Diff: targets/TARGET_Maxim/TARGET_MAX32625/mxc/aes.c

Revision:

151:02e0a0aed4ec

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Maxim/TARGET_MAX32625/mxc/aes.c	Tue Nov 08 17:45:16 2016 +0000
@@ -0,0 +1,213 @@
+/**
+ * @file aes.c
+ * @brief      This file contains the function implementations for the Advanced
+ *             Encryption Standard (AES) peripheral module.
+ */
+
+/* ****************************************************************************
+ * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of Maxim Integrated
+ * Products, Inc. shall not be used except as stated in the Maxim Integrated
+ * Products, Inc. Branding Policy.
+ *
+ * The mere transfer of this software does not imply any licenses
+ * of trade secrets, proprietary technology, copyrights, patents,
+ * trademarks, maskwork rights, or any other form of intellectual
+ * property whatsoever. Maxim Integrated Products, Inc. retains all
+ * ownership rights.
+ *
+ * $Date: 2016-08-02 13:39:05 -0500 (Tue, 02 Aug 2016) $
+ * $Revision: 23894 $
+ *
+ *************************************************************************** */
+
+/* **** Includes **** */
+#include <string.h>    /* Included for memcpy() & #includes stddef for NULL */
+
+#include "mxc_config.h"
+#include "aes.h"
+
+/**
+ * @ingroup aes
+ * @{
+ */
+
+/* **** Definitions **** */
+
+/* **** Globals **** */
+
+/* **** Local Function Prototypes **** */
+static int aes_memcpy32(uint32_t *out, uint32_t *in, unsigned int count);
+
+/* **** Functions **** */
+
+/* ************************************************************************* */
+int AES_SetKey(const uint8_t *key, mxc_aes_mode_t mode)
+{
+    unsigned int len;
+
+    /* Erase any existing key */
+    MXC_AES_MEM->key[7] = MXC_AES_MEM->key[6] = MXC_AES_MEM->key[5] = MXC_AES_MEM->key[4] \
+                          = MXC_AES_MEM->key[3] = MXC_AES_MEM->key[2] = MXC_AES_MEM->key[1] = MXC_AES_MEM->key[0] \
+                                  = 0x00000000;
+
+    /* Determine length of key */
+    if (mode == MXC_E_AES_MODE_256) {
+        len = MXC_AES_KEY_256_LEN;
+    } else if (mode == MXC_E_AES_MODE_192) {
+        len = MXC_AES_KEY_192_LEN;
+    } else if (mode == MXC_E_AES_MODE_128) {
+        len = MXC_AES_KEY_128_LEN;
+    } else {
+        return E_BAD_PARAM;
+    }
+
+    /* Load new key, based on key mode */
+    if (aes_memcpy32((uint32_t *)MXC_AES_MEM->key, (uint32_t *)key, len / sizeof(uint32_t)) < 0) {
+        return E_NULL_PTR;
+    }
+
+    return E_SUCCESS;
+}
+
+/* ************************************************************************* */
+int AES_ECBOp(const uint8_t *in, uint8_t *out, mxc_aes_mode_t mode, mxc_aes_dir_t dir)
+{
+    /* Output array can't be a NULL, unless we are in _ASYNC mode */
+    if ((out == NULL)
+            && ((dir != MXC_E_AES_ENCRYPT_ASYNC) && (dir != MXC_E_AES_DECRYPT_ASYNC))) {
+        return E_NULL_PTR;
+    }
+
+    /* Another encryption is already in progress */
+    if (MXC_AES->ctrl & MXC_F_AES_CTRL_START) {
+        return E_BUSY;
+    }
+
+    /* Clear interrupt flag and any existing configuration*/
+    MXC_AES->ctrl = MXC_F_AES_CTRL_INTFL;
+
+    /* Select key size & direction
+     *
+     * Note: This is done first to detect argument errors, before sensitive data
+     *  is loaded into AES_MEM block
+     *
+     */
+    switch (mode) {
+        case MXC_E_AES_MODE_128:
+            MXC_AES->ctrl |= MXC_S_AES_CTRL_KEY_SIZE_128;
+            break;
+
+        case MXC_E_AES_MODE_192:
+            MXC_AES->ctrl |= MXC_S_AES_CTRL_KEY_SIZE_192;
+            break;
+
+        case MXC_E_AES_MODE_256:
+            MXC_AES->ctrl |= MXC_S_AES_CTRL_KEY_SIZE_256;
+            break;
+
+        default:
+            return E_BAD_PARAM;
+    }
+
+    switch (dir) {
+        case MXC_E_AES_ENCRYPT:
+        case MXC_E_AES_ENCRYPT_ASYNC:
+            MXC_AES->ctrl |= MXC_S_AES_CTRL_ENCRYPT_MODE;
+            break;
+
+        case MXC_E_AES_DECRYPT:
+        case MXC_E_AES_DECRYPT_ASYNC:
+            MXC_AES->ctrl |= MXC_S_AES_CTRL_DECRYPT_MODE;
+            break;
+
+        default:
+            return E_BAD_PARAM;
+    }
+
+    /* If non-blocking mode has been selected, interrupts are automatically enabled */
+    if ((dir == MXC_E_AES_ENCRYPT_ASYNC) ||
+            (dir == MXC_E_AES_DECRYPT_ASYNC)) {
+        MXC_AES->ctrl |= MXC_F_AES_CTRL_INTEN;
+    }
+
+    /* Load input into engine */
+    if (aes_memcpy32((uint32_t *)MXC_AES_MEM->inp, (uint32_t *)in, MXC_AES_DATA_LEN / sizeof(uint32_t)) < 0) {
+        return E_NULL_PTR;
+    }
+
+    /* Start operation */
+    MXC_AES->ctrl |= MXC_F_AES_CTRL_START;
+
+    /* Block, waiting on engine to complete, or fall through if non-blocking */
+    if ((dir != MXC_E_AES_ENCRYPT_ASYNC) &&
+            (dir != MXC_E_AES_DECRYPT_ASYNC)) {
+        while (MXC_AES->ctrl & MXC_F_AES_CTRL_START) {
+            /* Ensure that this wait loop is not optimized out */
+            __NOP();
+        }
+
+        /* Get output from engine */
+        return AES_GetOutput(out);
+    }
+
+    return E_SUCCESS;
+}
+
+/* ************************************************************************* */
+int AES_GetOutput(uint8_t *out)
+{
+    /* Don't read it out of the AES memory unless engine is idle */
+    if (MXC_AES->ctrl & MXC_F_AES_CTRL_START) {
+        return E_BUSY;
+    }
+
+    /* Pull out result */
+    if (aes_memcpy32((uint32_t *)out, (uint32_t *)MXC_AES_MEM->out, MXC_AES_DATA_LEN / sizeof(uint32_t)) < 0) {
+        return E_NULL_PTR;
+    }
+
+    /* Clear interrupt flag, write 1 to clear */
+    MXC_AES->ctrl |= MXC_F_AES_CTRL_INTFL;
+
+    return E_SUCCESS;
+}
+
+/**
+ * @internal This memory copy is used only by the AES module to avoid data leakage by the standard C library.
+ * Copy count number of 32-bit locations from in to out
+ */
+static int aes_memcpy32(uint32_t *out, uint32_t *in, unsigned int count)
+{
+    if ((out == NULL) || (in == NULL)) {
+        /* Invalid arguments, but is internal-only so don't use error codes */
+        return -1;
+    }
+
+    while (count--) {
+        *out++ = *in++;
+    }
+
+    return 0;
+}
+
+/**@} end of group aes */