diff options
| -rw-r--r-- | Documentation/core-api/printk-formats.rst | 32 | ||||
| -rw-r--r-- | lib/vsprintf.c | 35 | ||||
| -rwxr-xr-x | scripts/checkpatch.pl | 2 |
3 files changed, 62 insertions, 7 deletions
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 4bdc394e86af..125fd0397510 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -648,6 +648,38 @@ Examples:: %p4cc Y10 little-endian (0x20303159) %p4cc NV12 big-endian (0xb231564e) +Generic FourCC code +------------------- + +:: + %p4c[hnlb] gP00 (0x67503030) + +Print a generic FourCC code, as both ASCII characters and its numerical +value as hexadecimal. + +The generic FourCC code is always printed in the big-endian format, +the most significant byte first. This is the opposite of V4L/DRM FourCCs. + +The additional ``h``, ``n``, ``l``, and ``b`` specifiers define what +endianness is used to load the stored bytes. The data might be interpreted +using the host byte order, network byte order, little-endian, or big-endian. + +Passed by reference. + +Examples for a little-endian machine, given &(u32)0x67503030:: + + %p4ch gP00 (0x67503030) + %p4cn 00Pg (0x30305067) + %p4cl gP00 (0x67503030) + %p4cb 00Pg (0x30305067) + +Examples for a big-endian machine, given &(u32)0x67503030:: + + %p4ch gP00 (0x67503030) + %p4cn 00Pg (0x30305067) + %p4cl 00Pg (0x30305067) + %p4cb gP00 (0x67503030) + Rust ---- diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 01699852f30c..6bc64ae52166 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1793,27 +1793,50 @@ char *fourcc_string(char *buf, char *end, const u32 *fourcc, char output[sizeof("0123 little-endian (0x01234567)")]; char *p = output; unsigned int i; + bool pixel_fmt = false; u32 orig, val; - if (fmt[1] != 'c' || fmt[2] != 'c') + if (fmt[1] != 'c') return error_string(buf, end, "(%p4?)", spec); if (check_pointer(&buf, end, fourcc, spec)) return buf; orig = get_unaligned(fourcc); - val = orig & ~BIT(31); + switch (fmt[2]) { + case 'h': + break; + case 'n': + orig = swab32(orig); + break; + case 'l': + orig = (__force u32)cpu_to_le32(orig); + break; + case 'b': + orig = (__force u32)cpu_to_be32(orig); + break; + case 'c': + /* Pixel formats are printed LSB-first */ + pixel_fmt = true; + break; + default: + return error_string(buf, end, "(%p4?)", spec); + } + + val = pixel_fmt ? swab32(orig & ~BIT(31)) : orig; for (i = 0; i < sizeof(u32); i++) { - unsigned char c = val >> (i * 8); + unsigned char c = val >> ((3 - i) * 8); /* Print non-control ASCII characters as-is, dot otherwise */ *p++ = isascii(c) && isprint(c) ? c : '.'; } - *p++ = ' '; - strcpy(p, orig & BIT(31) ? "big-endian" : "little-endian"); - p += strlen(p); + if (pixel_fmt) { + *p++ = ' '; + strcpy(p, orig & BIT(31) ? "big-endian" : "little-endian"); + p += strlen(p); + } *p++ = ' '; *p++ = '('; diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 3d22bf863eec..44e233b6f428 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6891,7 +6891,7 @@ sub process { ($extension eq "f" && defined $qualifier && $qualifier !~ /^w/) || ($extension eq "4" && - defined $qualifier && $qualifier !~ /^cc/)) { + defined $qualifier && $qualifier !~ /^c[hnlbc]/)) { $bad_specifier = $specifier; last; } |