Use architected timers for delay loop
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- v1 Latest2 patches 0 repliesNew
Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/2 | ARM: arch timer: implement read_current_timer and get_cycles | +0 | 2 replies | |
| 2/2 | ARM: delay: allow timer-based delay implementation to be selected | +0 | 6 replies |
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Cover letter [PATCH 0/2] Use architected timers for delay loop
Quoted 8 lines · Will Deacon
Hello,
This patch series reworks our delay loop implementation to allow the busy-loop to be replaced with the physical counter included as part of the architected timer on recent CPUs. The polling implementation is still maintained to support cores without the timers and we use the same maths and upper delay bound of 2ms.
Quoted 5 lines
Russell - I think my maths is correct, but why can't we increase the
precision by using a magic constant of 4398046U and a right shift of 31?As usual, all feedback is welcome,
I have posted a read_current_timer implementation to the list a couple times but had no success in getting it merged. The patches are still in the patch tracker but I haven't really pushed them to get merged.
http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=6874/1 http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=6873/1 http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=6875/1
So far we've just been carrying them internally. I suppose ARM needs this now because of big little?
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