dts: Add support for Device Tree

This patch adds support for using device tree configuration files for
configuring ARM platforms.

In this patch, only the FLASH_SIZE, SRAM_SIZE, NUM_IRQS, and
NUM_IRQ_PRIO_BITS were removed from the Kconfig options.  A minimal set
of options were removed so that it would be easier to work through the
plumbing of the build system.

It should be noted that the host system must provide access to the
device tree compiler (DTC).  The DTC can usually be installed on host
systems through distribution packages or by downloading and compiling
from https://git.kernel.org/pub/scm/utils/dtc/dtc.git

This patch also requires the Python yaml package.

This change implements parts of each of the following Jira:
ZEP-1304
ZEP-1305
ZEP-1306
ZEP-1307
ZEP-1589

Change-Id: If1403801e19d9d85031401b55308935dadf8c9d8
Signed-off-by: Andy Gross <andy.gross@linaro.org>

Kbuild

@@ -73,10 +73,12 @@ misc/generated/configs.c: include/config/auto.conf FORCE
 	$(call filechk,configs.c)
 
 targets := misc/generated/configs.c
+targets += include/generated/generated_dts_board.h
 targets += include/generated/offsets.h
 
 
 always := misc/generated/configs.c
+always += include/generated/generated_dts_board.h
 always += include/generated/offsets.h
 
 ifeq ($(CONFIG_MDEF),y)
@@ -90,7 +92,8 @@ endef
 
 cmd_cc_o_c_1 = $(CC) $(KBUILD_CFLAGS) $(ZEPHYRINCLUDE) -c -o $@ $<
 
-arch/$(ARCH)/core/offsets/offsets.o: arch/$(ARCH)/core/offsets/offsets.c $(KCONFIG_CONFIG)
+arch/$(ARCH)/core/offsets/offsets.o: arch/$(ARCH)/core/offsets/offsets.c $(KCONFIG_CONFIG) \
+				include/generated/generated_dts_board.h
 	$(Q)mkdir -p $(dir $@)
 	$(call if_changed,cc_o_c_1)
 
@@ -112,3 +115,28 @@ include/generated/offsets.h: arch/$(ARCH)/core/offsets/offsets.o \
 			     include/config/auto.conf FORCE
 	$(call offsetchk,arch/$(ARCH)/core/offsets/offsets.o)
 
+ifeq ($(CONFIG_HAS_DTS),y)
+define filechk_generated_dts_board.h
+	(echo "/* WARNING. THIS FILE IS AUTO-GENERATED. DO NOT MODIFY! */"; \
+		extract_dts_includes.py dts/$(ARCH)/$(BOARD_NAME).dts_compiled $(ZEPHYR_BASE)/dts/$(ARCH)/yaml; \
+		if test -e $(ZEPHYR_BASE)/dts/$(ARCH)/$(BOARD_NAME).fixup; then \
+			echo; echo; \
+			echo "/* Following definitions fixup the generated include */"; \
+			echo; \
+			cat $(ZEPHYR_BASE)/dts/$(ARCH)/$(BOARD_NAME).fixup; \
+		fi; \
+		)
+endef
+else
+define filechk_generated_dts_board.h
+	(echo "/* WARNING. THIS FILE IS AUTO-GENERATED. DO NOT MODIFY! */";)
+endef
+endif
+
+
+include/generated/generated_dts_board.h: include/config/auto.conf FORCE
+ifeq ($(CONFIG_HAS_DTS),y)
+	$(Q)$(MAKE) $(build)=dts/$(ARCH)
+endif
+	$(call filechk,generated_dts_board.h)
+

Makefile

@@ -1019,12 +1019,14 @@ depend dep:
 
 # Directories & files removed with 'make clean'
 CLEAN_DIRS  += $(MODVERDIR)
+CLEAN_DIRS  += $(MODVERDIR) dts/
 
 CLEAN_FILES += 	misc/generated/sysgen/kernel_main.c \
 		misc/generated/sysgen/sysgen.h \
 		misc/generated/sysgen/prj.mdef \
 		misc/generated/sysgen/micro_private_types.h \
 		misc/generated/sysgen/kernel_main.h \
+		include/generated/generated_dts_board.h \
 		.old_version .tmp_System.map .tmp_version \
 		.tmp_* System.map *.lnk *.map *.elf *.lst \
 		*.bin *.hex *.stat *.strip staticIdt.o linker.cmd

