diff --git a/.readthedocs.yml b/.readthedocs.yml
index bea9451..668fa38 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -31,6 +31,11 @@ conda:
 submodules:
   include:
    - libraries/sky130_fd_io/latest
+   - libraries/sky130_fd_sc_hd/latest
+   - libraries/sky130_fd_sc_hdll/latest
+   - libraries/sky130_fd_sc_hs/latest
+   - libraries/sky130_fd_sc_ls/latest
+   - libraries/sky130_fd_sc_ms/latest
   recursive: false
 
 formats:
diff --git a/docs/_ext/skywater_pdk b/docs/_ext/skywater_pdk
new file mode 120000
index 0000000..c5fe58c
--- /dev/null
+++ b/docs/_ext/skywater_pdk
@@ -0,0 +1 @@
+../../scripts/python-skywater-pdk/skywater_pdk/
\ No newline at end of file
diff --git a/docs/conf.py b/docs/conf.py
index f5c16d7..625b88a 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -31,9 +31,9 @@
 import docutils
 import os
 import re
-# import sys
+import sys
 # sys.path.insert(0, os.path.abspath('.'))
-
+sys.path.insert(0, os.path.abspath('./_ext'))
 
 # -- Project information -----------------------------------------------------
 
@@ -67,6 +67,8 @@ extensions = [
     'sphinx.ext.todo',
     'sphinxcontrib_hdl_diagrams',
     'sphinxcontrib.bibtex',
+    'skywater_pdk.cells.cross_index',
+    'skywater_pdk.cells.generate.readme',
 ]
 
 bibtex_default_style = 'plain'
@@ -410,3 +412,6 @@ def setup(app):
     app.add_role('lib', lib_role)
     app.add_role('cell', cell_role)
     app.add_role('model', cell_role)
+
+    app.emit("cells_generate_readme", 'contents/libraries/*/cells/*')
+
diff --git a/docs/contents/cell-index.rst b/docs/contents/cell-index.rst
new file mode 100644
index 0000000..448c981
--- /dev/null
+++ b/docs/contents/cell-index.rst
@@ -0,0 +1 @@
+.. cross_index:: libraries/*
diff --git a/docs/contents/libraries.rst b/docs/contents/libraries.rst
index b7b29de..d760ec6 100644
--- a/docs/contents/libraries.rst
+++ b/docs/contents/libraries.rst
@@ -146,3 +146,8 @@ The SKY130 currently offers two :lib_type:`build space` libraries. Build space l
 
     libraries/sky130_ef_io/README
 
+.. toctree::
+    :maxdepth: 1
+    :name: Cells in libraries cross-index
+
+    cell-index
diff --git a/scripts/python-skywater-pdk/skywater_pdk/cells/cross_index.py b/scripts/python-skywater-pdk/skywater_pdk/cells/cross_index.py
new file mode 100755
index 0000000..fa9bf69
--- /dev/null
+++ b/scripts/python-skywater-pdk/skywater_pdk/cells/cross_index.py
@@ -0,0 +1,307 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright 2020 SkyWater PDK Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import argparse
+import json
+import os
+import pathlib
+import pprint
+import sys
+import textwrap
+from docutils import nodes
+from docutils.parsers.rst import Directive
+from docutils.statemachine import ViewList
+from sphinx.util.nodes import nested_parse_with_titles
+
+from typing import Tuple, List, Dict
+
+verbose = False
+
+# using a list-table here to allow for easier line breaks in description
+rst_header_line_char = '-'
+rst_header = 'Cells in libraries cross-index'
+rst_template ="""\
+{header_line}
+{header_underline}
+
+.. list-table::
+   :header-rows: 1
+
+   * - Cell name
+     - {lib_suffixes}
+     - Number of libraries
+{cell_list}
+"""
+
+cell_template = """\
+   * - {cell_name}
+     - {lib_suffixes_match}
+     - {lib_count}
+"""
+
+tab_entry = '\n     - '
+
+def collect(library_dir) -> Tuple[str, List[str]]:
+    """Collect the available definitions for cells in a library
+
+    Parameters
+    ----------
+    library_dir: str or pathlib.Path
+        Path to a library.
+
+    Returns
+    -------
+    lib : str
+        Library name
+
+    cells : list of pathlib.Path
+        definition files for cells in the library.
