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 c1aa43b8236abf787f929049e230b83e8b83b60a..edb6152bb9d43ee8ef95d379a76d0a9b1af595de 100644 (file)
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -8,6 +8,14 @@ config DM_RNG
 
 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 35170055415846a59239d46cce93d790a2ad70e7..6a8a66779b5b30e4a077612d10e7eb6578d30a0a 100644 (file)
--- 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 (file)
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,
+};