dt-bindings: DTB based validation

PATCH Applied Rob Herring 1 participant 4 messages Mar 10, 2022 – Mar 11, 2022

Subsystems (3)

Device tree bindings Kbuild Device tree

lore

Share & tools

lore

Rob Herring

author maintainer

2022-03-10 16:05 UTC #0 lore raw

v2 cover dt-bindings: DTB based validation

This series switches the kernel's DT schema validation from YAML encoded DT files to using DTB files directly. See patch 2 for the full reasoning of why. The diffstat also shows this is a nice simplification (at least from the kernel side). Patch 1 is further reworking of how DT_SCHEMA_FILES works and builds on [1].

Overall, the build time is about the same (still slow) though we do save a dtc call for dtbs_check. Extracting the type information is not cached in any way, so there's some opportunity for a slight optimization there.

Switching to DTB validation found various issues in the bindings and examples. Patches for those issues have already been posted and applied over the last month or so.

v2:
- Drop processed-schema.json dependency when building 'dtbs'
- Don't allow override of DT_TMP_SCHEMA

Rob

[1] https://lore.kernel.org/all/[email protected]/

Rob Herring (2):
dt-bindings: kbuild: Pass DT_SCHEMA_FILES to dt-validate
dt-bindings: kbuild: Use DTB files for validation

 Documentation/devicetree/bindings/Makefile    | 35 ++++---------------
 .../devicetree/bindings/writing-schema.rst    | 12 -------
 scripts/Makefile.lib                          | 25 +++++--------
 scripts/dtc/Makefile                          | 13 -------
 scripts/dtc/update-dtc-source.sh              |  2 +-
 5 files changed, 16 insertions(+), 71 deletions(-)

Signature · 1 line

2.32.0

Rob Herring

author maintainer

2022-03-10 16:05 UTC #1 lore raw

PATCH v2 1/2 dt-bindings: kbuild: Pass DT_SCHEMA_FILES to dt-validate

In preparation for supporting validation of DTB files, the full processed schema will always be needed in order to extract type information from it. Therefore, the processed schema containing only what DT_SCHEMA_FILES specifies won't work. Instead, dt-validate has gained an option, -l or --limit, to specify which schema(s) to use for validation.

As the command line option is new, we the minimum dtschema version must be updated.

Cc Masahiro Yamada <[email protected]>

Signed-off-by Rob Herring <[email protected]>

---
v2:
- Change DT_TMP_SCHEMA from '?=' to ':='

---
 Documentation/devicetree/bindings/Makefile | 28 +++-------------------
 scripts/Makefile.lib                       |  5 ++--
 2 files changed, 5 insertions(+), 28 deletions(-)

Documentation/devicetree/bindings/Makefile +3 ~~-25~~

index 29b5dbd0807e..2716f7b9e25e 100644
@@ -6,7 +6,7 @@ DT_MK_SCHEMA ?= dt-mk-schema
 DT_SCHEMA_LINT := $(shell which yamllint || \
   echo "warning: python package 'yamllint' not installed, skipping" >&2)
 
-DT_SCHEMA_MIN_VERSION = 2021.2.1
+DT_SCHEMA_MIN_VERSION = 2022.3
 
 PHONY += check_dtschema_version
 check_dtschema_version:

@@ -25,9 +25,6 @@ quiet_cmd_extract_ex = DTEX    $@
 $(obj)/%.example.dts: $(src)/%.yaml check_dtschema_version FORCE
 	$(call if_changed,extract_ex)
 
-# Use full schemas when checking %.example.dts
-DT_TMP_SCHEMA := $(obj)/processed-schema-examples.json
-
 find_all_cmd = find $(srctree)/$(src) \( -name '*.yaml' ! \
 		-name 'processed-schema*' ! \
 		-name '*.example.dt.yaml' \)

@@ -70,29 +67,10 @@ override DTC_FLAGS := \
 # Disable undocumented compatible checks until warning free
 override DT_CHECKER_FLAGS ?=
 