+    """
+
+    if not isinstance(library_dir, pathlib.Path):
+        library_dir = pathlib.Path(library_dir)
+
+    libname = None
+    cells = set()
+
+    for p in library_dir.rglob("definition.json"):
+        if not p.is_file():
+            continue
+        define_data = json.load(open(p))
+        if not define_data['type'] == 'cell':
+            continue
+        cells.add(p)
+        if libname is None:
+            libname = define_data['library']
+
+    cells = list(sorted(cells))
+    if not len(cells):
+        raise FileNotFoundError("No cell definitions found")
+    assert len(libname) > 0
+    return libname, cells
+
+def get_cell_names(cells):
+    """Get cell names from definition filess
+
+    Parameters
+    ----------
+    cells: list of pathlib.Path
+        List of paths to JSON description files
+
+    Returns
+    -------
+    cell_list: list of str
+        List of cell names
+    """
+
+    cell_list = []
+
+    for cell in cells:
+        with open(str(cell), "r") as c:
+            cell_json = json.load(c)
+            cell_list.append( cell_json['name'] )
+    return cell_list
+
+
+def generate_crosstable (cells_lib, link_template=''):
+    """Generate the RST paragraph containing cell cross reference table
+
+    Parameters:
+        cells_lib: dictionary with list of libraries per cell name [dict]
+        link_template: cell README generic path (with {lib} and {cell} tags) [str]
+
+    Returns:
+        paragraph: Generated paragraph [str]
+
+    """
+
+    assert isinstance (cells_lib, dict)
+
+    paragraph = ""
+    cell_list = ""
+
+    lib_suffixes = set()
+    for v in cells_lib.values():
+        lib_suffixes.update( [lib.rpartition('_')[2] for lib in v] )
+    lib_suffixes = list(lib_suffixes)
+    lib_suffixes.sort()
+    #print (lib_suffixes)
+
+    for c in sorted(cells_lib):
+        ls = {} # dictionary of cell library shorts (suffixes)
+        for lib in cells_lib[c]:
+            ls [lib.rpartition('_')[2]] = lib
+        mark = ' :doc:`x <' + link_template + '>`'  # lib match mark with link
+        suff_match = [ mark.format(cell=c,lib=ls[s]) if s in ls else '' for s in lib_suffixes ]
+        cell_list += cell_template.format(
+            cell_name = c,
+            lib_suffixes_match = tab_entry.join(suff_match),
+            lib_count = str (len(ls))
+        )
+
+    paragraph = rst_template.format(
+                header_line = rst_header,
+                header_underline = rst_header_line_char * len(rst_header),
+                lib_suffixes = tab_entry.join(lib_suffixes),
+                cell_list = cell_list
+            )
+    return paragraph
+
+
+def cells_in_libs (libpaths):
+    """Generate the RST paragraph containing cell cross reference table
+
+    Parameters:
+        libpaths: list of cell library paths [list of pathlib.Path]
+
+    Returns:
+        cells_lib: dictionary with list of libraries containing each cell name [dict]
+    """
+
+    lib_dirs = [pathlib.Path(d) for d in libpaths]
+    lib_dirs = [d for d in lib_dirs if d.is_dir()]
+    libs_toc = dict()
+
+    for lib in lib_dirs:
+        try:
+            libname, cells = collect(lib)
+            if verbose:
+                print(f"{lib} \tLibrary name: {libname}, found {len(cells)} cells")
+            libs_toc[libname] = get_cell_names(cells)
+        except FileNotFoundError:
+            if verbose:
+                print (f'{lib} \t- no cells found') 
+
+    all_cells = set()
+    cells_lib = {}
+    for lib,cells in libs_toc.items():
+        all_cells.update(set(cells))
+        for c in cells:
+            cells_lib[c]  = cells_lib.get(c, []) + [lib]
+
+    return cells_lib
+
+
+
+# --- Sphinx extension wrapper ---
+
+class CellCrossIndex(Directive):
+
+    required_arguments = 1
+    optional_arguments = 1
+    has_content = True
+
+    def run(self):
+        env = self.state.document.settings.env
+        dirname = env.docname.rpartition('/')[0]
+        arg = self.arguments[0]
+        arg = dirname + '/' + arg
+        output = dirname + '/' + self.arguments[1] if len(self.arguments)>2 else None
+
+        path = pathlib.Path(arg).expanduser()
+        parts = path.parts[1:] if path.is_absolute() else path.parts
+        paths = pathlib.Path(path.root).glob(str(pathlib.Path("").joinpath(*parts)))
+        paths = list(paths)    
+        paths = [d.resolve() for d in paths if d.is_dir()]
