[PATCH v6 RESEND 0/5] ARM/ARM64 architected timer updates

[Sudeep KarkadaNagesha]

From: Sudeep KarkadaNagesha <sudeep.karkadanagesha at arm.com>

Hi Olof/Kevin,

I am reposting this series as suggested by Olof[1]. This is reviewed and
acked by Will and Catalin. Daniel needs Ack from arm-soc maintainers
to take these through his tree. Can you review this ?

Regards,
Sudeep
[1] http://www.spinics.net/lists/arm-kernel/msg270926.html
-----------

This patch series adds support to configure the rate and enable the
event stream for architected timer. The event streams can be used to
impose a timeout on a wfe, to safeguard against any programming error
in case an expected event is not generated or even to implement
wfe-based timeouts for userspace locking implementations. This feature
can be disabled(enabled by default).

Since the timer control register is reset to zero on warm boot, CPU
PM notifier is added to save and restore the value.

Changes v5->v6:
1. Disabling event stream by default on boot and enable it
   only if CONFIG_ARM_ARCH_TIMER_EVTSTREAM=y
   This removes runtime configuration of timer event stream.
2. Moved COMPAT_ELF_HWCAP_DEFAULT to arch/arm64/kernel/setup.c

Changes v4->v5:
1. Removed compat_dyn_elf_hwcap and used just compat_elf_hwcap as per
   Catalin's suggestion
2. Instead of resetting event stream in CPU PM callbacks, saving and
   restoring counter control register now.

Changes v3->v4:
1. Added a config option to en/disable the timer event stream feature.
   Due to this the ordering of the patches as well as some cosmetic
   code changes are done.( So dropped previous reviewed-by tags)
2. Removed exporting compat_dyn_elf_hwcap as there are no modules
   requiring it for now.

Changes v2->v3:
1. Moved ARM and ARM64 changes into separate patches
2. Added native hwcaps definations(ARM/ARM64) and compat-specific
   definitions(ARM64) to the users for the event stream feature. 

Changes v1->v2:
1. Saved event stream divider value on cold reset path and re-used it
   in CPU PM notifier instead of calculating every time.
2. Rebased on v3.11-rc2(to avoid conflicts with __cpuinit* deletion)
3. Dropped "ARM/ARM64: arch_timer: remove __cpuinit attribute for
   arch_counter_set_user_access"(already done as part of __cpuinit*
   deletion)

Sudeep KarkadaNagesha (4):
  ARM/ARM64: arch_timer: add macros for bits in control register
  ARM: arch_timer: add support to configure and enable event stream
  ARM64: arch_timer: add support to configure and enable event stream
  drivers: clocksource: add CPU PM notifier for ARM architected timer

Will Deacon (1):
  drivers: clocksource: add support for ARM architected timer event
    stream

 arch/arm/include/asm/arch_timer.h    | 36 ++++++++++++++++++++++----
 arch/arm/include/uapi/asm/hwcap.h    |  1 +
 arch/arm/kernel/setup.c              |  1 +
 arch/arm64/include/asm/arch_timer.h  | 42 ++++++++++++++++++++++++++-----
 arch/arm64/include/asm/hwcap.h       | 11 ++++----
 arch/arm64/include/uapi/asm/hwcap.h  |  1 +
 arch/arm64/kernel/setup.c            | 11 ++++++++
 drivers/clocksource/Kconfig          | 15 +++++++++++
 drivers/clocksource/arm_arch_timer.c | 49 ++++++++++++++++++++++++++++++++++++
 include/clocksource/arm_arch_timer.h | 10 ++++++++
 10 files changed, 161 insertions(+), 16 deletions(-)

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1.8.1.2