[Yaffs] [PATCH YAFFS2] fix-wrong-blocks-erased

Correct the calculation of the block number to erase.

The use of ">> 5" to calculate the block number from the chunk number
was incorrect for the actual value of PAGES_PER_BLOCK (64).

At the same time, make this less error prone.

Luc Van Oostenryck
diff --git a/fs/yaffs2/mtdemul/nandemul2k.c b/fs/yaffs2/mtdemul/nandemul2k.c
--- a/fs/yaffs2/mtdemul/nandemul2k.c
+++ b/fs/yaffs2/mtdemul/nandemul2k.c
@@ -44,13 +44,14 @@

-#define EM_SIZE_IN_MEG 4
-#define PAGE_DATA_SIZE  (2048)
-#define PAGE_SPARE_SIZE (64)
-#define PAGES_PER_BLOCK (64)
 #define NAND_SHIFT      (11)   // Shifter for 2k
+#define PAGE_DATA_SIZE  (1 << NAND_SHIFT)
+#define PAGE_SPARE_SIZE (64)
+#define BLK_SHIFT    6
+#define PAGES_PER_BLOCK (1 << BLK_SHIFT)    // = 64

+#define EM_SIZE_IN_MEG 4
#define EM_SIZE_IN_BYTES (EM_SIZE_IN_MEG * (1<<20))

 #define PAGE_TOTAL_SIZE (PAGE_DATA_SIZE+PAGE_SPARE_SIZE)
@@ -557,8 +558,8 @@ static int nand_erase (struct mtd_info *
         return -EINVAL;
     }

-    nBlocks = instr->len >> (NAND_SHIFT + 5);
-    block = instr->addr >> (NAND_SHIFT + 5);
+    nBlocks = instr->len >> (NAND_SHIFT + BLK_SHIFT);
+    block = instr->addr >> (NAND_SHIFT + BLK_SHIFT);

     for(i = 0; i < nBlocks; i++)
     {