board/ti/dra7xx: add support for parallel NAND

This patch adds support for x16 NAND device (MT29F2G16AAD) connected to GPMC
chip-select[0] on DRA7xx EVM.
As GPMC pins are shared by multiple devices, so in addition to this patch
following board settings are required for NAND device detection [1]:

  SW5.9 (GPMC_WPN)   = OFF (logic-1)
  SW5.1 (NAND_BOOTn) = ON  (logic-0) /* Active-low */
  SW5.2 (NOR_BOOTn)  = OFF (logic-1)
  SW5.3 (eMMC_BOOTn) = OFF (logic-1)
  SW5.4 (QSPI_BOOTn) = OFF (logic-1)

And also set appropriate SYSBOOT configurations
  SW2.1 (SYSBOOT[0]) = ON  (logic-1) /* selects NAND Boot */
  SW2.2 (SYSBOOT[1]) = OFF (logic-0) /* selects NAND Boot */
  SW2.3 (SYSBOOT[2]) = OFF (logic-0) /* selects NAND Boot */
  SW2.4 (SYSBOOT[3]) = OFF (logic-0) /* selects NAND Boot */
  SW2.5 (SYSBOOT[4]) = ON  (logic-1) /* selects NAND Boot */
  SW2.6 (SYSBOOT[5]) = ON  (logic-1) /* selects NAND Boot */
  SW2.7 (SYSBOOT[6]) = OFF (logic-0) /* reserved */
  SW2.8 (SYSBOOT[7]) = OFF (logic-0) /* reserved */

  SW3.1 (SYSBOOT[ 8])= ON  (logic-1) /* selects SYS_CLK1 speed */
  SW3.2 (SYSBOOT[ 9])= OFF (logic-0) /* selects SYS_CLK1 speed */
  SW3.3 (SYSBOOT[10])= ON  (logic-1) /* wait-pin monitoring = enabled */
  SW3.4 (SYSBOOT[11])= OFF (logic-0) /* device type: Addr/Data Muxed */
  SW3.5 (SYSBOOT[12])= ON  (logic-1) /* device type: Addr/Data Muxed */
  SW3.6 (SYSBOOT[13])= ON  (logic-1) /* device bus-width: 1(x16) */
  SW3.7 (SYSBOOT[14])= OFF (logic-0) /* reserved */
  SW3.8 (SYSBOOT[15])= ON  (logic-1) /* reserved */

Following changes are required in board.cfg to enable NAND on J6-EVM:
diff --git a/include/configs/dra7xx_evm.h b/include/configs/dra7xx_evm.h
index 8d0a0eb..10c88dc 100644
--- a/include/configs/dra7xx_evm.h
+++ b/include/configs/dra7xx_evm.h
@@ -143,4 +143,54 @@
 #define CONFIG_SYS_SCSI_MAX_DEVICE	(CONFIG_SYS_SCSI_MAX_SCSI_ID * \
 						CONFIG_SYS_SCSI_MAX_LUN)
 
+/* NAND support */
+#ifdef CONFIG_NAND
+/* NAND: device related configs */
+#define CONFIG_SYS_NAND_PAGE_SIZE	2048
+#define CONFIG_SYS_NAND_OOBSIZE		64
+#define CONFIG_SYS_NAND_BLOCK_SIZE	(128*1024)
+#define CONFIG_SYS_NAND_BUSWIDTH_16BIT
+#define CONFIG_SYS_NAND_PAGE_COUNT	(CONFIG_SYS_NAND_BLOCK_SIZE / \
+					 CONFIG_SYS_NAND_PAGE_SIZE)
+#define CONFIG_SYS_NAND_5_ADDR_CYCLE
+/* NAND: driver related configs */
+#define CONFIG_NAND_OMAP_GPMC
+#define CONFIG_NAND_OMAP_ELM
+#define CONFIG_SYS_NAND_ONFI_DETECTION
+#define CONFIG_NAND_OMAP_ECCSCHEME	OMAP_ECC_BCH8_CODE_HW
+#define CONFIG_SYS_NAND_BAD_BLOCK_POS	NAND_LARGE_BADBLOCK_POS
+#define CONFIG_SYS_NAND_ECCPOS		{ 2, 3, 4, 5, 6, 7, 8, 9, \
+					 10, 11, 12, 13, 14, 15, 16, 17, \
+					 18, 19, 20, 21, 22, 23, 24, 25, \
+					 26, 27, 28, 29, 30, 31, 32, 33, \
+					 34, 35, 36, 37, 38, 39, 40, 41, \
+					 42, 43, 44, 45, 46, 47, 48, 49, \
+					 50, 51, 52, 53, 54, 55, 56, 57, }
+#define CONFIG_SYS_NAND_ECCSIZE		512
+#define CONFIG_SYS_NAND_ECCBYTES	14
+#define MTDIDS_DEFAULT			"nand0=nand.0"
+#define MTDPARTS_DEFAULT		"mtdparts=nand.0:" \
+					"128k(NAND.SPL)," \
+					"128k(NAND.SPL.backup1)," \
+					"128k(NAND.SPL.backup2)," \
+					"128k(NAND.SPL.backup3)," \
+					"256k(NAND.u-boot-spl-os)," \
+					"1m(NAND.u-boot)," \
+					"128k(NAND.u-boot-env)," \
+					"128k(NAND.u-boot-env.backup1)," \
+					"8m(NAND.kernel)," \
+					"-(NAND.rootfs)"
+#define CONFIG_SYS_NAND_U_BOOT_OFFS	0x000c0000
+/* NAND: SPL related configs */
+#ifdef CONFIG_SPL_NAND_SUPPORT
+#define CONFIG_SPL_NAND_AM33XX_BCH
+#endif
+/* NAND: SPL falcon mode configs */
+#ifdef CONFIG_SPL_OS_BOOT
+#define CONFIG_CMD_SPL_NAND_OFS		0x00080000 /* os-boot params*/
+#define CONFIG_SYS_NAND_SPL_KERNEL_OFFS	0x00200000 /* kernel offset */
+#define CONFIG_CMD_SPL_WRITE_SIZE	0x2000
+#endif
+#endif /* !CONFIG_NAND */
+
 #endif /* __CONFIG_DRA7XX_EVM_H */