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-rw-r--r--doc/README.SPL16
-rw-r--r--doc/README.TPL4
-rw-r--r--doc/driver-model/README.txt4
-rw-r--r--include/dm/ofnode.h6
-rw-r--r--include/dm/util.h6
5 files changed, 32 insertions, 4 deletions
diff --git a/doc/README.SPL b/doc/README.SPL
index 7a30fefa96..6eed83f8c5 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 980debe777..c94129fdc9 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 07b120d512..532a771f68 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
diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index 4ab2ae1ba5..704f91589a 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -676,12 +676,14 @@ int ofnode_read_simple_size_cells(ofnode node);
* After relocation and jumping into the real U-Boot binary it is possible to
* determine if a node was bound in one of SPL/TPL stages.
*
- * There are 3 settings currently in use
- * -
+ * There are 4 settings currently in use
+ * - u-boot,dm-pre-proper: U-Boot proper pre-relocation only
* - u-boot,dm-pre-reloc: legacy and indicates any of TPL or SPL
* Existing platforms only use it to indicate nodes needed in
* SPL. Should probably be replaced by u-boot,dm-spl for
* new platforms.
+ * - u-boot,dm-spl: SPL and U-Boot pre-relocation
+ * - u-boot,dm-tpl: TPL and U-Boot pre-relocation
*
* @node: node to check
* @return true if node is needed in SPL/TL, false otherwise
diff --git a/include/dm/util.h b/include/dm/util.h
index 60d3b93dec..348c2ace3c 100644
--- a/include/dm/util.h
+++ b/include/dm/util.h
@@ -52,12 +52,14 @@ static inline void dm_dump_devres(void)
* it is possible to determine if a node was bound in one of
* SPL/TPL stages.
*
- * There are 3 settings currently in use
- * -
+ * There are 4 settings currently in use
+ * - u-boot,dm-pre-proper: U-Boot proper pre-relocation only
* - u-boot,dm-pre-reloc: legacy and indicates any of TPL or SPL
* Existing platforms only use it to indicate nodes needed in
* SPL. Should probably be replaced by u-boot,dm-spl for
* existing platforms.
+ * - u-boot,dm-spl: SPL and U-Boot pre-relocation
+ * - u-boot,dm-tpl: TPL and U-Boot pre-relocation
* @node: of node
*
* Returns true if node is needed in SPL/TL, false otherwise.