5c04dceaa1
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>
32 lines
830 B
ReStructuredText
32 lines
830 B
ReStructuredText
==============================
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Decoding an IOCTL Magic Number
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==============================
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To decode a hex IOCTL code:
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Most architectures use this generic format, but check
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include/ARCH/ioctl.h for specifics, e.g. powerpc
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uses 3 bits to encode read/write and 13 bits for size.
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====== ==================================
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bits meaning
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====== ==================================
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31-30 00 - no parameters: uses _IO macro
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10 - read: _IOR
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01 - write: _IOW
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11 - read/write: _IOWR
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29-16 size of arguments
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15-8 ascii character supposedly
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unique to each driver
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7-0 function #
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====== ==================================
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So for example 0x82187201 is a read with arg length of 0x218,
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character 'r' function 1. Grepping the source reveals this is::
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#define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct dirent [2])
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