7 To unify all existing implementations for a secondary program loader (SPL)
8 and to allow simply adding of new implementations this generic SPL framework
9 has been created. With this framework almost all source files for a board
10 can be reused. No code duplication or symlinking is necessary anymore.
16 There is a new directory TOPDIR/spl which contains only a Makefile.
17 The object files are built separately for SPL and placed in this directory.
18 The final binaries which are generated are u-boot-spl, u-boot-spl.bin and
21 During the SPL build a variable named CONFIG_SPL_BUILD is exported
22 in the make environment and also appended to CPPFLAGS with -DCONFIG_SPL_BUILD.
23 Source files can therefore be compiled for SPL with different settings.
24 ARM-based boards have previously used the option CONFIG_PRELOADER for it.
28 ifeq ($(CONFIG_SPL_BUILD),y)
29 COBJS-y += board_spl.o
34 COBJS-$(CONFIG_SPL_BUILD) += foo.o
36 #ifdef CONFIG_SPL_BUILD
41 The building of SPL images can be with:
45 Because SPL images normally have a different text base, one have to be
46 configured by defining CONFIG_SPL_TEXT_BASE. The linker script have to be
47 defined with CONFIG_SPL_LDSCRIPT.
49 To support generic U-Boot libraries and drivers in the SPL binary one can
50 optionally define CONFIG_SPL_XXX_SUPPORT. Currently following options
53 CONFIG_SPL_LIBCOMMON_SUPPORT (common/libcommon.o)
54 CONFIG_SPL_LIBDISK_SUPPORT (disk/libdisk.o)
55 CONFIG_SPL_I2C_SUPPORT (drivers/i2c/libi2c.o)
56 CONFIG_SPL_GPIO_SUPPORT (drivers/gpio/libgpio.o)
57 CONFIG_SPL_MMC_SUPPORT (drivers/mmc/libmmc.o)
58 CONFIG_SPL_SERIAL_SUPPORT (drivers/serial/libserial.o)
59 CONFIG_SPL_SPI_FLASH_SUPPORT (drivers/mtd/spi/libspi_flash.o)
60 CONFIG_SPL_SPI_SUPPORT (drivers/spi/libspi.o)
61 CONFIG_SPL_FAT_SUPPORT (fs/fat/libfat.o)
62 CONFIG_SPL_LIBGENERIC_SUPPORT (lib/libgeneric.o)
63 CONFIG_SPL_POWER_SUPPORT (drivers/power/libpower.o)
64 CONFIG_SPL_NAND_SUPPORT (drivers/mtd/nand/libnand.o)
65 CONFIG_SPL_DMA_SUPPORT (drivers/dma/libdma.o)
66 CONFIG_SPL_POST_MEM_SUPPORT (post/drivers/memory.o)
67 CONFIG_SPL_NAND_LOAD (drivers/mtd/nand/nand_spl_load.o)