diff --git a/tools/patman/patchstream.py b/tools/patman/patchstream.py
new file mode 100644
index 0000000..be40af3
--- /dev/null
+++ b/tools/patman/patchstream.py
@@ -0,0 +1,444 @@
+# Copyright (c) 2011 The Chromium OS Authors.
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+# MA 02111-1307 USA
+#
+
+import os
+import re
+import shutil
+import tempfile
+
+import command
+import commit
+import gitutil
+from series import Series
+
+# Tags that we detect and remove
+re_remove = re.compile('^BUG=|^TEST=|^Change-Id:|^Review URL:'
+    '|Reviewed-on:|Reviewed-by:')
+
+# Lines which are allowed after a TEST= line
+re_allowed_after_test = re.compile('^Signed-off-by:')
+
+# The start of the cover letter
+re_cover = re.compile('^Cover-letter:')
+
+# Patch series tag
+re_series = re.compile('^Series-(\w*): *(.*)')
+
+# Commit tags that we want to collect and keep
+re_tag = re.compile('^(Tested-by|Acked-by|Signed-off-by|Cc): (.*)')
+
+# The start of a new commit in the git log
+re_commit = re.compile('^commit (.*)')
+
+# We detect these since checkpatch doesn't always do it
+re_space_before_tab = re.compile('^[+].* \t')
+
+# States we can be in - can we use range() and still have comments?
+STATE_MSG_HEADER = 0        # Still in the message header
+STATE_PATCH_SUBJECT = 1     # In patch subject (first line of log for a commit)
+STATE_PATCH_HEADER = 2      # In patch header (after the subject)
+STATE_DIFFS = 3             # In the diff part (past --- line)
+
+class PatchStream:
+    """Class for detecting/injecting tags in a patch or series of patches
+
+    We support processing the output of 'git log' to read out the tags we
+    are interested in. We can also process a patch file in order to remove
+    unwanted tags or inject additional ones. These correspond to the two
+    phases of processing.
+    """
+    def __init__(self, series, name=None, is_log=False):
+        self.skip_blank = False          # True to skip a single blank line
+        self.found_test = False          # Found a TEST= line
+        self.lines_after_test = 0        # MNumber of lines found after TEST=
+        self.warn = []                   # List of warnings we have collected
+        self.linenum = 1                 # Output line number we are up to
+        self.in_section = None           # Name of start...END section we are in
+        self.notes = []                  # Series notes
+        self.section = []                # The current section...END section
+        self.series = series             # Info about the patch series
+        self.is_log = is_log             # True if indent like git log
+        self.in_change = 0               # Non-zero if we are in a change list
+        self.blank_count = 0             # Number of blank lines stored up
+        self.state = STATE_MSG_HEADER    # What state are we in?
+        self.tags = []                   # Tags collected, like Tested-by...
+        self.signoff = []                # Contents of signoff line
+        self.commit = None               # Current commit
+
+    def AddToSeries(self, line, name, value):
+        """Add a new Series-xxx tag.
+
+        When a Series-xxx tag is detected, we come here to record it, if we
+        are scanning a 'git log'.
+
+        Args:
+            line: Source line containing tag (useful for debug/error messages)
+            name: Tag name (part after 'Series-')
+            value: Tag value (part after 'Series-xxx: ')
+        """
+        if name == 'notes':
+            self.in_section = name
+            self.skip_blank = False
+        if self.is_log:
+            self.series.AddTag(self.commit, line, name, value)
+
+    def CloseCommit(self):
+        """Save the current commit into our commit list, and reset our state"""
+        if self.commit and self.is_log:
+            self.series.AddCommit(self.commit)
+            self.commit = None
+
+    def FormatTags(self, tags):
+        out_list = []
+        for tag in sorted(tags):
+            if tag.startswith('Cc:'):
+                tag_list = tag[4:].split(',')
+                out_list += gitutil.BuildEmailList(tag_list, 'Cc:')
+            else:
+                out_list.append(tag)
+        return out_list
+
+    def ProcessLine(self, line):
+        """Process a single line of a patch file or commit log
+
+        This process a line and returns a list of lines to output. The list
+        may be empty or may contain multiple output lines.
+
+        This is where all the complicated logic is located. The class's
+        state is used to move between different states and detect things
+        properly.
+
+        We can be in one of two modes:
+            self.is_log == True: This is 'git log' mode, where most output is
+                indented by 4 characters and we are scanning for tags
+
+            self.is_log == False: This is 'patch' mode, where we already have
+                all the tags, and are processing patches to remove junk we
+                don't want, and add things we think are required.
