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