arch/arm/core/cortex_m/Kconfig

@@ -170,6 +170,7 @@ config XIP
 
 config SRAM_SIZE
 	int "SRAM Size in kB"
+	depends on !HAS_DTS
 	help
 	This option specifies the size of the SRAM in kB.  It is normally set by
 	the board's defconfig file and the user should generally avoid modifying
@@ -177,6 +178,7 @@ config SRAM_SIZE
 
 config SRAM_BASE_ADDRESS
 	hex "SRAM Base Address"
+	depends on !HAS_DTS
 	help
 	This option specifies the base address of the SRAM on the board.  It is
 	normally set by the board's defconfig file and the user should generally
@@ -184,6 +186,7 @@ config SRAM_BASE_ADDRESS
 
 config FLASH_SIZE
 	int "Flash Size in kB"
+	depends on !HAS_DTS
 	help
 	This option specifies the size of the flash in kB.  It is normally set by
 	the board's defconfig file and the user should generally avoid modifying
@@ -191,6 +194,7 @@ config FLASH_SIZE
 
 config FLASH_BASE_ADDRESS
 	hex "Flash Base Address"
+	depends on !HAS_DTS
 	help
 	This option specifies the base address of the flash on the board.  It is
 	normally set by the board's defconfig file and the user should generally

arch/arm/core/cortex_m/irq_vector_table.c

@@ -21,6 +21,7 @@
 
 #include <toolchain.h>
 #include <sections.h>
+#include <generated_dts_board.h>
 
 extern void _isr_wrapper(void);
 typedef void (*vth)(void); /* Vector Table Handler */

arch/arm/core/cortex_m/prep_c.c

@@ -22,6 +22,7 @@
 #include <linker-defs.h>
 #include <nano_internal.h>
 #include <arch/arm/cortex_m/cmsis.h>
+#include <generated_dts_board.h>
 
 #ifdef CONFIG_ARMV6_M
 static inline void relocate_vector_table(void) { /* do nothing */ }

arch/arm/core/cortex_m/reset.S

@@ -17,6 +17,7 @@
 #include <arch/cpu.h>
 #include <offsets_short.h>
 #include "vector_table.h"
+#include <generated_dts_board.h>
 
 _ASM_FILE_PROLOGUE
 

dts/arm/Makefile

@@ -0,0 +1,3 @@
+ifeq ($(CONFIG_HAS_DTS),y)
+always	:= $(dtb-y)
+endif

include/arch/arm/cortex_m/scripts/linker.ld

@@ -16,6 +16,7 @@
 
 #include <autoconf.h>
 #include <sections.h>
+#include <generated_dts_board.h>
 
 #include <linker-defs.h>
 #include <linker-tool.h>

include/sw_isr_table.h

@@ -15,6 +15,7 @@
 #define _SW_ISR_TABLE__H_
 
 #include <arch/cpu.h>
+#include <generated_dts_board.h>
 
 #ifdef __cplusplus
 extern "C" {

kernel/Kconfig

@@ -8,6 +8,13 @@
 
 
 menu "General Kernel Options"
+
+config HAS_DTS
+	bool "Uses Device Tree"
+	help
+	This option specifies that the target platform supports device tree
+	configuration.
+
 config MULTITHREADING
 	bool
 	prompt "Multi-threading"

scripts/Makefile.lib

@@ -153,6 +153,8 @@ cpp_flags      = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(ZEPHYRINCLUDE)     \
 ld_flags       = $(LDFLAGS) $(ldflags-y)
 
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
+		 $(ZEPHYRINCLUDE)                                        \
+		 -I$(srctree)/dts/common				 \
 		 -I$(srctree)/drivers/of/testcase-data                   \
 		 -undef -D__DTS__
 
@@ -276,9 +278,10 @@ cmd_dt_S_dtb=						\
 $(obj)/%.dtb.S: $(obj)/%.dtb
 	$(call cmd,dt_S_dtb)
 
+
 quiet_cmd_dtc = DTC     $@
 cmd_dtc = $(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
-	$(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 \
+	$(DTC) -O dts -o $@ -b 0 \
 		-i $(dir $<) $(DTC_FLAGS) \
 		-d $(depfile).dtc.tmp $(dtc-tmp) ; \
 	cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
@@ -286,6 +289,9 @@ cmd_dtc = $(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
 $(obj)/%.dtb: $(src)/%.dts FORCE
 	$(call if_changed_dep,dtc)
 
