1 files changed, 39 insertions, 0 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 6c56c62fd9a5..f0c35d9b65bf 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1734,6 +1734,42 @@ char *netdev_bits(char *buf, char *end, const void *addr,
 }
 
 static noinline_for_stack
+char *fourcc_string(char *buf, char *end, const u32 *fourcc,
+		    struct printf_spec spec, const char *fmt)
+{
+	char output[sizeof("0123 little-endian (0x01234567)")];
+	char *p = output;
+	unsigned int i;
+	u32 val;
+
+	if (fmt[1] != 'c' || fmt[2] != 'c')
+		return error_string(buf, end, "(%p4?)", spec);
+
+	if (check_pointer(&buf, end, fourcc, spec))
+		return buf;
+
+	val = *fourcc & ~BIT(31);
+
+	for (i = 0; i < sizeof(*fourcc); i++) {
+		unsigned char c = val >> (i * 8);
+
+		/* Print non-control ASCII characters as-is, dot otherwise */
+		*p++ = isascii(c) && isprint(c) ? c : '.';
+	}
+
+	strcpy(p, *fourcc & BIT(31) ? " big-endian" : " little-endian");
+	p += strlen(p);
+
+	*p++ = ' ';
+	*p++ = '(';
+	p = special_hex_number(p, output + sizeof(output) - 2, *fourcc, sizeof(u32));
+	*p++ = ')';
+	*p = '\0';
+
+	return string(buf, end, output, spec);
+}
+
+static noinline_for_stack
 char *address_val(char *buf, char *end, const void *addr,
 		  struct printf_spec spec, const char *fmt)
 {
@@ -2249,6 +2285,7 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
  *       Use only for procfs, sysfs and similar files, not printk(); please
  *       read the documentation (path below) first.
  * - 'NF' For a netdev_features_t
+ * - '4cc' V4L2 or DRM FourCC code, with endianness and raw numerical value.
  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
  *            a certain separator (' ' by default):
  *              C colon
@@ -2347,6 +2384,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 		return restricted_pointer(buf, end, ptr, spec);
 	case 'N':
 		return netdev_bits(buf, end, ptr, spec, fmt);
+	case '4':
+		return fourcc_string(buf, end, ptr, spec, fmt);
 	case 'a':
 		return address_val(buf, end, ptr, spec, fmt);
 	case 'd':