[PATCH v3 0/2] WFE for long delays

Julien Thierry julien.thierry at arm.com
Fri Sep 29 03:52:28 PDT 2017


It was pointed out that there are some windows where the event stream might not
be configured, meaning we cannot safely use WFE (e.g. when using PSCI
CPU_SUSPEND for idle, PSCI might reset CPU state).

The first patch provide a function to check whether the task is in state where
it can expect events from the event stream.

Second patch actually makes use of WFE in delays.

Changes since v1:
- Keep track of event stream state
- Do not use WFE when event stream might be misconfigured

Changes since v2:
- Use cpumask to track event stream state instead of percpu variable
- Tidy a bit code in arm64/lib/delay
- Do not factor asm-generic/delay code

Julien Thierry (2):
  arm_arch_timer: Expose event stream status
  arm64: use WFE for long delays

 arch/arm/include/asm/arch_timer.h    |  1 +
 arch/arm64/include/asm/arch_timer.h  |  1 +
 arch/arm64/lib/delay.c               | 23 +++++++++++++++++++----
 drivers/clocksource/arm_arch_timer.c | 20 ++++++++++++++++++--
 include/clocksource/arm_arch_timer.h | 10 +++++++++-
 5 files changed, 48 insertions(+), 7 deletions(-)

--
1.9.1



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