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| -rw-r--r-- | doc/README.SPL | 28 |
1 files changed, 6 insertions, 22 deletions
diff --git a/doc/README.SPL b/doc/README.SPL index 2b4b0b8..c283dcf 100644 --- a/doc/README.SPL +++ b/doc/README.SPL @@ -13,34 +13,29 @@ can be reused. No code duplication or symlinking is necessary anymore. How it works ------------ -There is a new directory $(srctree)/spl which contains only a Makefile. -The object files are built separately for SPL and placed in this directory. +The object files for SPL are built separately and placed in the "spl" directory. The final binaries which are generated are u-boot-spl, u-boot-spl.bin and u-boot-spl.map. -During the SPL build a variable named CONFIG_SPL_BUILD is exported -in the make environment and also appended to CPPFLAGS with -DCONFIG_SPL_BUILD. +A config option named CONFIG_SPL_BUILD is enabled by Kconfig for SPL. Source files can therefore be compiled for SPL with different settings. -ARM-based boards have previously used the option CONFIG_PRELOADER for it. For example: ifeq ($(CONFIG_SPL_BUILD),y) -COBJS-y += board_spl.o +obj-y += board_spl.o else -COBJS-y += board.o +obj-y += board.o endif -COBJS-$(CONFIG_SPL_BUILD) += foo.o +obj-$(CONFIG_SPL_BUILD) += foo.o #ifdef CONFIG_SPL_BUILD foo(); #endif -The building of SPL images can be with: - -#define CONFIG_SPL 1 +The building of SPL images can be enabled by CONFIG_SPL option in Kconfig. Because SPL images normally have a different text base, one has to be configured by defining CONFIG_SPL_TEXT_BASE. The linker script has to be @@ -70,17 +65,6 @@ CONFIG_SPL_SPI_LOAD (drivers/mtd/spi/spi_spl_load.o) CONFIG_SPL_RAM_DEVICE (common/spl/spl.c) CONFIG_SPL_WATCHDOG_SUPPORT (drivers/watchdog/libwatchdog.o) -Normally CPU is assumed to be the same between the SPL and normal -u-boot build. However it is possible to specify a different CPU for -the SPL build for cases where the SPL is expected to run on a -different CPU model from the main u-boot. This is done by specifying -an SPL CPU in boards.cfg as follows: - - normal_cpu:spl_cpu - -This case CPU will be set to "normal_cpu" during the main u-boot -build and "spl_cpu" during the SPL build. - Debugging --------- |