Add a printk modifier %p4cc (for pixel format) for printing V4L2 and DRM pixel formats denoted by fourccs. The fourcc encoding is the same for both so the same implementation can be used.
Suggested-by: Mauro Carvalho Chehab mchehab@kernel.org Signed-off-by: Sakari Ailus sakari.ailus@linux.intel.com Reviewed-by: Petr Mladek pmladek@suse.com Reviewed-by: Sergey Senozhatsky sergey.senozhatsky@gmail.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com --- Documentation/core-api/printk-formats.rst | 18 +++++++++++ lib/test_printf.c | 18 +++++++++++ lib/vsprintf.c | 39 +++++++++++++++++++++++ scripts/checkpatch.pl | 6 ++-- 4 files changed, 79 insertions(+), 2 deletions(-)
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 160e710d992f..8267675ea95c 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -567,6 +567,24 @@ For printing netdev_features_t.
Passed by reference.
+V4L2 and DRM FourCC code (pixel format) +--------------------------------------- + +:: + + %p4cc + +Print a FourCC code used by V4L2 or DRM, including format endianness and +its numerical value as hexadecimal. + +Passed by reference. + +Examples:: + + %p4cc BG12 little-endian (0x32314742) + %p4cc Y10 little-endian (0x20303159) + %p4cc NV12 big-endian (0xb231564e) + Thanks ======
diff --git a/lib/test_printf.c b/lib/test_printf.c index 7d60f24240a4..8558ddbde692 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -647,6 +647,23 @@ static void __init fwnode_pointer(void) software_node_unregister_nodes(softnodes); }
+static void __init fourcc_pointer(void) +{ + struct { + u32 code; + char *str; + } const try[] = { + { 0x3231564e, "NV12 little-endian (0x3231564e)", }, + { 0xb231564e, "NV12 big-endian (0xb231564e)", }, + { 0x10111213, ".... little-endian (0x10111213)", }, + { 0x20303159, "Y10 little-endian (0x20303159)", }, + }; + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(try); i++) + test(try[i].str, "%p4cc", &try[i].code); +} + static void __init errptr(void) { @@ -692,6 +709,7 @@ test_pointer(void) flags(); errptr(); fwnode_pointer(); + fourcc_pointer(); }
static void __init selftest(void) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 3b53c73580c5..62c7224a5076 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1733,6 +1733,42 @@ char *netdev_bits(char *buf, char *end, const void *addr, return special_hex_number(buf, end, num, size); }
+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) @@ -2162,6 +2198,7 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, * correctness of the format string and va_list arguments. * - 'K' For a kernel pointer that should be hidden from unprivileged users * - '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 @@ -2259,6 +2296,8 @@ 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': diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 92e888ed939f..79858e07d023 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6557,9 +6557,11 @@ sub process { $specifier = $1; $extension = $2; $qualifier = $3; - if ($extension !~ /[SsBKRraEehMmIiUDdgVCbGNOxtf]/ || + if ($extension !~ /[4SsBKRraEehMmIiUDdgVCbGNOxtf]/ || ($extension eq "f" && - defined $qualifier && $qualifier !~ /^w/)) { + defined $qualifier && $qualifier !~ /^w/) || + ($extension eq "4" && + defined $qualifier && $qualifier !~ /^cc/)) { $bad_specifier = $specifier; last; }