+$(obj)/%.dts_compiled: $(src)/%.dts FORCE
+	$(call if_changed_dep,dtc)
+
 dtc-tmp = $(subst $(comma),_,$(dot-target).dts.tmp)
 
 # Bzip2

scripts/Makefile.toolchain.zephyr

@@ -109,7 +109,7 @@ QEMU_BIOS=$(TOOLCHAIN_HOME)/usr/share/qemu
 
 TOOLCHAIN_LIBS = gcc
 
-DTC ?= ${TOOLCHAIN_HOME}/usr/bin/dtc
+DTC = ${TOOLCHAIN_HOME}/usr/bin/dtc
 OPENOCD ?= ${TOOLCHAIN_HOME}/usr/bin/openocd
 OPENOCD_DEFAULT_PATH ?= ${TOOLCHAIN_HOME}/usr/share/openocd/scripts
 

scripts/extract_dts_includes.py

@@ -0,0 +1,632 @@
+#!/usr/bin/python
+import sys
+from os import walk
+import os
+import re
+import yaml
+import pprint
+
+from devicetree import parse_file
+
+# globals
+compatibles = {}
+phandles = {}
+aliases = {}
+chosen = {}
+reduced = {}
+
+def convert_string_to_label(s):
+  # Transmute ,- to _
+  s = s.replace("-", "_");
+  s = s.replace(",", "_");
+  return s
+
+def get_all_compatibles(d, name, comp_dict):
+  if 'props' in d:
+    compat = d['props'].get('compatible')
+    enabled = d['props'].get('status')
+
+  if enabled == "disabled":
+    return comp_dict
+
+  if compat != None:
+    comp_dict[name] = compat
+
+  if name != '/':
+    name += '/'
+
+  if isinstance(d,dict):
+    if d['children']:
+      for k,v in d['children'].items():
+        get_all_compatibles(v, name + k, comp_dict)
+
+  return comp_dict
+
+def get_aliases(root):
+  if 'children' in root:
+    if 'aliases' in root['children']:
+      for k,v in root['children']['aliases']['props'].items():
+        aliases[v] = k
+
+  return
+
+def get_compat(node):
+
+  compat = None
+
+  if 'props' in node:
+    compat = node['props'].get('compatible')
+
+  if isinstance(compat, list):
+    compat = compat[0]
+
+  return compat
+
+def get_chosen(root):
+
+  if 'children' in root:
+    if 'chosen' in root['children']:
+      for k,v in root['children']['chosen']['props'].items():
+        chosen[k] = v
+
+  return
+
+def get_phandles(root, name, handles):
+
+  if 'props' in root:
+    handle = root['props'].get('phandle')
+    enabled = root['props'].get('status')
+
+  if enabled == "disabled":
+    return
+
+  if handle != None:
+    phandles[handle] = name
+
+  if name != '/':
+    name += '/'
+
+  if isinstance(root, dict):
+    if root['children']:
+      for k,v in root['children'].items():
+        get_phandles(v, name + k, handles)
+
+  return
+
+class Loader(yaml.Loader):
+    def __init__(self, stream):
+        self._root = os.path.realpath(stream.name)
+        super(Loader, self).__init__(stream)
+        Loader.add_constructor('!include', Loader.include)
+        Loader.add_constructor('!import',  Loader.include)
+
+    def include(self, node):
+        if isinstance(node, yaml.ScalarNode):
+            return self.extractFile(self.construct_scalar(node))
+
+        elif isinstance(node, yaml.SequenceNode):
+            result = []
+            for filename in self.construct_sequence(node):
+                result += self.extractFile(filename)
+            return result
+
+        elif isinstance(node, yaml.MappingNode):
+            result = {}
+            for k,v in self.construct_mapping(node).iteritems():
+                result[k] = self.extractFile(v)
+            return result
+
+        else:
+            print("Error:: unrecognised node type in !include statement")
+            raise yaml.constructor.ConstructorError
+
+    def extractFile(self, filename):
+        filepath = os.path.join(os.path.dirname(self._root), filename)
+        if not os.path.isfile(filepath):
+            # we need to look in common directory
+            # take path and back up 2 directories and tack on '/common/yaml'
+            filepath = os.path.dirname(self._root).split('/')
+            filepath = '/'.join(filepath[:-2])
