dt-bindings: Use json for processed-schema*

Change the format of processed-schema* from yaml to json to speed up
validation. With json output, using xargs and appending the output won't
work since json has explicit list begin and end characters. Instead,
we pass the schema files as a list in a temp file.

The parsing time for the processed schema goes down from ~2sec to 70ms.
Also, 'make dtbs_check' becomes 33% faster.

Some error messages are affected by this change. For example, "True was
expected" becomes "... is not of type 'boolean'". The order of messages
is also changed.

Signed-off-by: Andrei Ziureaev <andrei.ziureaev@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/.gitignore

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 *.example.dts
 processed-schema*.yaml
+processed-schema*.json

Documentation/devicetree/bindings/Makefile

@@ -19,18 +19,19 @@ $(obj)/%.example.dts: $(src)/%.yaml check_dtschema_version FORCE
 	$(call if_changed,chk_binding)
 
 # Use full schemas when checking %.example.dts
-DT_TMP_SCHEMA := $(obj)/processed-schema-examples.yaml
+DT_TMP_SCHEMA := $(obj)/processed-schema-examples.json
 
 find_cmd = find $(srctree)/$(src) \( -name '*.yaml' ! \
 		-name 'processed-schema*' ! \
 		-name '*.example.dt.yaml' \)
 
 quiet_cmd_mk_schema = SCHEMA  $@
-      cmd_mk_schema = rm -f $@ ; \
+      cmd_mk_schema = f=$$(mktemp) ; \
                       $(if $(DT_MK_SCHEMA_FLAGS), \
                            echo $(real-prereqs), \
-                           $(find_cmd)) | \
-                      xargs $(DT_MK_SCHEMA) $(DT_MK_SCHEMA_FLAGS) >> $@
+                           $(find_cmd)) > $$f ; \
+                      $(DT_MK_SCHEMA) -j $(DT_MK_SCHEMA_FLAGS) @$$f > $@ ; \
+		      rm -f $$f
 
 DT_DOCS = $(shell $(find_cmd) | sed -e 's|^$(srctree)/||')
 
@@ -39,33 +40,33 @@ override DTC_FLAGS := \
 	-Wno-graph_child_address \
 	-Wno-interrupt_provider
 
-$(obj)/processed-schema-examples.yaml: $(DT_DOCS) check_dtschema_version FORCE
+$(obj)/processed-schema-examples.json: $(DT_DOCS) check_dtschema_version FORCE
 	$(call if_changed,mk_schema)
 
 ifeq ($(DT_SCHEMA_FILES),)
 
 # Unless DT_SCHEMA_FILES is specified, use the full schema for dtbs_check too.
-# Just copy processed-schema-examples.yaml
+# Just copy processed-schema-examples.json
 
-$(obj)/processed-schema.yaml: $(obj)/processed-schema-examples.yaml FORCE
+$(obj)/processed-schema.json: $(obj)/processed-schema-examples.json FORCE
 	$(call if_changed,copy)
 
 DT_SCHEMA_FILES = $(DT_DOCS)
 
 else
 
-# If DT_SCHEMA_FILES is specified, use it for processed-schema.yaml
+# If DT_SCHEMA_FILES is specified, use it for processed-schema.json
 
-$(obj)/processed-schema.yaml: DT_MK_SCHEMA_FLAGS := -u
-$(obj)/processed-schema.yaml: $(DT_SCHEMA_FILES) check_dtschema_version FORCE
+$(obj)/processed-schema.json: DT_MK_SCHEMA_FLAGS := -u
+$(obj)/processed-schema.json: $(DT_SCHEMA_FILES) check_dtschema_version FORCE
 	$(call if_changed,mk_schema)
 
 endif
 
 extra-$(CHECK_DT_BINDING) += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES))
 extra-$(CHECK_DT_BINDING) += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES))
-extra-$(CHECK_DT_BINDING) += processed-schema-examples.yaml
-extra-$(CHECK_DTBS) += processed-schema.yaml
+extra-$(CHECK_DT_BINDING) += processed-schema-examples.json
+extra-$(CHECK_DTBS) += processed-schema.json
 
 # Hack: avoid 'Argument list too long' error for 'make clean'. Remove most of
 # build artifacts here before they are processed by scripts/Makefile.clean

scripts/Makefile.lib

@@ -328,7 +328,7 @@ $(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
 DT_CHECKER ?= dt-validate
 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.yaml
+DT_TMP_SCHEMA ?= $(objtree)/$(DT_BINDING_DIR)/processed-schema.json
 
 quiet_cmd_dtb_check =	CHECK   $@
       cmd_dtb_check =	$(DT_CHECKER) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@