fourcc.py: Handle AFBC modifiers

ARM Framebuffer Compression is a structured modifier that we just gave
up on parsing before. This adds the code to generate all of the possible
combinations of arguments for printing.

There are 8 bits that can be set, plus 5 possible block sizes (including
not specified). This adds over 2000 lines of C code to tables.h, so it
has been split out into a C file instead of an inline function inside of
the header.

This also makes our matching a bit more strict, so future complex
modifers should not be matched, and require to be added explicitly.

3 files changed, 65 insertions, 29 deletions

diff --git a/fourcc.py b/fourcc.py
index 3613cce..8e95436 100755
--- a/fourcc.py
+++ b/fourcc.py
@@ -2,57 +2,82 @@
 
 import sys
 import re
+from itertools import chain, combinations
 
-fourcc_include = sys.argv[1]
+def powerset(s):
+	return chain.from_iterable(combinations(s, r) for r in range(len(s) + 1))
 
-fmt_list = []
-mod_list = []
+def case_print(f, c, s):
+	f.write('\tcase {}:\n'.format(c))
+	f.write('\t\treturn "{}";\n'.format(s))
 
-fmt = re.compile(r'^#define (\w+)\s*(?:\\$\s*)?fourcc_code', flags=re.M)
-mod = re.compile(r'^#define (\w+)\s*(?:\\$\s*)?fourcc_mod_code', flags=re.M)
-mod_broadcom = re.compile(r'^#define (DRM_FORMAT_MOD_BROADCOM\w+(?=\s))', flags=re.M)
+def afbc_print(f, l):
+	fmt = 'DRM_FORMAT_MOD_ARM_AFBC({})'
+	if l:
+		# Strip prefix to stop string being stupidly long
+		short = [s[len('AFBC_FORMAT_MOD_'):] for s in l]
+		case_print(f, fmt.format('|'.join(l)), fmt.format('|'.join(short)))
+	else:
+		case_print(f, fmt.format(0), fmt.format(0))
 
-f = open(fourcc_include).read()
-fmt_list = fmt.findall(f)
-mod_list = set(mod.findall(f) + mod_broadcom.findall(f))
+info = {
+	'fmt': r'^#define (\w+)\s*(?:\\$\s*)?fourcc_code',
+	'basic_pre': r'\bI915_FORMAT_MOD_\w+\b',
+	'basic_post': r'\b(DRM_FORMAT_MOD_(?:INVALID|LINEAR|SAMSUNG|QCOM|VIVANTE|NVIDIA|BROADCOM|ALLWINNER)\w*)\s',
+	'afbc_block': r'\bAFBC_FORMAT_MOD_BLOCK_SIZE(?:_\d+x\d+)+\b',
+	'afbc_bitmask': r'\bAFBC_FORMAT_MOD_[A-Z]+\b',
+}
 
-f_name = sys.argv[2]
+with open(sys.argv[1], 'r') as f:
+	data = f.read()
+	for k, v in info.items():
+		info[k] = re.findall(v, data, flags=re.M)
 
-with open(f_name, 'w') as f:
+with open(sys.argv[2], 'w') as f:
 	f.write('''\
 #include <stdint.h>
 #include <drm_fourcc.h>
 
-static inline const char *format_str(uint32_t format)
+#include "tables.h"
+
+const char *format_str(uint32_t format)
 {
 	switch (format) {
 	case DRM_FORMAT_INVALID:
 		return "INVALID";
 ''')
-	for ident in fmt_list:
-		f.write('\tcase {}:\n\t\treturn "{}";\n'.format(ident, ident[len('DRM_FORMAT_'):]))
+
+	for ident in info['fmt']:
+		case_print(f, ident, ident[len('DRM_FORMAT_'):])
+
 	f.write('''\
 	default:
-		return "unknown";
+		return "Unknown";
 	}
 }
 
-static inline const char *modifier_str(uint64_t modifier)
+const char *modifier_str(uint64_t modifier)
 {
-	/*
-	 * ARM has a complex format which we can't be bothered to parse.
-	 */
-	if ((modifier >> 56) == DRM_FORMAT_MOD_VENDOR_ARM) {
-		return "DRM_FORMAT_MOD_ARM_AFBC()";
-	}
-
 	switch (modifier) {
 ''')
-	for ident in mod_list:
-		f.write('\tcase {}:\n\t\treturn "{}";\n'.format(ident, ident))
+
+	for ident in info['basic_pre'] + info['basic_post']:
+		case_print(f, ident, ident)
+
+	# ARM framebuffer compression
+	# Not all of the combintations we generate will be valid modifers exposed
+	# by the driver
+
+	for bits in powerset(info['afbc_bitmask']):
+		bits = list(bits)
+		bits.sort()
+		afbc_print(f, bits)
+		for block in info['afbc_block']:
+			afbc_print(f, bits + [block])
+
 	f.write('''\
 	default:
-		return "unknown";
+		return "Unknown";
 	}
 }
 ''')
diff --git a/meson.build b/meson.build
index a58bc4a..8279c06 100644
--- a/meson.build
+++ b/meson.build
@@ -64,12 +64,12 @@ endif
 
 python3 = import('python').find_installation()
 
-tables_h = custom_target('tables_h',
-  output : 'tables.h',
+tables_c = custom_target('tables_c',
+  output : 'tables.c',
   command : [python3, files('fourcc.py'), fourcc_h, '@OUTPUT@'])
 
 executable('drm_info',
-  [files('main.c', 'json.c', 'pretty.c'), tables_h],
+  [files('main.c', 'json.c', 'pretty.c'), tables_c],
   include_directories: inc,
   dependencies: [libdrm, jsonc],
   install: true,
diff --git a/tables.h b/tables.h
new file mode 100644
index 0000000..8510f18
--- /dev/null
+++ b/tables.h
@@ -0,0 +1,11 @@
+#ifndef TABLES_H
+#define TABLES_H
+
+#include <stdint.h>
+
+/* The implementation of these functions are generated by fourcc.py */
+
+const char *format_str(uint32_t format);
+const char *modifier_str(uint64_t modifier);
+
+#endif