+            filepath = os.path.join(filepath + '/common/yaml', filename)
+            with open(filepath, 'r') as f:
+                return yaml.load(f, Loader)
+
+def insert_defs(node_address, defs, new_defs, new_aliases):
+  if node_address in defs:
+    if 'aliases' in defs[node_address]:
+      defs[node_address]['aliases'].update(new_aliases)
+    else:
+      defs[node_address]['aliases'] = new_aliases
+
+    defs[node_address].update(new_defs)
+  else:
+    new_defs['aliases'] = new_aliases
+    defs[node_address] = new_defs
+
+  return
+
+def find_node_by_path(nodes, path):
+  d = nodes
+  for k in path[1:].split('/'):
+    d = d['children'][k]
+
+  return d
+
+def compress_nodes(nodes, path):
+  if 'props' in nodes:
+    status = nodes['props'].get('status')
+
+  if status == "disabled":
+    return
+
+  if isinstance(nodes, dict):
+    reduced[path] = dict(nodes)
+    reduced[path].pop('children', None)
+    if path != '/':
+      path += '/'
+    if nodes['children']:
+      for k,v in nodes['children'].items():
+        compress_nodes(v, path + k)
+
+  return
+
+def find_parent_irq_node(node_address):
+  address = ''
+
+  for comp in node_address.split('/')[1:]:
+    address += '/' + comp
+    if 'interrupt-parent' in reduced[address]['props']:
+      interrupt_parent = reduced[address]['props'].get('interrupt-parent')
+
+  return reduced[phandles[interrupt_parent]]
+
+def extract_interrupts(node_address, yaml, y_key, names, defs, def_label):
+  node = reduced[node_address]
+
+  try:
+    props = list(node['props'].get(y_key))
+  except:
+    props = [node['props'].get(y_key)]
+
+  irq_parent = find_parent_irq_node(node_address)
+
+  l_base = def_label.split('/')
+  index = 0
+
+  while props:
+    prop_def = {}
+    prop_alias = {}
+    l_idx = [str(index)]
+
+    if y_key == 'interrupts-extended':
+      cell_parent = reduced[phandles[props.pop(0)]]
+      name = []
+    else:
+      try:
+        name = [names.pop(0).upper()]
+      except:
+        name = []
+
+      cell_parent = irq_parent
+
+    cell_yaml = yaml[get_compat(cell_parent)]
+    l_cell_prefix = [yaml[get_compat(irq_parent)].get('cell_prefix', []).upper()]
+
+    for i in range(cell_parent['props']['#interrupt-cells']):
+      l_cell_name = [cell_yaml['#cells'][i].upper()]
+      if l_cell_name == l_cell_prefix:
+        l_cell_name = []
+
+      l_fqn = '_'.join(l_base + l_cell_prefix + l_idx)
+      prop_def[l_fqn] = props.pop(0)
+      if len(name):
+        prop_alias['_'.join(l_base + name + l_cell_prefix)] = l_fqn
+
+    index += 1
+    insert_defs(node_address, defs, prop_def, prop_alias)
+
+  return
+
+def extract_reg_prop(node_address, names, defs, def_label, div):
+  node = reduced[node_address]
+
+  props = list(reduced[node_address]['props']['reg'])
+
+  address_cells = reduced['/']['props'].get('#address-cells')
+  size_cells = reduced['/']['props'].get('#size-cells')
+  address = ''
+  for comp in node_address.split('/')[1:]:
+    address += '/' + comp
+    address_cells = reduced[address]['props'].get('#address-cells', address_cells)
+    size_cells = reduced[address]['props'].get('#size-cells', size_cells)
+
+  index = 0
+  l_base = def_label.split('/')
+  l_addr = ["BASE_ADDRESS"]
+  l_size = ["SIZE"]
+
+  while props:
+    prop_def = {}
+    prop_alias = {}
+    addr = 0
+    size = 0
+    l_idx = [str(index)]
+
+    try:
+      name = [names.pop(0).upper()]
+    except:
+      name = []
+
+    for x in range(address_cells):
+      addr += props.pop(0) << (32 * x)
+    for x in range(size_cells):
+      size += props.pop(0) << (32 * x)
+
+    l_addr_fqn = '_'.join(l_base + l_addr + l_idx)
+    l_size_fqn = '_'.join(l_base + l_size + l_idx)
+    prop_def[l_addr_fqn] = hex(addr)
+    prop_def[l_size_fqn] = int(size / div)
+    if len(name):
