base + VIC_STAT)) ==
+		    VIC_CTRL_CMD_GEN_RANDOM) {
+			dev_info(hrng->dev, "Need Update Buffer\r\n");
+		}
+		*/
+	}
+	vic_rng_irq_mask_clear(hrng);
+
+	return IRQ_HANDLED;
+}
+
+static void vic_rng_cleanup(struct hwrng *rng)
+{
+	struct vic_rng *hrng = to_vic_rng(rng);
+
+	writel(0, hrng->base + VIC_CTRL);
+}
+
+static int vic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct vic_rng *hrng = to_vic_rng(rng);
+
+	vic_trng_cmd(hrng, VIC_CTRL_CMD_ZEROIZE);
+	vic_trng_cmd(hrng, VIC_CTRL_CMD_GEN_NOISE);
+	vic_trng_cmd(hrng, VIC_CTRL_CMD_CREATE_STATE);
+
+	vic_wait_till_idle(hrng);
+	max = min_t(size_t, max, (VIC_RAND_LEN * 4));
+
+	writel(0x0, hrng->base + VIC_MODE);
+	vic_trng_cmd(hrng, VIC_CTRL_CMD_GEN_RANDOM);
+
+	vic_wait_till_idle(hrng);
+	memcpy_fromio(buf, hrng->base + VIC_RAND0, max);
+	vic_trng_cmd(hrng, VIC_CTRL_CMD_ZEROIZE);
+
+	vic_wait_till_idle(hrng);
+	return max;
+}
+
+static int vic_rng_probe(struct platform_device *pdev)
+{
+	int ret;
+	int irq;
+	struct vic_rng *rng;
+	struct resource *res;
+
+	rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
+	if (!rng){
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, rng);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rng->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rng->base)){
+		return PTR_ERR(rng->base);
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0) {
+		dev_err(&pdev->dev, "Couldn't get irq %d\n", irq);
+		return irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, vic_rng_irq, 0, pdev->name,
+				(void *)rng);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't get interrupt working.\n");
+		return ret;
+	}
+
+	rng->rng.name = pdev->name;
+	rng->rng.init = vic_rng_init;
+	rng->rng.cleanup = vic_rng_cleanup;
+	rng->rng.read = vic_rng_read;
+
+	rng->dev = &pdev->dev;
+
+	ret = devm_hwrng_register(&pdev->dev, &rng->rng);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register hwrng\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "Initialized\n");
+
+	return 0;
+}
+
+static const struct of_device_id vic_rng_dt_ids[] = {
+	{ .compatible = "starfive,vic-rng" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, vic_rng_dt_ids);
+
+static struct platform_driver vic_rng_driver = {
+	.probe		= vic_rng_probe,
+	.driver		= {
+		.name		= "vic-rng",
+		.of_match_table	= of_match_ptr(vic_rng_dt_ids),
+	},
+};
+
+module_platform_driver(vic_rng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Huan Feng <huan.feng@starfivetech.com>");
+MODULE_DESCRIPTION("Starfive VIC random number generator driver");