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Merged
merged 13 commits into from
Nov 29, 2016
Merged

xtimer: Allow arbitrary timer frequency, second attempt #5608

merged 13 commits into from
Nov 29, 2016

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jnohlgard
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@jnohlgard jnohlgard commented Jul 5, 2016 •
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Significantly simplified version of #3990, using the ideas from #4002.
The public API of xtimer now uses two new types xtimer_ticks32_t, and xtimer_ticks64_t, to catch any missing usec/sec/nanosec to tick conversions. Internally, all timer scheduling and offsets are using hardware ticks instead of microseconds.
All internal xtimer functions use untyped (i.e. uint32_t, uint64_t) ticks and are prefixed with underscore to avoid mistakes. This extra level of abstraction is only a thin wrapper and the conversions between ticks and microseconds are inlined and will become a no-op if the hardware timer also runs at 1 MHz.

xtimer_usleep_until has been renamed xtimer_periodic_wakeup, to better reflect the purpose (and since it is now using ticks and not microseconds as parameters). This change was forked off into #5612.

Based on #5294, #5607.

Marked as WIP until all tests and drivers have been adapted to use the new xtimer_ticks*_t type.

@jnohlgard jnohlgard added Type: enhancement The issue suggests enhanceable parts / The PR enhances parts of the codebase / documentation State: WIP State: The PR is still work-in-progress and its code is not in its final presentable form yet CI: needs squashing Commits in this PR need to be squashed; If set, CI systems will mark this PR as unmergable TimerTaskForce Area: timers Area: timer subsystems labels Jul 5, 2016
@jnohlgard jnohlgard added this to the Release 2016.07 milestone Jul 5, 2016
@jnohlgard jnohlgard added the CI: ready for build If set, CI server will compile all applications for all available boards for the labeled PR label Jul 5, 2016
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Adding the CI build flag to assist in finding missing API updates..

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Verified that the inline function for usec->tick conversion of a compile time constant generates no extra code via manual inspection of assembly output. Optimization level -O0 generates function calls for the compile time constants. -O1, -Os, and -Og all precompute the constant to store it as ticks directly in the binary instead of storing as microseconds.

Conversion of run time variable values will of course generate conversion instructions since it is not possible to rescale them during compile time.

@jnohlgard jnohlgard removed the CI: ready for build If set, CI server will compile all applications for all available boards for the labeled PR label Jul 6, 2016
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@jnohlgard jnohlgard force-pushed the pr/xtimer-ticks branch 4 times, most recently from 4320828 to f68ba74 Compare July 6, 2016 20:52
@jnohlgard jnohlgard added CI: ready for build If set, CI server will compile all applications for all available boards for the labeled PR and removed CI: ready for build If set, CI server will compile all applications for all available boards for the labeled PR labels Jul 6, 2016
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@jnohlgard jnohlgard force-pushed the pr/xtimer-ticks branch 2 times, most recently from 9fc7a0f to 12f73f2 Compare July 7, 2016 13:40
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#5612 was split off from this PR as a separate change.

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@jnohlgard jnohlgard force-pushed the pr/xtimer-ticks branch 2 times, most recently from d4f231c to f59948a Compare July 7, 2016 15:13
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@jnohlgard jnohlgard modified the milestones: Release 2016.10, Release 2016.07 Jul 13, 2016
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postponing to release 2016.10

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rebased

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kYc0o commented Nov 29, 2016

Can you squash your fixup? I think everything is OK now so we could have this PR merged soon :)

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@kYc0o
squashed the fixup

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kYc0o approved these changes Nov 29, 2016
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ACK

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kYc0o commented Nov 29, 2016

And go!

@kYc0o kYc0o merged commit 84d0d61 into RIOT-OS:master Nov 29, 2016
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Wow, cool!

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immesys commented Nov 30, 2016

Awesome! Thank you all for your work here

@jnohlgard jnohlgard deleted the pr/xtimer-ticks branch December 1, 2016 08:06
miri64 added a commit to miri64/RIOT that referenced this pull request Jan 11, 2017
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evtimer: adapt for RIOT-OS#5608
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cc2538: revert xtimer params from RIOT-OS#5608
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cc2538: revert xtimer params from RIOT-OS#5608
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cc2538: revert xtimer params from RIOT-OS#5608
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cc2538: revert xtimer params from RIOT-OS#5608
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Area: timers Area: timer subsystems CI: ready for build If set, CI server will compile all applications for all available boards for the labeled PR Process: API change Integration Process: PR contains or issue proposes an API change. Should be handled with care. Type: enhancement The issue suggests enhanceable parts / The PR enhances parts of the codebase / documentation
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