1 files changed, 119 insertions, 0 deletions
diff --git a/drivers/char/hw_random/pasemi-rng.c b/drivers/char/hw_random/pasemi-rng.c
new file mode 100644
index 000000000..2498d4ef9
--- /dev/null
+++ b/drivers/char/hw_random/pasemi-rng.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2007 PA Semi, Inc
+ *
+ * Maintained by: Olof Johansson <olof@lixom.net>
+ *
+ * Driver for the PWRficient onchip rng
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+
+#define SDCRNG_CTL_REG			0x00
+#define   SDCRNG_CTL_FVLD_M		0x0000f000
+#define   SDCRNG_CTL_FVLD_S		12
+#define   SDCRNG_CTL_KSZ		0x00000800
+#define   SDCRNG_CTL_RSRC_CRG		0x00000010
+#define   SDCRNG_CTL_RSRC_RRG		0x00000000
+#define   SDCRNG_CTL_CE			0x00000004
+#define   SDCRNG_CTL_RE			0x00000002
+#define   SDCRNG_CTL_DR			0x00000001
+#define   SDCRNG_CTL_SELECT_RRG_RNG	(SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG)
+#define   SDCRNG_CTL_SELECT_CRG_RNG	(SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG)
+#define SDCRNG_VAL_REG			0x20
+
+#define MODULE_NAME "pasemi_rng"
+
+static int pasemi_rng_data_present(struct hwrng *rng, int wait)
+{
+	void __iomem *rng_regs = (void __iomem *)rng->priv;
+	int data, i;
+
+	for (i = 0; i < 20; i++) {
+		data = (in_le32(rng_regs + SDCRNG_CTL_REG)
+			& SDCRNG_CTL_FVLD_M) ? 1 : 0;
+		if (data || !wait)
+			break;
+		udelay(10);
+	}
+	return data;
+}
+
+static int pasemi_rng_data_read(struct hwrng *rng, u32 *data)
+{
+	void __iomem *rng_regs = (void __iomem *)rng->priv;
+	*data = in_le32(rng_regs + SDCRNG_VAL_REG);
+	return 4;
+}
+
+static int pasemi_rng_init(struct hwrng *rng)
+{
+	void __iomem *rng_regs = (void __iomem *)rng->priv;
+	u32 ctl;
+
+	ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ;
+	out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
+	out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);
+
+	return 0;
+}
+
+static void pasemi_rng_cleanup(struct hwrng *rng)
+{
+	void __iomem *rng_regs = (void __iomem *)rng->priv;
+	u32 ctl;
+
+	ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE;
+	out_le32(rng_regs + SDCRNG_CTL_REG,
+		 in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);
+}
+
+static struct hwrng pasemi_rng = {
+	.name		= MODULE_NAME,
+	.init		= pasemi_rng_init,
+	.cleanup	= pasemi_rng_cleanup,
+	.data_present	= pasemi_rng_data_present,
+	.data_read	= pasemi_rng_data_read,
+};
+
+static int rng_probe(struct platform_device *pdev)
+{
+	void __iomem *rng_regs;
+
+	rng_regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rng_regs))
+		return PTR_ERR(rng_regs);
+
+	pasemi_rng.priv = (unsigned long)rng_regs;
+
+	pr_info("Registering PA Semi RNG\n");
+	return devm_hwrng_register(&pdev->dev, &pasemi_rng);
+}
+
+static const struct of_device_id rng_match[] = {
+	{ .compatible      = "1682m-rng", },
+	{ .compatible      = "pasemi,pwrficient-rng", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rng_match);
+
+static struct platform_driver rng_driver = {
+	.driver = {
+		.name = "pasemi-rng",
+		.of_match_table = rng_match,
+	},
+	.probe		= rng_probe,
+};
+
+module_platform_driver(rng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
+MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");