v4.19.13 snapshot.
diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h
new file mode 100644
index 0000000..bee0827
--- /dev/null
+++ b/include/linux/hw_random.h
@@ -0,0 +1,65 @@
+/*
+ Hardware Random Number Generator
+
+ Please read Documentation/hw_random.txt for details on use.
+
+ ----------------------------------------------------------
+ This software may be used and distributed according to the terms
+ of the GNU General Public License, incorporated herein by reference.
+
+ */
+
+#ifndef LINUX_HWRANDOM_H_
+#define LINUX_HWRANDOM_H_
+
+#include <linux/completion.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/kref.h>
+
+/**
+ * struct hwrng - Hardware Random Number Generator driver
+ * @name: Unique RNG name.
+ * @init: Initialization callback (can be NULL).
+ * @cleanup: Cleanup callback (can be NULL).
+ * @data_present: Callback to determine if data is available
+ * on the RNG. If NULL, it is assumed that
+ * there is always data available. *OBSOLETE*
+ * @data_read: Read data from the RNG device.
+ * Returns the number of lower random bytes in "data".
+ * Must not be NULL. *OBSOLETE*
+ * @read: New API. drivers can fill up to max bytes of data
+ * into the buffer. The buffer is aligned for any type
+ * and max is a multiple of 4 and >= 32 bytes.
+ * @priv: Private data, for use by the RNG driver.
+ * @quality: Estimation of true entropy in RNG's bitstream
+ * (per mill).
+ */
+struct hwrng {
+ const char *name;
+ int (*init)(struct hwrng *rng);
+ void (*cleanup)(struct hwrng *rng);
+ int (*data_present)(struct hwrng *rng, int wait);
+ int (*data_read)(struct hwrng *rng, u32 *data);
+ int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);
+ unsigned long priv;
+ unsigned short quality;
+
+ /* internal. */
+ struct list_head list;
+ struct kref ref;
+ struct completion cleanup_done;
+};
+
+struct device;
+
+/** Register a new Hardware Random Number Generator driver. */
+extern int hwrng_register(struct hwrng *rng);
+extern int devm_hwrng_register(struct device *dev, struct hwrng *rng);
+/** Unregister a Hardware Random Number Generator driver. */
+extern void hwrng_unregister(struct hwrng *rng);
+extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng);
+/** Feed random bits into the pool. */
+extern void add_hwgenerator_randomness(const char *buffer, size_t count, size_t entropy);
+
+#endif /* LINUX_HWRANDOM_H_ */