Split this information into subsections and expand it.
Signed-off-by: Simon Glass sjg@chromium.org ---
doc/develop/driver-model/of-plat.rst | 92 ++++++++++++++++++++++++++-- 1 file changed, 88 insertions(+), 4 deletions(-)
diff --git a/doc/develop/driver-model/of-plat.rst b/doc/develop/driver-model/of-plat.rst index 8a8eaed4c11..0bd978759c7 100644 --- a/doc/develop/driver-model/of-plat.rst +++ b/doc/develop/driver-model/of-plat.rst @@ -600,6 +600,11 @@ as a macro included in the driver definition:: Problems --------
+This section shows some common problems and how to fix them. + +Driver not found +~~~~~~~~~~~~~~~~ + In some cases you will you see something like this::
WARNING: the driver rockchip_rk3188_grf was not found in the driver list @@ -633,6 +638,9 @@ the devicetree. For example, if the devicetree has:: then dtoc looks at the first compatible string ("rockchip,rk3188-grf"), converts that to a C identifier (rockchip_rk3188_grf) and then looks for that.
+Missing .compatible or Missing .id +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + Various things can cause dtoc to fail to find the driver and it tries to warn about these. For example:
@@ -649,6 +657,82 @@ Checks are also made to confirm that the referenced driver has a .compatible member and a .id member. The first provides the array of compatible strings and the second provides the uclass ID.
+Missing parent +~~~~~~~~~~~~~~ + +When a device is used, its parent must be present as well. If you see an error +like:: + + Node '/i2c@0/emul/emul0' requires parent node '/i2c@0/emul' but it is not in + the valid list + +it indicates that you are using a node whose parent is not present in the +devicetree. In this example, if you look at the device tree output +(e.g. fdtdump tpl/u-boot-tpl.dtb in your build directory), you may see something +like this:: + + emul { + emul0 { + compatible = "sandbox,i2c-rtc-emul"; + #emul-cells = <0x00000000>; + phandle = <0x00000003>; + }; + }; + +In this example, 'emul0' exists but its parent 'emul' has no properties. These +have been dropped by fdtgrep in an effort to reduce the devicetree size. This +indicates that the two nodes have different phase settings. Looking at the +source .dts:: + + i2c_emul: emul { + u-boot,dm-spl; + reg = <0xff>; + compatible = "sandbox,i2c-emul-parent"; + emul0: emul0 { + u-boot,dm-pre-reloc; + compatible = "sandbox,i2c-rtc-emul"; + #emul-cells = <0>; + }; + }; + +you can see that the child node 'emul0' usees 'u-boot,dm-pre-reloc', indicating +that the node is present in all SPL builds, but its parent uses 'u-boot,dm-spl' +indicating it is only present in SPL, not TPL. For a TPL build, this will fail +with the above message. The fix is to change 'emul0' to use the same +'u-boot,dm-spl' condition, so that it is not present in TPL, like its parent. + +Link errors / undefined reference +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Sometimes dtoc does not find the problem for you, but something is wrong and +you get a link error, e.g.:: + + :(.u_boot_list_2_udevice_2_spl_test5+0x0): undefined reference to + `_u_boot_list_2_driver_2_sandbox_spl_test' + /usr/bin/ld: dts/dt-uclass.o:(.u_boot_list_2_uclass_2_misc+0x8): + undefined reference to `_u_boot_list_2_uclass_driver_2_misc' + +The first one indicates that the device cannot find its driver. This means that +there is a driver 'sandbox_spl_test' but it is not compiled into the build. +Check your Kconfig settings to make sure it is. If you don't want that in the +build, adjust your phase settings, e.g. by using 'u-boot,dm-spl' in the node +to exclude it from the TPL build:: + + spl-test5 { + u-boot,dm-tpl; + compatible = "sandbox,spl-test"; + stringarray = "tpl"; + }; + +We can drop the 'u-boot,dm-tpl' line so this node won't appear in the TPL +devicetree and thus the driver won't be needed. + +The second error above indicates that the MISC uclass is needed by the driver +(since it is in the MISC uclass) but that uclass is not compiled in the build. +The fix above would fix this error too. But if you do want this uclass in the +build, check your Kconfig settings to make sure the uclass is being built +(CONFIG_MISC in this case). +
Caveats ------- @@ -697,7 +781,7 @@ Internals ---------
Generated files -``````````````` +~~~~~~~~~~~~~~~
When enabled, dtoc generates the following five files:
@@ -738,7 +822,7 @@ spl/dt-plat.c.
CONFIG options -`````````````` +~~~~~~~~~~~~~~
Several CONFIG options are used to control the behaviour of of-platdata, all available for both SPL and TPL: @@ -793,7 +877,7 @@ READ_ONLY the nodes cannot be updated, OF_PLATDATA_NO_BIND is enabled.
Data structures -``````````````` +~~~~~~~~~~~~~~~
A few extra data structures are used with of-platdata:
@@ -821,7 +905,7 @@ A few extra data structures are used with of-platdata: `device_get_by_ofplat_idx()`.
Other changes -````````````` +~~~~~~~~~~~~~
Some other changes are made with of-platdata: