1 files changed, 70 insertions, 0 deletions
diff --git a/drivers/char/hw_random/powernv-rng.c b/drivers/char/hw_random/powernv-rng.c
new file mode 100644
index 000000000..8da1d7917
--- /dev/null
+++ b/drivers/char/hw_random/powernv-rng.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2013 Michael Ellerman, Guo Chao, IBM Corp.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+#include <linux/hw_random.h>
+
+static int powernv_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+	unsigned long *buf;
+	int i, len;
+
+	/* We rely on rng_buffer_size() being >= sizeof(unsigned long) */
+	len = max / sizeof(unsigned long);
+
+	buf = (unsigned long *)data;
+
+	for (i = 0; i < len; i++)
+		powernv_get_random_long(buf++);
+
+	return len * sizeof(unsigned long);
+}
+
+static struct hwrng powernv_hwrng = {
+	.name = "powernv-rng",
+	.read = powernv_rng_read,
+};
+
+static int powernv_rng_probe(struct platform_device *pdev)
+{
+	int rc;
+
+	rc = devm_hwrng_register(&pdev->dev, &powernv_hwrng);
+	if (rc) {
+		/* We only register one device, ignore any others */
+		if (rc == -EEXIST)
+			rc = -ENODEV;
+
+		return rc;
+	}
+
+	pr_info("Registered powernv hwrng.\n");
+
+	return 0;
+}
+
+static const struct of_device_id powernv_rng_match[] = {
+	{ .compatible	= "ibm,power-rng",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, powernv_rng_match);
+
+static struct platform_driver powernv_rng_driver = {
+	.driver = {
+		.name = "powernv_rng",
+		.of_match_table = powernv_rng_match,
+	},
+	.probe	= powernv_rng_probe,
+};
+module_platform_driver(powernv_rng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Bare metal HWRNG driver for POWER7+ and above");