Merge branch 'mauro' into docs-mw

Mauro says:

This changeset contains the kernel-doc.py script to replace the verable
kernel-doc originally written in Perl. It replaces the first version and the
second series I sent on the top of it.

I tried to stay as close as possible of the original Perl implementation
on the first patch introducing kernel-doc.py, as it helps to double check
if each function was  properly translated to Python.  This have been
helpful debugging troubles that happened during the conversion.

I worked hard to make it bug-compatible with the original one. Still, its
output has a couple of differences from the original one:

- The tab expansion works better with the Python script. With that, some
  outputs that contain tabs at kernel-doc markups are now different;

- The new script  works better stripping blank lines. So, there are a couple
  of empty new lines that are now stripped with this version;

- There is a buggy logic at kernel-doc to strip empty description and
  return sections. I was not able to replicate the exact behavior. So, I ended
  adding an extra logic to strip empty sections with a different algorithm.

Yet, on my tests, the results are compatible with the venerable script
output for all .. kernel-doc tags found in Documentation/. I double-checked
this by adding support to output the kernel-doc commands when V=1, and
then I ran a diff between kernel-doc.pl and kernel-doc.py for the same
command lines.

The only patch that doesn't belong to this series is a patch dropping
kernel-doc.pl. I opted to keep it for now, as it can help to better
test the new tools.

With such changes, if one wants to build docs with the old script,
all it is needed is to use KERNELDOC parameter, e.g.:

