crypto: caam - hwrng support

caam_read copies random bytes from two buffers into output.

caam rng can fill empty buffer 0xffff bytes at a time,
but the buffer sizes are rounded down to multiple of cacheline size.

Signed-off-by: Yuan Kang <Yuan.Kang@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/crypto/caam/Kconfig b/drivers/crypto/caam/Kconfig
index e61b7f5..502a7f3 100644
--- a/drivers/crypto/caam/Kconfig
+++ b/drivers/crypto/caam/Kconfig
@@ -82,3 +82,16 @@
 
 	  To compile this as a module, choose M here: the module
 	  will be called caamhash.
+
+config CRYPTO_DEV_FSL_CAAM_RNG_API
+	tristate "Register caam device for hwrng API"
+	depends on CRYPTO_DEV_FSL_CAAM
+	default y
+	select CRYPTO_RNG
+	select HW_RANDOM
+	help
+	  Selecting this will register the SEC4 hardware rng to
+	  the hw_random API for suppying the kernel entropy pool.
+
+	  To compile this as a module, choose M here: the module
+	  will be called caamrng.