-$(obj)/processed-schema-examples.json: $(DT_DOCS) $(src)/.yamllint check_dtschema_version FORCE
+$(obj)/processed-schema.json: $(DT_DOCS) $(src)/.yamllint check_dtschema_version FORCE
 	$(call if_changed_rule,chkdt)
 
-ifeq ($(DT_SCHEMA_FILES),)
-
-# Unless DT_SCHEMA_FILES is specified, use the full schema for dtbs_check too.
-# Just copy processed-schema-examples.json
-
-$(obj)/processed-schema.json: $(obj)/processed-schema-examples.json FORCE
-	$(call if_changed,copy)
-
-else
-
-# If DT_SCHEMA_FILES is specified, use it for processed-schema.json
-
-$(obj)/processed-schema.json: DT_MK_SCHEMA_FLAGS := -u
-$(obj)/processed-schema.json: $(CHK_DT_DOCS) check_dtschema_version FORCE
-	$(call if_changed,mk_schema)
-
-endif
-
-always-$(CHECK_DT_BINDING) += processed-schema-examples.json
-always-$(CHECK_DTBS)       += processed-schema.json
+always-y += processed-schema.json
 always-$(CHECK_DT_BINDING) += $(patsubst $(srctree)/$(src)/%.yaml,%.example.dts, $(CHK_DT_DOCS))
 always-$(CHECK_DT_BINDING) += $(patsubst $(srctree)/$(src)/%.yaml,%.example.dt.yaml, $(CHK_DT_DOCS))

scripts/Makefile.lib +2 -3

index 79be57fdd32a..c8c6f1745d03 100644
@@ -361,10 +361,9 @@ $(multi-dtb-y): FORCE
 $(call multi_depend, $(multi-dtb-y), .dtb, -dtbs)
 
 DT_CHECKER ?= dt-validate
-DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),,-m)
+DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),-l $(DT_SCHEMA_FILES),-m)
 DT_BINDING_DIR := Documentation/devicetree/bindings
-# DT_TMP_SCHEMA may be overridden from Documentation/devicetree/bindings/Makefile
-DT_TMP_SCHEMA ?= $(objtree)/$(DT_BINDING_DIR)/processed-schema.json
+DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.json
 
 quiet_cmd_dtb_check =	CHECK   $@
       cmd_dtb_check =	$(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@

Signature · 1 line

2.32.0

Rob Herring

author maintainer Applied

2022-03-11 15:30 UTC #2 lore raw

Re: [PATCH v2 1/2] dt-bindings: kbuild: Pass DT_SCHEMA_FILES to dt-validate

Quoted 12 lines · Rob Herring

In preparation for supporting validation of DTB files, the full processed schema will always be needed in order to extract type information from it. Therefore, the processed schema containing only what DT_SCHEMA_FILES specifies won't work. Instead, dt-validate has gained an option, -l or --limit, to specify which schema(s) to use for validation.
As the command line option is new, we the minimum dtschema version must be updated.
Cc Masahiro Yamada <[email protected]>
Signed-off-by Rob Herring <[email protected]>

Quoted 8 lines

---
v2:
- Change DT_TMP_SCHEMA from '?=' to ':='

---
 Documentation/devicetree/bindings/Makefile | 28 +++-------------------
 scripts/Makefile.lib                       |  5 ++--
 2 files changed, 5 insertions(+), 28 deletions(-)

Applied, thanks!

Rob Herring

author maintainer

2022-03-10 16:05 UTC #3 lore raw

PATCH v2 2/2 dt-bindings: kbuild: Use DTB files for validation

In reply to Rob Herring

Switch the DT validation to use DTB files directly instead of a DTS to YAML conversion.

The original motivation for supporting validation on DTB files was to enable running validation on a running system (e.g. 'dt-validate /sys/firmware/fdt') or other cases where the original source DTS is not available.

The YAML format was not without issues. Using DTBs with the schema type information solves some of those problems. The YAML format relies on the DTS source level information including bracketing of properties, size directives, and phandle tags all of which are lost in a DTB file. While standardizing the bracketing is a good thing, it does cause a lot of extra warnings and churn to fix them.

