omap3: nand: configurable transfer type per board

nand transfer type (sDMA, Polled, prefetch) can be select from board file,
enabling all transfer type in driver, by default.

this helps in multi-omap build and to select different transfer type for
different board.

Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/plat-omap/include/plat/nand.h b/arch/arm/plat-omap/include/plat/nand.h
index 6562cd0..78c0bdb 100644
--- a/arch/arm/plat-omap/include/plat/nand.h
+++ b/arch/arm/plat-omap/include/plat/nand.h
@@ -10,6 +10,12 @@
 
 #include <linux/mtd/partitions.h>
 
+enum nand_io {
+	NAND_OMAP_PREFETCH_POLLED = 0,	/* prefetch polled mode, default */
+	NAND_OMAP_POLLED,		/* polled mode, without prefetch */
+	NAND_OMAP_PREFETCH_DMA		/* prefetch enabled sDMA mode */
+};
+
 struct omap_nand_platform_data {
 	unsigned int		options;
 	int			cs;
@@ -20,6 +26,7 @@
 	int			(*nand_setup)(void);
 	int			(*dev_ready)(struct omap_nand_platform_data *);
 	int			dma_channel;
+	enum nand_io		xfer_type;
 	unsigned long		phys_base;
 	int			devsize;
 };