drivers/rng: add Amlogic hardware RNG driver
Add support for the hardware random number generator of Amlogic SOCs.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Sughosh Ganu <sughosh.ganu@linaro.org>
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index c1aa43b..edb6152 100644
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -8,6 +8,14 @@
if DM_RNG
+config RNG_MESON
+ bool "Amlogic Meson Random Number Generator support"
+ depends on ARCH_MESON
+ default y
+ help
+ Enable support for hardware random number generator
+ of Amlogic Meson SoCs.
+
config RNG_SANDBOX
bool "Sandbox random number generator"
depends on SANDBOX
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 3517005..6a8a667 100644
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -4,5 +4,6 @@
#
obj-$(CONFIG_DM_RNG) += rng-uclass.o
+obj-$(CONFIG_RNG_MESON) += meson-rng.o
obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
diff --git a/drivers/rng/meson-rng.c b/drivers/rng/meson-rng.c
new file mode 100644
index 0000000..4b81a62
--- /dev/null
+++ b/drivers/rng/meson-rng.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ *
+ * Driver for Amlogic hardware random number generator
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <rng.h>
+#include <asm/io.h>
+
+struct meson_rng_platdata {
+ fdt_addr_t base;
+ struct clk clk;
+};
+
+/**
+ * meson_rng_read() - fill buffer with random bytes
+ *
+ * @buffer: buffer to receive data
+ * @size: size of buffer
+ *
+ * Return: 0
+ */
+static int meson_rng_read(struct udevice *dev, void *data, size_t len)
+{
+ struct meson_rng_platdata *pdata = dev_get_platdata(dev);
+ char *buffer = (char *)data;
+
+ while (len) {
+ u32 rand = readl(pdata->base);
+ size_t step;
+
+ if (len >= 4)
+ step = 4;
+ else
+ step = len;
+ memcpy(buffer, &rand, step);
+ buffer += step;
+ len -= step;
+ }
+ return 0;
+}
+
+/**
+ * meson_rng_probe() - probe rng device
+ *
+ * @dev: device
+ * Return: 0 if ok
+ */
+static int meson_rng_probe(struct udevice *dev)
+{
+ struct meson_rng_platdata *pdata = dev_get_platdata(dev);
+ int err;
+
+ err = clk_enable(&pdata->clk);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+/**
+ * meson_rng_remove() - deinitialize rng device
+ *
+ * @dev: device
+ * Return: 0 if ok
+ */
+static int meson_rng_remove(struct udevice *dev)
+{
+ struct meson_rng_platdata *pdata = dev_get_platdata(dev);
+
+ return clk_disable(&pdata->clk);
+}
+
+/**
+ * meson_rng_ofdata_to_platdata() - transfer device tree data to plaform data
+ *
+ * @dev: device
+ * Return: 0 if ok
+ */
+static int meson_rng_ofdata_to_platdata(struct udevice *dev)
+{
+ struct meson_rng_platdata *pdata = dev_get_platdata(dev);
+ int err;
+
+ pdata->base = dev_read_addr(dev);
+ if (!pdata->base)
+ return -ENODEV;
+
+ err = clk_get_by_name(dev, "core", &pdata->clk);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static const struct dm_rng_ops meson_rng_ops = {
+ .read = meson_rng_read,
+};
+
+static const struct udevice_id meson_rng_match[] = {
+ {
+ .compatible = "amlogic,meson-rng",
+ },
+ {},
+};
+
+U_BOOT_DRIVER(meson_rng) = {
+ .name = "meson-rng",
+ .id = UCLASS_RNG,
+ .of_match = meson_rng_match,
+ .ops = &meson_rng_ops,
+ .probe = meson_rng_probe,
+ .remove = meson_rng_remove,
+ .platdata_auto_alloc_size = sizeof(struct meson_rng_platdata),
+ .ofdata_to_platdata = meson_rng_ofdata_to_platdata,
+};