nand: extend .raw accesses to work on multiple pages

A use for this is to read, modify, erase, and write an entire block as a
single unit, as a replacement for the biterr command.  This way gives
more flexibility in that you can also test multiple bit errors, errors
in the ECC, etc.

Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/doc/README.nand b/doc/README.nand
index 04a87c9..1602b5e 100644
--- a/doc/README.nand
+++ b/doc/README.nand
@@ -94,14 +94,14 @@
       of data for one 512-byte page or 2 256-byte pages. There is no check
       for bad blocks.
 
-   nand read.raw addr ofs|partition
-      Read page from `ofs' in NAND flash to `addr'. This reads the raw page,
-      so ECC is avoided and the OOB area is read as well.
-
-   nand write.raw addr ofs|partition
-      Write page from `addr' to `ofs' in NAND flash. This writes the raw page,
-      so ECC is avoided and the OOB area is written as well, making the whole
-      page written as-is.
+   nand read.raw addr ofs|partition [count]
+   nand write.raw addr ofs|partition [count]
+      Read or write one or more pages at "ofs" in NAND flash, from or to
+      "addr" in memory.  This is a raw access, so ECC is avoided and the
+      OOB area is transferred as well.  If count is absent, it is assumed
+      to be one page.  As with .yaffs2 accesses, the data is formatted as
+      a packed sequence of "data, oob, data, oob, ..." -- no alignment of
+      individual pages is maintained.
 
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