Cosmetic updates to comments and READMEs

arch/arm/src/sama5/sam_pmecc.c

@@ -1153,7 +1153,9 @@ int pmecc_configure(struct sam_nandcs_s *priv, bool protected)
     }
 
   /* Save the size of the spare area.
-   * REVISIT: Could we save a bit by setting this to eccend?
+   *
+   * REVISIT: Could we save a bit by setting this to eccend since there is
+   * no need to read beyond that?
    */
 
   g_pmecc.desc.sparesize = priv->raw.model.sparesize;

configs/sama5d3x-ek/README.txt

@@ -1466,7 +1466,8 @@ NAND Support
 
     Another option is Smart FS.  Smart FS is another small file system
     designed to work with FLASH.  Properties:  It does support some wear-
-    leveling, but like FAT, cannot handle bad blocks.
+    leveling like NXFFS, but like FAT, cannot handle bad blocks and like
+    NXFFS, it will try to re-write erased bits.
 
     Using NAND with NXFFS
     ---------------------

drivers/mtd/README.txt

@@ -123,11 +123,12 @@ NAND MEMORY
     SMART FS
     --------
 
-    I have not yet tried SmartFS.  But I know that it does not perform bad
-    block checking (like FAT).  I do not know if it assumes that it can write
-    into erased regions of a sector multiple times (like NXFFS).
+    I have not yet tried SmartFS.  It does support some wear-leveling
+    similar to NXFFS, but like FAT, cannot handle bad blocks and like NXFFS,
+    it will try to re-write erased bits.  So SmartFS is not really an
+    option either.
 
-     What is Needed
+    What is Needed
     --------------
 
     What is needed to work with FAT properly would be another MTD layer
@@ -136,3 +137,5 @@ NAND MEMORY
     on top of the NAND.
 
     Another, less general, option would be support bad blocks within FAT.
+    Such a solution migh be possible for SLC NAND, but would not be
+    sufficiently general for all NAND types.