u-boot porting

Template file :7

File Name: include/configs/am335x_evm.h

This file talks about different configurations of System parametrs 
-> DMA size,
    #define CONFIG_DMA_COHERENT_SIZE        (1 << 20)
->system Malloc len
  #define CONFIG_SYS_MALLOC_LEN           (1024 << 10)

->Machine type and number to pass to atag list[for identification of Machine]  
  #define MACH_TYPE_TIAM335EVM            3589    /* Until the next sync */
  #define CONFIG_MACH_TYPE                MACH_TYPE_TIAM335EVM
  

->Environment setting variables


  #define CONFIG_EXTRA_ENV_SETTINGS \
        "loadaddr=0x80200000\0" \
        "kloadaddr=0x80007fc0\0" \
        "rdaddr=0x81000000\0" \
        "bootfile=uImage\0" \
        "console=ttyO0,115200n8\0" \
        "optargs=\0" \
        "ip_method=none\0" \
        "bootargs_defaults=setenv bootargs " \
                "console=${console} " \
                "${optargs}\0" \



->Physical memory map size

 /* Physical Memory Map */
#define CONFIG_NR_DRAM_BANKS            1               /*  1 bank of DRAM */
#define PHYS_DRAM_1                     0x80000000      /* DRAM Bank #1 */
#define CONFIG_MAX_RAM_BANK_SIZE        (1024 << 20)    /* 1GB */

#define CONFIG_SYS_SDRAM_BASE           PHYS_DRAM_1
#define CONFIG_SYS_INIT_SP_ADDR         (NON_SECURE_SRAM_END - \
                                                GENERATED_GBL_DATA_SIZE)


->platform/board spec

 /* Platform/Board specific defs */
#define CONFIG_SYS_TIMERBASE            0x48040000      /* Use Timer2 */
#define CONFIG_SYS_PTV                  2       /* Divisor: 2^(PTV+1) => 8 */
#define CONFIG_SYS_HZ                   1000

->NAND support


/* NAND support */
#ifdef CONFIG_NAND
#define CONFIG_CMD_NAND
#define CONFIG_CMD_MTDPARTS
#define MTDIDS_DEFAULT                  "nand0=omap2-nand.0"
#define MTDPARTS_DEFAULT                "mtdparts=omap2-nand.0:128k(SPL)," \
                                        "128k(SPL.backup1)," \
                                        "128k(SPL.backup2)," \
                                        "128k(SPL.backup3),1920k(u-boot)," \
                                        "128k(u-boot-env),5m(kernel),-(rootfs)"
#define CONFIG_NAND_OMAP_GPMC
#define GPMC_NAND_ECC_LP_x16_LAYOUT     1
#define CONFIG_SYS_NAND_BASE            (0x08000000)    /* physical address */
                                                        /* to access nand at */
                                                        /* CS0 */
#define CONFIG_SYS_MAX_NAND_DEVICE      1               /* Max number of NAND
                                                           devices */
#if !defined(CONFIG_SPI_BOOT) && !defined(CONFIG_NOR_BOOT)
#undef CONFIG_ENV_IS_NOWHERE
#define CONFIG_ENV_IS_IN_NAND
#define CONFIG_ENV_OFFSET               0x260000 /* environment starts here */
#define CONFIG_SYS_ENV_SECT_SIZE        (128 << 10)     /* 128 KiB */
#endif


->This file adds system parameters for NAND, NOR, DMA size, System clock etc..