diff options
| author | Mauro Carvalho Chehab | 2019-04-18 16:38:26 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab | 2019-07-15 14:20:26 +0200 |
| commit | 5c04dceaa152d9dd9fe94dec6594965069e19e9e (patch) | |
| tree | 7ffe8164c81596ad04a913e9da22f1cedb88d9e3 /Documentation/ioctl/ioctl-decoding.rst | |
| parent | docs: ioctl-number.txt: convert it to ReST format (diff) | |
| download | kernel-qcow2-linux-5c04dceaa152d9dd9fe94dec6594965069e19e9e.tar.gz kernel-qcow2-linux-5c04dceaa152d9dd9fe94dec6594965069e19e9e.tar.xz kernel-qcow2-linux-5c04dceaa152d9dd9fe94dec6594965069e19e9e.zip | |
docs: ioctl: convert to ReST
Rename the iio documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
The cdrom.txt and hdio.txt have their own particular syntax.
In order to speedup the conversion, I used a small ancillary
perl script:
my $d;
$d .= $_ while(<>);
$d =~ s/(\nCDROM\S+)\s+(\w[^\n]*)/$1\n\t$2\n/g;
$d =~ s/(\nHDIO\S+)\s+(\w[^\n]*)/$1\n\t$2\n/g;
$d =~ s/(\n\s*usage:)[\s\n]*(\w[^\n]*)/$1:\n\n\t $2\n/g;
$d =~ s/(\n\s*)(E\w+[\s\n]*\w[^\n]*)/$1- $2/g;
$d =~ s/(\n\s*)(inputs|outputs|notes):\s*(\w[^\n]*)/$1$2:\n\t\t$3\n/g;
print $d;
It basically add blank lines on a few interesting places. The
script is not perfect: still several things require manual work,
but it saved quite some time doing some obvious stuff.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation/ioctl/ioctl-decoding.rst')
| -rw-r--r-- | Documentation/ioctl/ioctl-decoding.rst | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/ioctl/ioctl-decoding.rst b/Documentation/ioctl/ioctl-decoding.rst new file mode 100644 index 000000000000..380d6bb3e3ea --- /dev/null +++ b/Documentation/ioctl/ioctl-decoding.rst @@ -0,0 +1,31 @@ +============================== +Decoding an IOCTL Magic Number +============================== + +To decode a hex IOCTL code: + +Most architectures use this generic format, but check +include/ARCH/ioctl.h for specifics, e.g. powerpc +uses 3 bits to encode read/write and 13 bits for size. + + ====== ================================== + bits meaning + ====== ================================== + 31-30 00 - no parameters: uses _IO macro + 10 - read: _IOR + 01 - write: _IOW + 11 - read/write: _IOWR + + 29-16 size of arguments + + 15-8 ascii character supposedly + unique to each driver + + 7-0 function # + ====== ================================== + + +So for example 0x82187201 is a read with arg length of 0x218, +character 'r' function 1. Grepping the source reveals this is:: + + #define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct dirent [2]) |