KeyRing implementation

libraries/Crypto/utility/SamFlashUtil.h

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+/*
+ * Copyright (C) 2018 Southern Storm Software, Pty Ltd.
+ *
+ * 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 THE
+ * AUTHORS OR COPYRIGHT HOLDERS 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.
+ */
+
+#ifndef CRYPTO_SAMFLASHUTIL_H
+#define CRYPTO_SAMFLASHUTIL_H
+
+// Utility definitions for accessing flash memory in the
+// Arduino Due and other SAM-based Arduino variants.
+
+#if defined (__arm__) && defined (__SAM3X8E__)
+
+#include <Arduino.h>
+
+// Find the highest-numbered flash memory region on this device.
+#if defined(IFLASH1_ADDR)
+#define SAM_FLASH_ADDR         IFLASH1_ADDR
+#define SAM_FLASH_SIZE         IFLASH1_SIZE
+#define SAM_FLASH_PAGE_SIZE    IFLASH1_PAGE_SIZE
+#define SAM_FLASH_REGION_SIZE  IFLASH1_LOCK_REGION_SIZE
+#define SAM_EFC                EFC1
+#elif defined(IFLASH0_ADDR)
+#define SAM_FLASH_ADDR         IFLASH0_ADDR
+#define SAM_FLASH_SIZE         IFLASH0_SIZE
+#define SAM_FLASH_PAGE_SIZE    IFLASH0_PAGE_SIZE
+#define SAM_FLASH_REGION_SIZE  IFLASH0_LOCK_REGION_SIZE
+#define SAM_EFC                EFC0
+#else
+#define SAM_FLASH_ADDR         IFLASH_ADDR
+#define SAM_FLASH_SIZE         IFLASH_SIZE
+#define SAM_FLASH_PAGE_SIZE    IFLASH_PAGE_SIZE
+#define SAM_FLASH_REGION_SIZE  IFLASH_LOCK_REGION_SIZE
+#define SAM_EFC                EFC
+#endif
+
+// Storage for the RNG seed in the last page of flash memory.
+#define RNG_SEED_ADDR (SAM_FLASH_ADDR + SAM_FLASH_SIZE - SAM_FLASH_PAGE_SIZE)
+#define RNG_SEED_PAGE ((SAM_FLASH_SIZE / SAM_FLASH_PAGE_SIZE) - 1)
+
+// Storage for the KeyRing implementation.
+#define KEY_RING_STORAGE_SIZE       4096
+#define KEY_RING_STORAGE_ADDR \
+    (SAM_FLASH_ADDR + SAM_FLASH_SIZE - KEY_RING_STORAGE_SIZE - \
+     SAM_FLASH_PAGE_SIZE)
+#define KEY_RING_STORAGE_NUM_PAGES \
+    (KEY_RING_STORAGE_SIZE / SAM_FLASH_PAGE_SIZE)
+#define KEY_RING_STORAGE_FIRST_PAGE \
+    ((SAM_FLASH_SIZE / SAM_FLASH_PAGE_SIZE) - KEY_RING_STORAGE_NUM_PAGES - 1)
+
+// Initialize the device for write access to flash memory.
+inline void crypto_sam_flash_init(void)
+{
+    // Initialize the flash memory chip for access mode 128 and 6 wait states.
+    efc_init(SAM_EFC, EFC_ACCESS_MODE_128, 6);
+}
+
+// Erase and write a specific page.  It is assumed that the data
+// to write has already been loaded into the latch registers.
+inline void crypto_sam_erase_and_write(unsigned page)
+{
+    // Erase the page and write its new contents.
+    efc_perform_command(SAM_EFC, EFC_FCMD_EWP, page);
+}
+
+// Unlock the memory region containing a page.
+inline void crypto_sam_unlock_page(unsigned page)
+{
+    unsigned pagesPerRegion = SAM_FLASH_REGION_SIZE / SAM_FLASH_PAGE_SIZE;
+    unsigned region = page - (page % pagesPerRegion);
+    efc_perform_command(SAM_EFC, EFC_FCMD_CLB, region);
+}
+
+// Lock the memory region containing a page.
+inline void crypto_sam_lock_page(unsigned page)
+{
+    unsigned pagesPerRegion = SAM_FLASH_REGION_SIZE / SAM_FLASH_PAGE_SIZE;
+    unsigned region = page - (page % pagesPerRegion);
+    efc_perform_command(SAM_EFC, EFC_FCMD_SLB, region);
+}
+
+#endif
+
+#endif