From a2487684003b0bc380955e1a38cdd71da3ca4366 Mon Sep 17 00:00:00 2001
From: Sughosh Ganu <sughosh.ganu@linaro.org>
Date: Sat, 28 Dec 2019 23:58:27 +0530
Subject: [PATCH] dm: rng: Add random number generator(rng) uclass
Add a uclass for reading a random number seed from a random number
generator device.
Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
drivers/Kconfig | 2 ++
drivers/Makefile | 1 +
drivers/rng/Kconfig | 7 +++++++
drivers/rng/Makefile | 6 ++++++
drivers/rng/rng-uclass.c | 23 +++++++++++++++++++++++
include/dm/uclass-id.h | 1 +
include/rng.h | 33 +++++++++++++++++++++++++++++++++
7 files changed, 73 insertions(+)
create mode 100644 drivers/rng/Kconfig
create mode 100644 drivers/rng/Makefile
create mode 100644 drivers/rng/rng-uclass.c
create mode 100644 include/rng.h
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 9d99ce0226..e34a22708c 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -90,6 +90,8 @@ source "drivers/remoteproc/Kconfig"
source "drivers/reset/Kconfig"
+source "drivers/rng/Kconfig"
+
source "drivers/rtc/Kconfig"
source "drivers/scsi/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index cb8c215e76..8eec4e8176 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -116,4 +116,5 @@ obj-$(CONFIG_W1_EEPROM) += w1-eeprom/
obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
obj-$(CONFIG_DM_HWSPINLOCK) += hwspinlock/
+obj-$(CONFIG_DM_RNG) += rng/
endif
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
new file mode 100644
index 0000000000..dd44cc0242
--- /dev/null
+++ b/drivers/rng/Kconfig
@@ -0,0 +1,7 @@
+config DM_RNG
+ bool "Driver support for Random Number Generator devices"
+ depends on DM
+ help
+ Enable driver model for random number generator(rng) devices.
+ This interface is used to initialise the rng device and to
+ read the random seed from the device.
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
new file mode 100644
index 0000000000..311705b6e6
--- /dev/null
+++ b/drivers/rng/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (c) 2019, Linaro Limited
+#
+
+obj-$(CONFIG_DM_RNG) += rng-uclass.o
diff --git a/drivers/rng/rng-uclass.c b/drivers/rng/rng-uclass.c
new file mode 100644
index 0000000000..b6af3b8606
--- /dev/null
+++ b/drivers/rng/rng-uclass.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+
+int dm_rng_read(struct udevice *dev, void *buffer, size_t size)
+{
+ const struct dm_rng_ops *ops = device_get_ops(dev);
+
+ if (!ops->read)
+ return -ENOSYS;
+
+ return ops->read(dev, buffer, size);
+}
+
+UCLASS_DRIVER(rng) = {
+ .name = "rng",
+ .id = UCLASS_RNG,
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index c1bab17ad1..67f5d673cb 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -88,6 +88,7 @@ enum uclass_id {
UCLASS_REGULATOR, /* Regulator device */
UCLASS_REMOTEPROC, /* Remote Processor device */
UCLASS_RESET, /* Reset controller device */
+ UCLASS_RNG, /* Random Number Generator */
UCLASS_RTC, /* Real time clock device */
UCLASS_SCSI, /* SCSI device */
UCLASS_SERIAL, /* Serial UART */
diff --git a/include/rng.h b/include/rng.h
new file mode 100644
index 0000000000..d2c0f9af62
--- /dev/null
+++ b/include/rng.h
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#if !defined _RNG_H_
+#define _RNG_H_
+
+struct udevice;
+
+/**
+ * dm_rng_read() - read a random number seed from the rng device
+ * @buffer: input buffer to put the read random seed into
+ * @size: number of bytes of random seed read
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int dm_rng_read(struct udevice *dev, void *buffer, size_t size);
+
+/* struct dm_rng_ops - Operations for the hwrng uclass */
+struct dm_rng_ops {
+ /**
+ * @read() - read a random number seed
+ *
+ * @data: input buffer to read the random seed
+ * @max: total number of bytes to read
+ *
+ * Return: 0 if OK, -ve on error
+ */
+ int (*read)(struct udevice *dev, void *data, size_t max);
+};
+
+#endif /* _RNG_H_ */
--
2.39.5