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path: root/arch/arc/include/asm/timex.h
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2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-02-11ARC: Timers/counters/delay managementVineet Gupta
ARC700 includes 2 in-core 32bit timers TIMER0 and TIMER1. Both have exactly same capabilies. * programmable to count from TIMER<n>_CNT to TIMER<n>_LIMIT * for count 0 and LIMIT ~1, provides a free-running counter by auto-wrapping when limit is reached. * optionally interrupt when LIMIT is reached (oneshot event semantics) * rearming the interrupt provides periodic semantics * run at CPU clk ARC Linux uses TIMER0 for clockevent (periodic/oneshot) and TIMER1 for clocksource (free-running clock). Newer cores provide RTSC insn which gives a 64bit cpu clk snapshot hence is more apt for clocksource when available. SMP poses a bit of challenge for global timekeeping clocksource / sched_clock() backend: -TIMER1 based local clocks are out-of-sync hence can't be used (thus we default to jiffies based cs as well as sched_clock() one/both of which platform can override with it's specific hardware assist) -RTSC is only allowed in SMP if it's cross-core-sync (Kconfig glue ensures that) and thus usable for both requirements. Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Thomas Gleixner <tglx@linutronix.de>