	$ make KERNELDOC=scripts/kernel-doc.pl htmldocs

1 files changed, 282 insertions, 0 deletions

diff --git a/scripts/lib/kdoc/kdoc_files.py b/scripts/lib/kdoc/kdoc_files.py
new file mode 100644
index 000000000000..dd003feefd1b
--- /dev/null
+++ b/scripts/lib/kdoc/kdoc_files.py
@@ -0,0 +1,282 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+#
+# pylint: disable=R0903,R0913,R0914,R0917
+
+"""
+Parse lernel-doc tags on multiple kernel source files.
+"""
+
+import argparse
+import logging
+import os
+import re
+
+from kdoc_parser import KernelDoc
+from kdoc_output import OutputFormat
+
+
+class GlobSourceFiles:
+    """
+    Parse C source code file names and directories via an Interactor.
+    """
+
+    def __init__(self, srctree=None, valid_extensions=None):
+        """
+        Initialize valid extensions with a tuple.
+
+        If not defined, assume default C extensions (.c and .h)
+
+        It would be possible to use python's glob function, but it is
+        very slow, and it is not interactive. So, it would wait to read all
+        directories before actually do something.
+
+        So, let's use our own implementation.
+        """
+
+        if not valid_extensions:
+            self.extensions = (".c", ".h")
+        else:
+            self.extensions = valid_extensions
+
+        self.srctree = srctree
+
+    def _parse_dir(self, dirname):
+        """Internal function to parse files recursively"""
+
+        with os.scandir(dirname) as obj:
+            for entry in obj:
+                name = os.path.join(dirname, entry.name)
+
+                if entry.is_dir():
+                    yield from self._parse_dir(name)
+
+                if not entry.is_file():
+                    continue
+
+                basename = os.path.basename(name)
+
+                if not basename.endswith(self.extensions):
+                    continue
+
+                yield name
+
+    def parse_files(self, file_list, file_not_found_cb):
+        """
+        Define an interator to parse all source files from file_list,
+        handling directories if any
+        """
+
+        if not file_list:
+            return
+
+        for fname in file_list:
+            if self.srctree:
+                f = os.path.join(self.srctree, fname)
+            else:
+                f = fname
+
+            if os.path.isdir(f):
+                yield from self._parse_dir(f)
+            elif os.path.isfile(f):
+                yield f
+            elif file_not_found_cb:
+                file_not_found_cb(fname)
+
+
+class KernelFiles():
+    """
+    Parse kernel-doc tags on multiple kernel source files.
+
+    There are two type of parsers defined here:
+        - self.parse_file(): parses both kernel-doc markups and
+          EXPORT_SYMBOL* macros;
+        - self.process_export_file(): parses only EXPORT_SYMBOL* macros.
+    """
+
+    def warning(self, msg):
+        """Ancillary routine to output a warning and increment error count"""
+
+        self.config.log.warning(msg)
+        self.errors += 1
+
+    def error(self, msg):
+        """Ancillary routine to output an error and increment error count"""
+
+        self.config.log.error(msg)
+        self.errors += 1
+
+    def parse_file(self, fname):
+        """
+        Parse a single Kernel source.
+        """
+
+        # Prevent parsing the same file twice if results are cached
+        if fname in self.files:
+            return
+
+        doc = KernelDoc(self.config, fname)
+        export_table, entries = doc.parse_kdoc()
+
+        self.export_table[fname] = export_table
+
+        self.files.add(fname)
+        self.export_files.add(fname)      # parse_kdoc() already check exports
+
+        self.results[fname] = entries
+
+    def process_export_file(self, fname):
+        """
+        Parses EXPORT_SYMBOL* macros from a single Kernel source file.
+        """
+
+        # Prevent parsing the same file twice if results are cached
+        if fname in self.export_files:
+            return
+
+        doc = KernelDoc(self.config, fname)
+        export_table = doc.parse_export()
+
+        if not export_table:
+            self.error(f"Error: Cannot check EXPORT_SYMBOL* on {fname}")
+            export_table = set()
+
+        self.export_table[fname] = export_table
+        self.export_files.add(fname)
+
+    def file_not_found_cb(self, fname):
+        """
+        Callback to warn if a file was not found.
+        """
+
+        self.error(f"Cannot find file {fname}")
+
+    def __init__(self, verbose=False, out_style=None,
+                 werror=False, wreturn=False, wshort_desc=False,
+                 wcontents_before_sections=False,
+                 logger=None):
+        """
+        Initialize startup variables and parse all files
+        """
+
+        if not verbose:
+            verbose = bool(os.environ.get("KBUILD_VERBOSE", 0))
+
+        if out_style is None:
+            out_style = OutputFormat()
+
+        if not werror:
+            kcflags = os.environ.get("KCFLAGS", None)
+            if kcflags:
+                match = re.search(r"(\s|^)-Werror(\s|$)/", kcflags)
+                if match:
+                    werror = True
+
+            # reading this variable is for backwards compat just in case
+            # someone was calling it with the variable from outside the
+            # kernel's build system
+            kdoc_werror = os.environ.get("KDOC_WERROR", None)
+            if kdoc_werror:
+                werror = kdoc_werror
+
+        # Some variables are global to the parser logic as a whole as they are
+        # used to send control configuration to KernelDoc class. As such,
+        # those variables are read-only inside the KernelDoc.
+        self.config = argparse.Namespace
+
+        self.config.verbose = verbose
+        self.config.werror = werror
+        self.config.wreturn = wreturn
+        self.config.wshort_desc = wshort_desc
+        self.config.wcontents_before_sections = wcontents_before_sections
+
+        if not logger:
+            self.config.log = logging.getLogger("kernel-doc")
+        else:
+            self.config.log = logger
+
+        self.config.warning = self.warning
+
+        self.config.src_tree = os.environ.get("SRCTREE", None)
+
+        # Initialize variables that are internal to KernelFiles
+
+        self.out_style = out_style
+
+        self.errors = 0
+        self.results = {}
+
+        self.files = set()
+        self.export_files = set()
+        self.export_table = {}
+
+    def parse(self, file_list, export_file=None):
+        """
+        Parse all files
+        """
+
+        glob = GlobSourceFiles(srctree=self.config.src_tree)
+
+        for fname in glob.parse_files(file_list, self.file_not_found_cb):
+            self.parse_file(fname)
+
+        for fname in glob.parse_files(export_file, self.file_not_found_cb):
+            self.process_export_file(fname)
+
+    def out_msg(self, fname, name, arg):
+        """
+        Return output messages from a file name using the output style
+        filtering.
+
+        If output type was not handled by the syler, return None.
+        """
+
+        # NOTE: we can add rules here to filter out unwanted parts,
+        # although OutputFormat.msg already does that.
+
+        return self.out_style.msg(fname, name, arg)
+
+    def msg(self, enable_lineno=False, export=False, internal=False,
+            symbol=None, nosymbol=None, no_doc_sections=False,
+            filenames=None, export_file=None):
+        """
+        Interacts over the kernel-doc results and output messages,
+        returning kernel-doc markups on each interaction
+        """
+
+        self.out_style.set_config(self.config)
+
+        if not filenames:
+            filenames = sorted(self.results.keys())
+
+        for fname in filenames:
+            function_table = set()
+
+            if internal or export:
+                if not export_file:
+                    export_file = [fname]
+
+                for f in export_file:
+                    function_table |= self.export_table[f]
+
+            if symbol:
+                for s in symbol:
+                    function_table.add(s)
+
+            self.out_style.set_filter(export, internal, symbol, nosymbol,
+                                      function_table, enable_lineno,
+                                      no_doc_sections)
+
+            msg = ""
+            for name, arg in self.results[fname]:
+                msg += self.out_msg(fname, name, arg)
+
+                if msg is None:
+                    ln = arg.get("ln", 0)
+                    dtype = arg.get('type', "")
+
+                    self.config.log.warning("%s:%d Can't handle %s",
+                                            fname, ln, dtype)
+            if msg:
+                yield fname, msg