+
+        Args:
+            line: text line to process
+
+        Returns:
+            list of output lines, or [] if nothing should be output
+        """
+        # Initially we have no output. Prepare the input line string
+        out = []
+        line = line.rstrip('\n')
+        if self.is_log:
+            if line[:4] == '    ':
+                line = line[4:]
+
+        # Handle state transition and skipping blank lines
+        series_match = re_series.match(line)
+        commit_match = re_commit.match(line) if self.is_log else None
+        tag_match = None
+        if self.state == STATE_PATCH_HEADER:
+            tag_match = re_tag.match(line)
+        is_blank = not line.strip()
+        if is_blank:
+            if (self.state == STATE_MSG_HEADER
+                    or self.state == STATE_PATCH_SUBJECT):
+                self.state += 1
+
+            # We don't have a subject in the text stream of patch files
+            # It has its own line with a Subject: tag
+            if not self.is_log and self.state == STATE_PATCH_SUBJECT:
+                self.state += 1
+        elif commit_match:
+            self.state = STATE_MSG_HEADER
+
+        # If we are in a section, keep collecting lines until we see END
+        if self.in_section:
+            if line == 'END':
+                if self.in_section == 'cover':
+                    self.series.cover = self.section
+                elif self.in_section == 'notes':
+                    if self.is_log:
+                        self.series.notes += self.section
+                else:
+                    self.warn.append("Unknown section '%s'" % self.in_section)
+                self.in_section = None
+                self.skip_blank = True
+                self.section = []
+            else:
+                self.section.append(line)
+
+        # Detect the commit subject
+        elif not is_blank and self.state == STATE_PATCH_SUBJECT:
+            self.commit.subject = line
+
+        # Detect the tags we want to remove, and skip blank lines
+        elif re_remove.match(line):
+            self.skip_blank = True
+
+            # TEST= should be the last thing in the commit, so remove
+            # everything after it
+            if line.startswith('TEST='):
+                self.found_test = True
+        elif self.skip_blank and is_blank:
+            self.skip_blank = False
+
+        # Detect the start of a cover letter section
+        elif re_cover.match(line):
+            self.in_section = 'cover'
+            self.skip_blank = False
+
+        # If we are in a change list, key collected lines until a blank one
+        elif self.in_change:
+            if is_blank:
+                # Blank line ends this change list
+                self.in_change = 0
+            else:
+                self.series.AddChange(self.in_change, self.commit, line)
+            self.skip_blank = False
+
+        # Detect Series-xxx tags
+        elif series_match:
+            name = series_match.group(1)
+            value = series_match.group(2)
+            if name == 'changes':
+                # value is the version number: e.g. 1, or 2
+                try:
+                    value = int(value)
+                except ValueError as str:
+                    raise ValueError("%s: Cannot decode version info '%s'" %
+                        (self.commit.hash, line))
+                self.in_change = int(value)
+            else:
+                self.AddToSeries(line, name, value)
+                self.skip_blank = True
+
+        # Detect the start of a new commit
+        elif commit_match:
+            self.CloseCommit()
+            self.commit = commit.Commit(commit_match.group(1)[:7])
+
+        # Detect tags in the commit message
+        elif tag_match:
+            # Onlly allow a single signoff tag
+            if tag_match.group(1) == 'Signed-off-by':
+                if self.signoff:
+                    self.warn.append('Patch has more than one Signed-off-by '
+                            'tag')
+                self.signoff += [line]
+
+            # Remove Tested-by self, since few will take much notice
+            elif (tag_match.group(1) == 'Tested-by' and
+                    tag_match.group(2).find(os.getenv('USER') + '@') != -1):
+                self.warn.append("Ignoring %s" % line)
+            elif tag_match.group(1) == 'Cc':
+                self.commit.AddCc(tag_match.group(2).split(','))
+            else:
+                self.tags.append(line);
+
+        # Well that means this is an ordinary line
+        else:
+            pos = 1
+            # Look for ugly ASCII characters
+            for ch in line:
+                # TODO: Would be nicer to report source filename and line
+                if ord(ch) > 0x80:
+                    self.warn.append("Line %d/%d ('%s') has funny ascii char" %
+                        (self.linenum, pos, line))
+                pos += 1
+
+            # Look for space before tab
+            m = re_space_before_tab.match(line)
+            if m:
+                self.warn.append('Line %d/%d has space before tab' %
+                    (self.linenum, m.start()))
+
+            # OK, we have a valid non-blank line
+            out = [line]
+            self.linenum += 1
+            self.skip_blank = False
+            if self.state == STATE_DIFFS:
+                pass
+
+            # If this is the start of the diffs section, emit our tags and
+            # change log
+            elif line == '---':
+                self.state = STATE_DIFFS
+
+                # Output the tags (signeoff first), then change list
+                out = []
+                if self.signoff:
+                    out += self.signoff
+                log = self.series.MakeChangeLog(self.commit)
+                out += self.FormatTags(self.tags)
+                out += [line] + log
+            elif self.found_test:
+                if not re_allowed_after_test.match(line):
+                    self.lines_after_test += 1
+
+        return out
+
+    def Finalize(self):
+        """Close out processing of this patch stream"""
+        self.CloseCommit()
+        if self.lines_after_test:
+            self.warn.append('Found %d lines after TEST=' %
+                    self.lines_after_test)
+
+    def ProcessStream(self, infd, outfd):
+        """Copy a stream from infd to outfd, filtering out unwanting things.
