Add a uclass for reading a random number seed from a random number
generator device.

Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.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            | 25 +++++++++++++++++++++++++
 7 files changed, 65 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 9d99ce0..e34a227 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 0befedd..0fa4413 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -117,4 +117,5 @@ obj-$(CONFIG_W1_EEPROM) += w1-eeprom/
 
 obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
 obj-$(CONFIG_DM_HWSPINLOCK) += hwspinlock/
+obj-$(CONFIG_DM_RNG) += rng/
 endif
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
new file mode 100644
index 0000000..dd44cc0
--- /dev/null
+++ b/drivers/rng/Kconfig
@@ -0,0 +1,7 @@
+config DM_RNG
+       bool "Driver support for Random Number Generator devices"
+       depends on DM
+       help
+         Enable driver model for random number generator(rng) devices.
+         This interface is used to initialise the rng device and to
+         read the random seed from the device.
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
new file mode 100644
index 0000000..311705b
--- /dev/null
+++ b/drivers/rng/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (c) 2019, Linaro Limited
+#
+
+obj-$(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 0000000..de745d3
--- /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(hwrng) = {
+       .name = "rng",
+       .id = UCLASS_RNG,
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 0c563d8..192202d 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -86,6 +86,7 @@ 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 0000000..b5fd950
--- /dev/null
+++ b/include/rng.h
@@ -0,0 +1,25 @@
+#if !defined _RNG_H_
+#define _RNG_H_
+
+#include <dm.h>
+
+/**
+ * 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
+ *
+ */
+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
+        */
+       int (*read)(struct udevice *dev, void *data, size_t max);
+};
+
+#endif /* _RNG_H_ */
-- 
2.7.4

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