[PATCH v2 0/3] arm_arch_timer: VDSO preparation, code consolidation

Nathan Lynch
2014-09-18T14:59:58Z

This series contains the necessary changes to allow architected timer
access from user-space on 32-bit ARM. This allows the VDSO to support
high resolution timestamps for clock_gettime and gettimeofday. This
also merges substantially similar code from arm and arm64 into the
core arm_arch_timer driver.

The functional changes are:
- When available, CNTVCT is made readable by user space on arm, as it
is on arm64.
- The clocksource name becomes "arch_mem_counter" if CP15 access to
the counter is not available.

These changes have been carried as part of the ARM VDSO patch set over
the last several months, but I am splitting them out here as I assume
they should go through the clocksource maintainers.

Changes since v1:
- Fix minor checkpatch complaints.
- Rework patches 2-4. v1 copied arm64's arch_timer_evtstrm_enable
and arch_counter_set_user_access to the driver with slightly
different names in one patch, then removed the unused functions in
subsequent patches for each of arm and arm64. This seemed kind of
awkward to me, so I've reorganized those changes into two patches
that should be easier to review. Patch #1 is unchanged.

Nathan Lynch (3):
clocksource: arm_arch_timer: change clocksource name if CP15
unavailable
clocksource: arm_arch_timer: enable counter access for 32-bit ARM
clocksource: arm_arch_timer: consolidate arch_timer_evtstrm_enable

arch/arm/include/asm/arch_timer.h | 25 --------------------
arch/arm64/include/asm/arch_timer.h | 31 -------------------------
drivers/clocksource/arm_arch_timer.c | 44 ++++++++++++++++++++++++++++++++++--
3 files changed, 42 insertions(+), 58 deletions(-)

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1.9.3