+
+        This is used to process patch files one at a time.
+
+        Args:
+            infd: Input stream file object
+            outfd: Output stream file object
+        """
+        # Extract the filename from each diff, for nice warnings
+        fname = None
+        last_fname = None
+        re_fname = re.compile('diff --git a/(.*) b/.*')
+        while True:
+            line = infd.readline()
+            if not line:
+                break
+            out = self.ProcessLine(line)
+
+            # Try to detect blank lines at EOF
+            for line in out:
+                match = re_fname.match(line)
+                if match:
+                    last_fname = fname
+                    fname = match.group(1)
+                if line == '+':
+                    self.blank_count += 1
+                else:
+                    if self.blank_count and (line == '-- ' or match):
+                        self.warn.append("Found possible blank line(s) at "
+                                "end of file '%s'" % last_fname)
+                    outfd.write('+\n' * self.blank_count)
+                    outfd.write(line + '\n')
+                    self.blank_count = 0
+        self.Finalize()
+
+
+def GetMetaData(start, count):
+    """Reads out patch series metadata from the commits
+
+    This does a 'git log' on the relevant commits and pulls out the tags we
+    are interested in.
+
+    Args:
+        start: Commit to start from: 0=HEAD, 1=next one, etc.
+        count: Number of commits to list
+    """
+    pipe = [['git', 'log', '--reverse', 'HEAD~%d' % start, '-n%d' % count]]
+    stdout = command.RunPipe(pipe, capture=True)
+    series = Series()
+    ps = PatchStream(series, is_log=True)
+    for line in stdout.splitlines():
+        ps.ProcessLine(line)
+    ps.Finalize()
+    return series
+
+def FixPatch(backup_dir, fname, series, commit):
+    """Fix up a patch file, by adding/removing as required.
+
+    We remove our tags from the patch file, insert changes lists, etc.
+    The patch file is processed in place, and overwritten.
+
+    A backup file is put into backup_dir (if not None).
+
+    Args:
+        fname: Filename to patch file to process
+        series: Series information about this patch set
+        commit: Commit object for this patch file
+    Return:
+        A list of errors, or [] if all ok.
+    """
+    handle, tmpname = tempfile.mkstemp()
+    outfd = os.fdopen(handle, 'w')
+    infd = open(fname, 'r')
+    ps = PatchStream(series)
+    ps.commit = commit
+    ps.ProcessStream(infd, outfd)
+    infd.close()
+    outfd.close()
+
+    # Create a backup file if required
+    if backup_dir:
+        shutil.copy(fname, os.path.join(backup_dir, os.path.basename(fname)))
+    shutil.move(tmpname, fname)
+    return ps.warn
+
+def FixPatches(series, fnames):
+    """Fix up a list of patches identified by filenames
+
+    The patch files are processed in place, and overwritten.
+
+    Args:
+        series: The series object
+        fnames: List of patch files to process
+    """
+    # Current workflow creates patches, so we shouldn't need a backup
+    backup_dir = None  #tempfile.mkdtemp('clean-patch')
+    count = 0
+    for fname in fnames:
+        commit = series.commits[count]
+        commit.patch = fname
+        result = FixPatch(backup_dir, fname, series, commit)
+        if result:
+            print '%d warnings for %s:' % (len(result), fname)
+            for warn in result:
+                print '\t', warn
+            print
+        count += 1
+    print 'Cleaned %d patches' % count
+    return series
+
+def InsertCoverLetter(fname, series, count):
+    """Inserts a cover letter with the required info into patch 0
+
+    Args:
+        fname: Input / output filename of the cover letter file
+        series: Series object
+        count: Number of patches in the series
+    """
+    fd = open(fname, 'r')
+    lines = fd.readlines()
+    fd.close()
+
+    fd = open(fname, 'w')
+    text = series.cover
+    prefix = series.GetPatchPrefix()
+    for line in lines:
+        if line.startswith('Subject:'):
+            # TODO: if more than 10 patches this should save 00/xx, not 0/xx
+            line = 'Subject: [%s 0/%d] %s\n' % (prefix, count, text[0])
+
+        # Insert our cover letter
+        elif line.startswith('*** BLURB HERE ***'):
+            # First the blurb test
+            line = '\n'.join(text[1:]) + '\n'
+            if series.get('notes'):
+                line += '\n'.join(series.notes) + '\n'
+
+            # Now the change list
+            out = series.MakeChangeLog(None)
+            line += '\n' + '\n'.join(out)
+        fd.write(line)
+    fd.close()