Add HPET driver as an alternative timer for x86 (default is TSC). HPET counter has constant frequency and does not need calibration. This change also makes TSC timer driver optional on x86. New HPET driver can also be selected as the early timer on x86.
v4: Using 64-bit pointer for main counter access.
v3: Added early timer choice in x86-specific configuration.
v2: Moved duplicated code to static functions.
Ivan Gorinov (1): timer: Add High Precision Event Timers (HPET) support
arch/Kconfig | 2 +- arch/x86/Kconfig | 21 ++++++ arch/x86/dts/hpet.dtsi | 7 ++ drivers/timer/Kconfig | 9 +++ drivers/timer/Makefile | 1 + drivers/timer/hpet_timer.c | 181 +++++++++++++++++++++++++++++++++++++++++++++ drivers/timer/tsc_timer.c | 8 ++ 7 files changed, 228 insertions(+), 1 deletion(-) create mode 100644 arch/x86/dts/hpet.dtsi create mode 100644 drivers/timer/hpet_timer.c