crypto: xilinx: Add ZynqMP RSA driver

Adds RSA driver support for the ZynqMP SoC.
ZynqMP SoC has RSA engine used for encryption and decryption.
The flow is
RSA encrypt/decrypt request from Userspace ->
ZynqMP RSA driver -> Firmware driver -> RSA Hardware Engine

RSA Hardware engine supports 2048, 3072 and 4096 keysizes are supported.
So RSA operations using these key sizes are done by hardware engine.
Software fallback is being used for other key sizes.

Signed-off-by: Harsha Harsha <harsha.harsha@amd.com>
Co-developed-by: Dhaval Shah <dhaval.r.shah@amd.com>
Signed-off-by: Dhaval Shah <dhaval.r.shah@amd.com>

drivers/crypto/Kconfig

@@ -685,6 +685,16 @@ config CRYPTO_DEV_ROCKCHIP_DEBUG
 	  This will create /sys/kernel/debug/rk3288_crypto/stats for displaying
 	  the number of requests per algorithm and other internal stats.
 
+config CRYPTO_DEV_XILINX_RSA
+	tristate "Support for Xilinx ZynqMP RSA hardware accelerator"
+	depends on ARCH_ZYNQMP || COMPILE_TEST
+	select CRYPTO_ENGINE
+	select CRYPTO_AKCIPHER
+	help
+	  Xilinx processors have RSA hardware accelerator used for signature
+	  generation and verification. This driver interfaces with RSA
+	  hardware accelerator. Select this if you want to use the ZynqMP
+	  module for RSA algorithms.
 
 config CRYPTO_DEV_ZYNQMP_AES
 	tristate "Support for Xilinx ZynqMP AES hw accelerator"

drivers/crypto/xilinx/Makefile

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_CRYPTO_DEV_ZYNQMP_AES) += zynqmp-aes-gcm.o
 obj-$(CONFIG_CRYPTO_DEV_ZYNQMP_SHA3) += zynqmp-sha.o
+obj-$(CONFIG_CRYPTO_DEV_XILINX_RSA) += xilinx-rsa.o