Another issue has been signed types are not validated correctly as sign information is not propagated to YAML. Using the schema type information allows for proper handling of signed types. YAML also can't represent the full range of 64-bit integers as numbers are stored as floats by most/all parsers.

The DTB validation works by decoding property values using the type information in the schemas themselves. The main corner case this does not work for is matrix types where neither dimension is fixed. For now, checking the dimensions in these cases are skipped.

Signed-off-by Rob Herring <[email protected]>

---
v2:
- Dependency on processed-schema.json needs to be conditional

---
 Documentation/devicetree/bindings/Makefile    |  7 +++----
 .../devicetree/bindings/writing-schema.rst    | 12 -----------
 scripts/Makefile.lib                          | 20 +++++++------------
 scripts/dtc/Makefile                          | 13 ------------
 scripts/dtc/update-dtc-source.sh              |  2 +-
 5 files changed, 11 insertions(+), 43 deletions(-)

Documentation/devicetree/bindings/Makefile +3 -4

index 2716f7b9e25e..e594e5898be0 100644
@@ -26,8 +26,7 @@ $(obj)/%.example.dts: $(src)/%.yaml check_dtschema_version FORCE
 	$(call if_changed,extract_ex)
 
 find_all_cmd = find $(srctree)/$(src) \( -name '*.yaml' ! \
-		-name 'processed-schema*' ! \
-		-name '*.example.dt.yaml' \)
+		-name 'processed-schema*' \)
 
 find_cmd = $(find_all_cmd) | grep -F "$(DT_SCHEMA_FILES)"
 CHK_DT_DOCS := $(shell $(find_cmd))

@@ -72,9 +71,9 @@ $(obj)/processed-schema.json: $(DT_DOCS) $(src)/.yamllint check_dtschema_version
 
 always-y += processed-schema.json
 always-$(CHECK_DT_BINDING) += $(patsubst $(srctree)/$(src)/%.yaml,%.example.dts, $(CHK_DT_DOCS))
-always-$(CHECK_DT_BINDING) += $(patsubst $(srctree)/$(src)/%.yaml,%.example.dt.yaml, $(CHK_DT_DOCS))
+always-$(CHECK_DT_BINDING) += $(patsubst $(srctree)/$(src)/%.yaml,%.example.dtb, $(CHK_DT_DOCS))
 
 # Hack: avoid 'Argument list too long' error for 'make clean'. Remove most of
 # build artifacts here before they are processed by scripts/Makefile.clean
 clean-files = $(shell find $(obj) \( -name '*.example.dts' -o \
-			-name '*.example.dt.yaml' \) -delete 2>/dev/null)
+			-name '*.example.dtb' \) -delete 2>/dev/null)

Documentation/devicetree/bindings/writing-schema.rst +0 ~~-12~~

index 3b00fe981494..b4258bf81be5 100644
@@ -123,18 +123,6 @@ project can be installed with pip::
 Several executables (dt-doc-validate, dt-mk-schema, dt-validate) will be
 installed. Ensure they are in your PATH (~/.local/bin by default).
 
