RSA Accelerator: Add mod_exp, refactor to avoid memory allocation & copying

Not fully working at the moment, mod_exp has a bug.

components/esp32/include/soc/hwcrypto_reg.h

@@ -0,0 +1,37 @@
+// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#ifndef __HWCRYPTO_REG_H__
+#define __HWCRYPTO_REG_H__
+
+#include "soc.h"
+
+/* registers for RSA acceleration via Multiple Precision Integer ops */
+#define RSA_MEM_M_BLOCK_BASE          ((DR_REG_RSA_BASE)+0x000)
+/* RB & Z use the same memory block, depending on phase of operation */
+#define RSA_MEM_RB_BLOCK_BASE         ((DR_REG_RSA_BASE)+0x200)
+#define RSA_MEM_Z_BLOCK_BASE          ((DR_REG_RSA_BASE)+0x200)
+#define RSA_MEM_Y_BLOCK_BASE          ((DR_REG_RSA_BASE)+0x400)
+#define RSA_MEM_X_BLOCK_BASE          ((DR_REG_RSA_BASE)+0x600)
+
+#define RSA_M_DASH_REG                (DR_REG_RSA_BASE + 0x800)
+#define RSA_MODEXP_MODE_REG           (DR_REG_RSA_BASE + 0x804)
+#define RSA_START_MODEXP_REG          (DR_REG_RSA_BASE + 0x808)
+#define RSA_MULT_MODE_REG             (DR_REG_RSA_BASE + 0x80c)
+#define RSA_MULT_START_REG            (DR_REG_RSA_BASE + 0x810)
+
+#define RSA_INTERRUPT_REG             (DR_REG_RSA_BASE + 0X814)
+
+#define RSA_CLEAN_ADDR                (DR_REG_RSA_BASE + 0X818)
+
+#endif

components/esp32/include/soc/soc.h

@@ -141,6 +141,7 @@
 //}}
 
 #define DR_REG_DPORT_BASE                       0x3ff00000
+#define DR_REG_RSA_BASE                         0x3ff02000
 #define DR_REG_UART_BASE                        0x3ff40000
 #define DR_REG_SPI1_BASE                        0x3ff42000
 #define DR_REG_SPI0_BASE                        0x3ff43000

components/mbedtls/port/include/mbedtls/esp_config.h

@@ -251,7 +251,7 @@
    Uncommenting these macros will use the hardware-accelerated
    implementations.
 */
-//#define MBEDTLS_MPI_EXP_MOD_ALT
+#define MBEDTLS_MPI_EXP_MOD_ALT
 #define MBEDTLS_MPI_MUL_MPI_ALT
 
 /**