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authorTom Rini <trini@konsulko.com>2018-10-10 13:35:17 -0400
committerTom Rini <trini@konsulko.com>2018-10-10 13:35:17 -0400
commit3d5ced9e22d32112a20f9dc0f5fb1f22ef088079 (patch)
tree2c1e1f34c4dad05dfd08bd3687e6aee634c58500 /doc
parent98068b3be51a77d8b931a2f5097b5c22c57bcea5 (diff)
parent41b781ddf1869f5349e05ace888979f3673fe8c6 (diff)
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Merge tag 'dm-9oct18' of git://git.denx.de/u-boot-dm
Test improvements to tidy up output and drop duplicate tests Sandbox SPL/TPL support Various dm-related improvements
Diffstat (limited to 'doc')
-rw-r--r--doc/README.fdt-control16
-rw-r--r--doc/driver-model/README.txt7
2 files changed, 20 insertions, 3 deletions
diff --git a/doc/README.fdt-control b/doc/README.fdt-control
index 634a106..d6ab7bf 100644
--- a/doc/README.fdt-control
+++ b/doc/README.fdt-control
@@ -56,7 +56,11 @@ In case you are wondering, OF stands for Open Firmware.
Tools
-----
-To use this feature you will need to get the device tree compiler here:
+To use this feature you will need to get the device tree compiler. This is
+provided by U-Boot automatically. If you have a system version of dtc
+(typically in the 'device-tree-compiler' package), it is currently not used.
+
+If you want to build your own dtc, it is kept here:
git://git.kernel.org/pub/scm/utils/dtc/dtc.git
@@ -170,6 +174,16 @@ After board configuration is done, fdt supported u-boot can be build in two ways
$ make DEVICE_TREE=<dts-file-name>
+Relocation, SPL and TPL
+-----------------------
+
+U-Boot can be divided into three phases: TPL, SPL and U-Boot proper.
+
+The full device tree is available to U-Boot proper, but normally only a subset
+(or none at all) is available to TPL and SPL. See 'Pre-Relocation Support' and
+'SPL Support' in doc/driver-model/README.txt for more details.
+
+
Limitations
-----------
diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt
index e949ff6..3654163 100644
--- a/doc/driver-model/README.txt
+++ b/doc/driver-model/README.txt
@@ -832,11 +832,14 @@ Pre-Relocation Support
For pre-relocation we simply call the driver model init function. Only
drivers marked with DM_FLAG_PRE_RELOC or the device tree
'u-boot,dm-pre-reloc' flag are initialised prior to relocation. This helps
-to reduce the driver model overhead.
+to reduce the driver model overhead. This flag applies to SPL and TPL as
+well, if device tree is enabled there.
It is possible to limit this to specific relocation steps, by using
the more specialized 'u-boot,dm-spl' and 'u-boot,dm-tpl' flags
-in the devicetree.
+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.
Then post relocation we throw that away and re-init driver model again.
For drivers which require some sort of continuity between pre- and