Add SPI Flash write data implementation and test

platform/drivers/NVM/W25Qx.c

@@ -212,3 +212,56 @@ ssize_t W25Qx_writePage(uint32_t addr, void* buf, size_t len)
     return -1;
 }
 
+bool W25Qx_writeData(uint32_t addr, void* buf, size_t len)
+{
+    // Fail if we are trying to write more than 4K bytes
+    if(len > 4096)
+        return false;
+    // Fail if we are trying to write across 4K blocks, 
+    // this would erase two 4K blocks for one write, which is not good for flash life
+    // We calculate block address using integer division of start and end address
+    uint32_t startBlockAddr = addr / 4096 * 4096;
+    uint32_t endBlockAddr = (addr + len - 1) / 4096 * 4096;
+    if(endBlockAddr != startBlockAddr)
+        return false;
+
+    // Read data from memory to check if it's already correct
+    // Allocate buffer for storing data read from memory
+    uint8_t *flashData;
+    flashData = (uint8_t *) malloc(len);
+    W25Qx_readData(addr, flashData, len);
+    // If data in flash corresponds to the passed data, do not perform the write
+    if(memcmp(buf, flashData, len) == 0)
+    {
+        // Free the buffer buffer
+        free(flashData);
+        return true;
+    }
+    // Free the flash data buffer
+    free(flashData);
+
+    // Perform the actual read-erase-write of flash data
+    // Allocate 4096 bytes block for storing flash block to be erased
+    uint8_t *flashBlock;
+    flashBlock = (uint8_t *) malloc(4096);
+    // Read the 4K block from flash
+    W25Qx_readData(startBlockAddr, flashBlock, 4096);
+    uint32_t blockOffset = addr % 4096;
+    // Overwrite changed portion
+    memcpy(flashBlock + blockOffset, buf, len);
+    // Erase the 4K block
+    if(!W25Qx_eraseSector(startBlockAddr))
+    {
+        // The erase operation failed, return failure
+        free(flashBlock);
+        return false;
+    }
+    // Write back the modified 4K block in 256 bytes chunks
+    for(uint32_t offset = 0; offset < 4096; offset += 256)
+    {
+        W25Qx_writePage(startBlockAddr + offset, flashBlock[offset], 256);
+    }
+    // Free the 4K buffer
+    free(flashBlock);
+    return true;
+}

platform/drivers/NVM/W25Qx.h

@@ -98,4 +98,19 @@ bool W25Qx_eraseSector(uint32_t addr);
  */
 ssize_t W25Qx_writePage(uint32_t addr, void *buf, size_t len);
 
+/**
+ * Write data to flash memory.
+ * Copies the 4K block to a memory buffer
+ * Overwrites the specified part
+ * Writes back the 4K block at chunks of 256Bytes.
+ * The write is not performed if the destination content matches the source
+ * Maximum write size = 4096 bytes.
+ * This function fails if you are trying to write across 4K blocks
+ *
+ * @param addr: start address for read operation.
+ * @param buf: pointer to a buffer where data is written to.
+ * @param len: number of bytes to read.
+ */
+bool W25Qx_writeData(uint32_t addr, void *buf, size_t len);
+
 #endif /* W25Qx_H */

tests/platform/overwriteExtFlash_MDx.c

@@ -0,0 +1,66 @@
+/***************************************************************************
+ *   Copyright (C) 2020 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN,                            *
+ *                         Frederik Saraci IU2NRO,                         *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <stdio.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include "W25Qx.h"
+
+uint8_t block[256] = {0};
+
+void printChunk(void *chunk)
+{
+    uint8_t *ptr = ((uint8_t *) chunk);
+    for(size_t i = 0; i < 16; i++) printf("%02x ", ptr[i]);
+    for(size_t i = 0; i < 16; i++)
+    {
+        if((ptr[i] > 0x22) && (ptr[i] < 0x7f)) printf("%c", ptr[i]);
+        else printf(".");
+    }
+    printf("\r\n");
+}
+
+int main()
+{
+    W25Qx_init();
+    W25Qx_wakeup();
+
+    while(1)
+    {
+        getchar();
+        
+        // On UV380 flash at 0x5F60 there are 36032 bytes of 0xFF
+        uint32_t addr = 0x5F60;
+        printf("Read memory @ 0x5F60\r\n");
+        W25Qx_readData(addr, block, 16);
+        printChunk(block);
+        
+        block[3] = 0xAA;
+        printf("Write memory @ 0x5F60... ");
+        bool success = W25Qx_writeData(addr, block, 16);
+        printf("%s\r\n", success ? "success" : "failed");
+
+        printf("Read memory @ 0x5F60\r\n");
+        W25Qx_readData(addr, block, 16);
+        printChunk(block);
+    }
+
+    return 0;
+}