-dtc must also be built with YAML output support enabled. This requires that
-libyaml and its headers be installed on the host system. For some distributions
-that involves installing the development package, such as:
-
-Debian::
-
-  apt-get install libyaml-dev
-
-Fedora::
-
-  dnf -y install libyaml-devel
-
 Running checks
 ~~~~~~~~~~~~~~

scripts/Makefile.lib +7 ~~-13~~

index c8c6f1745d03..9d5320a47ef8 100644
@@ -87,11 +87,6 @@ base-dtb-y := $(foreach m, $(multi-dtb-y), $(firstword $(call suffix-search, $m,
 
 always-y			+= $(dtb-y)
 
-ifneq ($(CHECK_DTBS),)
-always-y += $(patsubst %.dtb,%.dt.yaml, $(real-dtb-y))
-always-y += $(patsubst %.dtbo,%.dt.yaml, $(real-dtb-y))
-endif
-
 # Add subdir path
 
 extra-y		:= $(addprefix $(obj)/,$(extra-y))

@@ -347,12 +342,6 @@ cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ;
 		-d $(depfile).dtc.tmp $(dtc-tmp) ; \
 	cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
 
-$(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
-	$(call if_changed_dep,dtc)
-
-$(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
-	$(call if_changed_dep,dtc)
-
 quiet_cmd_fdtoverlay = DTOVL   $@
       cmd_fdtoverlay = $(objtree)/scripts/dtc/fdtoverlay -o $@ -i $(real-prereqs)

@@ -360,22 +349,27 @@ $(multi-dtb-y): FORCE
 	$(call if_changed,fdtoverlay)
 $(call multi_depend, $(multi-dtb-y), .dtb, -dtbs)
 
+ifneq ($(CHECK_DTBS)$(CHECK_DT_BINDING),)
 DT_CHECKER ?= dt-validate
 DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),-l $(DT_SCHEMA_FILES),-m)
 DT_BINDING_DIR := Documentation/devicetree/bindings
 DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.json
 
 quiet_cmd_dtb_check =	CHECK   $@
-      cmd_dtb_check =	$(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@
+      cmd_dtb_check =	$(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@ || true
+endif
 
 define rule_dtc
 	$(call cmd_and_fixdep,dtc)
 	$(call cmd,dtb_check)
 endef
 
-$(obj)/%.dt.yaml: $(src)/%.dts $(DTC) $(DT_TMP_SCHEMA) FORCE
+$(obj)/%.dtb: $(src)/%.dts $(DTC) $(DT_TMP_SCHEMA) FORCE
 	$(call if_changed_rule,dtc)
 
+$(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
+	$(call if_changed_dep,dtc)
+
 dtc-tmp = $(subst $(comma),_,$(dot-target).dts.tmp)
 
 # Bzip2

scripts/dtc/Makefile +0 ~~-13~~

index 1cba78e1dce6..4d32b9497da9 100644
@@ -17,20 +17,7 @@ fdtoverlay-objs	:= $(libfdt) fdtoverlay.o util.o
 
 # Source files need to get at the userspace version of libfdt_env.h to compile
 HOST_EXTRACFLAGS += -I $(srctree)/$(src)/libfdt
-
-ifeq ($(shell pkg-config --exists yaml-0.1 2>/dev/null && echo yes),)
-ifneq ($(CHECK_DT_BINDING)$(CHECK_DTBS),)
-$(error dtc needs libyaml for DT schema validation support. \
-	Install the necessary libyaml development package.)
-endif
 HOST_EXTRACFLAGS += -DNO_YAML
-else
-dtc-objs	+= yamltree.o
-# To include <yaml.h> installed in a non-default path
-HOSTCFLAGS_yamltree.o := $(shell pkg-config --cflags yaml-0.1)
-# To link libyaml installed in a non-default path
-HOSTLDLIBS_dtc	:= $(shell pkg-config --libs yaml-0.1)
-endif
 
 # Generated files need one more search path to include headers in source tree
 HOSTCFLAGS_dtc-lexer.lex.o := -I $(srctree)/$(src)

scripts/dtc/update-dtc-source.sh +1 -1

index 32ff17ffd089..94627541533e 100755
@@ -32,7 +32,7 @@ DTC_UPSTREAM_PATH=`pwd`/../dtc
 DTC_LINUX_PATH=`pwd`/scripts/dtc
 
 DTC_SOURCE="checks.c data.c dtc.c dtc.h flattree.c fstree.c livetree.c srcpos.c \
-		srcpos.h treesource.c util.c util.h version_gen.h yamltree.c \
+		srcpos.h treesource.c util.c util.h version_gen.h \
 		dtc-lexer.l dtc-parser.y"
 LIBFDT_SOURCE="fdt.c fdt.h fdt_addresses.c fdt_empty_tree.c \
 		fdt_overlay.c fdt_ro.c fdt_rw.c fdt_strerror.c fdt_sw.c \

Signature · 1 line

2.32.0