+      prop_alias['_'.join(l_base + name + l_addr)] = l_addr_fqn
+      prop_alias['_'.join(l_base + name + l_size)] = l_size_fqn
+
+    if index == 0:
+      prop_alias['_'.join(l_base + l_addr)] = l_addr_fqn
+      prop_alias['_'.join(l_base + l_size)] = l_size_fqn
+
+    insert_defs(node_address, defs, prop_def, prop_alias)
+
+    # increment index for definition creation
+    index += 1
+
+  return
+
+def extract_cells(node_address, yaml, y_key, names, index, prefix, defs, def_label):
+  try:
+    props = list(reduced[node_address]['props'].get(y_key))
+  except:
+    props = [reduced[node_address]['props'].get(y_key)]
+
+  cell_parent = reduced[phandles[props.pop(0)]]
+
+  try:
+    cell_yaml = yaml[get_compat(cell_parent)]
+  except:
+    raise Exception("Could not find yaml description for " + cell_parent['name'])
+
+  try:
+    name = names.pop(0).upper()
+  except:
+    name = []
+
+  l_cell = [str(cell_yaml.get('cell_string',''))]
+  l_base = def_label.split('/')
+  l_base += prefix
+  l_idx = [str(index)]
+
+  prop_def = {}
+  prop_alias = {}
+
+  for k in cell_parent['props'].keys():
+    if k[0] == '#' and '-cells' in k:
+      for i in range(cell_parent['props'].get(k)):
+        l_cellname = [str(cell_yaml['#cells'][i]).upper()]
+        if l_cell == l_cellname:
+          label = l_base + l_cell + l_idx
+        else:
+          label = l_base + l_cell + l_cellname + l_idx
+        label_name = l_base + name + l_cellname
+        prop_def['_'.join(label)] = props.pop(0)
+        if len(name):
+          prop_alias['_'.join(label_name)] = '_'.join(label)
+
+        if index == 0:
+          prop_alias['_'.join(label[:-1])] = '_'.join(label)
+
+    insert_defs(node_address, defs, prop_def, prop_alias)
+
+  # recurse if we have anything left
+  if len(props):
+    extract_cells(node_address, yaml, y_key, names, index + 1, prefix, defs, def_label)
+
+  return
+
+def extract_pinctrl(node_address, yaml, pinconf, names, index, defs, def_label):
+
+  prop_list = []
+  if not isinstance(pinconf,list):
+    prop_list.append(pinconf)
+  else:
+    prop_list = list(pinconf)
+
+  def_prefix = def_label.split('_')
+  target_node = node_address
+
+  prop_def = {}
+  for p in prop_list:
+    pin_node_address = phandles[p]
+    pin_entry = reduced[pin_node_address]
+    parent_address = '/'.join(pin_node_address.split('/')[:-1])
+    pin_parent = reduced[parent_address]
+    cell_yaml = yaml[get_compat(pin_parent)]
+    cell_prefix = cell_yaml.get('cell_string', None)
+    post_fix = []
+
+    if cell_prefix != None:
+      post_fix.append(cell_prefix)
+
+    for subnode in reduced.keys():
+      if pin_node_address in subnode and pin_node_address != subnode:
+        # found a subnode underneath the pinmux handle
+        node_label = subnode.split('/')[-2:]
+        pin_label = def_prefix + post_fix + subnode.split('/')[-2:]
+
+        for i, pin in enumerate(reduced[subnode]['props']['pins']):
+          key_label = list(pin_label) + [cell_yaml['#cells'][0]] + [str(i)]
+          func_label = key_label[:-2] + [cell_yaml['#cells'][1]] + [str(i)]
+          key_label = convert_string_to_label('_'.join(key_label)).upper()
+          func_label = convert_string_to_label('_'.join(func_label)).upper()
+
+          prop_def[key_label] = pin
+          prop_def[func_label] = reduced[subnode]['props']['function']
+
+  insert_defs(node_address, defs, prop_def, {})
+
+def extract_single(node_address, yaml, prop, key, prefix, defs, def_label):
+
+  prop_def = {}
+
+  if isinstance(prop, list):
+    for i, p in enumerate(prop):
+      k = convert_string_to_label(key).upper()
+      label = def_label + '_' + k
+      prop_def[label + '_' + str(i)] = p
+  else:
+      k = convert_string_to_label(key).upper()
