From e12538dcb7df17d916bb46580a01630b2f0436b7 Mon Sep 17 00:00:00 2001
From: Nikola Zivkovic <zivke85@gmail.com>
Date: Tue, 22 Dec 2015 16:16:41 +0100
Subject: [PATCH] Allow writing of data to the data partition as blocks (when
 memory supports it)

Minimize the amount of memory space that needs to be physically erased
---
 module_flash/include/flash.h | 19 +++++++++++++
 module_flash/src/flashlib.c  | 55 ++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/module_flash/include/flash.h b/module_flash/include/flash.h
index 592e0d5..c64a1fc 100644
--- a/module_flash/include/flash.h
+++ b/module_flash/include/flash.h
@@ -409,6 +409,25 @@ unsigned fl_getWriteScratchSize(unsigned offset, unsigned size);
 int fl_writeData(unsigned offset, unsigned size, const unsigned char src[],
                  unsigned char buffer[]);
 
+/* Block level functions */
+
+/**
+ * Write data to the data partition as blocks. A buffer is used to save
+ * the current data inside blocks that will be erased. The minimum size
+ * of the required buffer should be the same size as data being written, plus
+ * the size of 2 blocks. This function is used to minimize the regions of
+ * memory that need to be erased during data editing. Since not all memories
+ * support this feature, this function can be used on memories that have the
+ * sector erase size defined.
+ * \param offset The offset from the start of the data partition in bytes.
+ * \param size The number of bytes to write.
+ * \param src The data to write.
+ * \param buffer
+ * \return 0 on success, non zero on failure.
+ */
+int fl_writeDataAsBlocks(unsigned int offset, unsigned int size,
+                       const unsigned char src[], unsigned char buffer[]);
+
 /* Page level functions. */
 
 /**
diff --git a/module_flash/src/flashlib.c b/module_flash/src/flashlib.c
index 0c5d647..5080b55 100755
--- a/module_flash/src/flashlib.c
+++ b/module_flash/src/flashlib.c
@@ -963,6 +963,61 @@ int fl_writeData(unsigned int offset, unsigned int size,
   return( 0 );
 }
 
+/* Write and arbitrary number of bytes to the store (endangers data sharing pages/sectors),
+ * block by block.
+ */
+int fl_writeDataAsBlocks(unsigned int offset, unsigned int size,
+                      const unsigned char src[], unsigned char buffer[]) {
+  unsigned blockSize = g_flashAccess->sectorEraseSize;
+  if (blockSize == 0) {
+    return 1;   // Used memory type cannot erase individual blocks
+  }
+
+  unsigned startAddress = fl_getDataPartitionBase() + offset;
+
+  // Remember the address of the first block thet needs to be buffered.
+  // If block remainder is zero, then the address is the start address.
+  unsigned firstBlockDataStartAddress = startAddress % blockSize;
+  unsigned blockStartAddress = startAddress - firstBlockDataStartAddress;
+  unsigned firstBlockRemainder = blockSize - firstBlockDataStartAddress;
+
+  unsigned totalBlocksUsed = 1;
+  if (size > firstBlockRemainder) {
+    totalBlocksUsed += (size - firstBlockRemainder) / blockSize;
+    if ((size - firstBlockRemainder) % blockSize != 0) {
+      totalBlocksUsed++;
+    }
+  }
+
+  // Store all of the blocks that will be erased into a buffer
+  if (fl_int_readBytes(g_flashAccess, blockStartAddress, buffer, totalBlocksUsed * blockSize) != 0) {
+    return 1;
+  }
+
+  // Overwrite the old data with new
+  memcpy(buffer + firstBlockDataStartAddress, src, size);
+
+  // Erase blocks
+  for (int i = 0; i < totalBlocksUsed; i++) {
+    fl_int_waitWhileWriting(g_flashAccess);
+    fl_setWritability(1);
+    fl_int_issueShortCommand(g_flashAccess->sectorEraseCommand, blockStartAddress + i * blockSize, 3, 0, 0);
+  }
+
+  fl_int_waitWhileWriting(g_flashAccess);
+  fl_setWritability(0);
+
+  // Write the new blocks into memory page by page
+  int totalPagesToWriteBack = totalBlocksUsed * (blockSize / fl_getPageSize());
+  for (int i = 0; i < totalPagesToWriteBack; i++) {
+    if (fl_writePage(blockStartAddress + i * 256, buffer + i * 256) != 0) {
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
 int fl_int_copySpec( fl_DeviceSpec* dest )
 {
   if( NULL == g_flashAccess )