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author | Tom Rini <trini@konsulko.com> | 2019-07-11 18:10:11 -0400 |
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committer | Tom Rini <trini@konsulko.com> | 2019-07-11 18:10:11 -0400 |
commit | a9758ece08bceb60634145c2126582e5d282bd09 (patch) | |
tree | b391039a3bc2aa8222a14b3e960541296d585878 /doc | |
parent | 68deea2308141c26707da44654b273d7b072ab0d (diff) | |
parent | 7ea33579576d2bcd19df76bd8769e7ab3b4a169b (diff) | |
download | u-boot-a9758ece08bceb60634145c2126582e5d282bd09.zip u-boot-a9758ece08bceb60634145c2126582e5d282bd09.tar.gz u-boot-a9758ece08bceb60634145c2126582e5d282bd09.tar.bz2 |
Merge tag 'dm-pull-9jul19-take2' of https://gitlab.denx.de/u-boot/custodians/u-boot-dm
- Sandbox improvements including .dts refactor
- Minor tracing and PCI improvements
- Various other minor fixes
- Conversion of patman, dtoc and binman to support Python 3
Diffstat (limited to 'doc')
-rw-r--r-- | doc/README.SPL | 16 | ||||
-rw-r--r-- | doc/README.TPL | 4 | ||||
-rw-r--r-- | doc/driver-model/README.txt | 4 |
3 files changed, 24 insertions, 0 deletions
diff --git a/doc/README.SPL b/doc/README.SPL index 7a30fef..6eed83f 100644 --- a/doc/README.SPL +++ b/doc/README.SPL @@ -66,6 +66,22 @@ 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' + +ftgrep 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 driver-model/README.txt). Debugging --------- diff --git a/doc/README.TPL b/doc/README.TPL index 980debe..c94129f 100644 --- a/doc/README.TPL +++ b/doc/README.TPL @@ -34,6 +34,10 @@ determine which SPL options to choose based on whether CONFIG_TPL_BUILD is set. Source files can be compiled for TPL with options choosed in the board config file. +TPL use a small device tree (u-boot-tpl.dtb), containing only the nodes with +the pre-relocation properties: 'u-boot,dm-pre-reloc' and 'u-boot,dm-tpl' +(see README.SPL for details). + For example: spl/Makefile: diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt index 07b120d..532a771 100644 --- a/doc/driver-model/README.txt +++ b/doc/driver-model/README.txt @@ -849,6 +849,10 @@ in the device tree node. For U-Boot proper you can use 'u-boot,dm-pre-proper' which means that it will be processed (and a driver bound) in U-Boot proper prior to relocation, but will not be available in SPL or TPL. +To reduce the size of SPL and TPL, only the nodes with pre-relocation properties +('u-boot,dm-pre-reloc', 'u-boot,dm-spl' or 'u-boot,dm-tpl') are keept in their +device trees (see README.SPL for details); the remaining nodes are always bound. + Then post relocation we throw that away and re-init driver model again. For drivers which require some sort of continuity between pre- and post-relocation devices, we can provide access to the pre-relocation |