+      label = def_label + '_' +  k
+      prop_def[label] = prop
+
+  if node_address in defs:
+    defs[node_address].update(prop_def)
+  else:
+    defs[node_address] = prop_def
+
+  return
+
+def extract_property(yaml, node_address, y_key, y_val, names, prefix, defs):
+
+  node = reduced[node_address]
+  def_label = convert_string_to_label(get_compat(node)).upper()
+  def_label += '_' + node_address.split('@')[-1].upper()
+
+  if y_key == 'reg':
+    extract_reg_prop(node_address, names, defs, def_label, 1)
+  elif y_key == 'interrupts' or y_key == 'interupts-extended':
+    extract_interrupts(node_address, yaml, y_key, names, defs, def_label)
+  elif 'pinctrl-' in y_key:
+    p_index = int(y_key.split('-')[1])
+    extract_pinctrl(node_address, yaml, reduced[node_address]['props'][y_key],
+                    names[p_index], p_index, defs, def_label)
+  elif 'clocks' in y_key:
+    extract_cells(node_address, yaml, y_key,
+                  names, 0, prefix, defs, def_label)
+  else:
+    extract_single(node_address, yaml[get_compat(reduced[node_address])],
+                   reduced[node_address]['props'][y_key], y_key,
+                   prefix, defs, def_label)
+
+  return
+
+def extract_node_include_info(reduced, node_address, yaml, defs, structs):
+  node = reduced[node_address]
+  node_compat = get_compat(node)
+
+  if not node_compat in yaml.keys():
+    return {}, {}
+
+  y_node = yaml[node_compat]
+
+  # check to see if we need to process the properties
+  for yp in y_node['properties']:
+    for k,v in yp.items():
+      if 'generation' in v:
+        if v['generation'] == 'define':
+          label = v.get('define_string')
+          storage = defs
+        else:
+          label = v.get('structures_string')
+          storage = structs
+
+        prefix = []
+        if v.get('use-name-prefix') != None:
+          prefix = [convert_string_to_label(k.upper())]
+
+        for c in node['props'].keys():
+          if c.endswith("-names"):
+            pass
+
+          if re.match(k + '$', c):
+
+            if 'pinctrl-' in c:
+              names = node['props'].get('pinctrl-names', [])
+            else:
+              names = node['props'].get(c[:-1] + '-names', [])
+              if not names:
+                names = node['props'].get(c + '-names', [])
+
+            if not isinstance(names, list):
+              names = [names]
+
+            extract_property(yaml, node_address, c, v, names, prefix, defs)
+
+  return
+
+def yaml_collapse(yaml_list):
+  collapsed = dict(yaml_list)
+
+  for k,v in collapsed.items():
+    props = set()
+    if 'properties' in v:
+       for entry in v['properties']:
+         for key in entry:
+           props.add(key)
+
+    if 'inherits' in v:
+      for inherited in v['inherits']:
+        for prop in inherited['properties']:
+          for key in prop:
+            if key not in props:
+              v['properties'].append(prop)
+      v.pop('inherits')
+
+  return collapsed
+
+
+def print_key_value(k, v, tabstop):
+  label = "#define " + k
+
+  # calculate the name's tabs
+  if len(label) % 8:
+    tabs = (len(label) + 7)  >> 3
+  else:
+    tabs = (len(label) >> 3) + 1
+
+  sys.stdout.write(label)
+  for i in range(0, tabstop - tabs + 1):
+    sys.stdout.write('\t')
+  sys.stdout.write(str(v))
+  sys.stdout.write("\n")
+
+  return
+
+def generate_include_file(defs):
+    compatible = reduced['/']['props']['compatible'][0]
+
+    sys.stdout.write("/**************************************************\n")
+    sys.stdout.write(" * Generated include file for " + compatible)
+    sys.stdout.write("\n")
+    sys.stdout.write(" *               DO NOT MODIFY\n");
+    sys.stdout.write(" */\n")
+    sys.stdout.write("\n")
+    sys.stdout.write("#ifndef _DEVICE_TREE_BOARD_H" + "\n");
