libcamera: control: Add vendor control id range reservation

Add a new control_ranges.yaml file that is used to reserve control id
ranges/offsets for libcamera and vendor specific controls. This file is
used by the gen-controls.py script to generate control id values for
each control.

Draft controls now have a separate range from core libcamera controls,
breaking the existing numbering behaviour.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

include/libcamera/meson.build

@@ -74,12 +74,13 @@ foreach mode, entry : controls_map
     endif
 
     template_file = files(outfile + '.in')
+    ranges_file = files('../../src/libcamera/control_ranges.yaml')
     control_headers += custom_target(header + '_h',
                                      input : input_files,
                                      output : outfile,
                                      command : [gen_controls, '-o', '@OUTPUT@',
                                                 '--mode', mode, '-t', template_file,
-                                                '@INPUT@'],
+                                                '-r', ranges_file, '@INPUT@'],
                                      install : true,
                                      install_dir : libcamera_headers_install_dir)
 endforeach

src/libcamera/control_ranges.yaml

@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Copyright (C) 2023, Raspberry Pi Ltd
+#
+%YAML 1.1
+---
+# Specifies the control id ranges/offsets for core/draft libcamera and vendor
+# controls and properties.
+ranges:
+  # Core libcamera controls
+  libcamera: 0
+  # Draft designated libcamera controls
+  draft: 10000
+  # Raspberry Pi vendor controls
+  rpi: 20000
+  # Next range starts at 30000
+
+...

src/libcamera/meson.build

@@ -141,11 +141,13 @@ foreach mode, input_files : controls_mode_files
         template_file = files('property_ids.cpp.in')
     endif
 
+    ranges_file = files('control_ranges.yaml')
     control_sources += custom_target(mode + '_cpp',
                                      input : input_files,
                                      output : mode + '_ids.cpp',
                                      command : [gen_controls, '-o', '@OUTPUT@',
-                                                '--mode', mode, '-t', template_file, '@INPUT@'])
+                                                '--mode', mode, '-t', template_file,
+                                                '-r', ranges_file, '@INPUT@'])
 endforeach
 
 libcamera_sources += control_sources

utils/gen-controls.py

@@ -239,7 +239,7 @@ ${vendor_controls_str}
     }
 
 
-def generate_h(controls, mode):
+def generate_h(controls, mode, ranges):
     enum_template_start = string.Template('''enum ${name}Enum {''')
     enum_value_template = string.Template('''\t${name} = ${value},''')
     enum_values_template = string.Template('''extern const std::array<const ControlValue, ${size}> ${name}Values;''')
@@ -254,8 +254,10 @@ def generate_h(controls, mode):
 
         vendor = 'draft' if ctrl.is_draft else ctrl.vendor
         if vendor not in ctrls:
+            if vendor not in ranges.keys():
+                raise RuntimeError(f'Control id range is not defined for vendor {vendor}')
+            id_value[vendor] = ranges[vendor] + 1
             ids[vendor] = []
-            id_value[vendor] = 1
             ctrls[vendor] = []
 
         # Core and draft controls use the same ID value
@@ -341,6 +343,8 @@ def main(argv):
                         help='Mode of operation')
     parser.add_argument('--output', '-o', metavar='file', type=str,
                         help='Output file name. Defaults to standard output if not specified.')
+    parser.add_argument('--ranges', '-r', type=str, required=True,
+                        help='Control id range reservation file.')
     parser.add_argument('--template', '-t', dest='template', type=str, required=True,
                         help='Template file name.')
     parser.add_argument('input', type=str, nargs='+',
@@ -348,6 +352,11 @@ def main(argv):
 
     args = parser.parse_args(argv[1:])
 
+    ranges = {}
+    with open(args.ranges, 'rb') as f:
+        data = open(args.ranges, 'rb').read()
+        ranges = yaml.safe_load(data)['ranges']
+
     controls = []
     for input in args.input:
         with open(input, 'rb') as f:
@@ -359,7 +368,7 @@ def main(argv):
     if args.template.endswith('.cpp.in'):
         data = generate_cpp(controls)
     elif args.template.endswith('.h.in'):
-        data = generate_h(controls, args.mode)
+        data = generate_h(controls, args.mode, ranges)
     else:
         raise RuntimeError('Unknown template type')