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Ian Lepore ff3468ac94 Provide userland notification of gpio pin changes ("userland gpio interrupts").
This is an import of the Google Summer of Code 2018 project completed by
Christian Kramer (and, sadly, ignored by us for two years now).  The goals
stated for that project were:

    FreeBSD already has support for interrupts implemented in the GPIO
    controller drivers of several SoCs, but there are no interfaces to take
    advantage of them out of user space yet. The goal of this work is to
    implement such an interface by providing descriptors which integrate
    with the common I/O system calls and multiplexing mechanisms.

The initial imported code supports the following functionality:

 -  A kernel driver that provides an interface to the user space; the
    existing gpioc(4) driver was enhanced with this functionality.
 -  Implement support for the most common I/O system calls / multiplexing
    mechanisms:
     -  read() Places the pin number on which the interrupt occurred in the
        buffer. Blocking and non-blocking behaviour supported.
     -	poll()/select()
     -	kqueue()
     -	signal driven I/O. Posting SIGIO when the O_ASYNC was set.
 -  Many-to-many relationship between pins and file descriptors.
     -  A file descriptor can monitor several GPIO pins.
     -  A GPIO pin can be monitored by multiple file descriptors.
 -  Integration with gpioctl and libgpio.

I added some fixes (mostly to locking) and feature enhancements on top of
the original gsoc code.  The feature ehancements allow the user to choose
between detailed and summary event reporting.  Detailed reporting provides
a record describing each pin change event.  Summary reporting provides the
time of the first and last change of each pin, and a count of how many times
it changed state since the last read(2) call.  Another enhancement allows
the recording of multiple state change events on multiple pins between each
call to read(2) (the original code would track only a single event at a time).

The phabricator review for these changes timed out without approval, but I
cite it below anyway, because the review contains a series of diffs that
show how I evolved the code from its original state in Christian's github
repo for the gsoc project to what is being commited here.  (In effect,
the phab review extends the VC history back to the original code.)

Submitted by:	Christian Kramer
Obtained from:	https://github.com/ckraemer/freebsd/tree/gsoc2018
Differential Revision:	https://reviews.freebsd.org/D27398
2020-12-12 18:34:15 +00:00
.github/workflows GH Actions: Use pre-installed clang packages 2020-11-26 14:42:16 +00:00
bin Remove unused headers. 2020-12-12 02:26:43 +00:00
cddl dtrace: honor LC_NUMERIC for %'d and alike, and LC_TIME for %T 2020-12-03 11:59:40 +00:00
contrib ee(1): Whitespace cleanup 2020-12-10 10:58:30 +00:00
crypto Merge OpenSSL 1.1.1i. 2020-12-09 02:05:14 +00:00
etc Missed adding netgraph to mtree in r368443: 2020-12-08 17:44:34 +00:00
gnu gnu: don't build libgnuregex for WITH_GNU_GREP_COMPAT 2020-12-04 15:21:12 +00:00
include Import OpenSSL 1.1.1i. 2020-12-08 18:10:16 +00:00
kerberos5 Fix more -Wundef warnings during bootstrap 2020-10-14 12:28:54 +00:00
lib Change getlocalbase() to not allocate any heap memory 2020-12-12 11:23:52 +00:00
libexec Fix the TFTP client when performing a RRQ for files smaller than 512 bytes 2020-12-10 19:36:33 +00:00
release Fix staging riscv images. 2020-12-09 20:38:26 +00:00
rescue ping: add a ping6 hard link for backwards compatibility 2020-11-26 18:33:04 +00:00
sbin geom(8): list geoms with /dev/ prefix 2020-12-12 07:22:38 +00:00
secure caroot: update bundle 2020-12-11 18:14:43 +00:00
share ndis(4): expand deprecation to the whole driver 2020-12-11 21:51:50 +00:00
stand lualoader: config: fix module enabled check 2020-12-12 14:53:34 +00:00
sys Provide userland notification of gpio pin changes ("userland gpio interrupts"). 2020-12-12 18:34:15 +00:00
targets Add WITH_CLANG_FORMAT option 2020-06-24 17:03:42 +00:00
tests posixshm_test.c: remove tautological checks 2020-12-11 22:52:20 +00:00
tools Provide userland notification of gpio pin changes ("userland gpio interrupts"). 2020-12-12 18:34:15 +00:00
usr.bin xargs: compile yesexpr as ERE 2020-12-12 15:38:32 +00:00
usr.sbin Provide userland notification of gpio pin changes ("userland gpio interrupts"). 2020-12-12 18:34:15 +00:00
.arcconfig arcconfig: add callsign again 2020-11-23 04:39:29 +00:00
.arclint arc lint: ignore /tests/ in chmod 2017-12-19 03:38:06 +00:00
.cirrus.yml CI: switch to qemu42 package 2020-10-29 02:02:30 +00:00
.clang-format clang-format: Avoid breaking after the opening paren of function definitions 2020-10-28 11:54:00 +00:00
.gitattributes Add a basic clang-format configuration file 2019-06-07 15:23:52 +00:00
.gitignore Stop ignoring makeLINT generated files 2020-10-09 00:27:45 +00:00
COPYRIGHT Happy New Year 2020! 2019-12-31 16:01:36 +00:00
LOCKS LOCKS: update current locks 2018-06-09 03:08:04 +00:00
MAINTAINERS Add a pointer to csprng@ for the CSPRNG driver. This is enforced anyway by 2020-09-01 08:02:12 +00:00
Makefile Makefile: re-wordsmith the blurb about xtoolchain ports 2020-11-14 18:06:35 +00:00
Makefile.inc1 crunchgen: fix NULL-deref bug introduced in r364647 2020-12-04 15:53:37 +00:00
Makefile.libcompat Race in 32-bit fixed 2020-10-08 17:30:05 +00:00
Makefile.sys.inc AUTO_OBJ: For all top-level targets enforce using an OBJDIR. 2017-12-05 21:29:47 +00:00
ObsoleteFiles.inc hme(4): Remove as previous announced 2020-12-11 21:40:38 +00:00
README Import OpenSSL 1.1.1i. 2020-12-08 18:10:16 +00:00
README.md README: add generic notes about GENERIC and NOTES 2018-06-17 19:44:24 +00:00
RELNOTES Note removal of hme(4) 2020-12-11 21:43:44 +00:00
UPDATING Merge ping6 to ping 2020-11-26 04:29:30 +00:00

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