davinci: am18x/da850/omap-l138 evm: setup NAND flash timing

Setup the NAND flash timings for DA850 EVM

Before configuring the timing values, throughput calculation
using dd command yielded 469 kB/s write and 966 kB/s read speed.

After the timing configuration, the throughput was measured to
be 2.4 MB/s write and 5 MB/s read.

[Mukul Bhatnagar: actual calculation of timing values from the
NAND datasheet]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Cc: Mukul Bhatnagar <mbhatnagar@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-davinci/board-da850-evm.c

@@ -36,6 +36,7 @@
 #include <mach/da8xx.h>
 #include <mach/nand.h>
 #include <mach/mux.h>
+#include <mach/aemif.h>
 
 #define DA850_EVM_PHY_MASK		0x1
 #define DA850_EVM_MDIO_FREQUENCY	2200000 /* PHY bus frequency */
@@ -143,12 +144,23 @@ static struct mtd_partition da850_evm_nandflash_partition[] = {
 	},
 };
 
+static struct davinci_aemif_timing da850_evm_nandflash_timing = {
+	.wsetup		= 24,
+	.wstrobe	= 21,
+	.whold		= 14,
+	.rsetup		= 19,
+	.rstrobe	= 50,
+	.rhold		= 0,
+	.ta		= 20,
+};
+
 static struct davinci_nand_pdata da850_evm_nandflash_data = {
 	.parts		= da850_evm_nandflash_partition,
 	.nr_parts	= ARRAY_SIZE(da850_evm_nandflash_partition),
 	.ecc_mode	= NAND_ECC_HW,
 	.ecc_bits	= 4,
 	.options	= NAND_USE_FLASH_BBT,
+	.timing		= &da850_evm_nandflash_timing,
 };
 
 static struct resource da850_evm_nandflash_resource[] = {