mtd: Flex-OneNAND support

Add support for Samsung Flex-OneNAND devices.

Flex-OneNAND combines SLC and MLC technologies into a single device.
SLC area provides increased reliability and speed, suitable for storing
code such as bootloader, kernel and root file system.  MLC area
provides high density and is suitable for storing user data.

SLC and MLC regions can be configured through kernel parameter.

[akpm@linux-foundation.org: export flexoand_region and onenand_addr]
Signed-off-by: Rohit Hagargundgi <h.rohit@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Vishak G <vishak.g@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Documentation/kernel-parameters.txt

@@ -1380,6 +1380,16 @@ and is between 256 and 4096 characters. It is defined in the file
 	mtdparts=	[MTD]
 			See drivers/mtd/cmdlinepart.c.
 
+	onenand.bdry=	[HW,MTD] Flex-OneNAND Boundary Configuration
+
+			Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
+
+			boundary - index of last SLC block on Flex-OneNAND.
+				   The remaining blocks are configured as MLC blocks.
+			lock	 - Configure if Flex-OneNAND boundary should be locked.
+				   Once locked, the boundary cannot be changed.
+				   1 indicates lock status, 0 indicates unlock status.
+
 	mtdset=		[ARM]
 			ARM/S3C2412 JIVE boot control