+
+        cells_lib = cells_in_libs ( list(paths) )
+        celllink = self.arguments[0].replace('*','{lib}') + '/cells/{cell}/README'
+        paragraph = generate_crosstable (cells_lib,celllink)
+
+        if output is None: #  dynamic output
+            # parse rst string to docutils nodes
+            rst = ViewList()
+            for i,line in enumerate(paragraph.split('\n')):
+                rst.append(line, "cell-index-tmp.rst", i+1) 
+            node = nodes.section()
+            node.document = self.state.document
+            nested_parse_with_titles(self.state, rst, node)
+            return node.children
+        else: # file output
+             if not output.endswith('.rst'):
+                output += '.rst'
+             with open(str(output),'w') as f:
+                f.write(paragraph)           
+             paragraph_node = nodes.paragraph()
+             return [paragraph_node]
+
+def setup(app):
+    app.add_directive("cross_index", CellCrossIndex)
+
+    return {
+        'version': '0.1',
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }
+
+# --- stand alone, command line operation ---
+
+def main():
+    global verbose
+    parser = argparse.ArgumentParser()
+    alllibpath = '../../../libraries/*/latest'
+    celllink = 'libraries/{lib}/cells/{cell}/README'
+
+    parser.add_argument(
+            "-v", 
+            "--verbose", 
+            help="increase verbosity", 
+            action="store_true"
+            )
+    parser.add_argument(
+            "--all_libs",
+            help="process all libs in "+alllibpath,
+            action="store_true")
+    parser.add_argument(
+            "libraries_dirs",
+            help="Paths to the library directories. Eg. " + alllibpath,
+            type=pathlib.Path,
+            nargs="*")
+    parser.add_argument(
+            "-o",
+            "--outfile",
+            help="Output file name", 
+            type=pathlib.Path,
+            default=pathlib.Path('./cell-index.rst'))
+    parser.add_argument(
+            "-c",
+            "--celllink",
+            help="Specify cell link template. Default: '" + celllink +"'", 
+            type=str,
+            default=celllink)
+
+    args = parser.parse_args()
+    verbose = args.verbose
+
+    if args.all_libs:
+        path = pathlib.Path(alllibpath).expanduser()
+        parts = path.parts[1:] if path.is_absolute() else path.parts
+        paths = pathlib.Path(path.root).glob(str(pathlib.Path("").joinpath(*parts)))
+        args.libraries_dirs = list(paths)
+
+
+    cells_lib = cells_in_libs (args.libraries_dirs)
+    par = generate_crosstable (cells_lib,args.celllink)
+
+    with open(str(args.outfile),'w') as f:
+        f.write(par)
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/scripts/python-skywater-pdk/skywater_pdk/cells/generate/readme.py b/scripts/python-skywater-pdk/skywater_pdk/cells/generate/readme.py
new file mode 100755
index 0000000..ff90d34
--- /dev/null
+++ b/scripts/python-skywater-pdk/skywater_pdk/cells/generate/readme.py
@@ -0,0 +1,235 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright 2020 The SkyWater PDK Authors.
+#
+# Use of this source code is governed by the Apache 2.0
+# license that can be found in the LICENSE file or at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+
+''' This is a prototype of cell documentation generation script.
+'''
+
+import csv
+import json
+import os
+import sys
+import argparse
+import pathlib
+import glob
+import subprocess
+import textwrap
+from docutils import nodes
+from docutils.parsers.rst import Directive
+from docutils.statemachine import ViewList
+from sphinx.util.nodes import nested_parse_with_titles
+
+verbose = False
+
+readme_template ="""\
+{header}
+
+**{description}**
+
+*This is a stub of cell description file*
+
+-  **Cell name**: {name}
+-  **Type**: {deftype}
+-  **Verilog name**: {verilog_name}
+-  **Library**: {library}
+-  **Inputs**:  {inputs}
+-  **Outputs**: {outputs}
+
+{subheader_sym}
+
+.. list-table:: 
+
+    * - .. figure:: {symbol1}
+      -
+      - .. figure:: {symbol2}
+
+{subheader_sch}
+
+.. figure:: {schematic}
+    :align: center
+
+{subheader_gds}
+
+"""
+
+figure_template ="""
+
+.. figure:: {fig}
+    :align: center
+    :width: 50%
+
+    {name}
+"""
+
+def write_readme(cellpath, define_data):
+    ''' Generates README for a given cell.