+    sys.stdout.write("#define _DEVICE_TREE_BOARD_H" + "\n");
+    sys.stdout.write("\n")
+
+    node_keys = sorted(defs.keys())
+    for node in node_keys:
+       sys.stdout.write('/* ' + node.split('/')[-1] + ' */')
+       sys.stdout.write("\n")
+
+       maxlength = max(len(s + '#define ') for s in defs[node].keys())
+       if maxlength % 8:
+           maxtabstop = (maxlength + 7) >> 3
+       else:
+         maxtabstop = (maxlength >> 3) + 1
+
+       if (maxtabstop * 8 - maxlength) <= 2:
+         maxtabstop += 1
+
+       prop_keys = sorted(defs[node].keys())
+       for prop in prop_keys:
+         if prop == 'aliases':
+           for entry in sorted(defs[node][prop]):
+             print_key_value(entry, defs[node][prop].get(entry), maxtabstop)
+         else:
+           print_key_value(prop, defs[node].get(prop), maxtabstop)
+       sys.stdout.write("\n")
+
+    sys.stdout.write("#endif\n");
+
+def main(args):
+  if len(args) < 2:
+    print('Usage: %s filename.dts path_to_yaml' % args[0])
+    return 1
+
+  try:
+    with open(args[1], "r") as fd:
+      d = parse_file(fd)
+  except:
+     raise Exception("Input file " + os.path.abspath(args[1]) + " does not exist.")
+
+  # compress list to nodes w/ paths, add interrupt parent
+  compress_nodes(d['/'], '/')
+
+  # build up useful lists
+  compatibles = get_all_compatibles(d['/'], '/', {})
+  get_phandles(d['/'], '/', {})
+  get_aliases(d['/'])
+  get_chosen(d['/'])
+
+  # find unique set of compatibles across all active nodes
+  s = set()
+  for k,v in compatibles.items():
+    if isinstance(v,list):
+      for item in v:
+        s.add(item)
+    else:
+      s.add(v)
+
+  # scan YAML files and find the ones we are interested in
+  yaml_files = []
+  for (dirpath, dirnames, filenames) in walk(args[2]):
+    yaml_files.extend([f for f in filenames if re.match('.*\.yaml\Z', f)])
+    yaml_files = [dirpath + '/' + t for t in yaml_files]
+    break
+
+  yaml_list = {}
+  file_load_list = set()
+  for file in yaml_files:
+    for line in open(file, 'r'):
+      if re.search('^\s+constraint:*', line):
+        c = line.split(':')[1].strip()
+        c = c.strip('"')
+        if c in s:
+          if not file in file_load_list:
+            file_load_list.add(file)
+            with open(file, 'r') as yf:
+              yaml_list[c] = yaml.load(yf, Loader)
+
+  if yaml_list == {}:
+    raise Exception("Missing YAML information.  Check YAML sources")
+
+  # collapse the yaml inherited information
+  yaml_list = yaml_collapse(yaml_list)
+
+  # load zephyr specific nodes
+  flash = {}
+  console = {}
+  sram = {}
+  if 'zephyr,flash' in chosen:
+    flash = reduced[chosen['zephyr,flash']]
+  if 'zephyr,console' in chosen:
+    console = reduced[chosen['zephyr,console']]
+  if 'zephyr,sram' in chosen:
+    sram = reduced[chosen['zephyr,sram']]
+
+  defs = {}
+  structs = {}
+  for k, v in reduced.items():
+    node_compat = get_compat(v)
+    if node_compat != None and node_compat in yaml_list:
+      extract_node_include_info(reduced, k, yaml_list, defs, structs)
+
+  if defs == {}:
+    raise Exception("No information parsed from dts file.")
+
+  if flash:
+    extract_reg_prop(chosen['zephyr,flash'], None, defs, "CONFIG_FLASH", 1024)
+  else:
+    # We will add address and size of 0 for systems with no flash controller
+    # This is what they already do in the Kconfig options anyway
+    defs['dummy-flash'] =  { 'CONFIG_FLASH_BASE_ADDRESS': 0, 'CONFIG_FLASH_SIZE': 0 }
+
+  if sram:
+    extract_reg_prop(chosen['zephyr,sram'], None, defs, "CONFIG_SRAM", 1024)
+
+  # generate include file
+  generate_include_file(defs)
+
+if __name__ == '__main__':
+  # test1.py executed as script
+  # do something
+  sys.exit(main(sys.argv))