mtd: nand: add support for diskonchip G4 nand flash device

This patch adds a driver for the M-Sys / Sandisk diskonchip G4 nand flash found
in various smartphones and PDAs, among them the Palm Treo680, HTC Prophet and
Wizard, Toshiba Portege G900, Asus P526, and O2 XDA Zinc.  It was tested on the
Treo 680, but should work generically.

Since v3, this patch adds power management functions, a scan of the factory bad
block table during initialization, several fixes, and more extensive testing.
Also, the platform data header file, which only contained partitioning
information, was removed.  Command-line partitioning can be used, at least until
an mtd parser is written for the saftl format with which these chips are
shipped.
Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/Kconfig

@@ -313,6 +313,26 @@ config MTD_NAND_DISKONCHIP_BBTWRITE
 	  load time (assuming you build diskonchip as a module) with the module
 	  parameter "inftl_bbt_write=1".
 
+config MTD_NAND_DOCG4
+	tristate "Support for DiskOnChip G4 (EXPERIMENTAL)"
+	depends on EXPERIMENTAL
+	select BCH
+	select BITREVERSE
+	help
+	  Support for diskonchip G4 nand flash, found in various smartphones and
+	  PDAs, among them the Palm Treo680, HTC Prophet and Wizard, Toshiba
+	  Portege G900, Asus P526, and O2 XDA Zinc.
+
+	  With this driver you will be able to use UBI and create a ubifs on the
+	  device, so you may wish to consider enabling UBI and UBIFS as well.
+
+	  These devices ship with the Mys/Sandisk SAFTL formatting, for which
+	  there is currently no mtd parser, so you may want to use command line
+	  partitioning to segregate write-protected blocks. On the Treo680, the
+	  first five erase blocks (256KiB each) are write-protected, followed
+	  by the block containing the saftl partition table.  This is probably
+	  typical.
+
 config MTD_NAND_SHARPSL
 	tristate "Support for NAND Flash on Sharp SL Series (C7xx + others)"
 	depends on ARCH_PXA

drivers/mtd/nand/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_MTD_NAND_PPCHAMELEONEVB)	+= ppchameleonevb.o
 obj-$(CONFIG_MTD_NAND_S3C2410)		+= s3c2410.o
 obj-$(CONFIG_MTD_NAND_DAVINCI)		+= davinci_nand.o
 obj-$(CONFIG_MTD_NAND_DISKONCHIP)	+= diskonchip.o
+obj-$(CONFIG_MTD_NAND_DOCG4)		+= docg4.o
 obj-$(CONFIG_MTD_NAND_FSMC)		+= fsmc_nand.o
 obj-$(CONFIG_MTD_NAND_H1900)		+= h1910.o
 obj-$(CONFIG_MTD_NAND_RTC_FROM4)	+= rtc_from4.o