+
+    Args:
+        cellpath - path to a cell [str of pathlib.Path]
+        define_data - cell data from json [dic]
+
+    '''
+    outpath = os.path.join(cellpath, 'README.rst')
+    prefix = define_data['file_prefix'] 
+    header = f':cell:`{prefix}`'
+    subheader_sym = header + ' symbols'
+    subheader_sch = header + ' schematic'
+    subheader_gds = header + ' GDSII layouts'
+
+    header += '\n' + '=' * len(header)
+    subheader_sym += '\n' + '-' * len(subheader_sym)
+    subheader_sch += '\n' + '-' * len(subheader_sch)
+    subheader_gds += '\n' + '-' * len(subheader_gds)
+
+
+    symbol1 = prefix + '.symbol.svg'
+    symbol2 = prefix + '.pp.symbol.svg'
+    schematic = prefix + '.schematic.svg'
+    inputs = []
+    outputs = []
+    for p in define_data['ports']:
+        try:
+            if p[0]=='signal' and p[2]=='input':
+                inputs.append(p[1])
+            if p[0]=='signal' and p[2]=='output':
+                outputs.append(p[1])
+        except: 
+            pass
+    gdssvg = []       
+    svglist = list(pathlib.Path(cellpath).glob('*.svg'))
+    for s in svglist:
+        gdsfile = pathlib.Path(os.path.join(cellpath, s.stem +'.gds'))
+        if gdsfile.is_file():
+            gdssvg.append(s)
+
+    with open(outpath, 'w') as f:
+        f.write (readme_template.format (
+            header = header,
+            subheader_sym = subheader_sym,
+            subheader_sch = subheader_sch,
+            subheader_gds = subheader_gds,
+            description = define_data['description'].rstrip('.'),
+            name = ':cell:`' + prefix +'`',
+            deftype = define_data['type'],
+            verilog_name = define_data['verilog_name'],
+            library = define_data['library'],
+            inputs  = f'{len(inputs)} ('  + ', '.join(inputs) + ')',
+            outputs = f'{len(outputs)} (' + ', '.join(outputs) + ')',
+            symbol1 = symbol1,
+            symbol2 = symbol2,
+            schematic = schematic,
+        ))
+        for gs in sorted(gdssvg):
+            f.write (figure_template.format (
+                fig  = gs.name,
+                name = gs.stem
+        ))
+
+def process(cellpath):
+    ''' Processes cell indicated by path.
+        Opens cell definiton and calls further processing
+
+    Args:
+        cellpath - path to a cell [str of pathlib.Path]
+    '''
+    if verbose:
+        print()
+        print(cellpath)
+    define_json = os.path.join(cellpath, 'definition.json')
+    if not os.path.exists(define_json):
+        print("No definition.json in", cellpath)
+    assert os.path.exists(define_json), define_json
+    define_data = json.load(open(define_json))
+
+    if define_data['type'] == 'cell':
+        write_readme(cellpath, define_data)
+
+    return
+
+# --- Sphinx extension wrapper ----------------
+
+def GenerateCellReadme (app, cellpath):
+
+        print (f'GenerateCellReadme: generating files for {cellpath}')
+        path = pathlib.Path(cellpath).expanduser()
+        parts = path.parts[1:] if path.is_absolute() else path.parts
+        paths = pathlib.Path(path.root).glob(str(pathlib.Path("").joinpath(*parts)))
+        paths = list(paths)    
+        cell_dirs = [d.resolve() for d in paths if d.is_dir()]
+
+        errors = 0
+        for d in cell_dirs:
+            try:
+                process(d)
+            except (AssertionError, FileNotFoundError, ChildProcessError) as ex:
+                print (f'GenerateCellReadme: {type(ex).__name__}')
+                print (f'{ex.args}')
+                errors +=1
+        print (f'GenerateCellReadme: {len(cell_dirs)} files processed, {errors} errors.')
+
+def setup(app):
+    app.add_event("cells_generate_readme")
+    app.connect('cells_generate_readme', GenerateCellReadme)
+
+    return {
+        'version': '0.1',
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+           }
+
+# ----------------------------------------------      
+
+def main():
+    ''' Generates README.rst for cell.'''
+
+    prereq_txt = ''
+    output_txt = 'output:\n  generates README.rst'
+    allcellpath = '../../../libraries/*/latest/cells/*'
+
+    parser = argparse.ArgumentParser(
+            description = main.__doc__,
+            epilog = prereq_txt +'\n\n'+ output_txt,
+            formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument(
+            "--all_libs",
+            help="process all cells in "+allcellpath,
+            action="store_true")
+    parser.add_argument(
+            "cell_dir",
+            help="path to the cell directory",
+            type=pathlib.Path,
+            nargs="*")
+
+    args = parser.parse_args()
+
+    if args.all_libs:
+        path = pathlib.Path(allcellpath).expanduser()
+        parts = path.parts[1:] if path.is_absolute() else path.parts
+        paths = pathlib.Path(path.root).glob(str(pathlib.Path("").joinpath(*parts)))
+        args.cell_dir = list(paths)
+
+    cell_dirs = [d.resolve() for d in args.cell_dir if d.is_dir()]
+
+    errors = 0
+    for d in cell_dirs:
+        try:
+            process(d)
+        except KeyboardInterrupt:
+            sys.exit(1)
+        except (AssertionError, FileNotFoundError, ChildProcessError) as ex:
+            print (f'Error: {type(ex).__name__}')
+            print (f'{ex.args}')
+            errors +=1
+    print (f'\n{len(cell_dirs)} files processed, {errors} errors.')
+    return 0 if errors else 1
+
+if __name__ == "__main__":
+    sys.exit(main())
+