diff --git a/drivers/char/random.c b/drivers/char/random.c
index 605969ed0f96..c81485e2f126 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -202,6 +202,9 @@
  *                                unsigned int value);
  *	void add_interrupt_randomness(int irq, int irq_flags);
  * 	void add_disk_randomness(struct gendisk *disk);
+ *	void add_hwgenerator_randomness(const char *buffer, size_t count,
+ *					size_t entropy);
+ *	void add_bootloader_randomness(const void *buf, unsigned int size);
  *
  * add_device_randomness() is for adding data to the random pool that
  * is likely to differ between two devices (or possibly even per boot).
@@ -228,6 +231,14 @@
  * particular randomness source.  They do this by keeping track of the
  * first and second order deltas of the event timings.
  *
+ * add_hwgenerator_randomness() is for true hardware RNGs, and will credit
+ * entropy as specified by the caller. If the entropy pool is full it will
+ * block until more entropy is needed.
+ *
+ * add_bootloader_randomness() is the same as add_hwgenerator_randomness() or
+ * add_device_randomness(), depending on whether or not the configuration
+ * option CONFIG_RANDOM_TRUST_BOOTLOADER is set.
+ *
  * Ensuring unpredictability at system startup
  * ============================================
  *