662b0bf765
Modern hardware all supports a TSC_DEADLINE mode for the APIC timer, where the same GHz-scale 64 bit TSC used for performance monitoring becomes the free-running counter used for cpu-local timer interrupts. Being a free running counter that does not need to be reset, it will not lose time in an interrupt. Being 64 bit, it needs no rollover or clamping logic in the driver when presented with a 32 bit tick count. Being a proper comparator, it will correctly trigger interrupts for times set "in the past" and thus needs no minimum/clamping logic. The counter is synchronized across the system architecturally (modulo one burp where firmware likes to change the adjustment value) so usage is SMP-safe by default. Access to the 64 bit counter and comparator value are single-instruction atomics even on 32 bit systems, so it beats even the RISC-V machine timer in complexity (which was our reigning champ for "simplest timer driver"). Really this is just ideal for Zephyr. So rather than try to add support for it to the existing APIC driver and increase complexity, make this a new standalone driver instead. All modern hardware has what it needs. The sole gotcha is that it's not easily emulatable (qemu supports it only under kvm where they can freeload on the host TSC) so it can be exercised only on hardware platforms right now. Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
28 lines
1.6 KiB
CMake
28 lines
1.6 KiB
CMake
# SPDX-License-Identifier: Apache-2.0
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zephyr_sources( sys_clock_init.c)
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zephyr_sources_ifdef(CONFIG_HPET_TIMER hpet.c)
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zephyr_sources_ifdef(CONFIG_ARCV2_TIMER arcv2_timer0.c)
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zephyr_sources_ifdef(CONFIG_ARM_ARCH_TIMER arm_arch_timer.c)
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zephyr_sources_ifdef(CONFIG_APIC_TIMER apic_timer.c)
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zephyr_sources_ifdef(CONFIG_ALTERA_AVALON_TIMER altera_avalon_timer_hal.c)
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zephyr_sources_ifdef(CONFIG_ITE_IT8XXX2_TIMER ite_it8xxx2_timer.c)
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zephyr_sources_ifdef(CONFIG_NRF_RTC_TIMER nrf_rtc_timer.c)
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zephyr_sources_ifdef(CONFIG_STM32_LPTIM_TIMER stm32_lptim_timer.c)
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zephyr_sources_ifdef(CONFIG_RISCV_MACHINE_TIMER riscv_machine_timer.c)
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zephyr_sources_ifdef(CONFIG_RV32M1_LPTMR_TIMER rv32m1_lptmr_timer.c)
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zephyr_sources_ifdef(CONFIG_CORTEX_M_SYSTICK cortex_m_systick.c)
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zephyr_sources_ifdef(CONFIG_XTENSA_TIMER xtensa_sys_timer.c)
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zephyr_sources_ifdef(CONFIG_NATIVE_POSIX_TIMER native_posix_timer.c)
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zephyr_sources_ifdef(CONFIG_SAM0_RTC_TIMER sam0_rtc_timer.c)
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zephyr_sources_ifdef(CONFIG_LITEX_TIMER litex_timer.c)
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zephyr_sources_ifdef(CONFIG_MCHP_XEC_RTOS_TIMER mchp_xec_rtos_timer.c)
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zephyr_sources_ifdef(CONFIG_XLNX_PSTTC_TIMER xlnx_psttc_timer.c)
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zephyr_sources_ifdef(CONFIG_CC13X2_CC26X2_RTC_TIMER cc13x2_cc26x2_rtc_timer.c)
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zephyr_sources_ifdef(CONFIG_CAVS_TIMER cavs_timer.c)
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zephyr_sources_ifdef(CONFIG_LEON_GPTIMER leon_gptimer.c)
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zephyr_sources_ifdef(CONFIG_NPCX_ITIM_TIMER npcx_itim_timer.c)
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zephyr_sources_ifdef(CONFIG_MCUX_OS_TIMER mcux_os_timer.c)
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zephyr_sources_ifdef(CONFIG_RCAR_CMT_TIMER rcar_cmt_timer.c)
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zephyr_sources_ifdef(CONFIG_APIC_TSC_DEADLINE_TIMER apic_tsc.c)
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