lib/vsprintf: Add support for printing V4L2 and DRM fourccs

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>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210216155723.17109-2-sakari.ailus@linux.intel.com
This commit is contained in:
Sakari Ailus 2021-02-16 17:57:20 +02:00 committed by Thomas Zimmermann
parent 4d36cf0702
commit af612e43de
4 changed files with 79 additions and 2 deletions

View File

@ -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
======

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@ -649,6 +649,23 @@ static void __init fwnode_pointer(void)
software_node_unregister(&softnodes[0]);
}
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)
{
@ -694,6 +711,7 @@ test_pointer(void)
flags();
errptr();
fwnode_pointer();
fourcc_pointer();
}
static void __init selftest(void)

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@ -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':

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@ -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;
}