colibri_imx6: fix video stdout in default environment

[oweals/u-boot.git] / doc / README.SPL

diff --git a/doc/README.SPL b/doc/README.SPL
index 7a30fefa9632d538b038e8cc8268c1f3326a2f26..2beb6d8f11b54fcf5c07814f846fed088b061c56 100644 (file)
--- a/doc/README.SPL
+++ b/doc/README.SPL
@@ -59,13 +59,29 @@ CONFIG_SPL_LIBGENERIC_SUPPORT (lib/libgeneric.o)
 CONFIG_SPL_POWER_SUPPORT (drivers/power/libpower.o)
 CONFIG_SPL_NAND_SUPPORT (drivers/mtd/nand/raw/libnand.o)
 CONFIG_SPL_DRIVERS_MISC_SUPPORT (drivers/misc)
-CONFIG_SPL_DMA_SUPPORT (drivers/dma/libdma.o)
+CONFIG_SPL_DMA (drivers/dma/libdma.o)
 CONFIG_SPL_POST_MEM_SUPPORT (post/drivers/memory.o)
 CONFIG_SPL_NAND_LOAD (drivers/mtd/nand/raw/nand_spl_load.o)
 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)
 
+Device tree
+-----------
+The U-Boot device tree is filtered by the fdtgrep tools during the build
+process to generate a much smaller device tree used in SPL (spl/u-boot-spl.dtb)
+with:
+- the mandatory nodes (/alias, /chosen, /config)
+- the nodes with one pre-relocation property:
+  'u-boot,dm-pre-reloc' or 'u-boot,dm-spl'
+
+fdtgrep is also used to remove:
+- the properties defined in CONFIG_OF_SPL_REMOVE_PROPS
+- all the pre-relocation properties
+  ('u-boot,dm-pre-reloc', 'u-boot,dm-spl' and 'u-boot,dm-tpl')
+
+All the nodes remaining in the SPL devicetree are bound
+(see doc/driver-model/design.rst).
 
 Debugging
 ---------